Probably Programming

curl -I http://tinyurl.com/c8f5bz
HTTP/1.1 301 Moved Permanently
X-Powered-By: PHP/5.2.9
Location: http://probablyprogramming.com/2009/04/11/untiny-that-url/
Content-type: text/html
Date: Sun, 12 Apr 2009 01:26:08 GMT
Server: TinyURL/1.6

$ curl -s -I http://tinyurl.com/c8f5bz | grep Location | awk '{print $2}'
http://probablyprogramming.com/2009/04/11/untiny-that-url/

import httplib
import urlparse
 
def untinyurl(tinyurl):
    url = urlparse.urlsplit(tinyurl)
    req = urlparse.urlunsplit(('', '', url.path, url.query, url.fragment))
    con = httplib.HTTPConnection(url.netloc)
    try:
        con.request('HEAD', req)
    except:
        return None
    response = con.getresponse()
    return response.getheader('Location', None)

<?php
 
function untinyurl($tinyurl) 
{
    $url = parse_url($tinyurl);
    $host = $url['host'];
    $port = isset($url['port']) ? $url['port'] : 80;
    $query = isset($url['query']) ? '?' . $url['query'] : '';
    $fragment = isset($url['fragment']) ? '#' . $url['fragment'] : '';
 
    $sock = @fsockopen($host, $port);
    if (!$sock) return $tinyurl;
 
    $url = $url['path'] . $query . $fragment;
    $request = "HEAD {$url} HTTP/1.0\r\nHost: {$host}\r\nConnection: Close\r\n\r\n";
 
    fwrite($sock, $request);
    $response = '';
    while (!feof($sock)) {
        $response .= fgets($sock, 128);
    }
    $lines = explode("\r\n", $response);
    foreach ($lines as $line) {
        if (strpos(strtolower($line), 'location:') === 0) {
            list(, $location) = explode(':', $line, 2);
            return ltrim($location);
        }
    }
    return $tinyurl;
}

require 'net/http'
require 'uri'
def untinyurl(tinyurl)
  Net::HTTP.get_response(URI.parse(tinyurl))['location'] or tinyurl
rescue
  tinyurl
end

-module(untinyurl).
-export([untinyurl/1]).
untinyurl(TinyUrl) ->
    case http:request(head, {TinyUrl, []}, [{autoredirect, false}], []) of
        {ok, {_Status, Headers, _Body}} -> proplists:get_value("location", Headers, TinyUrl);
        _ -> TinyUrl
    end.

13 Responses to “Untiny that url!”

1. jack Says:
   April 12th, 2009 at 4:04 am

   You don’t need grep when you use awk the way it is supposed.

   curl -s -I http://tinyurl.com/c8f5bz | awk ‘/Location:/ {print $2}’

   is enough. You can also use lynx -head -dump $URL instead of curl.

2. pib Says:
   April 12th, 2009 at 4:35 am

   I haven’t used awk that much. I knew there was a way to do that, I just didn’t want to bother looking it up

3. Tim Says:
   April 12th, 2009 at 8:51 am

   Jonathan Rockway talked about this the other day as well.

   http://blog.jrock.us/articles/Unshortening URLs with Modern Perl.pod

   Here is how you might write your untinyurl function in (not so modern) Perl.

   use LWP::UserAgent; sub untinyurl { my $url = shift; my $res = LWP::UserAgent->new->request(HTTP::Request->new(HEAD => $url)); return $res->previous ? $res->previous->header(‘location’) : $url; }

4. Dan Farina Says:
   April 12th, 2009 at 3:29 pm

   Not idiomatic Python. The first line in httplib docs says:

   “This module defines classes which implement the client side of the HTTP and HTTPS protocols. It is normally not used directly — the module urllib uses it to handle URLs that use HTTP and HTTPS.”

   With urllib, the following will suffice:

   import urllib
   
   def untinyurl(tinyurl):
       return urllib.urlopen(tinyurl).geturl()
   

   A sample interaction is as follows:

   >>> untinyurl('http://tinyurl.com/c8f5bz')
   'http://blog.paulbonser.com/2009/04/11/untiny-that-url/'
   

5. pib Says:
   April 12th, 2009 at 4:22 pm

   @Dan Farina

   I know it’s not idiomatic Python, and I even came up with that same shorter solution (with a try: except: to catch invalid URLS), but the problem with that version is that it actually does two HTTP requests. I couldn’t find a way to make it only do the first request.

   If somebody knows how to make urllib or urllib2 not follow redirects, then I will change it. Until then, this is the shortest version I could come up with that didn’t involve doing some crazy stuff with subclassing urllib2.HTTPRedirectHandler

6. skeptomai Says:
   April 12th, 2009 at 5:49 pm

   And a Common Lisp version, using Edi Weitz’s Drakma http client: (require ‘drakma) (lambda (url) (multiple-value-bind (body return headers) (drakma:http-request url :method :head :redirect nil) (or (cdr (assoc :LOCATION headers)) url)))

7. Nathan de Vries Says:
   April 13th, 2009 at 9:21 am

   You can perform a HEAD request using Ruby’s Net::HTTP like this http://gist.github.com/94463

8. Alexander Nyquist Says:
   April 14th, 2009 at 12:26 am

   For the PHP version, you have the get_headers()-function.

9. pib Says:
   April 14th, 2009 at 1:49 am

   @Alexander: That’s a good point. I didn’t even notice that function existed. It seems it just does a GET request, sadly, but it’s still better than having all the code in my version above.

10. Bill Says:
    April 14th, 2009 at 4:46 pm

    Perhaps I’m missing something but how do you propose someone would utilize one of these tools to “untiny” a url in a non-intrusive way; wouldn’t most people continue to just click on the URL even if they risk being Rick Rolled?

    Would going to the command line really be any less a pain in the ass than just clicking on the link and finding out where it goes?

    It seems like a more inline approach is what is needed (a greasemonkey script or something similar) that will show the expanded URL within the browser.

11. pib Says:
    April 14th, 2009 at 6:23 pm

    @Bill: The idea is that people should use these functions in their Twitter clients or apps that pull in tweets for one reason or another. I didn’t really intend that people would run a script in bash just to find out what URL something goes to.

12. Saleh Says:
    April 17th, 2009 at 5:15 pm

    Hi

    You can try http://untiny.com http://untiny.me .. It has been there for a while and supports over 75 tiny services It has about 10 addons as well (based on API http://untiny.com/api ) in Firefox, Mac, Linux … http://untiny.com/extra

    It’s in Arabic in time being, but it will be available in English hopefully after few days.

    You can check the English version while I’m translating it :=) at http://alzaid.ws/labs/untiny-en

    Thanks

13. Sam Johnston Says:
    April 22nd, 2009 at 4:10 am

    G’day,

    Did you know that “rel” is a space separated list, so “alternate shorter” is interpreted as “alternate” and “shorter”. “alternate” refers to the content itself, not the link (its used for e.g. atom, pdf, text versions of the same) and for “shorter”, what’s shorter? the content?

    If you want to avoid any confusion (including the rel=short[_- ]?ur[il] mess) then rel=shortlink is the answer you’re looking for.

    Sam

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