MiddlewareNameResolver.php

TLDR

This file, MiddlewareNameReslover.php, contains the MiddlewareNameResolver class. The class provides methods for resolving middleware names to class names in the Illuminate\Routing namespace.

Methods

resolve

This method takes in three parameters: $name, $map, and $middlewareGroups. It resolves the middleware name to a corresponding class name(s), preserving any parameters that are passed along with the middleware. The return type can be a Closure, a string, or an array.

parseMiddlewareGroup

This method is a protected method that takes in three parameters: $name, $map, and $middlewareGroups. It is used internally by the resolve method to parse a middleware group and format it for usage. It returns an array of the resolved middleware.

<?php

namespace Illuminate\Routing;

use Closure;

class MiddlewareNameResolver
{
    /**
     * Resolve the middleware name to a class name(s) preserving passed parameters.
     *
     * @param  \Closure|string  $name
     * @param  array  $map
     * @param  array  $middlewareGroups
     * @return \Closure|string|array
     */
    public static function resolve($name, $map, $middlewareGroups)
    {
        // When the middleware is simply a Closure, we will return this Closure instance
        // directly so that Closures can be registered as middleware inline, which is
        // convenient on occasions when the developers are experimenting with them.
        if ($name instanceof Closure) {
            return $name;
        }

        if (isset($map[$name]) && $map[$name] instanceof Closure) {
            return $map[$name];
        }

        // If the middleware is the name of a middleware group, we will return the array
        // of middlewares that belong to the group. This allows developers to group a
        // set of middleware under single keys that can be conveniently referenced.
        if (isset($middlewareGroups[$name])) {
            return static::parseMiddlewareGroup($name, $map, $middlewareGroups);
        }

        // Finally, when the middleware is simply a string mapped to a class name the
        // middleware name will get parsed into the full class name and parameters
        // which may be run using the Pipeline which accepts this string format.
        [$name, $parameters] = array_pad(explode(':', $name, 2), 2, null);

        return ($map[$name] ?? $name).(! is_null($parameters) ? ':'.$parameters : '');
    }

    /**
     * Parse the middleware group and format it for usage.
     *
     * @param  string  $name
     * @param  array  $map
     * @param  array  $middlewareGroups
     * @return array
     */
    protected static function parseMiddlewareGroup($name, $map, $middlewareGroups)
    {
        $results = [];

        foreach ($middlewareGroups[$name] as $middleware) {
            // If the middleware is another middleware group we will pull in the group and
            // merge its middleware into the results. This allows groups to conveniently
            // reference other groups without needing to repeat all their middlewares.
            if (isset($middlewareGroups[$middleware])) {
                $results = array_merge($results, static::parseMiddlewareGroup(
                    $middleware, $map, $middlewareGroups
                ));

                continue;
            }

            [$middleware, $parameters] = array_pad(
                explode(':', $middleware, 2), 2, null
            );

            // If this middleware is actually a route middleware, we will extract the full
            // class name out of the middleware list now. Then we'll add the parameters
            // back onto this class' name so the pipeline will properly extract them.
            if (isset($map[$middleware])) {
                $middleware = $map[$middleware];
            }

            $results[] = $middleware.($parameters ? ':'.$parameters : '');
        }

        return $results;
    }
}