wellrested/documentation/routes.md

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# Routes
WellRESTed comes with a few Route classes:
- `StaticRoute`: Matches request paths exactly
- `TemplateRoute`: Matches URI templates
- `RegexRoute`: Matches a custom regular expression
Each works basically the same way: It first checks to see if it is a match for the request. If it's a match, it instantiates a specific class implementing the `HandlerInterface` (autoloading the class, if needed). Finally, it uses the handler class to provide a response.
## StaticRoute
Use a `StaticRoute` when you know the exact path you want to handle. This route will match only requests to `/cats/`.
```php
$route = new StaticRoute("/cats/", "CatHandler");
```
You can also make a `StaticRoute` that matches multiple exact paths. For example, suppose you have a multi-use `AnimalHandler` that you want to invoke to handle requests to `/cats/`, `/dogs/`, and `/birds/`. You can make this by passing an array instead of a string as the first parameter.
```php
$route = new StaticRoute(array("/cats/", "/dogs/", "/birds/"), "AnimalHandler");
```
## TemplateRoute
`StaticRoutes` are the best choice if you know the exact path up front. But, what if you want to handle a path that includes a variable? That's where the `TemplateRoute` comes in.
Here's a route that will match a request to a specific cat by ID and send it to a `CatItemHandler`.
```php
$route = new TemplateRoute("/cats/{id}", "CatItemHandler");
```
A `TemplateRoute` use a URI template to match a request. To include a variable in your template, enclose it in `{}`. The variable will be extracted and made available for the handler in the handler's `args` member.
```php
class CatItemHandlder extends \pjdietz\WellRESTed\Handler
{
protected function get()
{
// Access the {id} variable from the $this->args member.
$id = $this->args["id"];
// ...Do something with the {id}.
}
}
```
Your template may have multiple variables. Be sure to give each a unique name.
With this `TemplateRoute`...
```php
$route = new TemplateRoute("/cats/{catId}/{dogId}", "CatItemHandler");
```
...the handler will have access to `$this->args["catId"]` and `$this->args["dogId"]`.
### Default Variable Pattern
By default, the `TemplateRoute` will accept for a variable any value consisting of numbers, letters, underscores, and hyphens. You can change this behavior by passing a pattern to use as the third parameter of the constructor. Here we'll restrict the template to match only numeric values.
```php
$route = new TemplateRoute("/cats/{id}", "CatItemHandler", TemplateRoute::RE_NUM);
```
The `TemplateRoute` includes constants for some common situations. The value of each constant is a partial regular expression. You can use one of the constants, or provide your own partial regular expression.
### Pattern Constants
| Constant | Pattern | Description |
| --------- | ----------------- | ----------- |
| `RE_SLUG` | `[0-9a-zA-Z\-_]+` | "URL-friendly" characters such as numbers, letters, underscores, and hyphens |
| `RE_NUM` | `[0-9]+` | Digits only |
| `RE_ALPHA` | `[a-zA-Z]+` | Letters only |
| `RE_ALPHANUM` | `[0-9a-zA-Z]+` | Letters and digits |
### Variable Patterns Array
You can also set a different pattern for each variable. To do this, pass an array to the `TemplateRoute` constructor as the fourth paramter. The array must have variable names as keys and patterns as values.
```php
$patterns = array(
"id" => TemplateRoute::RE_NUM,
"name" => TemplateRoute::RE_ALPHA
);
$route = new TemplateRoute(
"/cats/{id}/{name}/{more}",
"CatItemHandler",
TemplateRoute::RE_SLUG,
$patterns);
```
Here, `{id}` will need to match digits and `{name}` must be all letters. Since `{more}` is not explicitly provided in the `$patterns` array, it uses the default `TemplateRoute::RE_SLUG` passed as the third parameter.
### RegexRoute
If `TemplateRoute` doesn't give you enough control, you can make a route that matches a regular expression.
```php
$route = new RegexRoute("~/cat/[0-9]+~", "CatHandler")
```
This will match `/cat/102` or `/cat/999` or what have you. To make this more useful, we can add a capture group. The captures are made available to the `Handler` as the `$args` member, as with the URI template variables for the `TemplateRoute`
Note that the entire matched path will always be the `0` item, and captured groups will begin at `1`.
So this route...
```php
$route = new RegexRoute("~/cat/([0-9]+)~", "CatHandler")
```
...with the path `/cat/99` creates this array of matches:
```
Array
(
[0] => /cat/99
[1] => 99
)
```
You can also used named capture groups like this;
```php
$route = new RegexRoute("~/cat/(?<id>[0-9]+)~", "CatHandler")
```
...with the path `/cat/99` creates this array or matches:
```
Array
(
[0] => /cat/99
[1] => 99
[id] => 99
)
```