The Built-in URL Module
The URL module splits up a web address into readable parts.To include the URL module, use the
require()
method:
var url = require('url');
url.parse()
method, and it will return a URL object with each part of the address as
properties:Example
Split a web address into readable parts:
var url = require('url');
var adr = 'http://localhost:8080/default.htm?year=2017&month=february';
var q = url.parse(adr, true);
console.log(q.host); //returns 'localhost:8080'
console.log(q.pathname); //returns '/default.htm'console.log(q.search); //returns '?year=2017&month=february'
var qdata = q.query; //returns an object: { year: 2017, month: 'february' }
console.log(qdata.month); //returns 'february'
Node.js File Server
Now we know how to parse the query string, and in the previous chapter we learned how to make Node.js behave as a file server. Let us combine the two, and serve the file requested by the client.Create two html files and save them in the same folder as your node.js files.
summer.html
<!DOCTYPE html>
<html>
<body>
<h1>Summer</h1>
<p>I love
the sun!</p>
</body>
</html>
winter.html
<!DOCTYPE html>
<html>
<body>
<h1>Winter</h1>
<p>I love
the snow!</p>
</body>
</html>
Create a Node.js file that opens the requested file and returns the content to the client. If anything goes wrong, throw a 404 error:
demo_fileserver.js:
Remember to initiate the file:
var http = require('http');
var url = require('url');
var fs = require('fs');
http.createServer(function
(req, res) {
var q = url.parse(req.url, true);
var
filename = "." + q.pathname;
fs.readFile(filename,
function(err, data) {
if (err) {
res.writeHead(404, {'Content-Type': 'text/html'});
return res.end("404 Not Found");
}
res.writeHead(200, {'Content-Type': 'text/html'});
res.write(data);
return res.end();
});
}).listen(8080);
Initiate demo_fileserver.js:
If you have followed the same steps on your computer, you should see two
different results when opening these two addresses:
C:\Users\Your Name>node demo_fileserver.js
http://localhost:8080/summer.html
Will produce this result:
http://localhost:8080/winter.html
Summer
I love the sun!
Will produce this result:
Winter
I love the snow!
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