Node.JS

File Upload

The following sections describe how to handle file uploads on your server using Node.JS as a server-side language. For information on the upload workflow refer to the file upload documentation.

Dependencies

The node.JS file upload example requires the following dependencies:

Using npm you need package.json
Using bower you need bower.json

Make sure that you run npm install, or if you are using bower run bower install

Frontend

Setting up the index page.

On the head section include the Editor style.

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">

<link href="https://cdn.jsdelivr.net/npm/froala-editor@latest/css/froala_editor.pkgd.min.css" rel="stylesheet" type="text/css" />
</head>

On the body section include the Editor JS files and define the area for the editor.

<body>  
<script type="text/javascript" src="https://cdn.jsdelivr.net/npm/froala-editor@latest/js/froala_editor.pkgd.min.js"></script>

<div class="sample">
<h2>File upload example.</h2>
<form>
<textarea id="edit" name="content"></textarea>
</form>
</div>

Initialize the editor and set the file upload URL

<script>
new FroalaEditor('#edit', {
// Set the file upload URL.
fileUploadURL: '/UploadFiles',

fileUploadParams: {
id: 'my_editor'
}
})
</script>
</body>
</html>

The full code should look like this:

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<link href="https://cdn.jsdelivr.net/npm/froala-editor@latest/css/froala_editor.pkgd.min.css" rel="stylesheet" type="text/css" />
</head>

<body>
<script type="text/javascript" src="https://cdn.jsdelivr.net/npm/froala-editor@latest/js/froala_editor.pkgd.min.js"></script>

<div class="sample">
<h2>File upload example.</h2>
<form>
<textarea id="edit" name="content"></textarea>
</form>
</div>


<script>
new FroalaEditor('#edit', {

fileUploadURL: '/UploadFiles',

fileUploadParams: {
id: 'my_editor'
}
})
</script>
</body>
</html>

Backend

server.js handles the server part for Node.JS

server.js handles both image and file upload

// Include required libs
var express = require("express");
var app = express();
var bodyParser = require("body-parser")
var path = require("path");
var fs = require("fs");
var upload_file = require("./file_upload.js");
var upload_image = require("./image_upload.js");

app.use(express.static(__dirname + "/"));
app.use(bodyParser.urlencoded({ extended: false }));

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


// File POST handler.
app.post("/file_upload", function (req, res) {
upload_file(req, function(err, data) {

if (err) {
return res.status(404).end(JSON.stringify(err));
}

res.send(data);
});
});

// Image POST handler.
app.post("/image_upload", function (req, res) {
upload_image(req, function(err, data) {

if (err) {
return res.status(404).end(JSON.stringify(err));
}

res.send(data);
});
});


// Create folder for uploading files.
var filesDir = path.join(path.dirname(require.main.filename), "uploads");
if (!fs.existsSync(filesDir)){
fs.mkdirSync(filesDir);
}

// Init server.
app.listen(3000, function () {
console.log("Example app listening on port 3000!");
});

file_upload.js handles the upload part. It has basic file format validations that can be easily extended.

The uploads directory must be set to a valid location before making uploads. The path can be any folder that is accessible and writable.

If the uploaded file passes the validation step, the server responds with a JSON object containing a link to the uploaded file.

E.g.: {"link":"http://server_address/uploads/name_of_file"}

var Busboy = require("busboy");
var path = require("path");
var fs = require("fs");
var sha1 = require("sha1");

// Gets a filename extension.
function getExtension(filename) {
return filename.split(".").pop();
}

// Test if a file is valid based on its extension and mime type.
function isFileValid(filename, mimetype) {
var allowedExts = ["txt", "pdf", "doc"];
var allowedMimeTypes = ["text/plain", "application/msword", "application/x-pdf", "application/pdf"];

// Get file extension.
var extension = getExtension(filename);

return allowedExts.indexOf(extension.toLowerCase()) != -1  &&
allowedMimeTypes.indexOf(mimetype) != -1;
}

function upload (req, callback) {
// The route on which the file is saved.
var fileRoute = "/uploads/";

// Server side file path on which the file is saved.
var saveToPath = null;

// Flag to tell if a stream had an error.
var hadStreamError = null;

// Used for sending response.
var link = null;

// Stream error handler.
function handleStreamError(error) {
// Do not enter twice in here.
if (hadStreamError) {
return;
}

hadStreamError = error;

// Cleanup: delete the saved path.
if (saveToPath) {
return fs.unlink(saveToPath, function (err) {
return callback(error);
});
}

return callback(error);
}

// Instantiate Busboy.
try {
var busboy = new Busboy({ headers: req.headers });
} catch(e) {
return callback(e);
}

// Handle file arrival.
busboy.on("file", function(fieldname, file, filename, encoding, mimetype) {
// Check fieldname:
if ("file" != fieldname) {
// Stop receiving from this stream.
file.resume();

return callback("Fieldname is not correct. It must be "file".");
}

// Generate link.
var randomName = sha1(new Date().getTime()) + "." + getExtension(filename);
link = fileRoute + randomName;

// Generate path where the file will be saved.
var appDir = path.dirname(require.main.filename);
saveToPath = path.join(appDir, link);

// Pipe reader stream (file from client) into writer stream (file from disk).
file.on("error", handleStreamError);

// Create stream writer to save to file to disk.
var diskWriterStream = fs.createWriteStream(saveToPath);
diskWriterStream.on("error", handleStreamError);

// Validate file after it is successfully saved to disk.
diskWriterStream.on("finish", function() {
// Check if file is valid
var status = isFileValid(saveToPath, mimetype);

if (!status) {
return handleStreamError("File does not meet the validation.");
}

return callback(null, {link: link});
});

// Save file to disk.
file.pipe(diskWriterStream);
});

// Handle file upload termination.
busboy.on("error", handleStreamError);
req.on("error", handleStreamError);

// Pipe reader stream into writer stream.
return req.pipe(busboy);
}

module.exports = upload;

Additional Resources

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