step4.md

Step 4 - Request/responses

git checkout step4
git merge step3

At the moment our server only does one thing. When it receives any requests, it sends back the same response - your message.

If you don't believe try typing localhost:3000/chocolate and see what happens

We can make the server send different responses depending on the request it receives.

What is an endpoint?

An endpoint is the part of the url which comes after /, in above case it's /chocolate.

There is a particular method on request object which allows you to see the endpoint, which was put in the url.

Inside your handler function, at the top, add the following:

var endpoint = request.url;
console.log(endpoint);

All requests use one of the HTTP methods. The main ones are: GET, POST, PUT, DELETE.

Check which method was used for your request.

Type inside your handler function at the top :

var method = request.method;
console.log(method);

1. Create your own endpoints and send different responses.

Now, you know how to get the endpoint using request.url. Change your handler function so that it sends one message when requested url is /node and another one when requested url is /girls.

Good luck :) Feel free to discuss it with your team or mentor.

2. Serve index.html

Now you know how to send the message. How do you send a whole html page?

You will see that we have a public folder with index.html and an image.

To be able to send any file from the server we need a core node module called fs - file system. Fs allows you to read and write to and from your hard drive. Before we can send our index.html, our server first needs to read it.

One of the fs methods is fs.readFile('path to the file', callback);. You can read more about fs here.

Let's try it.

Use fs to read in index.html

Require fs module at the top of your file

var http = require('http');
var fs = require('fs');

function handler (request, response) {

  if (endpoint === "/") {
    response.writeHead(200, {"Content-Type": "text/html"});

    fs.readFile(__dirname + '/public/index.html', function(error, file) {
      if (error) {
        console.log(error);
        return;
      }

      response.end(file);
    });
  }
}

__dirname is a Node global object that gives you a path to current working directory. We can use this instead of writing the whole path.

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Commit your changes

git add .
git commit -m 'enter relevant message'
git push origin step4

next step >>>

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Keywords:

• http methods
• fs
• fs.readFile()
• __dirname