Javascript: Splitting a URL into parts using Regex
Sep 6, 2014 •
javaScript
How to split a URL into different parts in JS by using regex
JavaScript (js) is a lightweight, interpreted, object-oriented language with first-class functions, most known as the scripting language for Web pages. Most of the web application developers, designers etc.. use js on a daily basis. Recently I got selected for Google Summer of code 2014, and a part of my project was related to JavaScript where I had to make use of JavaScript for splitting a URL into corresponding parts. When I googled this, I came across many tutorials but later on I set down to write a function making use of the powerful JavaScript Regex (thanks to my friend, Arjun, who helped me in writing this). Here is the code that I wrote:
function subDomain(url) {
url = url.replace(new RegExp(/^s+/), "");
url = url.replace(new RegExp(/s+$/), "");
url = url.replace(new RegExp(/\/g), "/");
url = url.replace(new RegExp(/^http://|^https://|^ftp:///i), "");
url = url.replace(new RegExp(/^www./i), "");
url = url.replace(new RegExp(//(.*)/), "");
if (url.match(new RegExp(/.[a-z]{2,3}.[a-z]{2}$/i))) {
url = url.replace(new RegExp(/.[a-z]{2,3}.[a-z]{2}$/i), "");
} else if (url.match(new RegExp(/.[a-z]{2,4}$/i))) {
url = url.replace(new RegExp(/.[a-z]{2,4}$/i), "");
}
var subDomain = (url.match(new RegExp(/./g))) ? true : false;
return (subDomain);
}
function parseUrl(url) {
var parser = document.createElement('a');
parser.href = url;
var datas = [parser.hostname, parser.port, parser.pathname];
return (datas);
}
function printer(test_var) {
var k = "";
k = test_var.toString();
var k1 = addhttp(k);
q = k1[0];
scheme = k1[2];
k = k1[1];
k = parseUrl(k);
return k;
}
function addhttp(url) {
var k3 = ""
if (url.match(/http:///)) {
url = url.substring(7);
k3 = "http://"
}
if (url.match(/https:///)) {
url = url.substring(8);
k3 = "https://"
}
var k = "";
k = url;
if (url.match(/^www./)) {
url = url.substring(4);
}
if (!/^(f|ht)tps?:///i.test(url)) {
url = "http://" + url;
}
var k2 = [k, url, k3]
return k2;
}
//var q = 'https://demo.testfire.net:1234/hey'
//var output = document.getElementById('output');
var temp = "";
var hosts = "";
var port = "";
var scheme = "";
var path = "";
var sub = "";
var datas = printer(q);
sub = datas[0];
port = datas[1];
path = datas[2];
if (!subDomain(sub)) {
hosts = sub;
} else {
hosts = sub.split(".")[1] + "." + sub.split(".")[2];
};
if (!port) {
port = 80;
}
if (!scheme) {
scheme = 'http://';
}
One obvious question that comes to everyone’s mind is that, what the hell does this code do ?. I can explain that. Even though this code looks very huge, its functionality is very simple. Here I’m assuming that you have the URL to split it in a variable named “q”. If so, the URL is passed as an argument to the function printer and the splitting occurs. After the splitting, 5 new JavaScript variables are created namely scheme, host, port, path **and **sub.
For example, consider that the URL saved in the variable q is “http:/security.securethelock.com:443/hey”. After the splitting, the 5 new variables will be created with the following values in it:
scheme: http://
host: securethelock.com
port: 443
path: hey
sub: security.securethelock.com
If port is not specified, the default value, 80, will be stored. If q is a main domain (and not a subdomain) like “http://www.securethelock.com”, sub = host = securethelock.com . If path is not specified, the corresponding variable will be empty.
Anirudh Anand
Head of Product Security & DevSecOps at @CRED_club | Application Security ♥ | CTF lover - @teambi0s | Security Trainer - @7asecurity | certs - eWDP, OSCP, OSWE
