Создание сайта на Mongo DB, Express JS, Node JS и Angular

Создание сайта на Mongo DB, Express JS, Node JS и Angular

Видео курс по изучению стека MEAN. В курсе вы научитесь создавать сайты при помощи Node JS, Express JS, Angular JS и баз данных MongoDB. Вы ознакомитесь со всеми моментами разработки и в конце курса выгрузите сайт на удаленный сервер.

Видео курс по изучению стека MEAN. В курсе вы научитесь создавать сайты при помощи Node JS, Express JS, Angular JS и баз данных MongoDB. Вы ознакомитесь со всеми моментами разработки и в конце курса выгрузите сайт на удаленный сервер.

Build a REST API using Node.js, Express.js, Mongoose.js and MongoDB

Build a REST API using Node.js, Express.js, Mongoose.js and MongoDB

Node.js, Express.js, Mongoose.js, and MongoDB is a great combination for building easy and fast REST API. You will see how fast that combination than other existing frameworks because of Node.js is a packaged compilation of Google’s V8 JavaScript engine and it works on non-blocking and event-driven I/O. Express.js is a Javascript web server that has a complete function of web development including REST API.

Node.js, Express.js, Mongoose.js, and MongoDB is a great combination for building easy and fast REST API. You will see how fast that combination than other existing frameworks because of Node.js is a packaged compilation of Google’s V8 JavaScript engine and it works on non-blocking and event-driven I/O. Express.js is a Javascript web server that has a complete function of web development including REST API.

This tutorial divided into several steps:

Step #1. Create Express.js Application and Install Required Modules
Step #2. Add Mongoose.js Module as ORM for MongoDB
Step #3. Create Product Mongoose Model
Step #4. Create Routes for the REST API endpoint
Step #5. Test REST API Endpoints

Source codes here:
https://github.com/didinj/NodeRestApi...

How to Use Express.js, Node.js and MongoDB.js

How to Use Express.js, Node.js and MongoDB.js

In this post, I will show you how to use Express.js, Node.js and MongoDB.js. We will be creating a very simple Node application, that will allow users to input data that they want to store in a MongoDB database. It will also show all items that have been entered into the database.

In this post, I will show you how to use Express.js, Node.js and MongoDB.js. We will be creating a very simple Node application, that will allow users to input data that they want to store in a MongoDB database. It will also show all items that have been entered into the database.

Creating a Node Application

To get started I would recommend creating a new database that will contain our application. For this demo I am creating a directory called node-demo. After creating the directory you will need to change into that directory.

mkdir node-demo
cd node-demo

Once we are in the directory we will need to create an application and we can do this by running the command
npm init

This will ask you a series of questions. Here are the answers I gave to the prompts.

The first step is to create a file that will contain our code for our Node.js server.

touch app.js

In our app.js we are going to add the following code to build a very simple Node.js Application.

var express = require("express");
var app = express();
var port = 3000;
 
app.get("/", (req, res) => {
  res.send("Hello World");
});
 
app.listen(port, () => {
  console.log("Server listening on port " + port);
});

What the code does is require the express.js application. It then creates app by calling express. We define our port to be 3000.

The app.use line will listen to requests from the browser and will return the text “Hello World” back to the browser.

The last line actually starts the server and tells it to listen on port 3000.

Installing Express

Our app.js required the Express.js module. We need to install express in order for this to work properly. Go to your terminal and enter this command.

npm install express --save

This command will install the express module into our package.json. The module is installed as a dependency in our package.json as shown below.

To test our application you can go to the terminal and enter the command

node app.js

Open up a browser and navigate to the url http://localhost:3000

You will see the following in your browser

Creating Website to Save Data to MongoDB Database

Instead of showing the text “Hello World” when people view your application, what we want to do is to show a place for user to save data to the database.

We are going to allow users to enter a first name and a last name that we will be saving in the database.

To do this we will need to create a basic HTML file. In your terminal enter the following command to create an index.html file.

touch index.html

In our index.html file we will be creating an input filed where users can input data that they want to have stored in the database. We will also need a button for users to click on that will add the data to the database.

Here is what our index.html file looks like.

<!DOCTYPE html>
<html>
  <head>
    <title>Intro to Node and MongoDB<title>
  <head>

  <body>
    <h1>Into to Node and MongoDB<&#47;h1>
    <form method="post" action="/addname">
      <label>Enter Your Name<&#47;label><br>
      <input type="text" name="firstName" placeholder="Enter first name..." required>
      <input type="text" name="lastName" placeholder="Enter last name..." required>
      <input type="submit" value="Add Name">
    </form>
  <body>
<html>

If you are familiar with HTML, you will not find anything unusual in our code for our index.html file. We are creating a form where users can input their first name and last name and then click an “Add Name” button.

The form will do a post call to the /addname endpoint. We will be talking about endpoints and post later in this tutorial.

Displaying our Website to Users

We were previously displaying the text “Hello World” to users when they visited our website. Now we want to display our html file that we created. To do this we will need to change the app.use line our our app.js file.

We will be using the sendFile command to show the index.html file. We will need to tell the server exactly where to find the index.html file. We can do that by using a node global call __dirname. The __dirname will provide the current directly where the command was run. We will then append the path to our index.html file.

The app.use lines will need to be changed to
app.use("/", (req, res) => {   res.sendFile(__dirname + "/index.html"); });

Once you have saved your app.js file, we can test it by going to terminal and running node app.js

Open your browser and navigate to “http://localhost:3000”. You will see the following

Connecting to the Database

Now we need to add our database to the application. We will be connecting to a MongoDB database. I am assuming that you already have MongoDB installed and running on your computer.

To connect to the MongoDB database we are going to use a module called Mongoose. We will need to install mongoose module just like we did with express. Go to your terminal and enter the following command.
npm install mongoose --save

This will install the mongoose model and add it as a dependency in our package.json.

Connecting to the Database

Now that we have the mongoose module installed, we need to connect to the database in our app.js file. MongoDB, by default, runs on port 27017. You connect to the database by telling it the location of the database and the name of the database.

In our app.js file after the line for the port and before the app.use line, enter the following two lines to get access to mongoose and to connect to the database. For the database, I am going to use “node-demo”.

var mongoose = require("mongoose"); mongoose.Promise = global.Promise; mongoose.connect("mongodb://localhost:27017/node-demo");

Creating a Database Schema

Once the user enters data in the input field and clicks the add button, we want the contents of the input field to be stored in the database. In order to know the format of the data in the database, we need to have a Schema.

For this tutorial, we will need a very simple Schema that has only two fields. I am going to call the field firstName and lastName. The data stored in both fields will be a String.

After connecting to the database in our app.js we need to define our Schema. Here are the lines you need to add to the app.js.
var nameSchema = new mongoose.Schema({   firstName: String,   lastNameName: String });

Once we have built our Schema, we need to create a model from it. I am going to call my model “DataInput”. Here is the line you will add next to create our mode.
var User = mongoose.model("User", nameSchema);

Creating RESTful API

Now that we have a connection to our database, we need to create the mechanism by which data will be added to the database. This is done through our REST API. We will need to create an endpoint that will be used to send data to our server. Once the server receives this data then it will store the data in the database.

An endpoint is a route that our server will be listening to to get data from the browser. We already have one route that we have created already in the application and that is the route that is listening at the endpoint “/” which is the homepage of our application.

HTTP Verbs in a REST API

The communication between the client(the browser) and the server is done through an HTTP verb. The most common HTTP verbs are
GET, PUT, POST, and DELETE.

The following table explains what each HTTP verb does.

HTTP Verb Operation
GET Read
POST Create
PUT Update
DELETE Delete

As you can see from these verbs, they form the basis of CRUD operations that I talked about previously.

Building a CRUD endpoint

If you remember, the form in our index.html file used a post method to call this endpoint. We will now create this endpoint.

In our previous endpoint we used a “GET” http verb to display the index.html file. We are going to do something very similar but instead of using “GET”, we are going to use “POST”. To get started this is what the framework of our endpoint will look like.

app.post("/addname", (req, res) => {
 
});
Express Middleware

To fill out the contents of our endpoint, we want to store the firstName and lastName entered by the user into the database. The values for firstName and lastName are in the body of the request that we send to the server. We want to capture that data, convert it to JSON and store it into the database.

Express.js version 4 removed all middleware. To parse the data in the body we will need to add middleware into our application to provide this functionality. We will be using the body-parser module. We need to install it, so in your terminal window enter the following command.

npm install body-parser --save

Once it is installed, we will need to require this module and configure it. The configuration will allow us to pass the data for firstName and lastName in the body to the server. It can also convert that data into JSON format. This will be handy because we can take this formatted data and save it directly into our database.

To add the body-parser middleware to our application and configure it, we can add the following lines directly after the line that sets our port.

var bodyParser = require('body-parser');
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
Saving data to database

Mongoose provides a save function that will take a JSON object and store it in the database. Our body-parser middleware, will convert the user’s input into the JSON format for us.

To save the data into the database, we need to create a new instance of our model that we created early. We will pass into this instance the user’s input. Once we have it then we just need to enter the command “save”.

Mongoose will return a promise on a save to the database. A promise is what is returned when the save to the database completes. This save will either finish successfully or it will fail. A promise provides two methods that will handle both of these scenarios.

If this save to the database was successful it will return to the .then segment of the promise. In this case we want to send text back the user to let them know the data was saved to the database.

If it fails it will return to the .catch segment of the promise. In this case, we want to send text back to the user telling them the data was not saved to the database. It is best practice to also change the statusCode that is returned from the default 200 to a 400. A 400 statusCode signifies that the operation failed.

Now putting all of this together here is what our final endpoint will look like.

app.post("/addname", (req, res) => {
  var myData = new User(req.body);
  myData.save()
    .then(item => {
      res.send("item saved to database");
    })
    .catch(err => {
      res.status(400).send("unable to save to database");
    });
});
Testing our code

Save your code. Go to your terminal and enter the command node app.js to start our server. Open up your browser and navigate to the URL “http://localhost:3000”. You will see our index.html file displayed to you.

Make sure you have mongo running.

Enter your first name and last name in the input fields and then click the “Add Name” button. You should get back text that says the name has been saved to the database like below.

Access to Code

The final version of the code is available in my Github repo. To access the code click here. Thank you for reading !

Angular 8 Node & Express JS File Upload

Angular 8 Node & Express JS File Upload

In this Angular 8 and Node.js tutorial, we are going to look at how to upload files on the Node server. To create Angular image upload component, we will be using Angular 8 front-end framework along with ng2-file-upload NPM package; It’s an easy to use Angular directives for uploading the files.

In this Angular 8 and Node.js tutorial, we are going to look at how to upload files on the Node server. To create Angular image upload component, we will be using Angular 8 front-end framework along with ng2-file-upload NPM package; It’s an easy to use Angular directives for uploading the files.

We are also going to take the help of Node.js to create the backend server for Image or File uploading demo. Initially, we’ll set up an Angular 8 web app from scratch using Angular CLI. You must have Node.js and Angular CLI installed in your system.

We’ll create the local server using Node.js and multer middleware. Multer is a node.js middleware for handling multipart/form-data, which is primarily used for uploading files. Once we are done setting up front-end and backend for our File uploading demo then, we’ll understand step by step how to configure file uploading in Angular 8 app using Node server.

Prerequisite

In order to show you Angular 8 File upload demo, you must have Node.js and Angular CLI installed in your system. If not then check out this tutorial: Set up Node JS

Run following command to install Angular CLI:

npm install @angular/cli -g

Install Angular 8 App

Run command to install Angular 8 project:

ng new angular-node-file-upload

# ? Would you like to add Angular routing? No
# ? Which stylesheet format would you like to use? CSS
cd angular-node-file-upload

Show Alert Messages When File Uploaded

We are going to install and configure ngx-toastr an NPM package which helps in showing the alert message when the file is uploaded on the node server.

npm install ngx-toastr --save

The ngx-toastr NPM module requires @angular/animations dependency:

npm install @angular/animations --save

Then, add the ngx-toastr CSS in angular.json file:

"styles": [
    "src/styles.css",
    "node_modules/ngx-toastr/toastr.css"
]

Import BrowserAnimationsModule and ToastrModule in app.module.ts file:

import { BrowserAnimationsModule } from '@angular/platform-browser/animations';
import { ToastrModule } from 'ngx-toastr';
 
@NgModule({
  imports: [
    CommonModule,
    BrowserAnimationsModule, // required animations module
    ToastrModule.forRoot() // ToastrModule added
  ]
})

export class AppModule { }

Install & Configure ng-file-upload Directive

In this step, we’ll Install and configure ng-file-upload library in Angular 8 app. Run command to install ng-file-upload library.

npm install ng2-file-upload

Once the ng2-file-upload directive is installed, then import the FileSelectDirective and FormsModule in app.module.ts. We need FormsModule service so that we can create the file uploading component in Angular.

import { FileSelectDirective } from 'ng2-file-upload';
import { FormsModule } from '@angular/forms';

@NgModule({
  declarations: [
    FileSelectDirective
  ],
  imports: [
    FormsModule
  ]
})

export class AppModule { }

Setting Up Node Backend for File Upload Demo

To upload the file on the server, we need to set up a separate backend. In this tutorial, we will be using Node & Express js to create server locally along with multer, express js, body-parser, and dotenv libraries.

Run command to create backend folder in Angular app’s root directory:

mkdir backend && cd backend

In the next step, create a specific package.json file.

npm init

Run command to install required dependencies:

npm install express cors body-parser multer dotenv --save

In order to get rid from starting the server again and again, install nodemon NPM package. Use –-save-dev along with the npm command to register in the devDependencies array. It will make it available for development purpose only.

npm install nodemon --save-dev

Have a look at final pacakge.json file for file upload demo backend:

{
  "name": "angular-node-file-upload",
  "version": "1.0.0",
  "description": "Angualr 8 file upload demo app",
  "main": "server.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start": "node server.js"
  },
  "author": "Digamber Rawat",
  "license": "ISC",
  "dependencies": {
    "body-parser": "^1.19.0",
    "cors": "^2.8.5",
    "dotenv": "^8.0.0",
    "express": "^4.17.1",
    "multer": "^1.4.1"
  },
  "devDependencies": {
    "nodemon": "^1.19.1"
  }
}

Create a file by the name of server.js inside backend folder:

Configure Server.js

To configure our backend we need to create a server.js file. In this file we’ll keep our backend server’s settings.

touch server.js

Now, paste the following code in backend > server.js file:

const express = require('express'),
  path = require('path'),
  cors = require('cors'),
  multer = require('multer'),
  bodyParser = require('body-parser');

// File upload settings  
const PATH = './uploads';

let storage = multer.diskStorage({
  destination: (req, file, cb) => {
    cb(null, PATH);
  },
  filename: (req, file, cb) => {
    cb(null, file.fieldname + '-' + Date.now())
  }
});

let upload = multer({
  storage: storage
});

// Express settings
const app = express();
app.use(cors());
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
  extended: false
}));

app.get('/api', function (req, res) {
  res.end('File catcher');
});

// POST File
app.post('/api/upload', upload.single('image'), function (req, res) {
  if (!req.file) {
    console.log("No file is available!");
    return res.send({
      success: false
    });

  } else {
    console.log('File is available!');
    return res.send({
      success: true
    })
  }
});

// Create PORT
const PORT = process.env.PORT || 8080;
const server = app.listen(PORT, () => {
  console.log('Connected to port ' + PORT)
})

// Find 404 and hand over to error handler
app.use((req, res, next) => {
  next(createError(404));
});

// error handler
app.use(function (err, req, res, next) {
  console.error(err.message);
  if (!err.statusCode) err.statusCode = 500;
  res.status(err.statusCode).send(err.message);
});

Now, while staying in the backend folder run the below command to start the backend server:

nodemon server.js

If everything goes fine then you’ll get the following output:

[nodemon] 1.19.1
[nodemon] to restart at any time, enter `rs`
[nodemon] watching: *.*
[nodemon] starting `node server.js`
Connected to port 8080

Create Angular 8 File Upload Component

In this last step, we are going to create a file upload component in Angular 8 app using Express js API.

Get into the app.component.ts file and include the following code:

import { Component, OnInit } from '@angular/core';
import { FileUploader } from 'ng2-file-upload/ng2-file-upload';
import { ToastrService } from 'ngx-toastr';

const URL = 'http://localhost:8080/api/upload';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})

export class AppComponent implements OnInit {
  public uploader: FileUploader = new FileUploader({
    url: URL,
    itemAlias: 'image'
  });

  constructor(private toastr: ToastrService) { }

  ngOnInit() {
    this.uploader.onAfterAddingFile = (file) => {
      file.withCredentials = false;
    };
    this.uploader.onCompleteItem = (item: any, status: any) => {
      console.log('Uploaded File Details:', item);
      this.toastr.success('File successfully uploaded!');
    };
  }

}

Go to app.component.html file and add the given below code:

<div class="wrapper">
  <h2>Angular Image Upload Demo</h2>

  <div class="file-upload">
    <input type="file" name="image" ng2FileSelect [uploader]="uploader" accept="image/x-png,image/gif,image/jpeg" />
    <button type="button" (click)="uploader.uploadAll()" [disabled]="!uploader.getNotUploadedItems().length">
      Upload
    </button>
  </div>

</div>

Now, It’s time to start the Angular 8 app to check out the File upload demo in the browser. Run the following command:

ng serve --open

Make sure your NODE server must be running to manage the backend.

When you upload the image from front-end you’ll see your image files are saving inside the backend > uploads folder.

Conclusion

In this Angular 8 tutorial, we barely scratched the surface related to file uploading in a Node application. There are various other methods available on the internet through which you can achieve file uploading task quickly. However, this tutorial is suitable for beginners developers. I hope this tutorial will surely help and you if you liked this tutorial, please consider sharing it with others.