Routing to callback functions in WordPress – 07

June 6, 2014 3-minute read

I’m developing a working package of plugins and libraries in an attempt to create a more flexible routing in WordPress based around the possibility offered by the WP Router plugin and some wrapping classes I’ve created.
This article is the seventh in a series and skimming the previous ones will allow some deeper understanding of the problem at hand.

A first simple user story

To have a clear objective to code to I will implement a first user story

As a WordPress user I want to be able to add a page showing the content of a route endpoint to the navigation menus. An example would be the possibility to add a page showing the /posts route content to the navigation menus.

The process involved is composed of the following steps:

in a plugin adding routes the developer is given the possibility to assign meta information to each route
the \tad\wrappers\WP_Router\Route class will allow hooking before and after routes are added using WP Router
the plugin will hook into one of those hooks to persist some routes to the database based on the meta information
some pages will be programmatically added to the available pages and the user will be able to add those to the navigation menus

Assigning meta information to a route

That’s a simple addition to the \tad\wrappers\WP_Router\Route class and I’ve added the with method

/**
 * Allows adding additional information to a route.
 * 
 * Additional arguments will be ignored by WP Router.
 *
 * @param  string $key   The key for the information to add.
 * @param  mixed $value  The value for the information to add.
 *
 * @return Route         The calling instance.
 */
public function with($key, $value);

and an usage example, to add a description, is

Route::get('/hello', function(){
    echo "Hello there!"
    })->withTemplate('page')
      ->with('description', 'The hello route.');

Adding an hook

To allow persistence of routes I need to either delegate the \tad\wrappers\WP_Router\Route class with the task or to create an hook in it to allow for third party handling of the process.
The first solution seems to me a violation of the Single responsibility principle and will hence go with the second solution.
I’ve modified the \tad\wrappers\Wp_Router\Route::generateRoutes method to

public static function generateRoutes(\WP_router $router, FunctionsAdapter $f = null)
{
    if (is_null($f)) {
        $f = new Functions();
    }
    $f->do_action('route_before_adding_routes', self::$routes);
    foreach (self::$routes as $route => $args) {
        $router->add_route($route, $args);
    }
    $f->do_action('route_after_adding_routes', self::$routes);
}

where those $f in code are to allow for TDD to be applied and come from tdd-helpers. I’ve also added the general purpose with method to allow for appending additional arguments, ignored by WP Router, to the route.

Point 3 and 4 of the list above.

A first simple user story

Assigning meta information to a route

Adding an hook

Next