Routing
*******

<div class=perex>

The router is responsible for everything about URLs so that you no longer have to think about them. We will show:

- how to set up the router so that the URLs look like you want
- a few notes about SEO redirection
- and we'll show you how to write your own router

</div>


More human URLs (or cool or pretty URLs) are more usable, more memorable and contribute positively to SEO. Nette has this in mind and fully meets developers' desires. You can design your URL structure for your application exactly the way you want it.
You can even design it after the app is ready, as it can be done without any code or template changes. It is defined in an elegant way in [one single place |#Integration], in the router, and is not scattered in the form of annotations in all presenters.

The router in Nette is special because it is **bidirectional**, it can both decode HTTP request URLs as well as create links. So it plays a vital role in [Nette Application |how-it-works#Nette Application], because it decides which presenter and action will execute the current request, and is also used for [URL generation |creating-links] in the template, etc.

However, the router is not limited to this use, you can use it in applications where presenters are not used at all, for REST APIs, etc. More in the section [#separated usage].


Route Collection
================

The most pleasant way to define the URL addresses in the application is via the class [api:Nette\Application\Routers\RouteList]. The definition consists of a list of so-called routes, ie masks of URL addresses and their associated presenters and actions using a simple API. We do not have to name the routes.

```php
$router = new Nette\Application\Routers\RouteList;
$router->addRoute('rss.xml', 'Feed:rss');
$router->addRoute('article/<id>', 'Article:view');
// ...
```

The example says that if we open `https://any-domain.com/rss.xml` in the browser, the presenter `Feed` with the action `rss` will be displayed, if `https://domain.com/article/12`, the `Article` with the `view` action is displayed, etc. If no suitable route is found, Nette Application responds by throwing an exception [BadRequestException |api:Nette\Application\BadRequestException], which appears to the user as a 404 Not Found error page.

.[note]
In Nette 2.x, `$router[] = new Route(...)` was used instead of `$router->addRoute(...)`.


Order of Routes
---------------

The order in which the routes are listed is **very important** because they are evaluated sequentially from top to bottom. The rule is that we declare routes **from specific to general**:

```php
// WRONG: 'rss.xml' matches the first route and misunderstands this as <slug>
$router->addRoute('<slug>', 'Article:view');
$router->addRoute('rss.xml', 'Feed:rss');

// GOOD
$router->addRoute('rss.xml', 'Feed:rss');
$router->addRoute('<slug>', 'Article:view');
```

Routes are also evaluated from top to bottom when links are generated:

```php
// WRONG: generates a link to 'Feed:rss' as 'admin/feed/rss'
$router->addRoute('admin/<presenter>/<action>', 'Admin:default');
$router->addRoute('rss.xml', 'Feed:rss');

// GOOD
$router->addRoute('rss.xml', 'Feed:rss');
$router->addRoute('admin/<presenter>/<action>', 'Admin:default');
```

We won't keep it a secret from you that it takes some skill to build a list correctly. Until you get into it, the [routing panel |#Debugging Router] will be a useful tool.


Mask and Parameters
-------------------

The mask describes the relative path based on the site root. The simplest mask is a static URL:

```php
$router->addRoute('products', 'Products:default');
```

Often masks contain so-called **parameters**. They are enclosed in angle brackets (e.g. `<year>`) and are passed to the target presenter, for example to the `renderShow(int $year)` method or to persistent parameter `$year`:

```php
$router->addRoute('chronicle/<year>', 'History:show');
```

The example says that if we open `https://any-domain.com/chronicle/2020` in the browser, the presenter `History` and the action `show` with parameter `year => 2020` will be displayed.

We can specify a default value for the parameters directly in the mask and thus it becomes optional:

```php
$router->addRoute('chronicle/<year=2020>', 'History:show');
```

The route will now accept the URL `https://any-domain.com/chronicle/`, which will again display `History:show` with parameter `year => 2020`.

Of course, the name of the presenter and the action can also be a parameter. For example:

```php
$router->addRoute('<presenter>/<action>', 'Homepage:default');
```

This route accepts, for example, a URL in the form `/article/edit` resp. `/catalog/list` and translates them to presenters and actions `Article:edit` resp. `Catalog:list`.

It also gives to parameters `presenter` and `action` default values ​​`Homepage` and `default` and therefore they are optional. So the route also accepts a URL `/article` and translates it as `Article:default`. Or vice versa, a link to `Product:default` generates a path `/product`, a link to the default `Homepage:default` generates a path `/`.

The mask can describe not only the relative path based on the site root, but also the absolute path when it begins with a slash, or even the entire absolute URL when it begins with two slashes:

```php
// relative path to application document root
$router->addRoute('<presenter>/<action>', /* ... */);

// absolute path, relative to server hostname
$router->addRoute('/<presenter>/<action>', /* ... */);

// absolute URL including hostname (but scheme-relative)
$router->addRoute('//<lang>.example.com/<presenter>/<action>', /* ... */);

// absolute URL including schema
$router->addRoute('https://<lang>.example.com/<presenter>/<action>', /* ... */);
```


Validation Expressions
----------------------

A validation condition can be specified for each parameter using [regular expression |https://www.php.net/manual/en/reference.pcre.pattern.syntax.php]. For example, let's set `id` to be only numerical, using `\d+` regexp:

```php
$router->addRoute('<presenter>/<action>[/<id \d+>]', /* ... */);
```

The default regular expression for all parameters is `[^/]+`, ie everything except the slash. If a parameter is supposed to match a slash as well, we set the regular expression to `.+`.

```php
// accepts https://example.com/a/b/c, path is 'a/b/c'
$router->addRoute('<path .+>', /* ... */);
```


Optional Sequences
------------------

Square brackets denote optional parts of mask. Any part of mask may be set as optional, including those containing parameters:

```php
$router->addRoute('[<lang [a-z]{2}>/]<name>', /* ... */);

// Accepted URLs:      Parameters:
//   /en/download        lang => en, name => download
//   /download           lang => null, name => download
```

Of course, when a parameter is part of an optional sequence, it also becomes optional. If it does not have a default value, it will be null.

Optional sections can also be in the domain:

```php
$router->addRoute('//[<lang=en>.]example.com/<presenter>/<action>', /* ... */);
```

Sequences may be freely nested and combined:

```php
$router->addRoute(
	'[<lang [a-z]{2}>[-<sublang>]/]<name>[/page-<page=0>]',
	'Homepage:default'
);

// Accepted URLs:
//   /cs/hello
//   /en-us/hello
//   /hello
//   /hello/page-12
```

URL generator tries to keep the URL as short as possible, so what can be omitted is omitted. Therefore, for example, a route `index[.html]` generates a path `/index`. You can reverse this behavior by writing an exclamation mark after the left square bracket:

```php
// accepts both /hello and /hello.html, generates /hello
$router->addRoute('<name>[.html]', /* ... */);

// accepts both /hello and /hello.html, generates /hello.html
$router->addRoute('<name>[!.html]', /* ... */);
```

Optional parameters (ie. parameters having default value) without square brackets do behave as if wrapped like this:

```php
$router->addRoute('<presenter=Homepage>/<action=default>/<id=>', /* ... */);

// equals to:
$router->addRoute('[<presenter=Homepage>/[<action=default>/[<id>]]]', /* ... */);
```

To change how the rightmost slash is generated, i.e. instead of `/homepage/` get a `/homepage`, adjust the route this way:

```php
$router->addRoute('[<presenter=Homepage>[/<action=default>[/<id>]]]', /* ... */);
```


Wildcards
---------

In the absolute path mask, we can use the following wildcards to avoid, for example, the need to write a domain to the mask, which may differ in the development and production environment:

- `%tld%` = top level domain, e.g. `com` or `org`
- `%sld%` = second level domain, e.g. `example`
- `%domain%` = domain without subdomains, e.g. `example.com`
- `%host%` = whole host, e.g. `www.example.com`
- `%basePath%` = path to the root directory

```php
$router->addRoute('//www.%domain%/%basePath%/<presenter>/<action>', /* ... */);
$router->addRoute('//www.%sld%.%tld%/%basePath%/<presenter>/<action', /* ... */);
```


Advanced Notation
-----------------

The target of a route, usually written in the form `Presenter:action`, can also be expressed using an array that defines individual parameters and their default values:

```php
$router->addRoute('<presenter>/<action>[/<id \d+>]', [
	'presenter' => 'Homepage',
	'action' => 'default',
]);
```

For a more detailed specification, an even more extended form can be used, where in addition to default values, other parameter properties can be set, such as a validation regular expression (see the `id` parameter):

```php
use Nette\Routing\Route;

$router->addRoute('<presenter>/<action>[/<id>]', [
	'presenter' => [
		Route::VALUE => 'Homepage',
	],
	'action' => [
		Route::VALUE => 'default',
	],
	'id' => [
		Route::PATTERN => '\d+',
	],
]);
```

It is important to note that if the parameters defined in the array are not included in the path mask, their values cannot be changed, not even using query parameters specified after a question mark in the URL.


Filters and Translations
------------------------

It's a good practice to write source code in English, but what if you need your website to have translated URL to different language? Simple routes such as:

```php
$router->addRoute('<presenter>/<action>', 'Homepage:default');
```

will generate English URLs, such as `/product/123` or `/cart`. If we want to have presenters and actions in the URL translated to Deutsch (e.g. `/produkt/123` or `/einkaufswagen`), we can use a translation dictionary. To add it, we already need a "more talkative" variant of the second parameter:

```php
use Nette\Routing\Route;

$router->addRoute('<presenter>/<action>', [
	'presenter' => [
		Route::VALUE => 'Homepage',
		Route::FILTER_TABLE => [
			// string in URL => presenter
			'produkt' => 'Product',
			'einkaufswagen' => 'Cart',
			'katalog' => 'Catalog',
		],
	],
	'action' => [
		Route::VALUE => 'default',
		Route::FILTER_TABLE => [
			'liste' => 'list',
		],
	],
]);
```

Multiple dictionary keys can by used for the same presenter. They will create various aliases for it. The last key is considered to be the canonical variant (i.e. the one that will be in the generated URL).

The translation table can be applied to any parameter in this way. However, if the translation does not exist, the original value is taken. We can change this behavior by adding `Route::FILTER_STRICT => true` and the route will then reject the URL if the value is not in the dictionary.

In addition to the translation dictionary in the form of an array, it is possible to set own translation functions:

```php
use Nette\Routing\Route;

$router->addRoute('<presenter>/<action>/<id>', [
	'presenter' => [
		Route::VALUE => 'Homepage',
		Route::FILTER_IN => function (string $s): string { /* ... */ },
		Route::FILTER_OUT => function (string $s): string { /* ... */ },
	],
	'action' => 'default',
	'id' => null,
]);
```

The function `Route::FILTER_IN` converts between the parameter in the URL and the string, which is then passed to the presenter, the function `FILTER_OUT` ensures the conversion in the opposite direction.

The parameters `presenter`, `action` and `module` already have predefined filters that convert between the PascalCase resp. camelCase style and kebab-case used in the URL. The default value of the parameters is already written in the transformed form, so, for example, in the case of a presenter, we write `<presenter=ProductEdit>` instead of `<presenter=product-edit>`.


General Filters
---------------

Besides filters for specific parameters, you can also define general filters that receive an associative array of all parameters that they can modify in any way and then return. General filters are defined under `null` key.

```php
use Nette\Routing\Route;

$router->addRoute('<presenter>/<action>', [
	'presenter' => 'Homepage',
	'action' => 'default',
	null => [
		Route::FILTER_IN => function (array $params): array { /* ... */ },
		Route::FILTER_OUT => function (array $params): array { /* ... */ },
	],
]);
```

General filters give you the ability to adjust the behavior of the route in absolutely any way. We can use them, for example, to modify parameters based on other parameters. For example, translation `<presenter>` and `<action>` based on the current value of parameter `<lang>`.

If a parameter has a custom filter defined and a general filter exists at the same time, custom `FILTER_IN` is executed before the general and vice versa general `FILTER_OUT` is executed before the custom. Thus, inside the general filter are the values of the parameters `presenter` resp. `action` written in PascalCase resp. camelCase style.


ONE_WAY Flag
------------

One-way routes are used to preserve the functionality of old URLs that the application no longer generates but still accepts. We flag them with `ONE_WAY`:

```php
// old URL /product-info?id=123
$router->addRoute('product-info', 'Product:detail', $router::ONE_WAY);
// new URL /product/123
$router->addRoute('product/<id>', 'Product:detail');
```

When accessing the old URL, the presenter automatically redirects to the new URL so that search engines do not index these pages twice (see [#SEO and canonization]).


Modules
-------

If we have more routes that belong to one [module |modules], we can use `withModule()` to group them:

```php
$router = new RouteList;
$router->withModule('Forum') // the following routers are part of the Forum module
	->addRoute('rss', 'Feed:rss') // presenter is Forum:Feed
	->addRoute('<presenter>/<action>')

	->withModule('Admin') // the following routers are part of the Forum:Admin module
		->addRoute('sign:in', 'Sign:in');
```

An alternative is to use the `module` parameter:

```php
// URL manage/dashboard/default maps to presenter Admin:Dashboard
$router->addRoute('manage/<presenter>/<action>', [
	'module' => 'Admin'
]);
```


Subdomains
----------

Route collections can be grouped by subdomains:

```php
$router = new RouteList;
$router->withDomain('example.com')
	->addRoute('rss', 'Feed:rss')
	->addRoute('<presenter>/<action>');
```

You can also use [#wildcards] in your domain name:

```php
$router = new RouteList;
$router->withDomain('example.%tld%')
	// ...
```


Path Prefix
-----------

Route collections can be grouped by path in URL:

```php
$router = new RouteList;
$router->withPath('eshop')
	->addRoute('rss', 'Feed:rss') // matches URL /eshop/rss
	->addRoute('<presenter>/<action>'); // matches URL /eshop/<presenter>/<action>
```


Combinations
------------

The above usage can be combined:

```php
$router = (new RouteList)
	->withDomain('admin.example.com')
		->withModule('Admin')
			->addRoute(/* ... */)
			->addRoute(/* ... */)
		->end()
		->withModule('Images')
			->addRoute(/* ... */)
		->end()
	->end()
	->withDomain('example.com')
		->withPath('export')
			->addRoute(/* ... */)
			// ...
```


Query Parameters
----------------

Masks can also contain query parameters (parameters after the question mark in the URL). They cannot define a validation expression, but they can change the name under which they are passed to the presenter:

```php
// use query parameter 'cat' as a 'categoryId' in application
$router->addRoute('product ? id=<productId> & cat=<categoryId>', /* ... */);
```


Foo Parameters
--------------

We're going deeper now. Foo parameters are basically unnamed parameters which allow to match a regular expression. The following route matches `/index`, `/index.html`, `/index.htm` and `/index.php`:

```php
$router->addRoute('index<? \.html?|\.php|>', /* ... */);
```

It's also possible to explicitly define a string which will be used for URL generation. The string must be placed directly after the question mark. The following route is similar to the previous one, but generates `/index.html` instead of `/index` because the string `.html` is set as a "generated value".

```php
$router->addRoute('index<?.html \.html?|\.php|>', /* ... */);
```


Integration
===========

In order to connect the our router into the application, we must tell the DI container about it. The easiest way is to prepare the factory that will build the router object and tell the container configuration to use it. So let's say we write a method for this purpose `App\Core\RouterFactory::createRouter()`:

```php
namespace App\Core;

use Nette\Application\Routers\RouteList;

class RouterFactory
{
	public static function createRouter(): RouteList
	{
		$router = new RouteList;
		$router->addRoute(/* ... */);
		return $router;
	}
}
```

Then we write in [configuration |dependency-injection:services]:

```neon
services:
	- App\Core\RouterFactory::createRouter
```

In the case of Nette 3.0:

```neon
services:
	router: App\Router\RouterFactory::createRouter
```

Any dependencies, such as a database connection etc., are passed to the factory method as its parameters using [autowiring |dependency-injection:autowiring]:

```php
public static function createRouter(Nette\Database\Connection $db): RouteList
{
	// ...
}
```


SimpleRouter
============

A much simpler router than the Route Collection is [SimpleRouter |api:Nette\Application\Routers\SimpleRouter]. It can be used when there's no need for a specific URL format, when `mod_rewrite` (or alternatives) is not available or when we simply do not want to bother with user-friendly URLs yet.

Generates addresses in roughly this form:

```
http://example.com/?presenter=Product&action=detail&id=123
```

The parameter of the `SimpleRouter` constructor is a default presenter & action, ie. action to be executed if we open e.g. `http://example.com/` without additional parameters.

```php
// defaults to presenter 'Homepage' and action 'default'
$router = new Nette\Application\Routers\SimpleRouter('Homepage:default');
```

We recommend defining SimpleRouter directly in [configuration |dependency-injection:services]:

```neon
services:
	- Nette\Application\Routers\SimpleRouter('Homepage:default')
```


SEO and Canonization
====================

The framework increases SEO (search engine optimization) by preventing duplication of content at different URLs. If multiple addresses link to a same destination, eg `/index` and `/index.html`, the framework determines the first one as primary (canonical) and redirects the others to it using HTTP code 301. Thanks to this, search engines will not index pages twice and do not break their page rank. .

This process is called canonization. The canonical URL is the one generated by the router, i.e. by the first matching route in the [collection |#route-collection] without the ONE_WAY flag. Therefore, in the collection, we list **primary routes first**.

Canonization is performed by the presenter, more in the chapter [canonization |presenters#Canonization].


HTTPS
=====

In order to use the HTTPS protocol, it is necessary to activate it on hosting and to configure the server.

Redirection of the entire site to HTTPS must be performed at the server level, for example using the .htaccess file in the root directory of our application, with HTTP code 301. The settings may differ depending on the hosting and looks something like this:

```
<IfModule mod_rewrite.c>
	RewriteEngine On
	...
	RewriteCond %{HTTPS} off
	RewriteRule .* https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]
	...
</IfModule>
```

The router generates a URL with the same protocol as the page was loaded, so there is no need to set anything else.

However, if we exceptionally need different routes to run under different protocols, we will put it in the route mask:

```php
// Will generate an HTTP address
$router->addRoute('http://%host%/<presenter>/<action>', /* ... */);

// Will generate an HTTPS address
$router->addRoute('https://%host%/<presenter>/<action>', /* ... */);
```


Debugging Router
================

The routing bar displayed in [Tracy Bar |tracy:] is a useful tool that displays a list of routes and also the parameters that the router has obtained from the URL.

The green bar with symbol ✓ represents the route that matched the current URL, the blue bars with symbols ≈ indicate the routes that would also match the URL if green did not overtake them. We see the current presenter & action further.

[* routing-debugger.webp *]

At the same time, if there is an unexpected redirect due to [canonicalization |#SEO and Canonization], it is useful to look in the *redirect* bar to see how the router originally understood the URL and why it redirected.

.[note]
When debugging the router, it is recommended to open Developer Tools in the browser (Ctrl+Shift+I or Cmd+Option+I) and disable the cache in the Network panel so that redirects are not stored in it.


Performance
===========

The number of routes affects the speed of the router. Their number should certainly not exceed a few dozen. If your site has an overly complicated URL structure, you can write a [#custom router].

If the router has no dependencies, such as on a database, and its factory has no arguments, we can serialize its compiled form directly into a DI container and thus make the application slightly faster.

```neon
routing:
	cache: true
```


Custom Router
=============

The following lines are intended for very advanced users. You can create your own router and naturally add it into your route collection. The router is an implementation of the [api:Nette\Routing\Router] interface with two methods:

```php
use Nette\Http\IRequest as HttpRequest;
use Nette\Http\UrlScript;

class MyRouter implements Nette\Routing\Router
{
	public function match(HttpRequest $httpRequest): ?array
	{
		// ...
	}

	public function constructUrl(array $params, UrlScript $refUrl): ?string
	{
		// ...
	}
}
```

The `match` method processes the current [$httpRequest |http:request], from which not only the URL, but also headers etc. can be retrieved, into an array containing the presenter name and its parameters. If it cannot process the request, it returns null.
When processing the request, we must return at least the presenter and the action. The presenter name is complete and includes any modules:

```php
[
	'presenter' => 'Front:Homepage',
	'action' => 'default',
]
```

Method `constructUrl`, on the other hand, generates an absolute URL from the array of parameters. It can use the information from parameter `$refUrl`, which is the current URL.

To add custom router to the route collection, use `add()`:

```php
$router = new Nette\Application\Routers\RouteList;
$router->add($myRouter);
$router->addRoute(/* ... */);
// ...
```


Separated Usage
===============

By separated usage, we mean the use of the router's capabilities in an application that does not use Nette Application and presenters. Almost everything we have shown in this chapter applies to it, with the following differences:

- for route collections we use class [api:Nette\Routing\RouteList]
- as a simple router class [api:Nette\Routing\SimpleRouter]
- because there is no pair `Presenter:action`, we use [#Advanced notation]

So again we will create a method that will build a router, for example:

```php
namespace App\Core;

use Nette\Routing\RouteList;

class RouterFactory
{
	public static function createRouter(): RouteList
	{
		$router = new RouteList;
		$router->addRoute('rss.xml', [
			'controller' => 'RssFeedController',
		]);
		$router->addRoute('article/<id \d+>', [
			'controller' => 'ArticleController',
		]);
		// ...
		return $router;
	}
}
```

If you use a DI container, which we recommend, add the method to the configuration again and then get the router together with the HTTP request from the container:

```php
$router = $container->getByType(Nette\Routing\Router::class);
$httpRequest = $container->getByType(Nette\Http\IRequest::class);
```

Or we will create objects directly:

```php
$router = App\Core\RouterFactory::createRouter();
$httpRequest = (new Nette\Http\RequestFactory)->fromGlobals();
```

Now we have to let the router to work:

```php
$params = $router->match($httpRequest);
if ($params === null) {
	// no matching route found, we will send a 404 error
	exit;
}

// we process the received parameters
$controller = $params['controller'];
// ...
```

And vice versa, we will use the router to create the link:

```php
$params = ['controller' => 'ArticleController', 'id' => 123];
$url = $router->constructUrl($params, $httpRequest->getUrl());
```


{{composer: nette/router}}