React file upload: proper and easy way, with NodeJS

React file upload: proper and easy way, with NodeJS

React file upload: proper and easy way, with NodeJS

Aren't you tired of reloading the page every time you upload anything to the site? This is the ultimate answer to react file upload and issues!

Upload page reloads on submitting a file for upload. Are you a newbie to React, and using this generic style to upload files on the web?

There’s a better way to handle uploads in React.

This tutorial is the answer!

Today, it’ll change forever if you go through this tutorial and implement it on your site.

We’ll use Node with React to upload multiple files at once. As we go along, there will be simple client-side validation and finally with uploaded notification can be shown with react-toastify.

Like always, start a react app with create-react-app

Include the bootstrap CDN in index.html.

In contrast to creating the form from scratch, grab this snippet from bootsnipp.

This is our beautiful upload form to work with.

Single React file upload

Let’s start with a simple one, a single file upload.

Capture selected file

Add a change handler in toapp.js pick the file on change.

 

Log event.target.files, it is an array of all stored files. target.files[0]holds the actual file and its details.

onChangeHandler=event=>{

    console.log(event.target.files[0])

}

On saving, create-react-app will instantly refresh the browser.

Store the file in state, and only upload when a user clicks the upload button.

Initially, the selectedFilestate is set to null

constructor(props) {
    super(props);
      this.state = {
        selectedFile: null
      }

  }

To pass the file to the state, setselectedFile state to event.target.files[0].

 onChangeHandler=event=>{
    this.setState({
      selectedFile: event.target.files[0],
      loaded: 0,
    })
  }

Check the state variable again with react-devtools to verify.

Again, create-react-app will instantly refresh the browser and you’ll see the result

Send the files to the server

We have a state of files to upload.

We definitely need an upload button, upload is handled with onClick event handler.

 Upload 

onClickhandle will execute onClickHandler which sends a request to the server. The file from a state is appended as a file to FormData.

onClickHandler = () => {
    const data = new FormData() 
    data.append('file', this.state.selectedFile)
}

We’ll use axios to send AJAX requests.

Install and import axios.

import axios from 'axios';

Create form object and create POST request with axios. It needs endpoint URL and form data.

   axios.post("http://localhost:8000/upload", data, { // receive two parameter endpoint url ,form data 
      })
      .then(res => { // then print response status
        console.log(res.statusText)
      })

Here’s final,onClickhandler with axios POST request. It sends POST request to [http://localhost:8000/upload](http://localhost:8000/upload](http://localhost:8000/upload) "http://localhost:8000/upload](http://localhost:8000/upload)") and gets response.

onClickHandler = () => {
   const data = new FormData()
   data.append('file', this.state.selectedFile)
   axios.post("http://localhost:8000/upload", data, { 
      // receive two    parameter endpoint url ,form data
  })
.then(res => { // then print response status
    console.log(res.statusText)
 })
}

The file type attached is set as a state and needs to be checked. As a result, it’s a binary file.

Axios will send a request to the endpoint with a binary file in Form Data.

To receive the uploaded file, implement a backend server. It’ll receive the file sent from front-end.

Create a simple server with Node.

Create server.js file in the root directory

Install express, multer, and cors.

npm i express multer cors nodemon –save

We’ll use express to create a server, multer to handle files. Cors will be used to enable cross-origin request to this server. Nodemon to monitor the changes and auto-reload, it is optional and you’ll have to restart the server manually in it’s absence.

In,server.js initiate an express instance

var express = require('express');
var app = express();
var multer = require('multer')
var cors = require('cors');

Don’t forget CORS middleware.

app.use(cors())

Create a multer instance and set the destination folder. The code below uses /public folder. You can also assign a new file name upon upload. The code below uses ‘originalfilename’as the file name.

var storage = multer.diskStorage({
      destination: function (req, file, cb) {
      cb(null, 'public')
    },
    filename: function (req, file, cb) {
      cb(null, Date.now() + '-' +file.originalname )
    }
})

Create an upload instance and receive a single file

var upload = multer({ storage: storage }).single('file')

Setup thePOSTroute to upload a file

app.post('/upload',function(req, res) {

    upload(req, res, function (err) {
           if (err instanceof multer.MulterError) {
               return res.status(500).json(err)
           } else if (err) {
               return res.status(500).json(err)
           }
      return res.status(200).send(req.file)

    })

});

Start an upload object and handle an error, check formultererror before general errors. Status OK (200) with metadata is sent back to the client on successful upload.

Make the server listen on port 8000.

app.listen(8000, function() {

    console.log('App running on port 8000');

});

Run nodemon server.js in a terminal to start this server

Upload a file, you will see the file appear in the public directory.

It’s working, congratulations!

Uploading multiple files in React

It’s time for uploading multiple files at once.

Addmultiplein the input field to accept multiple files in the form.



Update andonChangeHandler remove zero indexes, it’s just event.target.files.

onChangeHandler=event=>{
    this.setState({
     selectedFile: event.target.files,
    })
}

Also, update functiononClickHandler to loop through the attached files.

onClickHandler = () => {
   const data = new FormData()
   for(var x = 0; x<this.state.selectedFile.length; x++) {
       data.append('file', this.state.selectedFile[x])
   }

  axios.post("http://localhost:8000/upload", data, { 
      // receive two    parameter endpoint url ,form data
  })

.then(res => { // then print response status
    console.log(res.statusText)
 })

}

In server.js update multer upload instance to accept an array of files.

var upload = multer({ storage: storage }).array('file')

Reload the server and upload multiple files this time.

Is it working for you as well? Let us know if it isn’t.

Handling Validation

Until now, nothing has gone wrong but it doesn’t mean it never will.

Here are situations where this application can crash:

  1. Too many images to upload
  2. Uploading an image with the wrong file extension
  3. Sending an image file that is too large

Client-side validation doesn’t secure the application but can throw errors early to the user and improves the user experience.

#1 There are too many files!

Create a separate function named maxSelectedFile and pass event object.

Use length to check a number of files attached. The code below returns false when a number of files reach 3.

maxSelectFile=(event)=>{
   let files = event.target.files // create file object
       if (files.length > 3) { 
          const msg = 'Only 3 images can be uploaded at a time'
          event.target.value = null // discard selected file
          console.log(msg)
         return false;

     }
   return true;

}

Update onChangeHandler to only set state when the maxSelectFile returns, that is when a number of files are less than 3.

onChangeHandler=event=>{
      var files = event.target.files
      if(this.maxSelectFile(event)){ 
      // if return true allow to setState
         this.setState({
         selectedFile: files
      })
   }
}

The result

#2 Uploading an image with the wrong file extension

Create a checkMimeType function and pass an event object

checkMimeType=(event)=>{
  //getting file object
  let files = event.target.files 
  //define message container
  let err = ''
  // list allow mime type
 const types = ['image/png', 'image/jpeg', 'image/gif']
  // loop access array
  for(var x = 0; x<files.length; x++) {
   // compare file type find doesn't matach
       if (types.every(type => files[x].type !== type)) {
       // create error message and assign to container   
       err += files[x].type+' is not a supported format\n';
     }
   };

 if (err !== '') { // if message not same old that mean has error 
      event.target.value = null // discard selected file
      console.log(err)
       return false; 
  }
 return true;

}

Update onChangeHandler again to include checkMimeType.

onChangeHandler=event=>{
      var files = event.target.files
      if(this.maxSelectFile(event) && this.checkMimeType(event))){ 
      // if return true allow to setState
         this.setState({
         selectedFile: files
      })
   }
}

See the output again.

#3 Uploading an image that is too large

Create another function checkFileSize to check the file size. Define your limiting size and return false if the uploaded file size is greater.

checkFileSize=(event)=>{
     let files = event.target.files
     let size = 15000 
     let err = ""; 
     for(var x = 0; x<files.length; x++) {
     if (files[x].size > size) {
      err += files[x].type+'is too large, please pick a smaller file\n';
    }
  };
  if (err !== '') {
     event.target.value = null
     console.log(err)
     return false
}

return true;

}

Update onChangeHandler again to handle checkFileSize.

onChangeHandler=event=>{
      var files = event.target.files
      if(this.maxSelectFile(event) && this.checkMimeType(event) &&    this.checkMimeType(event)){ 
      // if return true allow to setState
         this.setState({
         selectedFile: files
      })
   }
}

The output thereafter…

That’s all on client-side validation.

Improve UX with progress bar and Toastify

Letting the user know the happening is a lot better than having them stare at the screen until the upload is finished.

To improve the user experience, we can insert progress bar and a popup message

Progress Bar

Use state variable loaded to update real-time values.

Update the state, add loaded: 0

constructor(props) {
   super(props);
     this.state = {
       selectedFile: null,
       loaded:0
   }
}

The loaded state is changed from progressEvent of the POST request.

axios.post("http://localhost:8000/upload", data, {
       onUploadProgress: ProgressEvent => {
         this.setState({
           loaded: (ProgressEvent.loaded / ProgressEvent.total*100),
       })
   },
})

For progress bar, we use reactstrap.

Install and import progress bar from reactstrap

import {Progress} from 'reactstrap';

Add a progress bar after the file picker.



{Math.round(this.state.loaded,2) }%



See the result in action.

Beautiful, ain’t it?

Display the result message with toastify

Install react-toastify and import the following:

import { ToastContainer, toast } from 'react-toastify';
import 'react-toastify/dist/ReactToastify.css';

Put the container somewhere


   


Use toast wherever you want to display a message.

First of all, place upload result

.then(res => { 
    toast.success('upload success')
})
.catch(err => { 
    toast.error('upload fail')
})

See the result.

Also, place validation result.

Update checkMimeType function for validation.

checkMimeType=(event)=>{

    let files = event.target.files
    let err = [] // create empty array
    const types = ['image/png', 'image/jpeg', 'image/gif']
    for(var x = 0; x<files.length; x++) {
        if (types.every(type => files[x].type !== type)) {
        err[x] = files[x].type+' is not a supported format\n';
       // assign message to array
      }
    };
    for(var z = 0; z<err.length; z++) { // loop create toast massage
        event.target.value = null 
        toast.error(err[z])
    }
   return true;
}

You’ve the result

Also, add toast.warn(msg)

Include the checkFileSizeand changes from checkMimeType function

checkFileSize=(event)=>{
  let files = event.target.files
  let size = 2000000 
  let err = []; 
  for(var x = 0; x<files.length; x++) {
  if (files[x].size > size) {
   err[x] = files[x].type+'is too large, please pick a smaller file\n';
 }
};
for(var z = 0; z<err.length; z++) {
 toast.error(err[z])
 event.target.value = null
}
return true;
}

Change err variable to array and loop to create toast message from it.

Our react file upload is working fine, but we can have a lot of improvements like uploading to cloud providers , also use of third-party plugins for other services to improve upload experience are some possible additions.

Before we end of this tutorial, you can contribute to improve and refactor code from this tutorial send your PR to this repository.

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) => {
&nbsp;&nbsp;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 !

Node.js for Beginners - Learn Node.js from Scratch (Step by Step)

Node.js for Beginners - Learn Node.js from Scratch (Step by Step)

Node.js for Beginners - Learn Node.js from Scratch (Step by Step) - Learn the basics of Node.js. This Node.js tutorial will guide you step by step so that you will learn basics and theory of every part. Learn to use Node.js like a professional. You’ll learn: Basic Of Node, Modules, NPM In Node, Event, Email, Uploading File, Advance Of Node.

Node.js for Beginners

Learn Node.js from Scratch (Step by Step)

Welcome to my course "Node.js for Beginners - Learn Node.js from Scratch". This course will guide you step by step so that you will learn basics and theory of every part. This course contain hands on example so that you can understand coding in Node.js better. If you have no previous knowledge or experience in Node.js, you will like that the course begins with Node.js basics. otherwise if you have few experience in programming in Node.js, this course can help you learn some new information . This course contain hands on practical examples without neglecting theory and basics. Learn to use Node.js like a professional. This comprehensive course will allow to work on the real world as an expert!
What you’ll learn:

  • Basic Of Node
  • Modules
  • NPM In Node
  • Event
  • Email
  • Uploading File
  • Advance Of Node

Top 7 Most Popular Node.js Frameworks You Should Know

Top 7 Most Popular Node.js Frameworks You Should Know

Node.js is an open-source, cross-platform, runtime environment that allows developers to run JavaScript outside of a browser. In this post, you'll see top 7 of the most popular Node frameworks at this point in time (ranked from high to low by GitHub stars).

Node.js is an open-source, cross-platform, runtime environment that allows developers to run JavaScript outside of a browser.

One of the main advantages of Node is that it enables developers to use JavaScript on both the front-end and the back-end of an application. This not only makes the source code of any app cleaner and more consistent, but it significantly speeds up app development too, as developers only need to use one language.

Node is fast, scalable, and easy to get started with. Its default package manager is npm, which means it also sports the largest ecosystem of open-source libraries. Node is used by companies such as NASA, Uber, Netflix, and Walmart.

But Node doesn't come alone. It comes with a plethora of frameworks. A Node framework can be pictured as the external scaffolding that you can build your app in. These frameworks are built on top of Node and extend the technology's functionality, mostly by making apps easier to prototype and develop, while also making them faster and more scalable.

Below are 7of the most popular Node frameworks at this point in time (ranked from high to low by GitHub stars).

Express

With over 43,000 GitHub stars, Express is the most popular Node framework. It brands itself as a fast, unopinionated, and minimalist framework. Express acts as middleware: it helps set up and configure routes to send and receive requests between the front-end and the database of an app.

Express provides lightweight, powerful tools for HTTP servers. It's a great framework for single-page apps, websites, hybrids, or public HTTP APIs. It supports over fourteen different template engines, so developers aren't forced into any specific ORM.

Meteor

Meteor is a full-stack JavaScript platform. It allows developers to build real-time web apps, i.e. apps where code changes are pushed to all browsers and devices in real-time. Additionally, servers send data over the wire, instead of HTML. The client renders the data.

The project has over 41,000 GitHub stars and is built to power large projects. Meteor is used by companies such as Mazda, Honeywell, Qualcomm, and IKEA. It has excellent documentation and a strong community behind it.

Koa

Koa is built by the same team that built Express. It uses ES6 methods that allow developers to work without callbacks. Developers also have more control over error-handling. Koa has no middleware within its core, which means that developers have more control over configuration, but which means that traditional Node middleware (e.g. req, res, next) won't work with Koa.

Koa already has over 26,000 GitHub stars. The Express developers built Koa because they wanted a lighter framework that was more expressive and more robust than Express. You can find out more about the differences between Koa and Express here.

Sails

Sails is a real-time, MVC framework for Node that's built on Express. It supports auto-generated REST APIs and comes with an easy WebSocket integration.

The project has over 20,000 stars on GitHub and is compatible with almost all databases (MySQL, MongoDB, PostgreSQL, Redis). It's also compatible with most front-end technologies (Angular, iOS, Android, React, and even Windows Phone).

Nest

Nest has over 15,000 GitHub stars. It uses progressive JavaScript and is built with TypeScript, which means it comes with strong typing. It combines elements of object-oriented programming, functional programming, and functional reactive programming.

Nest is packaged in such a way it serves as a complete development kit for writing enterprise-level apps. The framework uses Express, but is compatible with a wide range of other libraries.

LoopBack

LoopBack is a framework that allows developers to quickly create REST APIs. It has an easy-to-use CLI wizard and allows developers to create models either on their schema or dynamically. It also has a built-in API explorer.

LoopBack has over 12,000 GitHub stars and is used by companies such as GoDaddy, Symantec, and the Bank of America. It's compatible with many REST services and a wide variety of databases (MongoDB, Oracle, MySQL, PostgreSQL).

Hapi

Similar to Express, hapi serves data by intermediating between server-side and client-side. As such, it's can serve as a substitute for Express. Hapi allows developers to focus on writing reusable app logic in a modular and prescriptive fashion.

The project has over 11,000 GitHub stars. It has built-in support for input validation, caching, authentication, and more. Hapi was originally developed to handle all of Walmart's mobile traffic during Black Friday.