MediaWiki Ingress Summary

This page documents how requests flow from IIS → Apache → MediaWiki, and what must be configured to keep the wiki stable, predictable, and successor‑friendly.

1. Overview

MediaWiki depends on three critical entry points:

load.php
api.php
rest.php

These must never be rewritten to index.php. If they are rewritten, MediaWiki returns HTML instead of JSON/JS, and the entire layout breaks.

Correct ingress requires:

the correct Apache vhost
the correct rewrite exceptions
the correct PHP-FPM handler
IIS forwarding the original Host header

2. Vhost Selection Logic

Apache chooses a vhost based on the Host header forwarded by IIS.

Requests with Host: localhost hit the default vhost
Requests with Host: mwiki.costasano.club hit the named vhost

If the wrong vhost handles the request, MediaWiki breaks even if the files and PHP are correct.

3. Required vhost configuration

<VirtualHost *:80>
    ServerName mwiki.costasano.club
    DocumentRoot /var/www/mediawiki

    <Directory /var/www/mediawiki>
        AllowOverride All
        Require all granted
    </Directory>

    <FilesMatch \.php$>
        SetHandler "proxy:unix:/run/php-fpm/www.sock|fcgi://localhost/"
    </FilesMatch>
</VirtualHost>

This ensures:

the correct document root
PHP-FPM execution
.htaccess support
correct vhost selection

4. Required rewrite exceptions

These rules prevent MediaWiki’s core entry points from being rewritten to index.php.

# Do NOT rewrite REST entry point
RewriteCond %{REQUEST_URI} ^/rest\.php
RewriteRule .* - [L]

# Do NOT rewrite API entry point
RewriteCond %{REQUEST_URI} ^/api\.php
RewriteRule .* - [L]

# Do NOT rewrite ResourceLoader entry point
RewriteCond %{REQUEST_URI} ^/load\.php
RewriteRule .* - [L]

These rules:

work in vhost context
work in per‑directory context
work with query strings
prevent accidental rewrites
ensure PHP-FPM executes the scripts directly

5. Catch‑all rewrite rule

Everything else can be rewritten to index.php:

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.+)$ /index.php?title=$1 [L,QSA]

This is the standard MediaWiki behavior.

6. How to diagnose layout failures

If the layout breaks, test:

curl -I -H "Host: mwiki.costasano.club" http://localhost/load.php

Expected result:

200 OK
Content-Type: text/javascript

If you get HTML or a 404, the issue is:

wrong vhost
wrong rewrite rule
PHP-FPM not invoked

7. Key Lessons

Everything depends on which vhost handles the request.
Rewrite rules behave differently in vhost vs per‑directory mode.
MediaWiki’s entry points must be explicitly protected.
IIS is not the problem if Apache receives the wrong Host header.
Once vhost + rewrite rules are correct, the wiki becomes stable and predictable.