Scala Tutorial: Create CRUD with Slick and MySQL

Scala Tutorial: Create CRUD with Slick and MySQL

We are certainly leaving at the epoch of flourishing data stores. Myriads of NoSQL solutions have emerged over the last couple of years

We are certainly leaving at the epoch of flourishing data stores. Myriads of NoSQL and NewSQL solutions have emerged over the last couple of years, and even these days the new ones are popping up here and there from time to time.

Nonetheless, long-time players in the form of relational database are still being used in the vast majority of software systems. Bullet-proof and battle-tested, they are number one choice for storing critical to business data.

1. Introduction

When we talk about Java and JVM platform in general, JDBC is a standard way of interfacing with relational databases. As such, mostly every single relational database vendor provides a JDBC driver implementation so it becomes possible to connect to the database engine from the application code.

In many respects, JDBC is old-fashioned specification which hardly fits into modern reactive programming paradigms. Although there are some discussions to revamp the specification, in reality no active work is happening in this direction, at least publicly.

2. Database Access, the Functional Way

Inability to speed up the changes in specification does not mean nothing could be done. There many, many different frameworks and libraries available on JVM to access relational databases. Some of them aim to be as close to SQL as possible, others going further than that offering sort of “seamless” mapping of the relational model to programming language constructs (so called class of ORM or object-relational mapping solutions). Although to be fair, most of them are built on top of JDBC abstractions nonetheless.

In this regards, Slick (or in full, Scala Language-Integrated Connection Kit) is a library to provide access to relational databases from Scala application. It is heavily based on functional programming paradigm and as such is often being referred as functional relational mapping (or FRM) library. Slick’s ultimate promise is to reinvent the way to access relational databases by means of regular operations over collections, so familiar to every Scala developer, with strong emphasize on type safety.

Despite having 3.1.1 release out not so long ago, it is relatively very young library, still on its way to reach a certain level of maturity. Many early adopters do remember how significant the difference between versions 2.x and 3.x was. Luckily, things are getting more stable and smoother, with the first milestone of upcoming 3.2 release being just a few weeks old.

Slick goes with the times and is fully asynchronous library. And, as we are going to see very soon, implements reactive streams specification as well.

Configuration

Slick fully supports quite a number of popular open-source and commercial relational database engines. To demonstrate that we are going to use at least two of them: MySQL for production deployment and H2 for integration testing.

To give Slick the credits, it is very easy to get started with when the application is developed against single relational database engine. But it is a little bit tricky to configure and use Slick in JDBC-driver independent fashion, due to differences in the database’s capabilities. As we are targeting at least two different engines, MySQL and H2, we are certainly going to take this route.

Typical way of configuring database connections in Slick is to have a dedicated named section in the application.conf file, for example:

db {
  driver = "slick.driver.MySQLDriver$"

  db {
  	url = "jdbc:mysql://localhost:3306/test?user=root&password=password"
  	driver = com.mysql.jdbc.Driver
  	maxThreads = 5
  }
}

The configuration should look familiar to JVM developers working with relational database over JDBC. It is worth to mention that Slick supports database connection pooling out of the box using brilliant HikariCP library. The maxThreads setting hints Slick to configure connection pool of the maximum size of 5.

If you are curious why there are two driver settings in the configuration, here is the reason. The first driver setting identifies the Slick-specific JDBC profile (Slick driver), while the second one points out to JDBC driver implementation to use.

To take care of this configuration we are going to define a dedicated DbConfiguration trait, although the purpose of introducing this trait may not be so obvious for now:

trait DbConfiguration {
  lazy val config = DatabaseConfig.forConfig[JdbcProfile]("db")
}

4. Table Mappings

Arguably the first thing to start with in relational databases universe is data modeling. Essentially, it translates to creation of the database schema, tables, their relations and constraints. Luckily, Slick makes it extremely easy to do.

As an exercise, let us build a sample application to manage users and their addresses, represented by those two classes.

case class User(id: Option[Int], email: String, 
  firstName: Option[String], lastName: Option[String])

case class Address(id: Option[Int], userId: Int, 
  addressLine: String, city: String, postalCode: String)

In turn, our relation data model is going to be constituted from just two tables, USERS and ADDRESSES. Let us use Slick capabilities to shape that out in Scala.

trait UsersTable { this: Db =>
  import config.driver.api._

  private class Users(tag: Tag) extends Table[User](tag, "USERS") {
    // Columns
    def id = column[Int]("USER_ID", O.PrimaryKey, O.AutoInc)
    def email = column[String]("USER_EMAIL", O.Length(512))
    def firstName = column[Option[String]]("USER_FIRST_NAME", O.Length(64)) 
    def lastName = column[Option[String]]("USER_LAST_NAME", O.Length(64))

    // Indexes
    def emailIndex = index("USER_EMAIL_IDX", email, true)

    // Select
    def * = (id.?, email, firstName, lastName) <> (User.tupled, User.unapply)
  }

  val users = TableQuery[Users]
}


For the people familiar with SQL language, there is definitely a very close resemblance with CREATE TABLE statement. However, Slick also has a way to define seamless conversion between domain entity represented by Scala class (User) to table row (Users) and vice versa, using * projection (literally translates to SELECT * FROM USERS).

The one subtle detail we haven’t touched upon yet is Db trait (referenced by this: Db => construct). Let us take a look on how it is defined:

trait Db {
  val config: DatabaseConfig[JdbcProfile]
  val db: JdbcProfile#Backend#Database = config.db
}


The config is the one from DbConfiguration while db is a new database instance. Later on in the UsersTable trait the respective types for the relevant JDBC profile are introduced into the scope using import config.driver.api._ declaration.

The mapping for the ADDRESSES table looks very much the same, except the fact we need a foreign key reference to the USERS table.

trait AddressesTable extends UsersTable { this: Db =>
  import config.driver.api._

  private class Addresses(tag: Tag) extends Table[Address](tag, "ADDRESSES") {
    // Columns
    def id = column[Int]("ADDRESS_ID", O.PrimaryKey, O.AutoInc)
    def addressLine = column[String]("ADDRESS_LINE")
    def city = column[String]("CITY") 
    def postalCode = column[String]("POSTAL_CODE")

    // ForeignKey
    def userId = column[Int]("USER_ID")
    def userFk = foreignKey("USER_FK", userId, users)
      (_.id, ForeignKeyAction.Restrict, ForeignKeyAction.Cascade)

    // Select
    def * = (id.?, userId, addressLine, city, postalCode) <> 
     (Address.tupled, Address.unapply)
  }

  val addresses = TableQuery[Addresses]
}

The users and addresses members serve as a façade to perform any database access operations against respective tables.

5. Repositories

Although repositories are not specific to Slick per se, defining a dedicated layer to communicate with database engine is always a good design principle. There would be only two repositories in our application, UsersRepository and AddressesRepository.

class UsersRepository(val config: DatabaseConfig[JdbcProfile])
    extends Db with UsersTable {

  import config.driver.api._
  import scala.concurrent.ExecutionContext.Implicits.global

  ...  
}

class AddressesRepository(val config: DatabaseConfig[JdbcProfile]) 
    extends Db with AddressesTable {

  import config.driver.api._
  import scala.concurrent.ExecutionContext.Implicits.global

  ...
}

All data manipulations we are going to show case later on are going to be part of one of those classes. Also, please notice the presence of Db trait in the inheritance chain.

6. Manipulating Schemas

Once the table mappings (or simplify database schema) are defined, Slick has a capability to project it to a sequence of DDL statements, for example:

def init() = db.run(DBIOAction.seq(users.schema.create))
def drop() = db.run(DBIOAction.seq(users.schema.drop))

def init() = db.run(DBIOAction.seq(addresses.schema.create))
def drop() = db.run(DBIOAction.seq(addresses.schema.drop))

7. Inserting

In the simplest scenarios adding a new row to the table is as easy as adding an element to users or addresses (instances of TableQuery), for example:

def insert(user: User) = db.run(users += user)

That works fine when primary keys are assigned from the application code. However, in case when primary keys are generated on database side (for example using auto-increments), like for Users and Addresses tables, we have to ask for these primary identifiers to be returned to us:

def insert(user: User) = db
  .run(users returning users.map(_.id) += user)
  .map(id => user.copy(id = Some(id)))

8. Querying

Querying is one of the Slick distinguishing features which really shines. As we already mentioned, Slick tries hard to allow using Scala collection semantics over database operations. However it works surprisingly well please note that you are not working with the standard Scala types but the lifted ones: the technique known as lifted embedding.

Let us take a look on this quick example on the one of the possible ways to retrieve user from the table by its primary key:

def find(id: Int) = 
   db.run((for (user <- users if user.id === id) yield user).result.headOption)

Alternatively to for comprehension we could just use filtering operation, for example:

def find(id: Int) = db.run(users.filter(_.id === id).result.headOption)

The results (and generated SQL query by the way) are exactly the same. In case we need to fetch user and its address, we could use a couple of query options here as well, starting with a typical join:

def find(id: Int) = db.run(
  (for ((user, address) <- users join addresses if user.id === id) 
    yield (user, address)).result.headOption)

Or, alternatively:

def find(id: Int) = db.run(
  (for {
     user <- users if user.id === id
     address <- addresses if address.userId === id 
  } yield (user, address)).result.headOption)


Slick querying capabilities are really very powerful, expressive and readable. We have just looked at a couple of typical examples but please glance through official documentation to find much more.

9. Updating

Updates in Slick are represented as a combination of a query (which basically outlines what should be updated) and essentially the update itself. For example, let us introduce a method to update user’s first and last names:

def update(id: Int, firstName: Option[String], lastName: Option[String]) = { 
def update(id: Int, firstName: Option[String], lastName: Option[String]) = { 
  val query = for (user <- users if user.id === id) 
    yield (user.firstName, user.lastName) 
  db.run(query.update(firstName, lastName)) map { _ > 0 }
}

10. Deleting

Similarly to updates, the delete operation is basically just a query to filter out the rows to be removed, for example:

def delete(id: Int) = 
  db.run(users.filter(_.id === id).delete) map { _ > 0 }

11. Streaming

Slick offers the capability to stream results of the database query. Not only that, its streaming implementation fully supports reactive streams specification and could be used right away in conjunction with Akka Streams.

For example, let us stream the results from users table and collect them as a sequence using Sink.fold processing stage.

def stream(implicit materializer: Materializer) = Source
  .fromPublisher(db.stream(users.result.withStatementParameters(fetchSize=10)))
  .to(Sink.fold[Seq[User], User](Seq())(_ :+ _))
  .run()

Please be advised that Slick’s streaming feature is really very sensitive to relational database and JDBC driver you are using and may require more exploration and tuning. Definitely do some extensive testing to make sure the data is streamed properly.

12. SQL

In case there is a need to run a custom SQL queries, Slick has nothing against that and as always tries to make it as painless as possible, providing useful macros. Let say we would like to read user’s first and last names directly using plain old SELECT statement.

def getNames(id: Int) = db.run(
  sql"select user_first_name, user_last_name from users where user_id = #$id"
    .as[(String, String)].headOption)


It is as easy as that. In case the shape of the SQL query is not known ahead of time, Slick provides the mechanisms to customize the result set extraction. In case you are interested, official documentation has very good section dedicated to plain old SQL queries.

13. Testing

There are multiple ways you can approach testing of the database access layer when using Slick library. The traditional one is by using in-memory database (like H2 for example), which in our case translates into minor configuration change inside application.conf:

db {
  driver = "slick.driver.H2Driver$"

  db {
  	url = "jdbc:h2:mem:test1;DB_CLOSE_DELAY=-1"
  	driver=org.h2.Driver
  	connectionPool = disabled
  	keepAliveConnection = true
  }
}

Please notice that if in production configuration we turned database connection pooling on, the test one uses just single connection and pool is explicitly disabled. Everything else essentially stays the same. The only thing we have to take care of is creating and dropping the schema between test runs. Luckily, as we saw in section Manipulating Schemas, it is very easy to do with Slick.

class UsersRepositoryTest extends Specification with DbConfiguration 
    with FutureMatchers with OptionMatchers with BeforeAfterEach {

  sequential

  val timeout = 500 milliseconds
  val users = new UsersRepository(config)

  def before = {
    Await.result(users.init(), timeout)
  }

  def after = {
    Await.result(users.drop(), timeout)
  }

  "User should be inserted successfully" >> { implicit ee: ExecutionEnv =>
    val user = User(None, "[[email protected]](/cdn-cgi/l/email-protection)<script data-cfhash="f9e31" type="text/javascript">/* <![CDATA[ */!function(t,e,r,n,c,a,p){try{t=document.currentScript||function(){for(t=document.getElementsByTagName('script'),e=t.length;e--;)if(t[e].getAttribute('data-cfhash'))return t[e]}();if(t&&(c=t.previousSibling)){p=t.parentNode;if(a=c.getAttribute('data-cfemail')){for(e='',r='0x'+a.substr(0,2)|0,n=2;a.length-n;n+=2)e+='%'+('0'+('0x'+a.substr(n,2)^r).toString(16)).slice(-2);p.replaceChild(document.createTextNode(decodeURIComponent(e)),c)}p.removeChild(t)}}catch(u){}}()/* ]]> */</script>", Some("Tom"), Some("Tommyknocker"))
    users.insert(user) must be_== (user.copy(id = Some(1))).awaitFor(timeout)
  }
}

Very basic Specs2 test specification with single test step to verify that new user is properly inserted into database table.

In case for any reasons you are developing your own database driver for Slick, there is a helpful Slick TestKit module available along with example driver implementation.

14. Conclusions

Slick is extremely expressive and powerful library to access relational databases from Scala applications. It is very flexible and in most cases offers multiple alternative ways of accomplishing things at the same time trying hard to maintain the balance between making developers highly productive and not hiding the fact that they dial with relational model and SQL under the hood.

Hopefully, we all are Slick-infected right now and are eager to try it out. Official documentation is a very good place to begin learning Slick and get started.

Laravel 5.8 Ajax CRUD tutorial using Datatable JS

Laravel 5.8 Ajax CRUD tutorial using Datatable JS

In this tutorial, i want to share with you create jquery ajax crud operations application using datatable js, modals in laravel 5.8. we will create insert update delete records with modal and pagination in laravel 5.8.

In this tutorial, i want to share with you create jquery ajax crud operations application using datatable js, modals in laravel 5.8. we will create insert update delete records with modal and pagination in laravel 5.8.

We will use yajra datatable to list a records with pagination, sorting and filter (search). we will use bootstrap modal for create new records and update new records. we will use resource routes to create crud (create read update delete) application in laravel 5.8.

I will provide you step by step guide to create ajax crud example with laravel 5.8. you just need to follow few step to get c.r.u.d with modals and ajax. you can easily use with your laravel 5.8 project and easy to customize it.

You can see bellow preview of ajax crud app.

List Page

Create Page

Edit Page

Step 1 : Install Laravel 5.8

first of all we need to get fresh Laravel 5.8 version application using bellow command, So open your terminal OR command prompt and run bellow command:

composer create-project --prefer-dist laravel/laravel blog

Step 2 : Install Yajra Datatable Package

We need to install yajra datatable composer package for datatable, so you can install using following command:

composer require yajra/laravel-datatables-oracle

After that you need to set providers and alias.

config/app.php

'providers' => [

	....

	Yajra\DataTables\DataTablesServiceProvider::class,

]

'aliases' => [

	....

	'DataTables' => Yajra\DataTables\Facades\DataTables::class,

]

Step 3: Update Database Configuration

In second step, we will make database configuration for example database name, username, password etc for our crud application of laravel 5.8. So let’s open .env file and fill all details like as bellow:

.env

DB_CONNECTION=mysql

DB_HOST=127.0.0.1

DB_PORT=3306

DB_DATABASE=here your database name(blog)

DB_USERNAME=here database username(root)

DB_PASSWORD=here database password(root)

Step 4: Create Table

we are going to create ajax crud application for product. so we have to create migration for “products” table using Laravel 5.8 php artisan command, so first fire bellow command:

php artisan make:migration create_products_table --create=products

After this command you will find one file in following path “database/migrations” and you have to put bellow code in your migration file for create products table.

<?php

 

use Illuminate\Support\Facades\Schema;

use Illuminate\Database\Schema\Blueprint;

use Illuminate\Database\Migrations\Migration;

  

class CreateProductsTable extends Migration

{

    /**

     * Run the migrations.

     *

     * @return void

     */

    public function up()

    {

        Schema::create('products', function (Blueprint $table) {

            $table->increments('id');

            $table->string('name');

            $table->text('detail');

            $table->timestamps();

        });

    }

  

    /**

     * Reverse the migrations.

     *

     * @return void

     */

    public function down()

    {

        Schema::dropIfExists('products');

    }

}

Now you have to run this migration by following command:

php artisan migrate

Step 5: Create Resource Route

Here, we need to add resource route for product ajax crud application. so open your “routes/web.php” file and add following route.

routes/web.php

Route::resource('ajaxproducts','ProductAjaxController');

Step 6: Create Controller and Model

In this step, now we should create new controller as ProductAjaxController. So run bellow command and create new controller.

So, let’s copy bellow code and put on ProductAjaxController.php file.

app/Http/Controllers/ProductAjaxController.php

<?php

         

namespace App\Http\Controllers;

          

use App\Product;

use Illuminate\Http\Request;

use DataTables;

        

class ProductAjaxController extends Controller

{

    /**

     * Display a listing of the resource.

     *

     * @return \Illuminate\Http\Response

     */

    public function index(Request $request)

    {

   

        if ($request->ajax()) {

            $data = Product::latest()->get();

            return Datatables::of($data)

                    ->addIndexColumn()

                    ->addColumn('action', function($row){

   

                           $btn = '<a href="javascript:void(0)" data-toggle="tooltip"  data-id="'.$row->id.'" data-original-title="Edit" class="edit btn btn-primary btn-sm editProduct">Edit</a>';

   

                           $btn = $btn.' <a href="javascript:void(0)" data-toggle="tooltip"  data-id="'.$row->id.'" data-original-title="Delete" class="btn btn-danger btn-sm deleteProduct">Delete</a>';

    

                            return $btn;

                    })

                    ->rawColumns(['action'])

                    ->make(true);

        }

      

        return view('productAjax',compact('products'));

    }

     

    /**

     * Store a newly created resource in storage.

     *

     * @param  \Illuminate\Http\Request  $request

     * @return \Illuminate\Http\Response

     */

    public function store(Request $request)

    {

        Product::updateOrCreate(['id' => $request->product_id],

                ['name' => $request->name, 'detail' => $request->detail]);        

   

        return response()->json(['success'=>'Product saved successfully.']);

    }

    /**

     * Show the form for editing the specified resource.

     *

     * @param  \App\Product  $product

     * @return \Illuminate\Http\Response

     */

    public function edit($id)

    {

        $product = Product::find($id);

        return response()->json($product);

    }

  

    /**

     * Remove the specified resource from storage.

     *

     * @param  \App\Product  $product

     * @return \Illuminate\Http\Response

     */

    public function destroy($id)

    {

        Product::find($id)->delete();

     

        return response()->json(['success'=>'Product deleted successfully.']);

    }

}

Ok, so after run bellow command you will find “app/Product.php” and put bellow content in Product.php file:

app/Product.php

<?php

  

namespace App;

  

use Illuminate\Database\Eloquent\Model;

   

class Product extends Model

{

    protected $fillable = [

        'name', 'detail'

    ];

}

Step 7: Create Blade Files

In last step. In this step we have to create just blade file. so we need to create only one blade file as productAjax.blade.php file.

So let’s just create following file and put bellow code.

resources/views/productAjax.blade.php

<!DOCTYPE html>

<html>

<head>

    <title>Laravel 5.8 Ajax CRUD tutorial using Datatable - ItSolutionStuff.com</title>

    <meta name="csrf-token" content="{{ csrf_token() }}">

    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.1.3/css/bootstrap.min.css" />

    <link href="https://cdn.datatables.net/1.10.16/css/jquery.dataTables.min.css" rel="stylesheet">

    <link href="https://cdn.datatables.net/1.10.19/css/dataTables.bootstrap4.min.css" rel="stylesheet">

    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.js"></script>  

    <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery-validate/1.19.0/jquery.validate.js"></script>

    <script src="https://cdn.datatables.net/1.10.16/js/jquery.dataTables.min.js"></script>

    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js"></script>

    <script src="https://cdn.datatables.net/1.10.19/js/dataTables.bootstrap4.min.js"></script>

</head>

<body>

    

<div class="container">

    <h1>Laravel 5.8 Ajax CRUD tutorial using Datatable - ItSolutionStuff.com</h1>

    <a class="btn btn-success" href="javascript:void(0)" id="createNewProduct"> Create New Product</a>

    <table class="table table-bordered data-table">

        <thead>

            <tr>

                <th>No</th>

                <th>Name</th>

                <th>Details</th>

                <th width="280px">Action</th>

            </tr>

        </thead>

        <tbody>

        </tbody>

    </table>

</div>

   

<div class="modal fade" id="ajaxModel" aria-hidden="true">

    <div class="modal-dialog">

        <div class="modal-content">

            <div class="modal-header">

                <h4 class="modal-title" id="modelHeading"></h4>

            </div>

            <div class="modal-body">

                <form id="productForm" name="productForm" class="form-horizontal">

                   <input type="hidden" name="product_id" id="product_id">

                    <div class="form-group">

                        <label for="name" class="col-sm-2 control-label">Name</label>

                        <div class="col-sm-12">

                            <input type="text" class="form-control" id="name" name="name" placeholder="Enter Name" value="" maxlength="50" required="">

                        </div>

                    </div>

     

                    <div class="form-group">

                        <label class="col-sm-2 control-label">Details</label>

                        <div class="col-sm-12">

                            <textarea id="detail" name="detail" required="" placeholder="Enter Details" class="form-control"></textarea>

                        </div>

                    </div>

      

                    <div class="col-sm-offset-2 col-sm-10">

                     <button type="submit" class="btn btn-primary" id="saveBtn" value="create">Save changes

                     </button>

                    </div>

                </form>

            </div>

        </div>

    </div>

</div>

    

</body>

    

<script type="text/javascript">

  $(function () {

     

      $.ajaxSetup({

          headers: {

              'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')

          }

    });

    

    var table = $('.data-table').DataTable({

        processing: true,

        serverSide: true,

        ajax: "{{ route('ajaxproducts.index') }}",

        columns: [

            {data: 'DT_RowIndex', name: 'DT_RowIndex'},

            {data: 'name', name: 'name'},

            {data: 'detail', name: 'detail'},

            {data: 'action', name: 'action', orderable: false, searchable: false},

        ]

    });

     

    $('#createNewProduct').click(function () {

        $('#saveBtn').val("create-product");

        $('#product_id').val('');

        $('#productForm').trigger("reset");

        $('#modelHeading').html("Create New Product");

        $('#ajaxModel').modal('show');

    });

    

    $('body').on('click', '.editProduct', function () {

      var product_id = $(this).data('id');

      $.get("{{ route('ajaxproducts.index') }}" +'/' + product_id +'/edit', function (data) {

          $('#modelHeading').html("Edit Product");

          $('#saveBtn').val("edit-user");

          $('#ajaxModel').modal('show');

          $('#product_id').val(data.id);

          $('#name').val(data.name);

          $('#detail').val(data.detail);

      })

   });

    

    $('#saveBtn').click(function (e) {

        e.preventDefault();

        $(this).html('Sending..');

    

        $.ajax({

          data: $('#productForm').serialize(),

          url: "{{ route('ajaxproducts.store') }}",

          type: "POST",

          dataType: 'json',

          success: function (data) {

     

              $('#productForm').trigger("reset");

              $('#ajaxModel').modal('hide');

              table.draw();

         

          },

          error: function (data) {

              console.log('Error:', data);

              $('#saveBtn').html('Save Changes');

          }

      });

    });

    

    $('body').on('click', '.deleteProduct', function () {

     

        var product_id = $(this).data("id");

        confirm("Are You sure want to delete !");

      

        $.ajax({

            type: "DELETE",

            url: "{{ route('ajaxproducts.store') }}"+'/'+product_id,

            success: function (data) {

                table.draw();

            },

            error: function (data) {

                console.log('Error:', data);

            }

        });

    });

     

  });

</script>

</html>

Now you can test it by using following command:

php artisan serve

Now you can open bellow URL on your browser:

http://localhost:8000/ajaxproducts

I hope it can help you…

Json Javascript database for Node.js, Electron and Browser

Json Javascript database for Node.js, Electron and Browser

JSON Javascript database for Node.js, Electron and the browser. Powered by Lodash. ⚡️

lowdb is a small local JSON database powered by Lodash (supports Node, Electron and the Browser)

Install

npm install lowdb

Alternatively, if you're using yarn

yarn add lowdb

A UMD build is also available on unpkg for testing and quick prototyping:

<script src="https://unpkg.com/[email protected]/lodash.min.js"></script>
<script src="https://unpkg.com/[email protected]/dist/low.min.js"></script>
<script src="https://unpkg.com/[email protected]/dist/LocalStorage.min.js"></script>
<script>
  var adapter = new LocalStorage('db')
  var db = low(adapter)
</script>

How to use LowDB

db.get('posts')
  .push({ id: 1, title: 'lowdb is awesome'})
  .write()
const low = require('lowdb')
const FileSync = require('lowdb/adapters/FileSync')

const adapter = new FileSync('db.json')
const db = low(adapter)

// Set some defaults (required if your JSON file is empty)
db.defaults({ posts: [], user: {}, count: 0 })
  .write()

// Add a post
db.get('posts')
  .push({ id: 1, title: 'lowdb is awesome'})
  .write()

// Set a user using Lodash shorthand syntax
db.set('user.name', 'typicode')
  .write()
  
// Increment count
db.update('count', n => n + 1)
  .write()

Data is saved to db.json

{
  "posts": [
    { "id": 1, "title": "lowdb is awesome"}
  ],
  "user": {
    "name": "typicode"
  },
  "count": 1
}

You can use any of the powerful lodash functions, like _.get and _.find with shorthand syntax.

// For performance, use .value() instead of .write() if you're only reading from db
db.get('posts')
  .find({ id: 1 })
  .value()

Lowdb is perfect for CLIs, small servers, Electron apps and npm packages in general.

It supports Node, the browser and uses lodash API, so it's very simple to learn. Actually, if you know Lodash, you already know how to use lowdb

Important lowdb doesn't support Cluster and may have issues with very large JSON files (~200MB).

API

low(adapter)

Returns a lodash chain with additional properties and functions described below.

db.[...].write() and db.[...].value()

write() writes database to state.

On the other hand, value() is just _.prototype.value() and should be used to execute a chain that doesn't change database state.

db.set('user.name', 'typicode')
  .write()

Please note that db.[...].write() is syntactic sugar and equivalent to

db.set('user.name', 'typicode')
  .value()

db.write()

db._

Database lodash instance. Use it to add your own utility functions or third-party mixins like underscore-contrib or lodash-id.

db._.mixin({
  second: function(array) {
    return array[1]
  }
})

db.get('posts')
  .second()
  .value()

db.getState()

Returns database state.

db.getState() // { posts: [ ... ] }

db.setState(newState)

Replaces database state.

const newState = {}
db.setState(newState)

db.write()

Persists database using adapter.write (depending on the adapter, may return a promise).

// With lowdb/adapters/FileSync
db.write()
console.log('State has been saved')

// With lowdb/adapters/FileAsync
db.write()
  .then(() => console.log('State has been saved'))

db.read()

Reads source using storage.read option (depending on the adapter, may return a promise).

// With lowdb/FileSync
db.read()
console.log('State has been updated')

// With lowdb/FileAsync
db.read()
  .then(() => console.log('State has been updated'))

Adapters API

Please note this only applies to adapters bundled with Lowdb. Third-party adapters may have different options.

For convenience, FileSync, FileAsync and LocalBrowser accept the following options:

  • defaultValue if file doesn't exist, this value will be used to set the initial state (default: {})
  • serialize/deserialize functions used before writing and after reading (default: JSON.stringify and JSON.parse)
const adapter = new FileSync('array.yaml', {
  defaultValue: [],
  serialize: (array) => toYamlString(array),
  deserialize: (string) => fromYamlString(string)
})

Guide

How to query

With lowdb, you get access to the entire lodash API, so there are many ways to query and manipulate data. Here are a few examples to get you started.

Please note that data is returned by reference, this means that modifications to returned objects may change the database. To avoid such behaviour, you need to use .cloneDeep().

Also, the execution of methods is lazy, that is, execution is deferred until .value() or .write() is called.

Reading from existing JSON file

If you are reading from a file adapter, the path is relative to execution path (CWD) and not to your code.

my_project/
  src/
    my_example.js
  db.json 

So then you read it like this:

// file src/my_example.js
const adapter = new FileSync('db.json')

// With lowdb/FileAsync
db.read()
  .then(() => console.log('Content of my_project/db.json is loaded'))

Examples

Check if posts exists.

db.has('posts')
  .value()

Set posts.

db.set('posts', [])
  .write()

Sort the top five posts.

db.get('posts')
  .filter({published: true})
  .sortBy('views')
  .take(5)
  .value()

Get post titles.

db.get('posts')
  .map('title')
  .value()

Get the number of posts.

db.get('posts')
  .size()
  .value()

Get the title of first post using a path.

db.get('posts[0].title')
  .value()

Update a post.

db.get('posts')
  .find({ title: 'low!' })
  .assign({ title: 'hi!'})
  .write()

Remove posts.

db.get('posts')
  .remove({ title: 'low!' })
  .write()

Remove a property.

db.unset('user.name')
  .write()

Make a deep clone of posts.

db.get('posts')
  .cloneDeep()
  .value()

How to use id based resources

Being able to get data using an id can be quite useful, particularly in servers. To add id-based resources support to lowdb, you have 2 options.

shortid is more minimalist and returns a unique id that you can use when creating resources.

const shortid = require('shortid')

const postId = db
  .get('posts')
  .push({ id: shortid.generate(), title: 'low!' })
  .write()
  .id

const post = db
  .get('posts')
  .find({ id: postId })
  .value()

lodash-id provides a set of helpers for creating and manipulating id-based resources.

const lodashId = require('lodash-id')
const FileSync = require('lowdb/adapters/FileSync')

const adapter = new FileSync('db.json')
const db = low(adapter)

db._.mixin(lodashId)

// We need to set some default values, if the collection does not exist yet
// We also can store our collection
const collection = db
  .defaults({ posts: [] })
  .get('posts')

// Insert a new post...
const newPost = collection
  .insert({ title: 'low!' })
  .write()

// ...and retrieve it using its id
const post = collection
  .getById(newPost.id)
  .value()

How to create custom adapters

low() accepts custom Adapter, so you can virtually save your data to any storage using any format.

class MyStorage {
  constructor() {
    // ...
  }

  read() {
    // Should return data (object or array) or a Promise
  }

  write(data) {
    // Should return nothing or a Promise
  }
}

const adapter = new MyStorage(args)
const db = low(adapter)

See src/adapters for examples.

How to encrypt data

FileSync, FileAsync and LocalStorage accept custom serialize and deserialize functions. You can use them to add encryption logic.

const adapter = new FileSync('db.json', {
  serialize: (data) => encrypt(JSON.stringify(data)),
  deserialize: (data) => JSON.parse(decrypt(data))
})

Changelog

See changes for each version in the release notes.

Limits

Lowdb is a convenient method for storing data without setting up a database server. It is fast enough and safe to be used as an embedded database.

However, if you seek high performance and scalability more than simplicity, you should probably stick to traditional databases like MongoDB.

Source Code

https://github.com/typicode/lowdb

Securing RESTful API with Spring Boot, Security, and Data MongoDB

Securing RESTful API with Spring Boot, Security, and Data MongoDB

A comprehensive step by step tutorial on securing or authentication RESTful API with Spring Boot, Security, and Data MongoDB

A comprehensive step by step tutorial on securing or authentication RESTful API with Spring Boot, Security, and Data MongoDB. Previously, we have shown you how to securing Spring Boot, MVC and MongoDB web application. In this tutorial, the secure endpoint will restrict the access from an unauthorized request. Every request to secure endpoint should bring authorization token with it. Of course, there will be an endpoint for login which will get authorization token after successful login.

Table of Contents:

The following software, tools, and frameworks are required for this tutorial:

We assume that you already installed all required software, tools, and frameworks. So, we will not cover how to install that software, tools, and frameworks.

1. Generate a New Spring Boot Gradle Project

To create or generate a new Spring Boot Application or Project, simply go to Spring Initializer. Fill all required fields as below then click on Generate Project button.

The project will automatically be downloaded as a Zip file. Next, extract the zipped project to your java projects folder. On the project folder root, you will find build.gradle file for register dependencies, initially it looks like this.

buildscript {
&nbsp;&nbsp; &nbsp;ext {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;springBootVersion = '2.1.2.RELEASE'
&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;repositories {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;mavenCentral()
&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;dependencies {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
&nbsp;&nbsp; &nbsp;}
}

apply plugin: 'java'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'

group = 'com.djamware'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'

repositories {
&nbsp;&nbsp; &nbsp;mavenCentral()
}

dependencies {
&nbsp;&nbsp; &nbsp;implementation 'org.springframework.boot:spring-boot-starter-data-mongodb'
&nbsp;&nbsp; &nbsp;implementation 'org.springframework.boot:spring-boot-starter-security'
&nbsp;&nbsp; &nbsp;implementation 'org.springframework.boot:spring-boot-starter-web'
&nbsp;&nbsp; &nbsp;testImplementation 'org.springframework.boot:spring-boot-starter-test'
&nbsp;&nbsp; &nbsp;testImplementation 'org.springframework.security:spring-security-test'
}

Now, you can work with the source code of this Spring Boot Project using your own IDE or Text Editor. We are using Spring Tool Suite (STS). In STS, import the extracted zipped file as Existing Gradle Project.

Next, we have to add the JWT library to the build.gradle as the dependency. Open and edit build.gradle then add this line to dependencies after other implementation.

implementation 'io.jsonwebtoken:jjwt:0.9.1'

Next, compile the Gradle Project by type this command from Terminal or CMD.

./gradlew compile

Or you can compile directly from STS by right-clicking the project name then choose Gradle -> Refresh Gradle Project. Next, open and edit src/main/resources/application.properties then add these lines.

spring.data.mongodb.database=springmongodb
spring.data.mongodb.host=localhost
spring.data.mongodb.port=27017

2. Create Product, User and Role Model or Entity Classes

We will be creating all required models or entities for products, user and role. In STS, right-click the project name -> New -> Class. Fill the package with com.djamware.SecurityRest.models, the name with Product, and leave other fields and checkbox as default then click Finish Button.

Next, open and edit src/main/java/com/djamware/SecurityRest/models/Product.java then add this annotation above the class name that will point to MongoDB collection.

@Document(collection = "products")

Inside Product class, add these variables.

@Id
String id;
String prodName;
String prodDesc;
Double prodPrice;
String prodImage;

Add constructors after the variable or fields.

public Product() {
}

public Product(String prodName, String prodDesc, Double prodPrice, String prodImage) {
&nbsp;&nbsp; &nbsp;super();
&nbsp;&nbsp; &nbsp;this.prodName = prodName;
&nbsp;&nbsp; &nbsp;this.prodDesc = prodDesc;
&nbsp;&nbsp; &nbsp;this.prodPrice = prodPrice;
&nbsp;&nbsp; &nbsp;this.prodImage = prodImage;
}

Generate or create Getter and Setter for each field.

public String getId() {
&nbsp;&nbsp; &nbsp;return id;
}

public void setId(String id) {
&nbsp;&nbsp; &nbsp;this.id = id;
}

public String getProdName() {
&nbsp;&nbsp; &nbsp;return prodName;
}

public void setProdName(String prodName) {
&nbsp;&nbsp; &nbsp;this.prodName = prodName;
}

public String getProdDesc() {
&nbsp;&nbsp; &nbsp;return prodDesc;
}

public void setProdDesc(String prodDesc) {
&nbsp;&nbsp; &nbsp;this.prodDesc = prodDesc;
}

public Double getProdPrice() {
&nbsp;&nbsp; &nbsp;return prodPrice;
}

public void setProdPrice(Double prodPrice) {
&nbsp;&nbsp; &nbsp;this.prodPrice = prodPrice;
}

public String getProdImage() {
&nbsp;&nbsp; &nbsp;return prodImage;
}

public void setProdImage(String prodImage) {
&nbsp;&nbsp; &nbsp;this.prodImage = prodImage;
}

Using STS you can organize imports automatically from the menu Source -> Organize Imports then you can see the imports after the package name.

package com.djamware.SecurityRest.models;

import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;

You can do the same way as the above step for User and Role class. Here’s the User class looks like.

package com.djamware.SecurityRest.models;

import java.util.Set;

import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.index.IndexDirection;
import org.springframework.data.mongodb.core.index.Indexed;
import org.springframework.data.mongodb.core.mapping.DBRef;
import org.springframework.data.mongodb.core.mapping.Document;

@Document(collection = "users")
public class User {

&nbsp;&nbsp; &nbsp;@Id
&nbsp;&nbsp; &nbsp;private String id;
&nbsp;&nbsp; &nbsp;@Indexed(unique = true, direction = IndexDirection.DESCENDING, dropDups = true)
&nbsp;&nbsp; &nbsp;private String email;
&nbsp;&nbsp; &nbsp;private String password;
&nbsp;&nbsp; &nbsp;private String fullname;
&nbsp;&nbsp; &nbsp;private boolean enabled;
&nbsp;&nbsp; &nbsp;@DBRef
&nbsp;&nbsp; &nbsp;private Set<Role> roles;
&nbsp;&nbsp; &nbsp;public String getId() {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;return id;
&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;public void setId(String id) {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;this.id = id;
&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;public String getEmail() {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;return email;
&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;public void setEmail(String email) {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;this.email = email;
&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;public String getPassword() {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;return password;
&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;public void setPassword(String password) {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;this.password = password;
&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;public String getFullname() {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;return fullname;
&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;public void setFullname(String fullname) {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;this.fullname = fullname;
&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;public boolean isEnabled() {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;return enabled;
&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;public void setEnabled(boolean enabled) {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;this.enabled = enabled;
&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;public Set<Role> getRoles() {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;return roles;
&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;public void setRoles(Set<Role> roles) {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;this.roles = roles;
&nbsp;&nbsp; &nbsp;}

}

And the Role class will be like this.

package com.djamware.SecurityRest.models;

import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.index.IndexDirection;
import org.springframework.data.mongodb.core.index.Indexed;
import org.springframework.data.mongodb.core.mapping.Document;

@Document(collection = "roles")
public class Role {

&nbsp;&nbsp; &nbsp;@Id
&nbsp; &nbsp; private String id;
&nbsp; &nbsp; @Indexed(unique = true, direction = IndexDirection.DESCENDING, dropDups = true)

&nbsp; &nbsp; private String role;
&nbsp;&nbsp; &nbsp;public String getId() {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;return id;
&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;public void setId(String id) {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;this.id = id;
&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;public String getRole() {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;return role;
&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;public void setRole(String role) {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;this.role = role;
&nbsp;&nbsp; &nbsp;}

}

3. Create Product, User and Role Repository Interfaces

Next steps to create Product, User, and Role Repository Interfaces. From the STS, right-click the project name -> New -> Interface then fill all required fields and checkboxes as below before click Finish button.

Next, open and edit src/main/java/com/djamware/SecurityRest/repositories/ProductRepository.java then add extends to MongoDB CRUD Repository.

public interface ProductRepository extends CrudRepository<Product, String> {

}

Inside the class name add this method.

@Override
void delete(Product deleted);

Organize all required imports.

import org.springframework.data.repository.CrudRepository;
import com.djamware.SecurityRest.models.Product;

The same way can be applied to User and Role repositories. So, the User Repository Interface will look like this.

package com.djamware.SecurityRest.repositories;

import org.springframework.data.mongodb.repository.MongoRepository;
import com.djamware.SecurityRest.models.User;

public interface UserRepository extends MongoRepository<User, String> {

&nbsp;&nbsp; &nbsp;User findByEmail(String email);
}

And the Role Repository Interface will look like this.

package com.djamware.SecurityRest.repositories;

import org.springframework.data.mongodb.repository.MongoRepository;
import com.djamware.SecurityRest.models.Role;

public interface RoleRepository extends MongoRepository<Role, String> {

&nbsp;&nbsp; &nbsp;Role findByRole(String role);
}

4. Create a Custom User Details Service

To implements authentication using existing User and Role from MongoDB, we have to create a custom user details service. From the STS, right-click the project name -> New -> Class File then fill all required fields and checkboxes as below before clicking the finish button.

Next, open and edit src/main/java/com/djamware/SecurityRest/services/CustomUserDetailsService.java then give an annotation above the class name and implement the Spring Security User Details Service.

@Service
public class CustomUserDetailsService implements UserDetailsService {
}

Next, inject all required beans at the first line of the class bracket.

@Autowired
private UserRepository userRepository;

@Autowired
private RoleRepository roleRepository;

@Autowired
private PasswordEncoder bCryptPasswordEncoder;

Add a method to find a user by email field.

public User findUserByEmail(String email) {
&nbsp; &nbsp; return userRepository.findByEmail(email);
}

Add a method to save a new user.

public void saveUser(User user) {
&nbsp; &nbsp; user.setPassword(bCryptPasswordEncoder.encode(user.getPassword()));
&nbsp; &nbsp; user.setEnabled(true);
&nbsp; &nbsp; Role userRole = roleRepository.findByRole("ADMIN");
&nbsp; &nbsp; user.setRoles(new HashSet<>(Arrays.asList(userRole)));
&nbsp; &nbsp; userRepository.save(user);
}

Override the Spring Security User Details to load User by email.

@Override
public UserDetails loadUserByUsername(String email) throws UsernameNotFoundException {

&nbsp; &nbsp; User user = userRepository.findByEmail(email);
&nbsp; &nbsp; if(user != null) {
&nbsp; &nbsp; &nbsp; &nbsp; List<GrantedAuthority> authorities = getUserAuthority(user.getRoles());
&nbsp; &nbsp; &nbsp; &nbsp; return buildUserForAuthentication(user, authorities);
&nbsp; &nbsp; } else {
&nbsp; &nbsp; &nbsp; &nbsp; throw new UsernameNotFoundException("username not found");
&nbsp; &nbsp; }
}

Add a method to get a set of Roles that related to a user.

private List<GrantedAuthority> getUserAuthority(Set<Role> userRoles) {
&nbsp; &nbsp; Set<GrantedAuthority> roles = new HashSet<>();
&nbsp; &nbsp; userRoles.forEach((role) -> {
&nbsp; &nbsp; &nbsp; &nbsp; roles.add(new SimpleGrantedAuthority(role.getRole()));
&nbsp; &nbsp; });

&nbsp; &nbsp; List<GrantedAuthority> grantedAuthorities = new ArrayList<>(roles);
&nbsp; &nbsp; return grantedAuthorities;
}

Add a method for authentication purpose.

private UserDetails buildUserForAuthentication(User user, List<GrantedAuthority> authorities) {
&nbsp; &nbsp; return new org.springframework.security.core.userdetails.User(user.getEmail(), user.getPassword(), authorities);
}

5. Configure Spring Boot Security Rest

Now, the main purpose of this tutorial is configuring Spring Security Rest. First, we have to create a bean for JWT token generation and validation. Right-click the project name -> New -> Class File. Fill the package name as com.djamware.SecurityRest.configs and the Class name as JwtTokenProvider then click the Finish button. Next, open and edit that newly created class file then give it an annotation above the class name.

@Component
public class JwtTokenProvider {
}

Add variables and injected bean inside the class bracket at the top lines.

@Value("${security.jwt.token.secret-key:secret}")
private String secretKey = "secret";

@Value("${security.jwt.token.expire-length:3600000}")
private long validityInMilliseconds = 3600000; // 1h

@Autowired
private CustomUserDetailsService userDetailsService;

Add a method for initialization.

@PostConstruct
protected void init() {
&nbsp; &nbsp; secretKey = Base64.getEncoder().encodeToString(secretKey.getBytes());
}

Add a method to create a JWT token.

public String createToken(String username, Set<Role> set) {
&nbsp; &nbsp; Claims claims = Jwts.claims().setSubject(username);
&nbsp; &nbsp; claims.put("roles", set);
&nbsp; &nbsp; Date now = new Date();
&nbsp; &nbsp; Date validity = new Date(now.getTime() + validityInMilliseconds);
&nbsp; &nbsp; return Jwts.builder()//
&nbsp; &nbsp; &nbsp; &nbsp; .setClaims(claims)//
&nbsp; &nbsp; &nbsp; &nbsp; .setIssuedAt(now)//
&nbsp; &nbsp; &nbsp; &nbsp; .setExpiration(validity)//
&nbsp; &nbsp; &nbsp; &nbsp; .signWith(SignatureAlgorithm.HS256, secretKey)//
&nbsp; &nbsp; &nbsp; &nbsp; .compact();
}

Add a method to load User by username.

public Authentication getAuthentication(String token) {
&nbsp; &nbsp; UserDetails userDetails = this.userDetailsService.loadUserByUsername(getUsername(token));
&nbsp; &nbsp; return new UsernamePasswordAuthenticationToken(userDetails, "", userDetails.getAuthorities());
}

Add a method to get the username by JWT token.

public String getUsername(String token) {
&nbsp; &nbsp; return Jwts.parser().setSigningKey(secretKey).parseClaimsJws(token).getBody().getSubject();
}

Add a method to resolve JWT token from request headers of Authorization that has a Bearer prefix.

public String resolveToken(HttpServletRequest req) {
&nbsp; &nbsp; String bearerToken = req.getHeader("Authorization");
&nbsp; &nbsp; if (bearerToken != null && bearerToken.startsWith("Bearer ")) {
&nbsp; &nbsp; &nbsp; &nbsp; return bearerToken.substring(7, bearerToken.length());
&nbsp; &nbsp; }
&nbsp; &nbsp; return null;
}

Add a method to validate a JWT token.

public boolean validateToken(String token) {
&nbsp; &nbsp; try {
&nbsp; &nbsp; &nbsp; &nbsp; Jws<Claims> claims = Jwts.parser().setSigningKey(secretKey).parseClaimsJws(token);
&nbsp; &nbsp; &nbsp; &nbsp; if (claims.getBody().getExpiration().before(new Date())) {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return false;
&nbsp; &nbsp; &nbsp; &nbsp; }
&nbsp; &nbsp; &nbsp; &nbsp; return true;
&nbsp; &nbsp; } catch (JwtException | IllegalArgumentException e) {
&nbsp; &nbsp; &nbsp; &nbsp; throw new JwtException("Expired or invalid JWT token");
&nbsp; &nbsp; }
}

Finally, organize imports like below.

package com.djamware.SecurityRest.configs;

import java.util.Base64;
import java.util.Date;
import java.util.Set;

import javax.annotation.PostConstruct;
import javax.servlet.http.HttpServletRequest;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.stereotype.Component;

import com.djamware.SecurityRest.models.Role;
import com.djamware.SecurityRest.services.CustomUserDetailsService;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jws;
import io.jsonwebtoken.JwtException;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;

Next, create a JWT filter class with the name JwtTokenFilter in configs package that extends Spring GenericFilterBean. Replace all Java codes with these lines of codes.

package com.djamware.SecurityRest.configs;

import java.io.IOException;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

import org.springframework.security.core.Authentication;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.web.filter.GenericFilterBean;

public class JwtTokenFilter extends GenericFilterBean {

&nbsp;&nbsp; &nbsp;private JwtTokenProvider jwtTokenProvider;

&nbsp; &nbsp; public JwtTokenFilter(JwtTokenProvider jwtTokenProvider) {
&nbsp; &nbsp; &nbsp; &nbsp; this.jwtTokenProvider = jwtTokenProvider;
&nbsp; &nbsp; }

&nbsp; &nbsp; @Override
&nbsp; &nbsp; public void doFilter(ServletRequest req, ServletResponse res, FilterChain filterChain)
&nbsp; &nbsp; &nbsp; &nbsp; throws IOException, ServletException {
&nbsp; &nbsp; &nbsp; &nbsp; String token = jwtTokenProvider.resolveToken((HttpServletRequest) req);
&nbsp; &nbsp; &nbsp; &nbsp; if (token != null && jwtTokenProvider.validateToken(token)) {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Authentication auth = token != null ? jwtTokenProvider.getAuthentication(token) : null;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; SecurityContextHolder.getContext().setAuthentication(auth);
&nbsp; &nbsp; &nbsp; &nbsp; }
&nbsp; &nbsp; &nbsp; &nbsp; filterChain.doFilter(req, res);
&nbsp; &nbsp; }
}

Next, create a class with the name JwtConfigurer for JWT configuration in configs package then replace all codes with these lines of codes.

package com.djamware.SecurityRest.configs;

import org.springframework.security.config.annotation.SecurityConfigurerAdapter;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.web.DefaultSecurityFilterChain;
import org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter;

public class JwtConfigurer extends SecurityConfigurerAdapter<DefaultSecurityFilterChain, HttpSecurity> {

&nbsp;&nbsp; &nbsp;private JwtTokenProvider jwtTokenProvider;

&nbsp; &nbsp; public JwtConfigurer(JwtTokenProvider jwtTokenProvider) {
&nbsp; &nbsp; &nbsp; &nbsp; this.jwtTokenProvider = jwtTokenProvider;
&nbsp; &nbsp; }

&nbsp; &nbsp; @Override
&nbsp; &nbsp; public void configure(HttpSecurity http) throws Exception {
&nbsp; &nbsp; &nbsp; &nbsp; JwtTokenFilter customFilter = new JwtTokenFilter(jwtTokenProvider);
&nbsp; &nbsp; &nbsp; &nbsp; http.addFilterBefore(customFilter, UsernamePasswordAuthenticationFilter.class);
&nbsp; &nbsp; }
}

Finally, we have to configure the Spring Security by creating a Java class file inside configs package with the name WebSecurityConfig. Give annotations to this class and extends Spring WebSecurityConfigurerAdapter.

@Configuration
@EnableWebSecurity
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {
}

Inject JWT token provider inside this class.

@Autowired
JwtTokenProvider jwtTokenProvider;

Add an override method to configure Authentication Manager Builder.

@Override
protected void configure(AuthenticationManagerBuilder auth) throws Exception {
&nbsp;&nbsp; &nbsp;UserDetailsService userDetailsService = mongoUserDetails();
&nbsp;&nbsp; &nbsp;auth.userDetailsService(userDetailsService).passwordEncoder(bCryptPasswordEncoder());

}

Next, add an override method to configure Spring Security Http Security.

@Override
protected void configure(HttpSecurity http) throws Exception {
&nbsp;&nbsp; &nbsp;http.httpBasic().disable().csrf().disable().sessionManagement()
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;.sessionCreationPolicy(SessionCreationPolicy.STATELESS).and().authorizeRequests()
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;.antMatchers("/api/auth/login").permitAll().antMatchers("/api/auth/register").permitAll()
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;.antMatchers("/api/products/**").hasAuthority("ADMIN").anyRequest().authenticated().and().csrf()
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;.disable().exceptionHandling().authenticationEntryPoint(unauthorizedEntryPoint()).and()
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;.apply(new JwtConfigurer(jwtTokenProvider));
}

Next, declare all required beans for this configuration.

@Bean
public PasswordEncoder bCryptPasswordEncoder() {
&nbsp;&nbsp; &nbsp;return new BCryptPasswordEncoder();
}

@Bean
@Override
public AuthenticationManager authenticationManagerBean() throws Exception {
&nbsp;&nbsp; &nbsp;return super.authenticationManagerBean();
}

@Bean
public AuthenticationEntryPoint unauthorizedEntryPoint() {
&nbsp;&nbsp; &nbsp;return (request, response, authException) -> response.sendError(HttpServletResponse.SC_UNAUTHORIZED,
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;"Unauthorized");
}

@Bean
public UserDetailsService mongoUserDetails() {
&nbsp;&nbsp; &nbsp;return new CustomUserDetailsService();
}

6. Create Product and Authentication Controllers

Now it’s time for REST API endpoint. All RESTful API will be created from each controller. Product controller will handle CRUD endpoint of product and Authentication controller will handle login and register endpoint. Right-click project name -> New -> Class then fill the package with com.djamware.SecurityRest.controllers and the class name as ProductController. Open and edit the newly created class file then replace all codes with these lines of codes.

package com.djamware.SecurityRest.controllers;

import java.util.Optional;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.djamware.SecurityRest.models.Product;
import com.djamware.SecurityRest.repositories.ProductRepository;

@RestController
public class ProductController {

&nbsp;&nbsp; &nbsp;@Autowired
&nbsp; &nbsp; ProductRepository productRepository;

&nbsp; &nbsp; @RequestMapping(method=RequestMethod.GET, value="/api/products")
&nbsp; &nbsp; public Iterable<Product> product() {
&nbsp; &nbsp; &nbsp; &nbsp; return productRepository.findAll();
&nbsp; &nbsp; }

&nbsp; &nbsp; @RequestMapping(method=RequestMethod.POST, value="/api/products")
&nbsp; &nbsp; public String save(@RequestBody Product product) {
&nbsp; &nbsp; &nbsp; &nbsp; productRepository.save(product);

&nbsp; &nbsp; &nbsp; &nbsp; return product.getId();
&nbsp; &nbsp; }

&nbsp; &nbsp; @RequestMapping(method=RequestMethod.GET, value="/api/products/{id}")
&nbsp; &nbsp; public Optional<Product> show(@PathVariable String id) {
&nbsp; &nbsp; &nbsp; &nbsp; return productRepository.findById(id);
&nbsp; &nbsp; }

&nbsp; &nbsp; @RequestMapping(method=RequestMethod.PUT, value="/api/products/{id}")
&nbsp; &nbsp; public Product update(@PathVariable String id, @RequestBody Product product) {
&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;Optional<Product> prod = productRepository.findById(id);
&nbsp; &nbsp; &nbsp; &nbsp; if(product.getProdName() != null)
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; prod.get().setProdName(product.getProdName());
&nbsp; &nbsp; &nbsp; &nbsp; if(product.getProdDesc() != null)
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; prod.get().setProdDesc(product.getProdDesc());
&nbsp; &nbsp; &nbsp; &nbsp; if(product.getProdPrice() != null)
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; prod.get().setProdPrice(product.getProdPrice());
&nbsp; &nbsp; &nbsp; &nbsp; if(product.getProdImage() != null)
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; prod.get().setProdImage(product.getProdImage());
&nbsp; &nbsp; &nbsp; &nbsp; productRepository.save(prod.get());
&nbsp; &nbsp; &nbsp; &nbsp; return prod.get();
&nbsp; &nbsp; }

&nbsp; &nbsp; @RequestMapping(method=RequestMethod.DELETE, value="/api/products/{id}")
&nbsp; &nbsp; public String delete(@PathVariable String id) {
&nbsp; &nbsp; &nbsp; &nbsp; Optional<Product> product = productRepository.findById(id);
&nbsp; &nbsp; &nbsp; &nbsp; productRepository.delete(product.get());

&nbsp; &nbsp; &nbsp; &nbsp; return "product deleted";
&nbsp; &nbsp; }
}

For login, we need to create a POJO to mapping required fields of User. Create a new class file with the name AuthBody inside controllers package then replace all Java codes with these lines of codes.

package com.djamware.SecurityRest.controllers;

public class AuthBody {

&nbsp;&nbsp; &nbsp;private String email;
&nbsp; &nbsp; private String password;

&nbsp;&nbsp; &nbsp;public String getEmail() {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;return email;
&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;public void setEmail(String email) {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;this.email = email;
&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;public String getPassword() {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;return password;
&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;public void setPassword(String password) {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;this.password = password;
&nbsp;&nbsp; &nbsp;}

}

Finally, create a controller for authentication with the name AuthController inside the controllers’ package. Open and edit that newly created file then replace all Java codes with these lines of codes.

package com.djamware.SecurityRest.controllers;

import static org.springframework.http.ResponseEntity.ok;

import java.util.HashMap;
import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.authentication.BadCredentialsException;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.AuthenticationException;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.djamware.SecurityRest.configs.JwtTokenProvider;
import com.djamware.SecurityRest.models.User;
import com.djamware.SecurityRest.repositories.UserRepository;
import com.djamware.SecurityRest.services.CustomUserDetailsService;

@RestController
@RequestMapping("/api/auth")
public class AuthController {

&nbsp;&nbsp; &nbsp;@Autowired
&nbsp;&nbsp; &nbsp;AuthenticationManager authenticationManager;

&nbsp;&nbsp; &nbsp;@Autowired
&nbsp;&nbsp; &nbsp;JwtTokenProvider jwtTokenProvider;

&nbsp;&nbsp; &nbsp;@Autowired
&nbsp;&nbsp; &nbsp;UserRepository users;

&nbsp;&nbsp; &nbsp;@Autowired
&nbsp;&nbsp; &nbsp;private CustomUserDetailsService userService;

&nbsp;&nbsp; &nbsp;@SuppressWarnings("rawtypes")
&nbsp;&nbsp; &nbsp;@PostMapping("/login")
&nbsp;&nbsp; &nbsp;public ResponseEntity login(@RequestBody AuthBody data) {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;try {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;String username = data.getEmail();
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;authenticationManager.authenticate(new UsernamePasswordAuthenticationToken(username, data.getPassword()));
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;String token = jwtTokenProvider.createToken(username, this.users.findByEmail(username).getRoles());
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;Map<Object, Object> model = new HashMap<>();
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;model.put("username", username);
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;model.put("token", token);
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;return ok(model);
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;} catch (AuthenticationException e) {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;throw new BadCredentialsException("Invalid email/password supplied");
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;}

&nbsp;&nbsp; &nbsp;@SuppressWarnings("rawtypes")
&nbsp;&nbsp; &nbsp;@PostMapping("/register")
&nbsp;&nbsp; &nbsp;public ResponseEntity register(@RequestBody User user) {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;User userExists = userService.findUserByEmail(user.getEmail());
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;if (userExists != null) {
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;throw new BadCredentialsException("User with username: " + user.getEmail() + " already exists");
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;}
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;userService.saveUser(user);
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;Map<Object, Object> model = new HashMap<>();
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;model.put("message", "User registered successfully");
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;return ok(model);
&nbsp;&nbsp; &nbsp;}
}

7. Run and Test Spring Boot Security Rest using Postman

Before run and test the application, we have to populate a Role data first. Open and edit src/main/java/com/djamware/SecurityRest/SecurityRestApplication.java then add these lines of codes inside the initialization method.

@Bean
CommandLineRunner init(RoleRepository roleRepository) {

&nbsp; &nbsp; return args -> {

&nbsp; &nbsp; &nbsp; &nbsp; Role adminRole = roleRepository.findByRole("ADMIN");
&nbsp; &nbsp; &nbsp; &nbsp; if (adminRole == null) {
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Role newAdminRole = new Role();
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; newAdminRole.setRole("ADMIN");
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; roleRepository.save(newAdminRole);
&nbsp; &nbsp; &nbsp; &nbsp; }
&nbsp; &nbsp; };

}

Next, make sure you have run the MongoDB server on your local machine then run the Gradle application using this command.

./gradlew bootRun

Or in STS just right-click the project name -> Run As -> Spring Boot App. Next, open the Postman application then change the method to GET and address to localhost:8080/api/products then click Send button.

You will see this response in the bottom panel of Postman.

{
&nbsp; &nbsp; "timestamp": "2019-03-07T13:16:34.935+0000",
&nbsp; &nbsp; "status": 401,
&nbsp; &nbsp; "error": "Unauthorized",
&nbsp; &nbsp; "message": "Unauthorized",
&nbsp; &nbsp; "path": "/api/products"
}

Next, change the method to POST then address to localhost:8080/api/auth/register then fill the body with raw data as below image then click Send button.

You will get the response in the bottom panel of Postman.

{
&nbsp; &nbsp; "message": "User registered successfully"
}

Next, change the address to localhost:8080/api/auth/login and change the body as below then click Send button.

{ "email":"[email&nbsp;protected]", "password": "q1w2we3r4" }

You will see this response in the bottom panel of Postman.

{
&nbsp; &nbsp; "username": "[email&nbsp;protected]",
&nbsp; &nbsp; "token": "eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiJpbmZvQGRqYW13YXJlLmNvbSIsInJvbGVzIjpbeyJpZCI6IjVjODBjNjIzYjIwMTkxNGIyYTY5N2U4ZCIsInJvbGUiOiJBRE1JTiJ9XSwiaWF0IjoxNTUxOTY0OTc3LCJleHAiOjE1NTE5Njg1Nzd9.j5CHZ_LCmeQtdxQeH9eluxVXcOsHPWV1p8WnBn0CULo"
}

Copy the token then back to the GET product. Add a header with the name Authorization and the value that paste from a token that gets by login with additional Bearer prefix (with space) as below.

Bearer eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiJpbmZvQGRqYW13YXJlLmNvbSIsInJvbGVzIjpbeyJpZCI6IjVjODBjNjIzYjIwMTkxNGIyYTY5N2U4ZCIsInJvbGUiOiJBRE1JTiJ9XSwiaWF0IjoxNTUxOTY0OTc3LCJleHAiOjE1NTE5Njg1Nzd9.j5CHZ_LCmeQtdxQeH9eluxVXcOsHPWV1p8WnBn0CULo

You should see this response after clicking the Send button.

[
&nbsp; &nbsp; {
&nbsp; &nbsp; &nbsp; &nbsp; "id": "5c80dc6cb20191520567b68a",
&nbsp; &nbsp; &nbsp; &nbsp; "prodName": "Dummy Product 1",
&nbsp; &nbsp; &nbsp; &nbsp; "prodDesc": "The Fresh Dummy Product in The world part 1",
&nbsp; &nbsp; &nbsp; &nbsp; "prodPrice": 100,
&nbsp; &nbsp; &nbsp; &nbsp; "prodImage": "https://dummyimage.com/600x400/000/fff"
&nbsp; &nbsp; }
]

You can test the POST product with the token in headers using the same way.

That it’s, the Securing RESTful API with Spring Boot, Security, and Data MongoDB tutorial. You can get the full source code from our GitHub.

Learn More

Build a Simple CRUD App with Spring Boot and Vue.js

Creating RESTful APIs with NodeJS and MongoDB Tutorial

MongoDB with Python Crash Course - Tutorial for Beginners

How to build RESTful APIs with ASP.NET Core

Understanding the basics of RESTful APIs

Developing RESTful APIs with Lumen (A PHP Micro-framework)

Java Programming Masterclass for Software Developers

Java In-Depth: Become a Complete Java Engineer!

JSP, Servlets and JDBC for Beginners: Build a Database App

JSP, Servlet, JSLT + Hibernate: A complete guide

First CRUD Node Express Js Mysql Example

First CRUD Node Express Js Mysql Example

In this node express js tutorial, we would love to share with you how to create a crud application in node express js with mysql

In this node express js tutorial, we would love to share with you how to create a crud application in node express js with mysql

Hello developers, Today we will discuss how to install node js framework express js and how to create crud (create, update, read, delete) application in node js using express js framework with mysql database. Today we would love to show you how to create crud application in node js.

We will create crud application in node express js framework with mysql database. we will do each thing step by step and easy.

In this node express js crud application. We will use ejs templating engine. It is very simple and easy to understand for everyone.

Let’s start create CRUD with Node.Js , Express, MySQL

Create Express js Project

Use the below command and create your express project with name expressfirst

express --view=ejs expressfirst

After successfully created expressfirst folder in your system. Next follow the below commands and install node js in your project :

cd expressfirst

npm install  

Next we need to install some required pacakges, go to terminal and use the below commands :

 npm install express-flash --save
 npm install express-session --save
 npm install express-validator --save
 npm install method-override --save
 npm install mysql --save

Flash is an extension of connect-flash with the ability to define a flash message and render it without redirecting the request.

In this node js mysql crud tutorial express flash is used to display a warning, error and information message

Express-session is used to made a session as like in PHP. In this node js mysql crud tutorial, session is needed as the express requirement of express-flash.

Express validator is used to validate form data it is easy to use. express-validator highly effective and efficient way to accelerate the creation of applications.

NPM is used to run a DELETE and PUT method from an HTML form. In several web browsers only support GET and POST methods.

Driver to connect node.js with MySQL

Database Connection with Mysql

Next we need to create one folder name lib and create a new file name db.js inside this folder. We will connect node js to mysql using this file

lib/db.js
 var mysql=require('mysql');
 var connection=mysql.createConnection({
   host:'localhost',
   user:'your username',
   password:'your password',
   database:'your database name'
 });
connection.connect(function(error){
   if(!!error){
     console.log(error);
   }else{
     console.log('Connected!:)');
   }
 });  
module.exports = connection; 

Changes in app.js

We need to some changes in app.js file. go to app.js file and put some code here :

 var createError = require('http-errors');
 var express = require('express');
 var path = require('path');
 var cookieParser = require('cookie-parser');
 var logger = require('morgan');
 var expressValidator = require('express-validator');
 var flash = require('express-flash');
 var session = require('express-session');
 var bodyParser = require('body-parser');

 var mysql = require('mysql');
 var connection  = require('./lib/db');

 var indexRouter = require('./routes/index');
 var usersRouter = require('./routes/users');
 var customersRouter = require('./routes/customers');

 var app = express();

// view engine setup
 app.set('views', path.join(__dirname, 'views'));
 app.set('view engine', 'ejs');

 app.use(logger('dev'));
 app.use(bodyParser.json());
 app.use(bodyParser.urlencoded({ extended: true }));
 app.use(cookieParser());
 app.use(express.static(path.join(__dirname, 'public')));

 app.use(session({ 
     secret: '123456cat',
     resave: false,
     saveUninitialized: true,
     cookie: { maxAge: 60000 }
 }))

 app.use(flash());
 app.use(expressValidator());

 app.use('/', indexRouter);
 app.use('/users', usersRouter);
 app.use('/customers', customersRouter);

 // catch 404 and forward to error handler
 app.use(function(req, res, next) {
   next(createError(404));
 });

 // error handler
 app.use(function(err, req, res, next) {
   // set locals, only providing error in development
   res.locals.message = err.message;
   res.locals.error = req.app.get('env') === 'development' ? err : {};
 // render the error page
   res.status(err.status || 500);
   res.render('error');
 });
 module.exports = app;

Create Route

Next We need to create one route file name customers.js inside routes folder. After created this file, We will implement crud logic in this file. Go to routes/customers.js and use the below code :

var express = require('express');
var router = express.Router();
var connection  = require('../lib/db');
 
 
/* GET home page. */
router.get('/', function(req, res, next) {
      
 connection.query('SELECT * FROM customers ORDER BY id desc',function(err,rows)     {
 
        if(err){
         req.flash('error', err); 
         res.render('customers',{page_title:"Customers - Node.js",data:''});   
        }else{
            
            res.render('customers',{page_title:"Customers - Node.js",data:rows});
        }
                            
         });
        
    });
 
 
// SHOW ADD USER FORM
router.get('/add', function(req, res, next){    
    // render to views/user/add.ejs
    res.render('customers/add', {
        title: 'Add New Customers',
        name: '',
        email: ''        
    })
})
 
// ADD NEW USER POST ACTION
router.post('/add', function(req, res, next){    
    req.assert('name', 'Name is required').notEmpty()           //Validate name
    req.assert('email', 'A valid email is required').isEmail()  //Validate email
  
    var errors = req.validationErrors()
     
    if( !errors ) {   //No errors were found.  Passed Validation!
         
     
        var user = {
            name: req.sanitize('name').escape().trim(),
            email: req.sanitize('email').escape().trim()
        }
         
     connection.query('INSERT INTO customers SET ?', user, function(err, result) {
                //if(err) throw err
                if (err) {
                    req.flash('error', err)
                     
                    // render to views/user/add.ejs
                    res.render('customers/add', {
                        title: 'Add New Customer',
                        name: user.name,
                        email: user.email                    
                    })
                } else {                
                    req.flash('success', 'Data added successfully!');
                    res.redirect('/customers');
                }
            })
    }
    else {   //Display errors to user
        var error_msg = ''
        errors.forEach(function(error) {
            error_msg += error.msg + '<br>'
        })                
        req.flash('error', error_msg)        
         
        /**
         * Using req.body.name 
         * because req.param('name') is deprecated
         */ 
        res.render('customers/add', { 
            title: 'Add New Customer',
            name: req.body.name,
            email: req.body.email
        })
    }
})
 
// SHOW EDIT USER FORM
router.get('/edit/(:id)', function(req, res, next){
   
connection.query('SELECT * FROM customers WHERE id = ' + req.params.id, function(err, rows, fields) {
            if(err) throw err
             
            // if user not found
            if (rows.length <= 0) {
                req.flash('error', 'Customers not found with id = ' + req.params.id)
                res.redirect('/customers')
            }
            else { // if user found
                // render to views/user/edit.ejs template file
                res.render('customers/edit', {
                    title: 'Edit Customer', 
                    //data: rows[0],
                    id: rows[0].id,
                    name: rows[0].name,
                    email: rows[0].email                    
                })
            }            
        })
  
})
 
// EDIT USER POST ACTION
router.post('/update/:id', function(req, res, next) {
    req.assert('name', 'Name is required').notEmpty()           //Validate nam           //Validate age
    req.assert('email', 'A valid email is required').isEmail()  //Validate email
  
    var errors = req.validationErrors()
     
    if( !errors ) {   
 
        var user = {
            name: req.sanitize('name').escape().trim(),
            email: req.sanitize('email').escape().trim()
        }
         
connection.query('UPDATE customers SET ? WHERE id = ' + req.params.id, user, function(err, result) {
                //if(err) throw err
                if (err) {
                    req.flash('error', err)
                     
                    // render to views/user/add.ejs
                    res.render('customers/edit', {
                        title: 'Edit Customer',
                        id: req.params.id,
                        name: req.body.name,
                        email: req.body.email
                    })
                } else {
                    req.flash('success', 'Data updated successfully!');
                    res.redirect('/customers');
                }
            })
         
    }
    else {   //Display errors to user
        var error_msg = ''
        errors.forEach(function(error) {
            error_msg += error.msg + '<br>'
        })
        req.flash('error', error_msg)
         
        /**
         * Using req.body.name 
         * because req.param('name') is deprecated
         */ 
        res.render('customers/edit', { 
            title: 'Edit Customer',            
            id: req.params.id, 
            name: req.body.name,
            email: req.body.email
        })
    }
})
       
// DELETE USER
router.get('/delete/(:id)', function(req, res, next) {
    var user = { id: req.params.id }
     
connection.query('DELETE FROM customers WHERE id = ' + req.params.id, user, function(err, result) {
            //if(err) throw err
            if (err) {
                req.flash('error', err)
                // redirect to users list page
                res.redirect('/customers')
            } else {
                req.flash('success', 'Customer deleted successfully! id = ' + req.params.id)
                // redirect to users list page
                res.redirect('/customers')
            }
        })
   })
 
 
module.exports = router;

Create views

First we will create one foleder name customers inside the views folder.

Next we need to create three views file name add.ejs, edit.ejs and index.ejs. We will create three view files inside the views/customers folder.

Create first file index.ejs

Index.ejs file, we will display the list of customers.

<!DOCTYPE html>
<html>
<head>
  <title>Customers</title>
  <link rel='stylesheet' href='/stylesheets/style.css' />
  <script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>
<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">
</head>
<body>
  <div>
    <a href="/" class="btn btn-primary ml-3">Home</a>  
    <a href="/customers/add" class="btn btn-secondary ml-3">New Customer</a> 
    <a href="/customers" class="btn btn-info ml-3">Customer List</a>
</div>    
<!--   <% if (messages.error) { %>
  <p style="color:red"><%- messages.error %></p>
<% } %> -->
  
<% if (messages.success) { %>
    <p class="alert alert-success mt-4"><%- messages.success %></p>
<% } %>  
<br>
  <table class="table">
<thead>
  <tr>
    <th scope="col">#</th>
    <th scope="col">Name</th>
    <th scope="col">Email</th>
    <th width="200px">Action</th>
 
  </tr>
</thead>
<tbody>
  <% if(data.length){
 
  for(var i = 0; i< data.length; i++) {%>  
  <tr>
    <th scope="row"><%= (i+1) %></th>
    <td><%= data[i].name%></td>
    <td><%= data[i].email%></td>
    <td>
    <a class="btn btn-success edit" href="../customers/edit/<%=data[i].id%>">Edit</a>                       
    <a class="btn btn-danger delete" onclick="return alert('Are You sure?')" href="../customers/delete/<%=data[i].id%>">Delete</a>                       
   </td>
  </tr>
  <% }
           
   }else{ %>
       <tr>
          <td colspan="3">No user</td>
       </tr>
    <% } %>    
  
</tbody>
</table>
</body>
</html>

Create second file name add.ejs

Add.ejs file, we will create form for sending to data in database.

<!DOCTYPE html>
<html>
<head>
  <title>Customers</title>
  <link rel='stylesheet' href='/stylesheets/style.css' />
  <script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>
<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">
</head>
<body>
  <% if (messages.error) { %>
  <p style="color:red"><%- messages.error %></p>
<% } %>
  
<% if (messages.success) { %>
    <p style="color:green"><%- messages.success %></p>
<% } %>
<form action="/customers/add" method="post" name="form1">
<div class="form-group">
  <label for="exampleInputPassword1">Name</label>
  <input type="text" class="form-control" name="name" id="name" value="" placeholder="Name">
</div>
<div class="form-group">
  <label for="exampleInputEmail1">Email address</label>
  <input type="email" name="email" class="form-control" id="email" aria-describedby="emailHelp" placeholder="Enter email" value="">
</div>
 
<input type="submit" class="btn btn-primary" value="Add">
</form>
</body>
</html>

Create third file name edit.ejs

Next create last file edit.ejs, we will to edit data in this form.

<!DOCTYPE html>
<html>
<head>
  <title>Customers</title>
  <link rel='stylesheet' href='/stylesheets/style.css' />
  <script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>
<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">
</head>
<body>
<form action="/customers/update/<%= id %>" method="post" name="form1">
<div class="form-group">
  <label for="exampleInputPassword1">Name</label>
  <input type="text" class="form-control" name="name" id="name" value="<%= name %>" placeholder="Name">
</div>
<div class="form-group">
  <label for="exampleInputEmail1">Email address</label>
  <input type="email" class="form-control" name="email" id="email" aria-describedby="emailHelp" placeholder="Enter email" value="<%= email %>">
  
</div>
 
<button type="submit" class="btn btn-info">Update</button>
</form>
</body>
</html>

Test Node js Crud app

run the below command

npm start

after run this command open your browser and hit 

http://127.0.0.1:3000/customers

Conclusion

In this node express js crud tutorial – We have created node js crud (create, read, update, delete) application with mysql database. We have also successfully install node js framework express with use ejs templating engine.

Learn More

MySQL Databases With Python Tutorial

Build a Basic CRUD App with Node and React

Build a Simple CRUD App with Python, Flask, and React

Build a Basic CRUD App with Laravel and Vue

Build a Simple CRUD App with Spring Boot and Vue.js

Build a Basic CRUD App with Laravel and Angular

Build a Basic CRUD App with Laravel and React

Express.js & Node.js Course for Beginners - Full Tutorial

Build a CRUD App with Angular and Firebase

Angular 7 + Spring Boot CRUD Example

The Complete Node.js Developer Course (3rd Edition)

Angular & NodeJS - The MEAN Stack Guide

NodeJS - The Complete Guide (incl. MVC, REST APIs, GraphQL)

Node.js: The Complete Guide to Build RESTful APIs (2018)

Building a full CRUD Angular 8 Universal and MongoDB SSR

Building a full CRUD Angular 8 Universal and MongoDB SSR

A comprehensive step by step tutorial to building a full CRUD Angular 8 Universal and MongoDB Server-side Rendering (SSR)

A comprehensive step by step tutorial to building a full CRUD Angular 8 Universal and MongoDB Server-side Rendering (SSR)

We will practically use Angular 8 universal for a CRUD (Create, Read, Update, Delete) operation application that store the data to the MongoDB server.

The Angular 8 application that we will build is a very simple application about Article CRUD. This might be a starting point to build your own complete blog engine or news engine because this application should be matched for SEO requirements.

Almost all codes in this application using Typescript and ES6 except a few files that still use plain ES5 code that uses by Express.js. For that, we need your suggestion for converting to working Angular 8/Typescript code styles. The following tools, frameworks, and modules are required for this tutorial:

As usual, before we move forward to the main steps of Angular 8 Universal and MongoDB Server-side Rendering (SSR). We have to check the latest Node and Angular versions then update them if necessary. Just type this command to see it.

ng version

You will see the currently installed Node, Angular and Angular CLI versions.

Angular CLI: 8.0.6
Node: 10.15.1
OS: darwin x64
Angular: 8.0.3
Create a New Angular 8 Application and Add Angular Universal

First, we will create a new Angular 8 application by type this command in the terminal.

ng new article-crud

Next, go to the newly created Angular 8 application folder then type this command to add Angular Universal SSR.

ng add @nguniversal/express-engine --clientProject article-crud

That command just added and updated a few files.

CREATE src/main.server.ts (361 bytes)
CREATE src/app/app.server.module.ts (427 bytes)
CREATE tsconfig.server.json (204 bytes)
CREATE webpack.server.config.js (1466 bytes)
CREATE server.ts (1980 bytes)
UPDATE package.json (1844 bytes)
UPDATE angular.json (4263 bytes)
UPDATE src/main.ts (432 bytes)
UPDATE src/app/app.module.ts (438 bytes)

Next, check the Angular Universal SSR application by running this application using these commands.

npm run build:ssr && npm run serve:ssr

Now, after go to localhost:4000 you see this standard Angular application page and feel the difference with the page that rendered in the browser.

Angular 8 Universal

Install and Configure Mongoose.js and Required Modules

To store and retrieve data from the MongoDB server, we will use Mongoose.js. To install it, just run these commands that including body-parser modules.

npm install --save mongoose body-parser

In this Angular 8 Universal SSR, body parser will use to parse the request body to the API. Next, open and edit server.ts in the root project folder then add these imports.

import * as mongoose from 'mongoose';
import bodyParser from "body-parser";

Next, add these lines of codes after the imports lines to connect to the MongoDB and use body-parser for every JSON requests.

mongoose.connect('mongodb://localhost/angular8-crud', { useNewUrlParser: true, useFindAndModify: false })
  .then(() =>  console.log('connection successful'))
  .catch((err) => console.error(err));

app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
Create a Mongoose Model and Router

We will create a Mongoose model that represent MongoDB fields. Create a models folder and a file to holds all required Article fields.

mkdir models
touch models/article.ts

Next, fill that file with this Mongoose Schema.

import mongoose, { Schema } from 'mongoose';

const ArticleSchema: Schema = new Schema({
  title: { type: String, required: true },
  author: { type: String, required: true },
  description: { type: String, required: true },
  content: { type: String, required: true },
  updatedAt: { type: Date, default: Date.now }
});

export default mongoose.model('Article', ArticleSchema);

Next, we will create a route that accesses the MongoDB data via API. Create a new folder call routes and a file inside it.

mkdir routes
touch routes/article-route.ts

Open and edit that file then add these imports.

import { Request, Response, NextFunction } from 'express';
import Article from '../models/article';

Add these lines of codes to create a CRUD method of RESTful API. The

route path starts with /api/ that will be called from the Angular 8

application using full URL [http://localhost:4000/api/.](http://localhost:4000/api/`.)

export class ArticleRoute {

  public articleRoute(app): void {
    app.route('/api/').get((req: Request, res: Response, next: NextFunction) => {
      Article.find((err, articles) => {
        if (err) { return next(err); }
        res.json(articles);
      });
    });

    app.route('/api/:id').get((req: Request, res: Response, next: NextFunction) => {
      Article.findById(req.params.id, (err, article) => {
        if (err) { return next(err); }
        res.json(article);
      });
    });

    app.route('/api/').post((req: Request, res: Response, next: NextFunction) => {
      console.log(req.body);
      Article.create(req.body, (err, article) => {
        if (err) { return next(err); }
        res.json(article);
      });
    });

    app.route('/api/:id').put((req: Request, res: Response, next: NextFunction) => {
      Article.findByIdAndUpdate(req.params.id, req.body, (err, article) => {
        if (err) { return next(err); }
        res.json(article);
      });
    });

    app.route('/api/:id').delete((req: Request, res: Response, next: NextFunction) => {
      Article.findByIdAndRemove(req.params.id, req.body, (err, article) => {
        if (err) { return next(err); }
        res.json(article);
      });
    });
  }
}

Next, open and edit server.ts then add this import.

import { ArticleRoute } from './routes/article-route';

Declare a constant after the import lines.

const articleRoute: ArticleRoute = new ArticleRoute();

Add this line before the all regular route lines.

articleRoute.articleRoute(app);

Don't declare API route after all regular route otherwise the API URL won't working.

Test the Angular 8 Universal SSR RESTful API

We will test the Angular 8 Universal SSR RESTful API using the Postman app. First, run the app using this command.

npm run build:ssr && npm run serve:ssr

Open the postman app then change the method to GET and address to localhost:4000/api/ then press SEND button. If there's any data in your MongoDB server then it's will be similar like this.

MongoDB SSR

To save data, change the method to POST with the same address then choose RAW body with type JSON. Fill the RAW body with this example or your own data example.

{
    "title": "Odong",
    "author": "Odong",
    "description": "Odong",
    "content": "Odong"
}

You will see this result for successful POST data.

CRUD Angular 8

Next, you can test the rest of PUT and DELETE using your own data to make sure the Angular 8 Universal SSR API working.

Create Angular 8 Routes for Page Navigation

To create Angular 8 Routes for navigation between Angular 8 pages/component, add or generate all required component.

ng g component articles --skip-import
ng g component show-article --skip-import
ng g component add-article --skip-import
ng g component edit-article --skip-import

There's an additional --skip-import variable because there will be a conflict between 2 modules, Angular 8 and Server modules.

More than one module matches. Use skip-import option to skip importing the component into the closest module.

Next, we will manually add or register those components to the src/app/app.module.ts. Add these imports to that file.

import { ArticlesComponent } from './articles/articles.component';
import { ShowArticleComponent } from './show-article/show-article.component';
import { AddArticleComponent } from './add-article/add-article.component';
import { EditArticleComponent } from './edit-article/edit-article.component';

Then add those components to @NgModule declaration.

@NgModule({
  declarations: [
    ...
    ArticlesComponent,
    ShowArticleComponent,
    AddArticleComponent,
    EditArticleComponent
  ],
  ...
})

Next, open and edit src/app/app-routing.module.ts then add these imports.

const routes: Routes = [
  {
    path: 'articles',
    component: ArticlesComponent,
    data: { title: 'Articles' }
  },
  {
    path: 'show-article/:id',
    component: ShowArticleComponent,
    data: { title: 'Show Article' }
  },
  {
    path: 'add-article',
    component: AddArticleComponent,
    data: { title: 'Add Article' }
  },
  {
    path: 'edit-article/:id',
    component: EditArticleComponent,
    data: { title: 'Edit Article' }
  },
  { path: '',
    redirectTo: '/articles',
    pathMatch: 'full'
  }
];

Open and edit src/app/app.component.html and you will see the existing router outlet. Next, modify this HTML page to fit the CRUD page.


  

Open and edit src/app/app.component.scss then replace all SASS codes with this.

.container {
  padding: 20px;
}
Create an Angular 8 Service using HttpClient, Observable and RXJS

To access RESTful API from Angular 8, we need to create an Angular 8 service which will handle all POST, GET, UPDATE, DELETE requests. The response from the RESTful API emitted by Observable that can subscribe and read from the Components. For error handler and data Extraction, we will use RXJS Library. Before creating a service for RESTful API access, first, we have to install or register HttpClientModule. Open and edit src/app/app.module.ts then add this import.

import { FormsModule } from '@angular/forms';
import { HttpClientModule } from '@angular/common/http';

Add it to @NgModule imports after BrowserModule.

imports: [
  BrowserModule,
  FormsModule,
  HttpClientModule,
  AppRoutingModule
],

We will use type specifier to get a typed result object. For that, create a new Typescript file src/app/article.ts then add these lines of Typescript codes.

export class Article {
  _id: string;
  title: string;
  author: string;
  description: string;
  content: string;
  updatedAt: Date;
}

Next, generate an Angular 8 service by typing this command.

ng g service api

Next, open and edit src/app/api.service.ts then add these imports.

import { Observable, of, throwError } from 'rxjs';
import { HttpClient, HttpHeaders, HttpErrorResponse } from '@angular/common/http';
import { catchError, tap, map } from 'rxjs/operators';
import { Article } from './article';

Add these constants before the @Injectable.

const httpOptions = {
  headers: new HttpHeaders({'Content-Type': 'application/json'})
};
const apiUrl = "/api/";

Inject HttpClient module to the constructor.

constructor(private http: HttpClient) { }

Add the error handler function.

private handleError(operation = 'operation', result?: T) {
  return (error: any): Observable => {
    console.error(error); // log to console instead
    return of(result as T);
  };
}

Add the functions for all CRUD (create, read, update, delete) RESTful call of article data.

getArticles(): Observable {
  return this.http.get(apiUrl)
    .pipe(
      tap(articles => console.log('fetched Articles')),
      catchError(this.handleError('getArticles', []))
    );
}

getArticle(id: number): Observable {
  const url = `${apiUrl}/${id}`;
  return this.http.get(url).pipe(
    tap(_ => console.log(`fetched Article id=${id}`)),
    catchError(this.handleError(`getArticle id=${id}`))
  );
}

addArticle(article: Article): Observable {
  return this.http.post(apiUrl, article, httpOptions).pipe(
    tap((art: Article) => console.log(`added Article w/ id=${art._id}`)),
    catchError(this.handleError('addArticle'))
  );
}

updateArticle(id: any, article: Article): Observable {
  const url = `${apiUrl}/${id}`;
  return this.http.put(url, article, httpOptions).pipe(
    tap(_ => console.log(`updated Article id=${id}`)),
    catchError(this.handleError('updateArticle'))
  );
}

deleteArticle(id: any): Observable {
  const url = `${apiUrl}/${id}`;
  return this.http.delete(url, httpOptions).pipe(
    tap(_ => console.log(`deleted Article id=${id}`)),
    catchError(this.handleError('deleteArticle'))
  );
}

You can find more details about Angular 8 Observable and RXJS here.

Display List of Articles using Angular 8 Material

We will display the list of articles published from API Service. The data published from the API service read by subscribing as an Article model in the Angular 8 component. For that, open and edit src/app/articles/articles.component.ts then add these imports.

import { ApiService } from '../api.service';

Next, inject the API Service to the constructor.

constructor(private api: ApiService) { }

Next, for the user interface (UI) we will use Angular 8 Material and CDK. There's a CLI for generating a Material component like Table as a component, but we will create or add the Table component from scratch to existing component. Type this command to install Angular 8 Material.

ng add @angular/material

If there are questions like below, just use the default answer.

? Choose a prebuilt theme name, or "custom" for a custom theme: Purple/Green       [ Preview: h
ttps://material.angular.io?theme=purple-green ]
? Set up HammerJS for gesture recognition? Yes
? Set up browser animations for Angular Material? Yes

We will register all required Angular 8 Material components or modules to src/app/app.module.ts. Open and edit that file then add these imports.

import {
  MatInputModule,
  MatPaginatorModule,
  MatProgressSpinnerModule,
  MatSortModule,
  MatTableModule,
  MatIconModule,
  MatButtonModule,
  MatCardModule,
  MatFormFieldModule } from "@angular/material";

Also, modify FormsModule import to add ReactiveFormsModule.

import { FormsModule, ReactiveFormsModule } from '@angular/forms';

Register the above modules to @NgModule imports.

imports: [
  BrowserModule,
  FormsModule,
  HttpClientModule,
  AppRoutingModule,
  ReactiveFormsModule,
  BrowserAnimationsModule,
  MatInputModule,
  MatTableModule,
  MatPaginatorModule,
  MatSortModule,
  MatProgressSpinnerModule,
  MatIconModule,
  MatButtonModule,
  MatCardModule,
  MatFormFieldModule
],

Next, back to src/app/articles/articles.component.ts then add these imports.

import { Article } from '../article';

Declare the variables of Angular 8 Material Table Data Source before the constructor.

displayedColumns: string[] = ['title', 'author'];
data: Article[] = [];
isLoadingResults = true;

Modify the ngOnInit function to get list of articles immediately.

ngOnInit() {
  this.api.getArticles()
    .subscribe((res: any) => {
      this.data = res;
      console.log(this.data);
      this.isLoadingResults = false;
    }, err => {
      console.log(err);
      this.isLoadingResults = false;
    });
}

Next, open and edit src/app/articles/articles.component.html then replace all HTML tags with this Angular Material tags.


  <div class="example-loading-shade"
       *ngIf="isLoadingResults">
    
  
  
    add
  
  
    <table mat-table [dataSource]="data" class="example-table"
           matSort matSortActive="title" matSortDisableClear matSortDirection="asc">

      
      
        Title
        {{row.title}}
      

      
      
        Author
        $ {{row.author}}
      

      
      
    
  

Finally, to make a little UI adjustment, open and edit src/app/articles/articles.component.scss then add this CSS codes.

/* Structure */
.example-container {
  position: relative;
  padding: 5px;
}

.example-table-container {
  position: relative;
  max-height: 400px;
  overflow: auto;
}

table {
  width: 100%;
}

.example-loading-shade {
  position: absolute;
  top: 0;
  left: 0;
  bottom: 56px;
  right: 0;
  background: rgba(0, 0, 0, 0.15);
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: center;
}

.example-rate-limit-reached {
  color: #980000;
  max-width: 360px;
  text-align: center;
}

/* Column Widths */
.mat-column-number,
.mat-column-state {
  max-width: 64px;
}

.mat-column-created {
  max-width: 124px;
}

.mat-flat-button {
  margin: 5px;
}
Show and Delete an Article Details using Angular 8 Material

To show article details after click or tap on the one of a row inside the Angular 8 Material table, open and edit src/app/show-article/show-article.component.ts then add these imports.

import { ActivatedRoute, Router } from '@angular/router';
import { ApiService } from '../api.service';
import { Article } from '../article';

Inject above modules to the constructor.

constructor(private route: ActivatedRoute, private api: ApiService, private router: Router) { }

Declare the variables before the constructor for hold article data that get from the API.

article: Article = { _id: '', title: '', author: '', description: '', content: '', updatedAt: null };
isLoadingResults = true;

Add a function for getting Article data from the API.

getArticleDetails(id: any) {
  this.api.getArticle(id)
    .subscribe((data: any) => {
      this.article = data;
      console.log(this.article);
      this.isLoadingResults = false;
    });
}

Call that function when the component is initiated.

ngOnInit() {
  this.getArticleDetails(this.route.snapshot.params.id);
}

Add this function for delete article.

deleteArticle(id: any) {
  this.isLoadingResults = true;
  this.api.deleteArticle(id)
    .subscribe(res => {
        this.isLoadingResults = false;
        this.router.navigate(['/articles']);
      }, (err) => {
        console.log(err);
        this.isLoadingResults = false;
      }
    );
}

For the view, open and edit src/app/article-detail/article-detail.component.html then replace all HTML tags with this.


  <div class="example-loading-shade"
       *ngIf="isLoadingResults">
    
  
  
    list
  
  
    
      ## {{article.title}}

      {{article.author}} | {{article.updatedAt}}
    
    
      ### {{article.description}}

      
{{article.content}}

    
    
      edit
      delete
    
  

Finally, open and edit src/app/article-detail/article-detail.component.scss then add this lines of CSS codes.

/* Structure */
.example-container {
  position: relative;
  padding: 5px;
}

.example-loading-shade {
  position: absolute;
  top: 0;
  left: 0;
  bottom: 56px;
  right: 0;
  background: rgba(0, 0, 0, 0.15);
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: center;
}

.mat-flat-button {
  margin: 5px;
}
Add an Article using Angular 8 Material

To create a form for adding a Article, open and edit src/app/add-article/add-article.component.ts then add these imports.

import { Router } from '@angular/router';
import { ApiService } from '../api.service';
import { FormControl, FormGroupDirective, FormBuilder, FormGroup, NgForm, Validators } from '@angular/forms';

Inject above modules to the constructor.

constructor(private router: Router, private api: ApiService, private formBuilder: FormBuilder) { }

Declare variables for the Form Group and all of the required fields inside the form before the constructor.

articleForm: FormGroup;
title = '';
author = '';
description = '';
content = '';
isLoadingResults = false;

Add initial validation for each field.

ngOnInit() {
  this.articleForm = this.formBuilder.group({
    'title' : [null, Validators.required],
    'author' : [null, Validators.required],
    'description' : [null, Validators.required],
    'content' : [null, Validators.required]
  });
}

Create a function for submitting or POST article form.

onFormSubmit() {
  this.isLoadingResults = true;
  this.api.addArticle(this.articleForm.value)
    .subscribe((res: any) => {
        const id = res._id;
        this.isLoadingResults = false;
        this.router.navigate(['/show-article', id]);
      }, (err: any) => {
        console.log(err);
        this.isLoadingResults = false;
      });
}

Next, add this import for implementing ErrorStateMatcher.

import { ErrorStateMatcher } from '@angular/material/core';

Create a new class before the main class @Components.

/** Error when invalid control is dirty, touched, or submitted. */
export class MyErrorStateMatcher implements ErrorStateMatcher {
  isErrorState(control: FormControl | null, form: FormGroupDirective | NgForm | null): boolean {
    const isSubmitted = form && form.submitted;
    return !!(control && control.invalid && (control.dirty || control.touched || isSubmitted));
  }
}

Instantiate that MyErrorStateMatcher as a variable in main class.

matcher = new MyErrorStateMatcher();

Next, open and edit src/app/add-article/add-article.component.html then replace all HTML tags with this.


  <div class="example-loading-shade"
       *ngIf="isLoadingResults">
    
  
  
    list
  
  
    
      
        <input matInput placeholder="Title" formControlName="title"
               [errorStateMatcher]="matcher">
        
          Please enter Title
        
      
      
        <input matInput placeholder="Author" formControlName="author"
               [errorStateMatcher]="matcher">
        
          Please enter Author
        
      
      
        <input matInput placeholder="Description" formControlName="description"
               [errorStateMatcher]="matcher">
        
          Please enter Description
        
      
      
        <textarea matInput placeholder="Content" formControlName="content"
               [errorStateMatcher]="matcher">
        
          Please enter Content
        
      
      
        save
      
    
  

Finally, open and edit src/app/article-add/article-add.component.scss then add this CSS codes.

/* Structure */
.example-container {
  position: relative;
  padding: 5px;
}

.example-form {
  min-width: 150px;
  max-width: 500px;
  width: 100%;
}

.example-full-width {
  width: 100%;
}

.example-full-width:nth-last-child(0) {
  margin-bottom: 10px;
}

.button-row {
  margin: 10px 0;
}

.mat-flat-button {
  margin: 5px;
}
Edit an Article using Angular 8 Material

We have put an edit button inside the Article Detail component for call Edit page. Now, open and edit src/app/edit-article/edit-article.component.ts then add these imports.

import { Router, ActivatedRoute } from '@angular/router';
import { ApiService } from '../api.service';
import { FormControl, FormGroupDirective, FormBuilder, FormGroup, NgForm, Validators } from '@angular/forms';

Inject above modules to the constructor.

constructor(private router: Router, private route: ActivatedRoute, private api: ApiService, private formBuilder: FormBuilder) { }

Declare the Form Group variable and all of the required variables for the article form before the constructor.

articleForm: FormGroup;
_id = '';
title = '';
author = '';
description = '';
content = '';
isLoadingResults = false;

Next, add validation for all fields when the component is initiated.

ngOnInit() {
  this.getArticle(this.route.snapshot.params.id);
  this.articleForm = this.formBuilder.group({
    'title' : [null, Validators.required],
    'author' : [null, Validators.required],
    'description' : [null, Validators.required],
    'content' : [null, Validators.required]
  });
}

Create a function for getting article data that filled to each form fields.

getArticle(id: any) {
  this.api.getArticle(id).subscribe((data: any) => {
    this._id = data._id;
    this.articleForm.setValue({
      title: data.title,
      author: data.author,
      description: data.description,
      content: data.content
    });
  });
}

Create a function to update the article changes.

onFormSubmit() {
  this.isLoadingResults = true;
  this.api.updateArticle(this._id, this.articleForm.value)
    .subscribe((res: any) => {
        const id = res._id;
        this.isLoadingResults = false;
        this.router.navigate(['/show-article', id]);
      }, (err: any) => {
        console.log(err);
        this.isLoadingResults = false;
      }
    );
}

Add a function for handling the show article details button.

articleDetails() {
  this.router.navigate(['/show-article', this._id]);
}

Next, add this import for implementing ErrorStateMatcher.

import { ErrorStateMatcher } from '@angular/material/core';

Create a new class before the main class @Components.

/** Error when invalid control is dirty, touched, or submitted. */
export class MyErrorStateMatcher implements ErrorStateMatcher {
  isErrorState(control: FormControl | null, form: FormGroupDirective | NgForm | null): boolean {
    const isSubmitted = form && form.submitted;
    return !!(control && control.invalid && (control.dirty || control.touched || isSubmitted));
  }
}

Instantiate that MyErrorStateMatcher as a variable in main class.

matcher = new MyErrorStateMatcher();

Next, open and edit src/app/edit-article/edit-article.component.html then replace all HTML tags with this.


  <div class="example-loading-shade"
       *ngIf="isLoadingResults">
    
  
  
    info
  
  
    
      
        <input matInput placeholder="Title" formControlName="title"
               [errorStateMatcher]="matcher">
        
          Please enter Title
        
      
      
        <input matInput placeholder="Author" formControlName="author"
               [errorStateMatcher]="matcher">
        
          Please enter Author
        
      
      
        <input matInput placeholder="Description" formControlName="description"
               [errorStateMatcher]="matcher">
        
          Please enter Description
        
      
      
        <textarea matInput placeholder="Content" formControlName="content"
               [errorStateMatcher]="matcher">
        
          Please enter Content
        
      
      
        save
      
    
  

Finally, open and edit src/app/edit-article/edit-article.component.scss then add this lines of CSS codes.

/* Structure */
.example-container {
  position: relative;
  padding: 5px;
}

.example-form {
  min-width: 150px;
  max-width: 500px;
  width: 100%;
}

.example-full-width {
  width: 100%;
}

.example-full-width:nth-last-child(0) {
  margin-bottom: 10px;
}

.button-row {
  margin: 10px 0;
}

.mat-flat-button {
  margin: 5px;
}
Test and Run Angular 8 Universal and MongoDB Server-side Rendering (SSR)

It's time to test and try the performance of Angular 8 Universal and MongoDB Server-side Rendering (SSR). First, run the MongoDB server in the different terminal or command line.

mongod

Next, run the Angular 8 Universal SSR in the current terminal and project folder.

npm run build:ssr && npm run serve:ssr

After build finished for both client and server then open the

application in the browser [http://localhost:4200/](http://localhost:4200/`) and you will see and

feel this Angular 8 application as below.

That it's, the example of Angular 8 Universal and MongoDB Server-side Rendering (SSR). You can get the full source codes from our Github.