Determine Final Destination of a Shortened URL in PHP?

问题

How can I do this in PHP? e.g.

bit.ly/f00b4r ==> http://www.google.com/search?q=cute+kittens

In Java, the solution is this:

You should issue a HEAD request to the url using a HttpWebRequest instance. In the returned HttpWebResponse, check the ResponseUri.

Just make sure the AllowAutoRedirect is set to true on the HttpWebRequest instance (it is true by default). (Thx, casperOne)

And the code is

private static string GetRealUrl(string url)
{
    WebRequest request = WebRequest.Create(url);
    request.Method = WebRequestMethods.Http.Head;
    WebResponse response = request.GetResponse();
    return response.ResponseUri.ToString();
}

(Thx, Fredrik Mork)

But I want to do it in PHP. HOWTO? :)

回答1:

The time to try, you already found the answer.

Still, I would have gone with something like this :

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "http://bit.ly/tqdUj");
curl_setopt($ch, CURLOPT_HEADER, false);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_NOBODY, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_exec($ch);

$url = curl_getinfo($ch, CURLINFO_EFFECTIVE_URL);

curl_close($ch);

var_dump($url);

Some explanations :

the requested URL is the short one
you don't want the headers
you want to make sure the body is not displayed -- probably useless
you do not want the body ; ie, you want a HEAD request, and not GET
you want locations to be followed, of course
once the request has been executed, you want to get the "real" URL that has been fetched

And, here, you get :

string 'http://wordpress.org/extend/plugins/wp-pubsubhubbub/' (length=52)

(Comes from one of the last tweets I saw that contained a short URL)

This should work with any shortening-URL service, independantly of their specific API.

You might also want to tweak some other options, like timeouts ; see curl_setopt for more informations.

回答2:

<?php
$url = 'http://www.example.com';

print_r(get_headers($url));

print_r(get_headers($url, 1));
?>

回答3:

Did you read the bit.ly API? specifically here ?

I can't see the issue. Are you talking about possible redirects ?

回答4:

CREDIT GOES TO http://forums.devshed.com/php-development-5/curl-get-final-url-after-inital-url-redirects-544144.html

function get_web_page( $url ) 
{ 
    $options = array( 
        CURLOPT_RETURNTRANSFER => true,     // return web page 
        CURLOPT_HEADER         => true,    // return headers 
        CURLOPT_FOLLOWLOCATION => true,     // follow redirects 
        CURLOPT_ENCODING       => "",       // handle all encodings 
        CURLOPT_USERAGENT      => "spider", // who am i 
        CURLOPT_AUTOREFERER    => true,     // set referer on redirect 
        CURLOPT_CONNECTTIMEOUT => 120,      // timeout on connect 
        CURLOPT_TIMEOUT        => 120,      // timeout on response 
        CURLOPT_MAXREDIRS      => 10,       // stop after 10 redirects 
    ); 

    $ch      = curl_init( $url ); 
    curl_setopt_array( $ch, $options ); 
    $content = curl_exec( $ch ); 
    $err     = curl_errno( $ch ); 
    $errmsg  = curl_error( $ch ); 
    $header  = curl_getinfo( $ch ); 
    curl_close( $ch ); 

    //$header['errno']   = $err; 
   // $header['errmsg']  = $errmsg; 
    //$header['content'] = $content; 
    print($header[0]); 
    return $header; 
}  
$thisurl = "http://www.example.com/redirectfrom";
$myUrlInfo = get_web_page( $thisurl ); 
echo $myUrlInfo["url"];

回答5:

Here is my solution. I coded it, because none of the above worked correctly.

function get_final_location($url, $index=null) {

    if (is_array($url)) {
        $headers = $url;
    }
    else {
        $headers = get_headers($url, 1)['Location'];    
        if (count($headers) == 0) {
            return $url;
        }
    }

    if (is_null($index)) {
        $to_check   = end($headers);
        $index      = count($headers) - 1;
    }
    else {
        $to_check = $headers[$index];
    }

    if (!filter_var($to_check, FILTER_VALIDATE_URL) === false) {
        if (count($headers) - 1 > $index) {
            $lp = parse_url($headers[$index], PHP_URL_SCHEME) . "://" . parse_url($headers[$index], PHP_URL_HOST) . $headers[$index+1];
        }
        else {
            $lp = $to_check;
        }
    }
    else {
        $index--;
        $lp = landingpage($headers, $index);
    }

    return $lp;

}

来源：https://stackoverflow.com/questions/1319621/determine-final-destination-of-a-shortened-url-in-php

标签

php

url-routing

bit.ly