Lumen with CORS and OPTIONS requests

CatchAllOptionsRequestsProvider.php

<?php namespace App\Providers;

use Illuminate\Support\ServiceProvider;

/**
 * If the incoming request is an OPTIONS request
 * we will register a handler for the requested route
 */
class CatchAllOptionsRequestsProvider extends ServiceProvider {

  public function register()
  {
    $request = app('request');

    if ($request->isMethod('OPTIONS'))
    {
      app()->options($request->path(), function() { return response('', 200); });
    }
  }

}

CorsMiddleware.php

<?php namespace App\Http\Middleware;

class CorsMiddleware {

  public function handle($request, \Closure $next)
  {
    $response = $next($request);

    $response->header('Access-Control-Allow-Methods', 'HEAD, GET, POST, PUT, PATCH, DELETE');
    $response->header('Access-Control-Allow-Headers', $request->header('Access-Control-Request-Headers'));
    $response->header('Access-Control-Allow-Origin', '*');

    return $response;
  }

}

usage.md

Register the CatchAllOptionsRequestsProvider service provider in bootstrap/app.php which will check the incoming request and response successfully if it is an OPTIONS request.

Add the CorsMiddleware to the $app->middleware([ array in bootstrap/app.php which will attach the following CORS headers to all responses:

• allow all headers
• allow requests from all origins
• allow all the headers which were provided in the request

My solution was creating CorsMiddleware as below:

<?php

/**
 * Location: /app/Http/Middleware
 */
namespace App\Http\Middleware;

use Closure;

class CorsMiddleware
{
	/**
	 * Handle an incoming request.
	 *
	 * @param  \Illuminate\Http\Request  $request
	 * @param  \Closure  $next
	 * @return mixed
	 */
	public function handle($request, Closure $next)
	{
		$headers = [
			'Access-Control-Allow-Origin' => '*',
			'Access-Control-Allow-Methods' => 'POST,GET,PATCH,PUT,DELETE,OPTIONS',
			'Access-Control-Max-Age' => '86400',
                        'Access-Control-Allow-Headers' => 'Content-Type,API-KEY'
                ];

		if ($request->isMethod('OPTIONS')) {
			return response()->json('', 200, $headers);
		}

		$response = $next($request);

		foreach ($headers as $key => $value) {
			$response->header($key, $value);
		}

		return $response;
	}
}

Then register the middleware with a name in bootstrap/app.php as below:

$app->routeMiddleware([
  'cors' => App\Http\Middleware\CorsMiddleware::class
]);

Then wrapping required routes between the defined middleware in routes/web.php as below, and adding an additional rule to handle preflight OPTIONS requests:

$router->group(['middleware' => 'cors'], function () use ($router) {
  //All the routes you want to allow CORS for

  $router->options('/{any:.*}', function (Request $req) {
    return;
  });
});

NOTE
Using Chrome, you can get a more detailed error message than Firefox, which will help you to fix the problem and exactly states why there is no Access-Control-Allow-Origin in the response header. Also, keep in mind that any kind of redirect is not allowed in the preflight request, so make sure you don't have such rule in your .htaccess or any other place.

I've tried all of the code, and LOL, no one work for me.

I'm still got this error

hello everyone. I have cors middleware in my lumen as above. cors midlleware works normally when i make a request to lumen from my app. however, whenever a function that I need to send mail runs, I get the error "Call to a member function header() on null".

A single file solution with CorsMiddleware.php worked like a charm with Lumen 8.x. The only issue I had that my .htaccess file was not default and was adjusted with the following command:

RewriteCond %{REQUEST_METHOD} OPTIONS
RewriteRule ^(.*)$ $1 [R=200,L]

In my case I had to remove these lines to make things work.

Hello everyone again. I solved my error related to this issue. I share my answer with you below.

Due to the middleware structure, it returns and switches to the next request after processing. If an error is encountered after the request middleware has passed and did not return, the return value will be null.

For example, after I pass the request from the cors middleware, I am sending a mail via a event as a result of a series of operations. However, even though I changed the mail blade I sent, the cors middleware response value returns null because the php document created in ~/storage/framework/views does not update, and an error occurs.

https://stackoverflow.com/questions/68739232/call-to-a-member-function-header-on-null-in-cors-middleware-in-lumen/68760328#68760328