What is the best way in PHP or JS to expand shortened URLs like Bitly, Tinyurl to find the original URL?

I am using the Twitter and Facewbook API to pull posts that potentially contain shortened URLs using bit.ly or TinyURL like services. I need to do a real-time expansion to get the original URL then pull conte开发者_开发知识库nt from that URL into my app.

You can use CURL to expand a short URL.

Try this:

    function traceUrl($url, $hops = 0)
    {
        if ($hops == MAX_URL_HOPS)
        {
            throw new Exception('TOO_MANY_HOPS');
        }

        $ch = curl_init($url);
        curl_setopt($ch, CURLOPT_HEADER, 1);
        curl_setopt($ch, CURLOPT_NOBODY, 1);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
        $r = curl_exec($ch);

        if (preg_match('/Location: (?P<url>.*)/i', $r, $match))
        {
            return traceUrl($match['url'], $hops + 1);
        }

        return rtrim($url);
    }

You can use this function as so traceUrl('http://bit.ly/example'). This function is recursive in the sense that it will even find short urls that are shortened (if it ever happens). Make sure you set the MAX_URL_HOPS constant. I use define('MAX_URL_HOPS', 5);.

• Christian

You can just use PHP and CURL to connect to the URL and get back the Location parameter:

Here is what comes back -

> $ curl -I http://bit.ly/2V6CFi
> HTTP/1.1 301 Moved Server:
> nginx/0.7.67 Date: Tue, 21 Dec 2010
> 01:58:47 GMT Content-Type: text/html;
> charset=utf-8 Connection: keep-alive
> Set-Cookie:
> _bit=4d1009d7-00298-02f7f-c6ac8fa8;domain=.bit.ly;expires=Sat
> Jun 18 21:58:47 2011;path=/; HttpOnly
> Cache-control: private; max-age=90
> Location: http://www.google.com/
> MIME-Version: 1.0

Content-Length: 284

So you can look for the Location parameter in the header to see where the page page actually goes.

With nodejs you can use the module request.

var request = require('request');
var shortUrl = 'the url that is shortened'
request({method: 'HEAD', url: shortUrl, followAllRedirects: true}, 
  function(err, response, body){
     console.log(response.request.href);
  })

I found a php library that does just that, it can be useful. Check it out: https://launchpad.net/longurl