CODEWITHSUNDEEP
phpapachehttpproxyreverse-proxy
Diepie
Diepie

Reputation: 782

Rerouting HTTP request from PHP back to Apache

We are given the task to check URLs for integrity by the parameters on an apache reverse proxy. One of them is a hash that was calculated from 3 others. If the URL seems intact the reverse proxy functionality should kick in. Our problem is that we don't know how to reroute the request from php after checking back to the apache so it would continue/restart processing it.

We tried to start a new request with file_get_contents() but that doesn't handle the redirect well and waits for a timeout.

It would be better not to reimplement a reverse proxy in php but let the apache do this. Our hash checking looks like this:

<?php
    $ss=$_SERVER['QUERY_STRING'];
    parse_str($ss,$qa);
    if (array_key_exists('hash', $qa)&&array_key_exists('id1', $qa)&&array_key_exists('id2', $qa)&&array_key_exists('id3', $qa)) {
        $hstr=$qa['id1'].$qa['id2'].$qa['id3'];
        $hash=hash_hmac('md5',$hstr, '@#$%^&**&^@ key !@^&*&T^%$');
        if ($qa['hash']==$hash) {

and here we should do something so php would pass the request back to apache process queue.

Thanks in advance!

Upvotes: 0

Views: 168

Answers (1)

haka
haka

Reputation: 26

A solution would be the Apache's URL rewrite module (mod_rewrite). That can pass the URL to an external program to rewrite it and in turn do something conditionally. For example:

RewriteEngine on
RewriteMap hash prg:/var/www/html/url.php
RewriteCond ${hash:%{QUERY_STRING}} !^.*hashis=bad$ [nocase]
RewriteRule ^/something/(.*)$ http://proxied.server:1234/$1 [proxy]
RewriteRule ^.*$ http://some.default.page [proxy]

The program should wait for the URLs on the stdin and write the modified URLs on stdout just make sure you put a \n at the end. Find more details in the module's documentation.

Upvotes: 1

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