Rewrite rules for new plugin

Have you tried something like this?

function foo_bar_rewrite_rules($rules) {
$newrules['foo/bar/(.*)$'] = '/wp-content/plugins/foo/bar.php?uri=$1';
$newrules['foo/baz/(.*)$'] = '/wp-content/plugins/foo/baz.php?uri=$1';
$newrules['foo/$'] = '/wp-content/plugins/foo/main.php';

return array_merge($newrules,$rules);
}

add_filter('rewrite_rules_array','foo_bar_rewrite_rules');

I have tried something similar … Maybe it would be more useful if I worked through and described a case where this definitely does not work.

I have set up a fresh version of WordPress 2.0 on a VirtualHost on my Windows XP laptop. I have dropped and recreated the database to make sure nothing pre-exists the installation. I perform the WP installation, and set up permalinks and category tags (ie the rewrite code and Apache mod_rewrite are definitely working). Then I add the following plugin into the plugins dir:

<?php
/*
Plugin Name: Test Plugin
Version: 1.0
Author: Me
Description: Test Plugin
*/

function foo_rewrite_rules( $rules ) {

$newrules[‘foo/(.*)$’] = ‘/wp-content/plugins/foo.php?uri=$1’;
return array_merge( $newrules, $rules );
}

add_filter( ‘rewrite_rules_array’, ‘foo_rewrite_rules’ );

?>

And created a dummy foo.php beside it with the content:

<h1>Foo</h1>

When I browse to https://test.local/foo/bar.html I see the WordPress index page. If I disable the test plugin and reload, I get a 404 error. So the rewrite rules must be doing _something_ …

This was done with Apache 2.0.55 and MySQL 4.1.6 on Windows XP SP2, and the URLs were viewed with Firefox 1.5.

PS: test.local is aliased to 127.0.0.1 in my hosts file, and Apache is set up to NameVirtualHost 127.0.0.1, so that I can set up and test multiple web sites like this one – I do not imagine that this will be affecting the issue, though.

Ok, I think I have something working in theory. It looks like I have to add threee filters:

1. Rewrite the URL so that it puts the path components into query variables, like so:

add_filter( ‘rewrite_rules_array’, ‘foo_rewrite_rules’ );

function foo_rewrite_rules ( $rewrite ) {
global $wp_rewrite;

// add rewrite tokens
$wp_rewrite->add_rewrite_tag( ‘%fooaction%’, ‘(.+)’, ‘fooaction=’ );

$foo_structure = $wp_rewrite->root . “foo/%fooaction%/”;
$foo_rewrite = $wp_rewrite->generate_rewrite_rules($foo_structure);

return ( $rewrite + $foo_rewrite );
}

2. Tell WP about the fooaction query variable:

add_filter( ‘query_vars’, ‘foo_query_vars’ );

function foo_query_vars ( $vars ) {
$vars[] = “fooaction”;
return $vars;
}

3. Write an is_foo() function so we can tell when we are in the foo ‘application’:

function is_foo () {
global $wp_query;

return $wp_query->get( “fooaction” );
}

4. Finally, override template reidrection to return the relevant foo page templates if we are in the foo application:

add_filter( ‘template_redirect’, ‘foo_redirect’ );

function foo_redirect () {

if ( is_foo() ) {

include( ABSPATH . ‘wp-content/plugins/foo/main.php’ );
exit;
}
}

And that’s it! The main.php file can still use the current theme just by calling the usual template functions, eg:

<?php get_header(); ?>

<div id=”content” class=”narrowcolumn”>

<div class=”post”>
<h2>Foo</h2>
<div class=”entrytext”>
You are in the foo application.
</div>
</div>
</div>

<?php get_sidebar(); ?>

<?php get_footer(); ?>

Also, the rewriting filter does not need to be as complicated as the one above (which I pinched from the Jerome’s Keywords example in the codex, btw). This works too, and also gives you an ‘index page’:

function foo_rewrite_rules ( $rules ) {
global $wp_rewrite;

$foo_rules[‘foo/?$’] = ‘index.php?fooaction=index’;
$foo_rules[‘foo/(.+)?$’] = ‘index.php?fooaction=$matches[1]’;

return ( $rules + $foo_rules );
}

Ohh and, the query vars tip came from Christine Davis of UltimateTagWarrior fame. She writes about it here:

https://www.neato.co.nz/archives/2005/12/05/wordpress-20-rc1-plugins-and-url-rewriting/