Server Path Parameters.md

Path Parameters

You can define path parameters when mapping routes.

Any path parameter has two components

1. a path component
2. a route handler component

Path

Path parameters are wrapped in {}

Path	Parameters Names Detected
/{username}/about	username
/{username}/articles/{articleId}	username, articleId
/{username}/articles/{articleId}/comments	username, articleId
/{username}/articles/{articleId}/comments/{commentId}	username, articleId, commentId
...	...

Route Handler

Route handlers can inject these parameters by name

// src/api/{username}/articles/{articleId}/comments/{commentId}
return static function(string $username, string $articleId, string $commentId){};

Note

It is important that the variables names match exactly the parameter names.

Type safety

Route handlers have the authority to define how parameters are matched.

You can configure this behavior using a #[Param] attribute

// src/api/{username}/articles/{articleId}/comments/{commentId}/get.php
use CatPaw\Web\Attributes\Param;

return static function(
    #[Param('\w{3,}')]    string $username,  // Require $username to be at least 3 characters long.
    #[Param('[A-z0-9-]')] string $articleId, // Require $articleId to include only characters from A to z, numbers and '-'
    #[Param('[A-z0-9-]')] string $commentId, // Require $articleId to include only characters from A to z, numbers and '-'
){};