laravel 路由上的可选参数

Question

I have a route like this. I want the first parameter will be an optional parameter. For example: students/service/123/detail & service/123/detail. What should I do? Thanks in advance.

Route::get('{optionalParam}/{slug}/{registrationCode}/detail', [SubmissionController::class, 'submissionDetail'])->name('submission.detail');

Answer 1

Following the official documentation , optionals parameters are in the last position.

The reason is simple. For example this route:

Route::get('{param1?}/{param2}/{param3}

If you pass nothing as param1 , then param2 will become param1 . So I advice you to use the same route, with a required parameter like this:

Route::get('{optionalParam}/{slug}/{registrationCode}/detail', [SubmissionController::class, 'submissionDetail'])->name('submission.detail');

And after in your controller, check if this parameter is the default you defined or not. For example, you can define a default value, like 0 and this value will indicate you that this parameter doesn't exist:

public function test($optionalParam, $slug, $registrationCode)
{
    if ($optionalParam === 0) {
        // here the parameter doesn't exist
    }

    // here the parameter exists
}

Answer 2

You can't have an optional parameter before mandatory parameters. Make registrationCode optional:

Route::get('{optionalParam}/{slug}/{registrationCode?}/detail', [SubmissionController::class, 'submissionDetail'])->name('submission.detail');

and change your submissionDetail method to be as:

public function submissionDetail($optionalParam, $slug, $registrationCode=null) {
    if ($registrationCode === null) {
        $registrationCode = $slug;
        $slug = $optionalParam;
        $optionalParam = null;
    } 
    // Rest of method
}