Purge function

From wikidev.net

This is called after editing a page, then the edited page is returned. If it's a new page or if a page is deleted a deferred call then purges all pages linking to it.

Note: this page might be out of date, current version from cvs at the end of http://cvs.sourceforge.net/viewcvs.py/wikipedia/phase3/includes/GlobalFunctions.php?view=markup.

/* Purges a list of Squids defined in $wgSquidServers.
$urlArr should contain the full URLs to purge as values 
(example: $urlArr[] = 'http://my.host/something')
XXX report broken Squids per mail or log */

function wfPurgeSquidServers ($urlArr) {
        global  $wgSquidServers;
        $maxsocketspersquid = 8; //  socket cap per Squid
        $urlspersocket = 400; // 400 seems to be a good tradeoff, opening a socket takes a while
        $firsturl = $urlArr[0];
        unset($urlArr[0]);
        $urlArr = array_values($urlArr);
        $sockspersq =  max(ceil(count($urlArr) / $urlspersocket ),1);
        if ($sockspersq == 1) {
                /* the most common case */
                $urlspersocket = count($urlArr);
        } else if ($sockspersq > $maxsocketspersquid ) {
                $urlspersocket = ceil(count($urlArr) / $maxsocketspersquid);
                $sockspersq = $maxsocketspersquid;
        }
        $totalsockets = count($wgSquidServers) * $sockspersq;
        $sockets = Array();

        /* this sets up the sockets and tests the first socket for each server. */
        for ($ss=0;$ss < count($wgSquidServers);$ss++) {
                $failed = false;
                $so = 0;
                while ($so < $sockspersq && !$failed) {
                        if ($so == 0) {
                                /* first socket for this server, do the tests */
                                list($server, $port) = explode(':', $wgSquidServers[$ss]);
                                if(!isset($port)) $port = 80;
                                $socket = @fsockopen($server, $port, $error, $errstr, 3);
                                if (!$socket) {
                                        $failed = true;
                                        $totalsockets -= $sockspersq;
                                } else {
                                        @fputs($socket,"PURGE " . $firsturl . " HTTP/1.0\r\n".
                                        "Connection: Keep-Alive\r\n\r\n");
                                        $res = @fread($socket,512);
                                        /* Squid only returns http headers with 200 or 404 status, 
                                        if there's more returned something's wrong */
                                        if (strlen($res) > 250) {
                                                fclose($socket);
                                                $failed = true;
                                                $totalsockets -= $sockspersq;
                                        } else {
                                                @stream_set_blocking($socket,false);
                                                $sockets[] = $socket;
                                        }
                                } 
                        } else {
                                /* open the remaining sockets for this server */
                                list($server, $port) = explode(':', $wgSquidServers[$ss]);
                                if(!isset($port)) $port = 80;
                                $sockets[] = @fsockopen($server, $port, $error, $errstr, 2);
                                @stream_set_blocking($sockets[$s],false);
                        }
                        $so++;
                }
        }

        if ($urlspersocket > 0) {
                /* now do the heavy lifting. The fread() relies on Squid returning only the headers */
                for ($r=0;$r < $urlspersocket;$r++) {
                        for ($s=0;$s < $totalsockets;$s++) {
                                if($r != 0) {
                                        $res = '';
                                        $esc = 0;
                                        while (strlen($res) < 100 && $esc < 200  ) {
                                                $res .= @fread($sockets[$s],512);
                                                $esc++;
                                                usleep(20);
                                        }
                                }
                                $urindex = $r + $urlspersocket * ($s - $sockspersq * floor($s / $sockspersq));
                                @fputs($sockets[$s],"PURGE " . $urlArr[$urindex] . " HTTP/1.0\r\n".
                                "Connection: Keep-Alive\r\n\r\n");
                        }
                }
        }

        foreach ($sockets as $socket) {
                $res = '';
                $esc = 0;
                while (strlen($res) < 100 && $esc < 200  ) {
                        $res .= @fread($socket,1024);
                        $esc++;
                        usleep(20);
                }

                @fclose($socket);
        }
        return;
}