Node.js HTTP Module
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Node.js HTTP Module
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The Built-in HTTP Module
Node.js has a built-in module called HTTP, which allows Node.js to transfer
data over the Hyper Text Transfer Protocol (HTTP).
To include the HTTP module, use therequire() method:
var http = require('http');Node.js as a Web Server
The HTTP module can create an HTTP server that listens to
server ports and gives a response back to
the client.
Use the createServer() method to create an
HTTP server:
Example
var http = require('http');
//create a server object:
http.createServer(function
(req, res) {
res.write('Hello World!'); //write a response to the
client
res.end(); //end the response
}).listen(8080); //the
server object listens on port 8080Run example »
The function passed into the http.createServer()
method, will be executed when someone tries to access the
computer on port 8080.
Save the code above in a file called "demo_http.js", and initiate
the file:
Initiate demo_http.js:
C:UsersYour Name>node demo_http.js
If you have followed the same steps on your computer, you will see the same result as the example: http://localhost:8080
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Add an HTTP Header
If the response from the HTTP server is supposed to be displayed as HTML, you
should include an HTTP header with the correct content type:
Example
var http = require('http');
http.createServer(function
(req, res) {
res.writeHead(200,
{'Content-Type': 'text/html'});
res.write('Hello
World!');
res.end();
}).listen(8080);Run example »
The first argument of the res.writeHead() method is the status code, 200 means
that
all is OK, the second argument is an object containing the response headers.
Read the Query String
The function passed into the http.createServer()
has a req argument that represents the request from the
client, as an object (http.IncomingMessage object).
This object has a property called "url" which holds the
part of the url that comes after the domain name:
demo_http_url.js
var http = require('http');
http.createServer(function
(req, res) {
res.writeHead(200, {'Content-Type': 'text/html'});
res.write(req.url);
res.end();
}).listen(8080);Save the code above in a file called "demo_http_url.js" and
initiate the file:
Initiate demo_http_url.js:
C:UsersYour Name>node demo_http_url.js
If you have followed the same steps on your computer, you should see two
different results when opening these two addresses:
http://localhost:8080/summer
Will produce this result:
/summerRun example »
http://localhost:8080/winter
Will produce this result:
/winterRun example »
Split the Query String
There are built-in modules to easily split the query string into readable
parts, such as the URL module.
Example
Split the query string into readable parts:
var http = require('http');
var url = require('url');
http.createServer(function (req, res) {
res.writeHead(200,
{'Content-Type': 'text/html'});
var q = url.parse(req.url,
true).query;
var txt = q.year + " " +
q.month;
res.end(txt);
}).listen(8080);
Save the code above in a file called "demo_querystring.js" and
initiate the file:
Initiate demo_querystring.js:
C:UsersYour Name>node demo_querystring.js
The address:
http://localhost:8080/?year=2017&month=July
Will produce this result:
2017 JulyRun example »
Read more about the URL module in the Node.js URL
Module chapter.
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