PHP : Slim Combination of Optional and Required Param

I want follwing type of route.

$app->get('/FetchImages/{catid}[/{subcatid}]/{page}', function ($request, $response, $args) {
    //Code
});

In Route I want following:

Category - Mandatory
SubCategory - Optional
Page - Mandatory

Can I do it in one route? If so, how can it be achieved? I want to have one function for these paths:

{catid}/{page}
{catid}/{subcatid}/{page}

Solution

You can't have mandatory placeholders after optional. If you try, fastRoute (router, utilized by Slim) will give you an error.

And even if we abstract from Slim and fastRoute, I suggest you reconsider the URL structure of your API. It is natural that mandatory comes first, optional comes later.

To be able to use same callback for the routes, I suggest you pass page as query parameter:

$this->get('/FetchImages/{categoryId}[/{subcategoryId}]', function($request, $response, $args) {

    $categoryId = $args['categoryId'];
    $subcategoryId = $args['subcategoryId'];

    //  Get requested page value.
    //  It defaults to null if no page specified
    $page = $request->getQueryParam('page', null);

});

And send request like this:

GET http://myapp.com/FetchImages/kittens/dangerous?page=2

In this case you're free to pass or skip page, and URL structure is still quite clean.