Express.js File Upload

In Express.js, file upload is slightly difficult because of its asynchronous nature and networking approach.

It can be done by using middleware to handle multipart/form data. There are many middleware that can be used like multer, connect, body-parser etc.

Let's take an example to demonstrate file upload in Node.js. Here, we are using the middleware 'multer'.

Create a folder "jtp file upload" having the following files:

uploads: It is an empty folder i.e. created to store the uploaded images.

package: It is JSON file, having the following data:

File: package.json

{
  "name": "file_upload",
  "version": "0.0.1",
  "dependencies": {
    "express": "4.13.3",
    "multer": "1.1.0"
  },
  "devDependencies": {
    "should": "~7.1.0",
    "mocha": "~2.3.3",
    "supertest": "~1.1.0"
  }
}

File: index.html

<html>
  <head>
    <title>File upload in Node.js by trainingtrains</title>
 <script src="../ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
  <script src="../cdnjs.cloudflare.com/ajax/libs/jquery.form/3.51/jquery.form.min.js"></script>
  <script>
  $(document).ready(function() {
     $('#uploadForm').submit(function() {
		 $("#status").empty().text("File is uploading...");

        $(this).ajaxSubmit({

            error: function(xhr) {
		            status('Error: ' + xhr.status);
            },

            success: function(response) {
					console.log(response)
					$("#status").empty().text(response);
            }
	});

	return false;
    });    
});
  </script>
  </head>
  <body>
      <h1>Express.js File Upload: by trainingtrains</h1>
      <form id="uploadForm" enctype="multipart/form-data" action="http://www.trainingtrains.com/uploadtrainingtrains" method="post">
       <input type="file" name="myfile" /><br/><br/>
       <input type="submit" value="Upload Image" name="submit"><br/><br/>
       <span id="status"></span>
      </form>
  </body>

<!-- Mirrored from www.trainingtrains.com/expressjs-file-upload by HTTrack Website Copier/3.x [XR&CO'2014], Tue, 21 Jun 2016 08:24:15 GMT -->
</html>

File: server.js

 
var express	=	require("express");
var multer	=	require('multer');
var app	=	express();
var storage	=	multer.diskStorage({
  destination: function (req, file, callback) {
    callback(null, './uploads');
  },
  filename: function (req, file, callback) {
	callback(null, file.originalname);
  }
});
var upload = multer({ storage : storage}).single('myfile');

app.get('/',function(req,res){
      res.sendFile(__dirname + "/index.html");
});

app.post('/uploadtrainingtrains',function(req,res){
	upload(req,res,function(err) {
		if(err) {
			return res.end("Error uploading file.");
		}
		res.end("File is uploaded successfully!");
	});
});

app.listen(2000,function(){
    console.log("Server is running on port 2000");
});

To install the package.json, execute the following code: