Steps to Install the express module
Step 1: Run the following commands to initialize the project and create an index file & env file. (Make sure you have node and npm installed)
npm init -y
Step 2: Installing required packages
npm install express
Folder Structure:
The updated dependencies in package.json file will look like:
"dependencies": {
"express": "^4.18.2",
}
Example: Below is the example of the expressjs res.sendFile() Function
Javascript
const express = require( 'express' ); const app = express(); const path = require( 'path' ); const PORT = 3000; // Without middleware app.get( '/' , function (req, res) { const options = { root: path.join(__dirname) }; const fileName = 'Hello.txt' ; res.sendFile(fileName, options, function (err) { if (err) { console.error( 'Error sending file:' , err); } else { console.log( 'Sent:' , fileName); } }); }); app.listen(PORT, function (err) { if (err) console.error(err); console.log( "Server listening on PORT" , PORT); }); |
Now, create a .txt file like here we have created Hello.txt in the root directory of the project with the following text:
Greetings from w3wiki
Steps to run the program:
node index.js
Output:
Server listening on PORT 3000
Console Output: Now open the browser and go to http://localhost:3000/, now check your console and you will see the following output:
Server listening on PORT 3000
Sent: Hello.txt
Express.js res.sendFile() Function
The res.sendFile() function transfers the file at the given path and it sets the Content-Type response HTTP header field based on the filename extension.
Syntax:
res.sendFile(path [, options] [, fn])
Parameter: The path parameter describes the path and the options parameter contains various properties like maxAge, root, etc and fn is the callback function.
Returns: It returns an Object.