Retrieving contents of re-directed url | curl vs. contexts - php

Question

I'm using file_get_contents as such
file_get_contents( $url1 ).
However the actual url's contents are coming from $url2.
Here is a specific case:
$url1 = gmail.com
$url2 = mail.google.com
I need a way to grab $url2 progrmatically in PHP or JavaScript.

Answer 1

I believe you can do this by creating a context with:
$context = stream_context_create(array('http' =>
array(
'follow_location' => false
)));
$stream = fopen($url, 'r', false, $context);
$meta = stream_get_meta_data($stream);
The $meta should include (among other things) the status code and the Location header used to hold the redirection url. If $meta indicates a 200, the you can fetch the data with:
$meta = stream_get_contents($stream)
The down side is when you get a 301/302, you have to set up the request again with the url from the Location header. Lather, rinse, repeat.

Answer 2

If your looking to pull the current url, in JS you can use window.location.hostname

Answer 3

I don't get why you would want either PHP or JavaScript. I mean... they are kind of different in approaching the problem.
Assuming you want a server-side PHP solution, there's a comprehensive solution here. Too much code to copy verbatim but:
function follow_redirect($url){
$redirect_url = null;
//they've also coded up an fsockopen alternative if you don't have curl installed
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_HEADER, true);
curl_setopt($ch, CURLOPT_NOBODY, true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$response = curl_exec($ch);
curl_close($ch);
//extract the new url from the header
$pos = strpos($response, "Location: ");
if($pos === false){
return false;//no new url means it's the "final" redirect
} else {
$pos += strlen($header);
$redirect_url = substr($response, $pos, strpos($response, "\r\n", $pos)-$pos);
return $redirect_url;
}
}
//output all the urls until the final redirect
//you could do whatever you want with these
while(($newurl = follow_redirect($url)) !== false){
echo $url, '<br/>';
$url = $newurl;
}