Node JS HTTP Module
Written By: Avinash Malhotra
Updated on
HTTP Module
http module is a build-in module in node js used to send and receive data over http (hypertext transfer protocol).
http Modules is a build in module in node js. To use http module, use require method.
http Module example
const http=require('http');
HTTP server
To create http server, NodeJS use createServer method of http object and a callback function with request and response. See example
const http=require('http');
const server=http.createServer((req,res)=>{
});
Request and Response
Request and response are two parameters of createServer method's callback function. We are using shortcuts for request and response here.
The request is incoming request stream and the response is outgoing request stream.
Request Properties
| Property | Meaning |
|---|---|
| req.url | requesr url |
| req.method | GET or POST |
| req.headers.host | host name |
Listen Server
To start http server, call the listen method of createServer function with three arguments, i.e. port, ip and callback function. See example below
server running at http://127.0.0.1:8080/
/*server.js*/
const http=require('http');
const server=http.createServer((req,res)=>{
res.write("hello node");
res.end();
});
server.listen(8080);
Run http on custom ip and port
To run node http server on custom ip address and port no, we have to assign a new ip address and port no in above code and then run listen method.
server running at http://127.0.0.1:3000/
/*server.js*/
const http=require('http');
const ip='127.0.0.1';
const port='3000';
const server=http.createServer((req,res)=>{
res.write("hello node");
res.end();
});
server.listen(port,ip,()=>{
console.log(`server running at http://${ip}:${port}/`);
});
Setting Status Code
The default status code of response stream is 200. To set other http status code like, 404, use response.statusCode.
server running at http://127.0.0.1:3000/
/*server.js*/
const http=require('http');
const ip='127.0.0.1';
const port='3000';
const server=http.createServer((req,res)=>{
res.statusCode=200;
res.write("<h1>hello node</h1>");
res.end();
});
server.listen(port,ip,()=>{
console.log(`server running at http://${ip}:${port}/`);
});
404 status
To set 404 status code for page not found, use res.statusCode=404. See example
server running at http://127.0.0.1:3000/
/*server.js*/
const http=require('http');
const ip='127.0.0.1';
const port='3000';
const server=http.createServer((req,res)=>{
res.statusCode=404;
res.write("404, page not found");
res.end();
});
server.listen(port,ip,()=>{
console.log(`server running at http://${ip}:${port}/`);
});
Setting Headers
To set http Headers for response, use response.setHeader function with two arguments, i.e. name and type. The main header name is Content-Type used to tell client what type of data is interpret in body. For example for html file, use res.setHeader('Content-Type','text/html'). See example below.
server running at http://127.0.0.1:3000/
/*server.js*/
const http=require('http');
const ip='127.0.0.1';
const port='3000';
const server=http.createServer((req,res)=>{
res.statusCode=200;
res.setHeader('Content-Type','text/html');
res.write("<p>Hello HTML</p>");
res.end();
});
server.listen(port,ip,()=>{
console.log(`server running at http://${ip}:${port}/`);
});
Popular MIME Type
| Name | MIME Type |
|---|---|
| HTML | text/html |
| CSS | text/css |
| JavaScript | application/javascript |
| JSON | application/json |
| jpeg image | image/jpeg |
| png image | image/png |
response.writeHead
we can also use response.writeHead method instead of response.setHeader to add multiple data of response head like, statusCode, Content-Type and cookies.
server running at http://127.0.0.1:3000/
/*server.js*/
const http=require('http');
const ip='127.0.0.1';
const port='3000';
const server=http.createServer((req,res)=>{
res.writeHead(200,{'Content-Type':'text/html'});
res.write("<p>Hello HTML</p>");
res.end();
});
server.listen(port,ip,()=>{
console.log(`server running at http://${ip}:${port}/`);
});
Server Html Page over http
To serve a html page over http, we have to use fs.readFile method and use res.write method in html page. See example
server running at http://127.0.0.1:3000/
/*server.js*/
const http=require('http');
const fs=require('fs');
const ip='127.0.0.1';
const port='3000';
const server=http.createServer((req,res)=>{
if( (req.method=="GET" && req.url=="/")){
fs.readFile('./src/home.html',(err,data)=>{
if(err){
res.writeHead(404);
res.write(err);
res.end();
}
else{
res.writeHead(200,{'Content-Type':'text/html'});
res.write(data);
res.end();
}
})
}
else{
res.end();
}
});
server.listen(port,ip,()=>{
console.log(`server running at http://${ip}:${port}/`);
});