如何将第二个参数作为可选项传递给LUMEN中的路线？

Question

My routes/web.php file

$router->group(['prefix' => 'api/v1'], function () use ($router) {    
    $router->get('post/{string}/comment/{length?}', 'PostController@index');
});

My controller file

public function index($string, $length = 0){
    // boy
}

URLs to execute

localhost/project/public/api/v1/post/abcd/comment/1
    OR
localhost/project/public/api/v1/post/abcd/comment

I want string and length values in my controller, string is not optional parameter but length is optional if i not provide it it should take 0

Answer 1

Lumen uses a different router so you need to define optional parameters a little differently:

From the documentation

$app->get('user[/{name}]', function ($name = null) {
    return $name;
});

So in your case it would be:

$router->get('post/{string}/comment[/{length}]', 'PostController@index');