4.10. Aura.Router

Provides a web router implementation: given a URL path and a copy of $_SERVER, it will extract path-info and $_SERVER values for a specific route.

This package does not provide a dispatching mechanism. Your application is expected to take the information provided by the matching route and dispatch it on its own. For one possible dispatch system, please see Aura.Dispatcher.

4.10.1. Foreword

4.10.1.1. Installation

This library requires PHP 5.3 or later; we recommend using the latest available version of PHP as a matter of principle. It has no userland dependencies.

It is installable and autoloadable via Composer as aura/router.

Alternatively, download a release or clone this repository, then require or include its autoload.php file.

4.10.1.2. Quality

To run the PHPUnit unit tests at the command line, issue composer install and then vendor/bin/phpunit at the package root. This requires Composer to be available as composer.

This library attempts to comply with PSR-1, PSR-2, and PSR-4. If you notice compliance oversights, please send a patch via pull request.

4.10.1.3. Community

To ask questions, provide feedback, or otherwise communicate with the Aura community, please join our Google Group, follow @auraphp on Twitter, or chat with us on #auraphp on Freenode.

4.10.2. Getting Started

4.10.2.1. Instantiation

Instantiate a Router like so:

<?php
use Aura\Router\RouterFactory;

$router_factory = new RouterFactory;
$router = $router_factory->newInstance();
?>

You will need to place the Router where you can get to it from your application; e.g., in a registry, a service locator, or a dependency injection container. One such system is the Aura.Di package.

4.10.2.2. Adding A Route

To create a route, call the add() method on the Router. Named path-info params are placed inside braces in the path.

<?php
// add a simple named route without params
$router->add('home', '/');

// add a simple unnamed route with params
$router->add(null, '/{controller}/{action}/{id}');

// add a named route with an extended specification
$router->add('blog.read', '/blog/read/{id}{format}')
    ->addTokens(array(
        'id'     => '\d+',
        'format' => '(\.[^/]+)?',
    ))
    ->addValues(array(
        'action'     => 'BlogReadAction',
        'format'     => '.html',
    ));
?>

You can create a route that matches only against a particular HTTP method as well. The following Router methods are identical to add() but require the related HTTP method:

$router->addHead()
$router->addGet()
$router->addDelete()
$router->addOptions()
$router->addPatch()
$router->addPost()
$router->addPut()

4.10.2.3. Matching A Route

To match a URL path against your routes, call match() with a path string and the $_SERVER values.

<?php
// get the incoming request URL path
$path = parse_url($_SERVER['REQUEST_URI'], PHP_URL_PATH);

// get the route based on the path and server
$route = $router->match($path, $_SERVER);
?>

The match() method does not parse the URL or use $_SERVER internally. This is because different systems may have different ways of representing that information; e.g., through a URL object or a context object. As long as you can pass the string path and a server array, you can use the Router in your application foundation or framework.

The returned $route object will contain, among other things, a $params array with values for each of the parameters identified by the route path. For example, matching a route with the path /{controller}/{action}/{id} will populate the $route->params array with controller, action, and id keys.

4.10.2.4. Handling Failure To Match

When $router->match() returns empty, it means there was no matching route for the URL path and server variables. However, we can still discover something about the matching process; in particular, whether the failure is related to an HTTP method or an Accept header.

<?php
// get the first of the best-available non-matched routes
$failure = $router->getFailedRoute();

// inspect the failed route
if ($failure->failedMethod()) {
    // the route failed on the allowed HTTP methods.
    // this is a "405 Method Not Allowed" error.
} elseif ($failure->failedAccept()) {
    // the route failed on the available content-types.
    // this is a "406 Not Acceptable" error.
} else {
    // there was some other unknown matching problem.
}
?>

4.10.2.5. Dispatching A Route

Now that you have route, you can dispatch it. The following is what a foundation or framework system might do with a route to invoke a page controller.

<?php
if (! $route) {
    // no route object was returned
    echo "No application route was found for that URL path.";
    exit();
}

// does the route indicate an action?
if (isset($route->params['action'])) {
    // take the action class directly from the route
    $action_class = $route->params['action'];
} else {
    // use a default action class
    $action_class = 'IndexAction';
}

// instantiate the action class
$action = new $action_class();

// call the __invoke() method on the action
// class using the route params
echo $action->__invoke($route->params);
?>

Again, note that the Router will not dispatch for you; the above is provided as a naive example only to show how to use route values. For a more complex dispatching system, try Aura.Dispatcher.

4.10.2.6. Generating A Route Path

To generate a URL path from a route so that you can create links, call generate() on the Router and provide the route name with optional data.

<?php
// $path => "/blog/read/42.atom"
$path = $router->generate('read', array(
    'id' => 42,
    'format' => '.atom',
));

$href = htmlspecialchars($path, ENT_QUOTES, 'UTF-8');
echo '<a href="' . $href .'">Atom feed for this blog entry</a>';
?>

The Router does not do dynamic matching of routes; a route must have a name to be able to generate a path from it.

The example shows that passing an array of data as the second parameter will cause that data to be interpolated into the route path. This data array is optional. If there are path params without matching data keys, those params will not be replaced, leaving the {param} token in the path. If there are data keys without matching params, those values will not be added to the path.

4.10.3. Advanced Usage

4.10.3.1. Extended Route Specification

You can extend a route specification with the following methods:

addTokens() -- Adds regular expression subpatterns that params must match.
```
  addTokens(array(
      'id' => '\d+',
  ))
```
Note that setTokens() is also available, but this will replace any previous subpatterns entirely, instead of merging with the existing subpatterns.
addServer() -- Adds regular expressions that server values must match.
```
  addServer(array(
      'REQUEST_METHOD' => 'PUT|PATCH',
  ))
```
Note that setServer() is also available, but this will replace any previous expressions entirely, instead of merging with the existing expressions.
addAccept() -- Adds a list of content types that the route responds to. Note that this is not content negotiation per se, only a "sanity check" to make sure the route can eventually provide the content types specified by the request.
```
  addAccept(array(
      'application/json',
      'application/xml',
      'text/csv',
  ));
```
Note that setAccept() is also available, but this will replace any previous content types entirely, instead of merging with the existing types.
addValues() -- Adds default values for the params.
```
  addValues(array(
      'year' => '1979',
      'month' => '11',
      'day' => '07'
  ))
```
Note that setValues() is also available, but this will replace any previous default values entirely, instead of merging with the existing default value.
setSecure() -- When true the $server['HTTPS'] value must be on, or the request must be on port 443; when false, neither of those must be in place.
setWildcard() -- Sets the name of a wildcard param; this is where arbitrary slash-separated values appearing after the route path will be stored.
setRoutable() -- When false the route will be used only for generating paths, not for matching (true by default).
setIsMatchCallable() -- A custom callable with the signature function(array $server, \ArrayObject $matches) that returns true on a match, or false if not. This allows developers to build any kind of matching logic for the route, and to change the $matches for param values from the path.
setGenerateCallable() -- A custom callable with the signature function(\ArrayObject $data). This allows developers to modify the data for path interpolation.

Here is a full extended route specification named read:

<?php
$router->add('blog.read', '/blog/read/{id}{format}')
    ->addTokens(array(
        'id' => '\d+',
        'format' => '(\.[^/]+)?',
        'REQUEST_METHOD' => 'GET|POST',
    ))
    ->addValues(array(
        'id' => 1,
        'format' => '.html',
    ))
    ->setSecure(false)
    ->setRoutable(false)
    ->setIsMatchCallable(function(array $server, \ArrayObject $matches) {

        // disallow matching if referred from example.com
        if ($server['HTTP_REFERER'] == 'http://example.com') {
            return false;
        }

        // add the referer from $server to the match values
        $matches['referer'] = $server['HTTP_REFERER'];
        return true;

    })
    ->setGenerateCallable(function (\ArrayObject $data) {
        $data['foo'] = 'bar';
    });
?>

4.10.3.2. Default Route Specifications

You can set the default route specifications with the following Router methods; the values will apply to all routes added thereafter.

<?php
// add to the default 'tokens' expressions; setTokens() is also available
$router->addTokens(array(
    'id' => '\d+',
));

// add to the default 'server' expressions; setServer() is also available
$router->addServer(array(
    'REQUEST_METHOD' => 'PUT|PATCH',
));

// add to the default param values; setValues() is also available
$router->addValues(array(
    'format' => null,
));

// set the default 'secure' value
$router->setSecure(true);

// set the default wildcard param name
$router->setWildcard('other');

// set the default 'routable' flag
$router->setRoutable(false);

// set the default 'isMatch()' callable
$router->setIsMatchCallable(function (...) { ... });

// set the default 'generate()' callable
$router->setGenerateCallable(function (...) { ... });
?>

4.10.3.3. Simple Routes

You don't need to specify an extended route specification. With the following simple route ...

<?php
$router->add('archive', '/archive/{year}/{month}/{day}');
?>

... the Router will use a default subpattern that matches everything except slashes for the path params. Thus, the above simple route is equivalent to the following extended route:

<?php
$router->add('archive', '/archive/{year}/{month}/{day}')
    ->setValues(array(
        'action' => 'archive',
    ))
    ->addTokens(array(
        'year'  => '[^/]+',
        'month' => '[^/]+',
        'day'   => '[^/]+',
    ));
?>

4.10.3.4. Automatic Params

The Router will automatically populate values for the action route param if one is not set manually.

<?php
// ['action' => 'foo.bar'] because it has not been set otherwise
$router->add('foo.bar', '/path/to/bar');

// ['action' => 'zim'] because we add it explicitly
$router->add('foo.dib', '/path/to/dib')
       ->addValues(array('action' => 'zim'));

// the 'action' param here will be whatever the path value for {action} is
$router->add('/path/to/{action}');
?>

4.10.3.5. Optional Params

Sometimes it is useful to have a route with optional named params. None, some, or all of the optional params may be present, and the route will still match.

To specify optional params, use the notation {/param1,param2,param3} in the path. For example:

<?php
$router->add('archive', '/archive{/year,month,day}')
    ->addTokens(array(
        'year'  => '\d{4}',
        'month' => '\d{2}',
        'day'   => '\d{2}'
    ));
?>

N.b.: The leading slash separator is inside the params token, not outside.

With that, the following routes will all match the 'archive' route, and will set the appropriate values:

/archive
/archive/1979
/archive/1979/11
/archive/1979/11/07

Optional params are sequentially optional. This means that, in the above example, you cannot have a "day" without a "month", and you cannot have a "month" without a "year".

Only one set of optional params per path is recognized by the Router.

Optional params belong at the end of a route path; placing them elsewhere may result in unexpected behavior.

If you generate() a link with optional params, the params will be filled in if they are present in the data for the link. Remember, the optional params are sequentially optional, so the params will not be filled in after the first missing one:

<?php
$router->add('archive', '/archive{/year,month,day}')
    ->addTokens(array(
        'year'  => '\d{4}',
        'month' => '\d{2}',
        'day'   => '\d{2}'
    ));

$link = $router->generate('archive', array(
    'year' => '1979',
    'month' => '11',
)); // "/archive/1979/11"
?>

Similarly, optional params can be used as a generic catchall route:

<?php
$router->add('generic', '{/controller,action,id}')
    ->setValues(array(
        'controller' => 'index',
        'action' => 'browse',
        'id' => null,
    );
?>

That will match these paths, with these param values:

/           : 'controller' => 'index', 'action' => 'browse', 'id' => null
/foo        : 'controller' => 'foo',   'action' => 'browse', 'id' => null
/foo/bar    : 'controller' => 'foo',   'action' => 'bar',    'id' => null
/foo/bar/42 : 'controller' => 'foo',   'action' => 'bar',    'id' => '42'

4.10.3.6. Wildcard Params

Sometimes it is useful to allow the trailing part of the path be anything at all. To allow arbitrary trailing params on a route, extend the route definition with setWildcard() to specify param name under which the arbitrary trailing param values will be stored.

<?php
$router->add('wild_post', '/post/{id}')
    ->setWildcard('other');

// this matches, with the following values
$route = $router->match('/post/88/foo/bar/baz', $_SERVER);
// $route->params['id'] = 88;
// $route->params['other'] = array('foo', 'bar', 'baz')

// this also matches, with the following values; note the trailing slash
$route = $router->match('/post/88/', $_SERVER);
// $route->params['id'] = 88;
// $route->params['other'] = array();

// this also matches, with the following values; note the missing slash
$route = $router->match('/post/88', $_SERVER);
// $route->params['id'] = 88;
// $route->params['other'] = array();
?>

If you generate() a link with wildcard params, the wildcard key in the data will be used for the trailing arbitrary param values:

<?php
$router->add('wild_post', '/post/{id}')
    ->setWildcard('other');

$link = $router->generate('wild_post', array(
    'id' => '88',
    'other' => array(
        'foo',
        'bar',
        'baz',
    );
)); // "/post/88/foo/bar/baz"
?>

4.10.3.7. Attaching Route Groups

You can add a series of routes all at once under a single "mount point" in your application. For example, if you want all your blog-related routes to be mounted at /blog in your application, you can do this:

<?php
$name_prefix = 'blog';
$path_prefix = '/blog';

$router->attach($name_prefix, $path_prefix, function ($router) {

    $router->add('browse', '{format}')
        ->addTokens(array(
            'format' => '(\.json|\.atom|\.html)?'
        ))
        ->addValues(array(
            'format' => '.html',
        ));

    $router->add('read', '/{id}{format}')
        ->addTokens(array(
            'id'     => '\d+',
            'format' => '(\.json|\.atom|\.html)?'
        ))
        ->addValues(array(
            'format' => '.html',
        ));

    $router->add('edit', '/{id}/edit{format}')
        ->addTokens(array(
            'id' => '\d+',
            'format' => '(\.json|\.atom|\.html)?'
        ))
        ->addValues(array(
            'format' => '.html',
        ));
});
?>

Each of the route names will be prefixed with 'blog.', and each of the route paths will be prefixed with /blog, so the effective route names and paths become:

blog.browse => /blog{format}
blog.read => /blog/{id}{format}
blog.edit => /blog/{id}/edit{format}

You can set other route specification values as part of the attachment specification; these will be used as the defaults for each attached route, so you don't need to repeat common information. (Setting these values will not affect routes outside the attached group.)

<?php
$name_prefix = 'blog';
$path_prefix = '/blog';

$router->attach($name_prefix, $path_prefix, function ($router) {

    $router->setTokens(array(
        'id'     => '\d+',
        'format' => '(\.json|\.atom)?'
    ));

    $router->setValues(array(
        'format' => '.html',
    ));

    $router->add('browse', '');
    $router->add('read', '/{id}{format}');
    $router->add('edit', '/{id}/edit');
});
?>

4.10.3.8. Attaching REST Resource Routes

The router can attach a series of REST resource routes for you with the attachResource() method:

<?php
$router->attachResource('blog', '/blog');
?>

That method call will result in the following routes being added:

| Route Name | HTTP Method | Route Path | Purpose | ------------- | ------------- | --------------------- | ------- | blog.browse | GET | /blog{format} | Browse multiple resources | blog.read | GET | /blog/{id}{format} | Read a single resource | blog.edit | GET | /blog/{id}/edit | The form for editing a resource | blog.add | GET | /blog/add | The form for adding a resource | blog.delete | DELETE | /blog/{id} | Delete a single resource | blog.create | POST | /blog | Create a new resource | blog.update | PATCH | /blog/{id} | Update part of an existing resource | blog.replace | PUT | /blog/{id} | Replace an entire existing resource

The {id} token is whatever has already been defined in the router; if not already defined, it will be any series of numeric digits. Likewise, the {format} token is whatever has already been defined in the router; if not already defined, it is an optional dot-format file extension (including the dot itself).

The action value is the same as the route name.

If you want calls to attachResource() to create a different series of REST routes, use the setResourceCallable() method to set your own callable to create them.

<?php
$router->setResourceCallable(function ($router) {
    $router->setTokens(array(
        'id' => '([a-f0-9]+)'
    ));
    $router->addPost('create', '/{id}');
    $router->addGet('read', '/{id}');
    $router->addPatch('update', '/{id}');
    $router->addDelete('delete', '/{id}');
});
?>

That example will cause only four CRUD routes, using hexadecimal resource IDs, to be added for the resource when you call attachResource().

4.10.3.9. Setting A Base Path

The router assumes that all URL paths begin at the top document root, but sometimes you will need them to begin in a subdirectory. In that case, you can instantiate the RouterFactory with an explicit base path; this base path will be used as a prefix for all route matching and path generation.

<?php
// create a factory with a base path
$router_factory = new RouterFactory('/path/to/subdir');

// define a route as normal
$router = $router_factory->getInstance();
$router->addGet('blog.read', '/blog/{id}');

// if the incoming request is for "/path/to/subdir/blog/{id}"
// then the route will match.
$path = parse_url($_SERVER['REQUEST_URI'], PHP_URL_PATH);
$route = $router->match($path, $_SERVER);

// generating a path from the route will add the base path automatically
$path = $router->generate('blog.read', '88');
echo $path; // "/path/to/subdir/blog/88"
?>

4.10.3.10. Caching Route Information

You may wish to cache the router for production deployments so that the router does not have to build the route objects from definitions on each page load. The methods getRoutes() and setRoutes() may be used for that purpose.

The following is a naive example for file-based caching and restoring of routes:

<?php
// the cache file location
$cache = '/path/to/routes.cache';

// does the cache exist?
if (file_exists($cache)) {

    // restore from the cache
    $routes = unserialize(file_get_contents($cache));
    $router->setRoutes($routes);

} else {

    // build the routes using add() and attach() ...
    // ... ... ...
    // ... then save to the cache for the next page load
    $routes = $router->getRoutes();
    file_put_contents($cache, serialize($routes));

}
?>

Note that if there are closures in the Route objects (e.g. for isMatch() or generate()), you will not be able to cache the routes; this is because closures cannot be serialized properly for caching. Consider using non-closure callables instead.

4.10.3.11. As a Micro-Framework

Sometimes you may wish to use the Router as a micro-framework. This is possible by assigning a callable as a default param value, usually action, then calling that param to dispatch it.

<?php
$router->add('read', '/blog/read/{id}{format}')
    ->addTokens(array(
        'id' => '\d+',
        'format' => '(\.[^/]+)?',
    ))
    ->addValues(array(
        'action' => function ($params) {
            if ($params['format'] == '.json') {
                $id = (int) $params['id'];
                header('Content-Type: application/json');
                echo json_encode(['id' => $id]);
            } else {
                $id = (int) $params['id'];
                header('Content-Type: text/plain');
                echo "Reading blog ID {$id}";
            }
        },
        'format' => '.html',
    ));
?>

Alternatively, and perhaps more easily, you may specify a third parameter to the add() method; this will be used as the action value in the params. The following is identical to the above:

<?php
$router->add(
    'read',
    '/blog/read/{id}{format}',
    function ($params) {
        if ($params['format'] == '.json') {
            $id = (int) $params['id'];
            header('Content-Type: application/json');
            echo json_encode(['id' => $id]);
        } else {
            $id = (int) $params['id'];
            header('Content-Type: text/plain');
            echo "Reading blog ID {$id}";
        }
    })
    ->addTokens(array(
        'id' => '\d+',
        'format' => '(\.[^/]+)?',
    ))
    ->addValues(array(
        'format' => '.html',
    ));
?>

A naive micro-framework dispatcher might then work like this:

<?php
// get the route params
$params = $route->params;

// extract the action callable from the params
$action = $params['action'];
unset($params['action']);

// invoke the callable
$action($params);
?>

With the above example action, the URL /blog/read/1.json will send JSON ouput, but for /blog/read/1 it will send plain text output.

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