Question

strange problem, i’m opening a connection with fsockopen() to a page,
that page has a header(location:xx) to the same page (i’m just refreshing the script), but it’seems that the redirect isn’t working…

obviously everything is working if i’m replicating it with a browser…

some code:

CONNECTION PAGE:

$socketcon = fsockopen($_SERVER['HTTP_HOST'],80,$errorno,$errorstr,10);
if($socketcon) {
    $socketdata = "GET http://www.example.com/test2.php HTTP/1.0\r\nHost: ".$_SERVER['HTTP_HOST']."\r\nConnection: Close\r\n\r\n";
    fwrite($socketcon,$socketdata); 
    fclose($socketcon);
}

CONNECTED PAGE (test2.php):

<?
//other code (working fine)

if($_GET["AAA"]){

     //REDIRECT WORKED !

} else {
     header("location:test2.php?AAA=1");   //same page but with a get param
}
?>

the REDIRECT WORKED part never get executed…

any suggestions ?

EDIT: the connection MUST be asynchronous

Answer 1

Consider Is making asynchronous HTTP requests possible with PHP? which is a similar question.

Using exec()-family functions might be a good bet if you don’t need return values; you can just call curl appended by & and it’ll run in the background.

If you really, truly want to do this in PHP, you can either: spawn a new process (using pcntl_fork()) or handle redirects yourself.

To handle redirects you’ll need to:

1. Determine what your response code is by looking at the first three characters read from the stream. A 200 means sucess, anything in the 300s means partial success.
2. Once you’ve found a 302 (or 307) in the first three characters, search for a location header. This will match the regex /\s*location:\s*(.+)$/m, I believe.
3. Validate that the URL you have from the location field matches your expectations and is trustworthy. It should be an absolute URL, but you’ll need to check it for a safe server, safe port, safe URL and safe parameters. parse_url() may come in handy, but does not check for potential security issues.
4. Open a new connection to the new URL matched above (or, if it’s the same host and you’re using HTTP 1.1 with Keep-Alive, reuse your connection) to send the appropriate data.
5. Deal with any results/clean-up as required.

You can see this is very complex. This will also be recursive. What you’re really talking about doing is writing a rudimentary HTTP parser in PHP. This is not a good idea – use cURL and find some other way to make it asynchronous.