PHP Redirect Function

This is our PHP redirect() function, it has been tested with PHP versions >= 4.2.0. Seen a lot of requests for this on various mailing lists so we thought we'd share.

We've added support for different HTTP/1.1 3XX status codes. Each of the response codes tell the requesting User-Agent how to respond as described below.

In the W3C specification it's stated that the server should also give some content back for the User-Agent to render if it does not obey the redirect. This redirect function will output some pretty HTML if the headers have already been sent following the W3C intentions.

301 Moved Permanently - Forget the old page existed
302 Found - Use the same method (GET/POST) to request the specified page.
303 See Other - Use GET to request the specified page. Use this to redirct after a POST.
307 Temporary Redirect - Good for response to POST.

Usage example

<?php
// Do stuff here before sending headers
redirect('/')
redirect("/my/page")
redirect("http://www.foo.bar/page.htm",303)
redirect("./index.php",307)
?>

The redirect function itself

You may copy and paste this code freely where you need to, please give us credit it if you use it

public static function redirect($uri,$code=302)
{
    // Specific URL
    $location = null;
    if (substr($uri,0,4)=='http') {
        $location = $uri;
    } else {
        $location = self::base(true);
        // Special Trick, // starts at webserver root / starts at app root
        if (substr($uri,0,2) == '//') {
            $location .= '/' . ltrim($uri,'/');
        } elseif (substr($uri,0,1) == '/') {
            $location .= '/' . ltrim($uri,'/');
        }
    }

    // $sn = \$_SERVER['SCRIPT_NAME'];
    // $cp = dirname($sn);
    // $schema = \$_SERVER['SERVER_PORT']=='443'?'https':'http';
    // $host = strlen(\$_SERVER['HTTP_HOST'])?\$_SERVER['HTTP_HOST']:\$_SERVER['SERVER_NAME'];
    // if (substr($to,0,1)=='/') $location = "$schema://$host$to";
    // elseif (substr($to,0,1)=='.') // Relative Path
    // {
    //   $location = "$schema://$host/";
    //   $pu = parse_url($to);
    //   $cd = dirname(\$_SERVER['SCRIPT_FILENAME']).'/';
    //   $np = realpath($cd.\$pu['path']);
    //   $np = str_replace(\$_SERVER['DOCUMENT_ROOT'],'',$np);
    //   $location.= $np;
    //   if ((isset(\$pu['query'])) && (strlen(\$pu['query'])>0)) $location.= '?'.\$pu['query'];
    // }
    // }

    $hs = headers_sent();
    if ($hs === false) {
        switch ($code) {
        case 301:
            // Convert to GET
            header("301 Moved Permanently HTTP/1.1",true,$code);
            break;
        case 302:
            // Conform re-POST
            header("302 Found HTTP/1.1",true,$code);
            break;
        case 303:
            // dont cache, always use GET
            header("303 See Other HTTP/1.1",true,$code);
            break;
        case 304:
            // use cache
            header("304 Not Modified HTTP/1.1",true,$code);
            break;
        case 305:
            header("305 Use Proxy HTTP/1.1",true,$code);
            break;
        case 306:
            header("306 Not Used HTTP/1.1",true,$code);
            break;
        case 307:
            header("307 Temporary Redirect HTTP/1.1",true,$code);
            break;
        }
        header('Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0');
        header("Location: $location");
    }
    // Show the HTML?
    if (($hs==true) || ($code==302) || ($code==303)) {
        // todo: draw some javascript to redirect
        $cover_div_style = 'background-color: #ccc; height: 100%; left: 0px; position: absolute; top: 0px; width: 100%;';
        echo "<div style='$cover_div_style'>\n";
        $link_div_style = 'background-color: #fff; border: 2px solid #f00; left: 0px; margin: 5px; padding: 3px; ';
        $link_div_style.= 'position: absolute; text-align: center; top: 0px; width: 95%; z-index: 99;';
        echo "<div style='$link_div_style'>\n";
        echo "<p>Please See: <a href='$uri'>".htmlspecialchars($location)."</a></p>\n";
        echo "</div>\n</div>\n";
    }
    exit(0);
}

Notes & Comments

thank you boss/vova on 26 Jan 2010

Excellent work. Very helpful./ratfactor on 26 Feb 2010

The redirect function itself

See Also

Notes & Comments

Add Comment or Note