WP 404 Auto Redirect to Similar Post

Advanced Usage: If you don’t know how to use filters & actions, please read the official WordPress Plugin API.

// Create a Group with only 3 Default Engines, and set a custom fire sequence
add_action('wp404arsp/search/init', 'my_404_group');
function my_404_group($query){

    wp404arsp_register_group(array(

        // Set Group Name
        'name' => 'My Group',

        // Set Group Slug
        'slug' => 'my_group',

        // Set Engines & the fire sequence
        'engines' => array(
            'default_post',     // Add Default: Search Post Engine
            'default_fix_url',  // Add Default: Fix URL Engine
            'default_direct',   // Add Default: Default: Direct Match Engine
        )

    ));

}

// Trigger the Custom Group: 'My Group' when the 404 Page URL starts with '/product/xxxx/'
add_filter('wp404arsp/search/group', 'my_404_group_trigger', 10, 2);
function my_404_group_trigger($group, $query){

    // Developers: Print $query array for more request context

    // Our condition: 404 Page URL starts with '/product/xxxx/'
    if(preg_match('#/product/(.+?)/?$#i', $query['request']['url'])){
        $group = 'my_group'; // My Group Slug
    }

    // Always return Group
    return $group;

}

Advanced Usage: If you don’t know how to use filters & actions, please read the official WordPress Plugin API.

// Create a Custom Engine
add_action('wp404arsp/search/init', 'my_404_group_engine');
function my_404_group_engine($query){

    wp404arsp_register_engine(array(

        // Set Engine Name
        'name' => 'My Engine',

        // Set Engine Slug
        'slug' => 'my_engine',

        // Set Engine Weight (Score = Keyword_Found * Weight)
        'weight' => 100,

        // Set Primary Option (true|false). If Primary is true, then stop fire sequence if the score > 0.
        'primary' => true

    ));

    // Use the engine in a new Group called 'My Group'
    wp404arsp_register_group(array(

        // Set Group Name
        'name' => 'My Group',

        // Set Group Slug
        'slug' => 'my_group',

        // Set Engines & the fire sequence
        'engines' => array(
            'my_engine', // Add My Engine
        )

    ));

}

// Trigger the Custom Group: 'My Group' when the 404 Page URL starts with '/product/xxxx/'
add_filter('wp404arsp/search/group', 'my_404_group_trigger', 10, 2);
function my_404_group_trigger($group, $query){

    // Developers: Print $query array for more request context

    // Our condition: 404 Page URL starts with '/product/xxxx/'
    if(preg_match('#/product/(.+?)/?$#i', $query['request']['url'])){
        $group = 'my_group'; // My Group Slug
    }

    // Always return Group
    return $group;

}

// Define a Custom Engine Logic
add_filter('wp404arsp/search/engine/my_engine', 'my_404_engine_definition', 10, 3);
function my_404_engine_definition($result, $query, $group){

    // Developers: Print $query array for more request context

    // You have access to $query & the current $group as a context for the engine logic
    // In this example 'My Engine' is the only engine in 'My Group'
    // 'My Group' is triggered when the 404 Page URL starts with '/product/xxxx/'

    // What we want: Search for a similar post inside a specific Post Type: 'project'

    // Grab all Keywords in the URL
    $keywords = explode('-', $query['request']['keywords']['all']);

    // Run Search
    $search = wp404arsp_search(array(
        'keywords'  => $keywords,   // Add keywords
        'mode'      => 'post',      // Search for Post
        'post_type' => 'project',   // inside Post Type: 'project'
    ), $query);

    // Found something!
    if($search['score'] > 0){

        // Return result
        return array(
            'score' => $search['score'],
            'url'   => get_permalink($search['post_id']),
            'why'   => "This engine is Awesome! We found a similar Product inside the Post Type <strong>project</strong>!"
        );

    }

    // Nothing found :(
    else{

        return "Mehh... No similar Product found inside the Post Type <strong>project</strong>.";

    }

}

Advanced Usage: If you don’t know how to use filters & actions, please read the official WordPress Plugin API.

add_action('wp404arsp/search/init', 'my_404_manipulate_groups_and_engines');
function my_404_manipulate_groups_and_engines($query){

    // Move the default engine 'Direct Match' at the end of the 'Default Group' fire Sequence
    wp404arsp_reorder_group_engines(array(

        // Target Group Slug
        'group' => 'default',

        // Target Engine Slug
        'engine' => 'default_direct',

        // Set new Position in fire sequence. (In this example: 4 instead of 2).
        'order' => 4

    ));

    // Register new Engines & Fire Sequence for the existing Group 'My Group'
    wp404arsp_register_group_engines(array(

        // Target Group Slug
        'group' => 'my_group',

        // New Engines & Fire Sequence
        'engines' => array(
            'my_engine',    // Add Custom: My Engine
            'default_post'  // Add Default: Search Post Engine
        )

    ));

    // Deregister an existing Engine.
    // The engine will be removed from any Groups which use it. The engine won't be registered anymore.

    // Target specific Engine Slug
    wp404arsp_deregister_engine('my_another_engine');

}

Advanced Usage: If you don’t know how to use filters & actions, please read the official WordPress Plugin API.

// Always trigger the Custom Group 'My Group' instead of the Default Group
add_filter('wp404arsp/search/group', 'my_404_group_trigger_forever', 10, 2);
function my_404_group_trigger_forever($group, $query){

    // Developers: Print $query array for more request context

    // Always return 'My Group'
    return 'my_group';

}

Advanced Usage: If you don’t know how to use filters & actions, please read the official WordPress Plugin API.

// Do not load the plugin if the 404 URL starts with '/calendar/xxxx/'
add_filter('wp404arsp/init', 'my_404_no_init', 10, 2);
function my_404_no_init($init, $query){

    // Developers: Print $query array for more request context

    if(preg_match('#/calendar/(.+?)/?$#i', $query['request']['url'])){
        $init = false;
    }

    return $init;

}

Advanced Usage: If you don’t know how to use filters & actions, please read the official WordPress Plugin API.

// Do something after a redirection
add_action('wp404arsp/after_redirect', 'my_404_after_redirect');
function my_404_after_redirect($query){

    // Developers: Print $query array for more request context

    // Send me an e-mail
    wp_mail(
        'my@email.com', 
        'WP 404 Auto Redirect: New redirection', 
        'Hi! New redirection from ' . $args['request']['url'] . ' to ' . $query['redirection']['url'], 
        array('Content-Type: text/html; charset=UTF-8')
    );

    return;
}