Getting parts of a URL (Regex)

Question

Given the URL (single line):
http://test.example.com/dir/subdir/file.html

How can I extract the following parts using regular expressions:

1. The Subd

Answer 1

I was trying to solve this in javascript, which should be handled by:

var url = new URL('http://a:b@example.com:890/path/wah@t/foo.js?foo=bar&bingobang=&king=kong@kong.com#foobar/bing/bo@ng?bang');

since (in Chrome, at least) it parses to:

{
  "hash": "#foobar/bing/bo@ng?bang",
  "search": "?foo=bar&bingobang=&king=kong@kong.com",
  "pathname": "/path/wah@t/foo.js",
  "port": "890",
  "hostname": "example.com",
  "host": "example.com:890",
  "password": "b",
  "username": "a",
  "protocol": "http:",
  "origin": "http://example.com:890",
  "href": "http://a:b@example.com:890/path/wah@t/foo.js?foo=bar&bingobang=&king=kong@kong.com#foobar/bing/bo@ng?bang"
}

However, this isn't cross browser (https://developer.mozilla.org/en-US/docs/Web/API/URL), so I cobbled this together to pull the same parts out as above:

^(?:(?:(([^:\/#\?]+:)?(?:(?:\/\/)(?:(?:(?:([^:@\/#\?]+)(?:\:([^:@\/#\?]*))?)@)?(([^:\/#\?\]\[]+|\[[^\/\]@#?]+\])(?:\:([0-9]+))?))?)?)?((?:\/?(?:[^\/\?#]+\/+)*)(?:[^\?#]*)))?(\?[^#]+)?)(#.*)?

Credit for this regex goes to https://gist.github.com/rpflorence who posted this jsperf http://jsperf.com/url-parsing (originally found here: https://gist.github.com/jlong/2428561#comment-310066) who came up with the regex this was originally based on.

The parts are in this order:

var keys = [
    "href",                    // http://user:pass@host.com:81/directory/file.ext?query=1#anchor
    "origin",                  // http://user:pass@host.com:81
    "protocol",                // http:
    "username",                // user
    "password",                // pass
    "host",                    // host.com:81
    "hostname",                // host.com
    "port",                    // 81
    "pathname",                // /directory/file.ext
    "search",                  // ?query=1
    "hash"                     // #anchor
];

There is also a small library which wraps it and provides query params:

https://github.com/sadams/lite-url (also available on bower)

If you have an improvement, please create a pull request with more tests and I will accept and merge with thanks.