Ticket #8964: trac-8964-demo.php

<?php
/*
Plugin Name: Plugin Header Test
Plugin URI: http://core.trac.wordpress.org/ticket/8964
Description: Test plugin for the "Custom Header" functionality introduced in <a href="http://core.trac.wordpress.org/ticket/8964">WP Trac ticket 8964</a>.  It outputs headers for itself to the PHP log.  See plugin source for notes.
Author: Stephen Rider
Author URI: http://striderweb.com/nerdaphernalie
Version: 0.1
Demo Header: Hello World
*/

// NOTE: Yes, we could add two headers in one function.  Using separate hooked functions demonstrates that two plugins separately adding new headers will work.

function header_demo( $extra_headers ) {
        $extra_headers[] = 'Demo Header';
        return $extra_headers;
}
add_filter( 'plugin_headers', 'header_demo' );

function header_demo2( $extra_headers ) {
        $extra_headers[] = 'Another Demo Header';
        return $extra_headers;
}
add_filter( 'plugin_headers', 'header_demo2' );

// This demonstrated that a person can NOT mess up existing headers
function header_demo_malicious_attempt( $extra_headers ) {
        // this adds new "foo" and "bar" headers, but doesn't affect the existing "Plugin URI" header
        $extra_headers['Plugin URI'] = 'foo';
        $extra_headers['PluginURI'] = 'bar';

        // this does nothing
        $extra_headers['fnord'] = 'Name';
        
        return $extra_headers;
}
add_filter( 'plugin_headers', 'header_demo_malicious_attempt' );

// echo to the PHP log
function log_headers_demo() {
        $plugin_data = get_plugin_data( __FILE__ );
        error_log( 'Plugin Header Test plugin output:' );
        error_log( print_r( $plugin_data, true ) );
}
add_action( 'admin_init', 'log_headers_demo' );

?>