43 lines
1.6 KiB
Markdown
43 lines
1.6 KiB
Markdown
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## HTTP
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Node.js has a set of built-in modules which you can use without any further installation. Similarly **HTTP module** contains a set of functions which are required to transfer data over the Hyper Text Transfer Protocol (HTTP).
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The HTTP module can create an HTTP server that listens to server ports and gives a response back to the client.
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In order to to include a module, use the ```require()``` function with the name of the module.
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```javascript
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const http = require('http');
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```
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## Node.js as a Web Server
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The ```createServer()``` method is used to create an HTTP server. 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.
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```javascript
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const http = require('http');
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//create a server object:
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http.createServer((req, res) => {
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res.writeHead(200, {'Content-Type': 'text/plain'});
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res.write('Hello World!'); //write a response to the client
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res.end(); //end the response
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}).listen(8000); //the server object listens on port 8000
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console.log("Server is listening on port no : 8000");
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```
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### Steps for execution :
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* You should have Node.js installed in your computer.
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* Create a file *app.js* and paste the above code.
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* Now open your console in the working directory and execute the command ``` node app.js ```.
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* Open your browser and enter ```http://localhost:8000```
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*Note:* In order to close the server then press ```ctrl + C``` in your console for windows users.
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## Resources
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* [Node.js API](https://nodejs.org/api/http.html#http_http)
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* [W3 Schools](https://www.w3schools.com/nodejs/nodejs_http.asp)
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