I am using Laravel 5.4 and unfortunately although the accepted answer seems fine, for preflighted requests (like PUT
and DELETE
) which will be preceded by an OPTIONS
request, specifying the middleware in the $routeMiddleware
array (and using that in the routes definition file) will not work unless you define a route handler for OPTIONS
as well. This is because without an OPTIONS
route Laravel will internally respond to that method without the CORS headers.
So in short either define the middleware in the $middleware
array which runs globally for all requests or if you're doing it in $middlewareGroups
or $routeMiddleware
then also define a route handler for OPTIONS
. This can be done like this:
Route::match(['options', 'put'], '/route', function () {
// This will work with the middleware shown in the accepted answer
})->middleware('cors');
I also wrote a middleware for the same purpose which looks similar but is larger in size as it tries to be more configurable and handles a bunch of conditions as well:
<?php
namespace App\Http\Middleware;
use Closure;
class Cors
{
private static $allowedOriginsWhitelist = [
'http://localhost:8000'
];
// All the headers must be a string
private static $allowedOrigin = '*';
private static $allowedMethods = 'OPTIONS, GET, POST, PUT, PATCH, DELETE';
private static $allowCredentials = 'true';
private static $allowedHeaders = '';
/**
* Handle an incoming request.
*
* @param \Illuminate\Http\Request $request
* @param \Closure $next
* @return mixed
*/
public function handle($request, Closure $next)
{
if (! $this->isCorsRequest($request))
{
return $next($request);
}
static::$allowedOrigin = $this->resolveAllowedOrigin($request);
static::$allowedHeaders = $this->resolveAllowedHeaders($request);
$headers = [
'Access-Control-Allow-Origin' => static::$allowedOrigin,
'Access-Control-Allow-Methods' => static::$allowedMethods,
'Access-Control-Allow-Headers' => static::$allowedHeaders,
'Access-Control-Allow-Credentials' => static::$allowCredentials,
];
// For preflighted requests
if ($request->getMethod() === 'OPTIONS')
{
return response('', 200)->withHeaders($headers);
}
$response = $next($request)->withHeaders($headers);
return $response;
}
/**
* Incoming request is a CORS request if the Origin
* header is set and Origin !== Host
*
* @param \Illuminate\Http\Request $request
*/
private function isCorsRequest($request)
{
$requestHasOrigin = $request->headers->has('Origin');
if ($requestHasOrigin)
{
$origin = $request->headers->get('Origin');
$host = $request->getSchemeAndHttpHost();
if ($origin !== $host)
{
return true;
}
}
return false;
}
/**
* Dynamic resolution of allowed origin since we can't
* pass multiple domains to the header. The appropriate
* domain is set in the Access-Control-Allow-Origin header
* only if it is present in the whitelist.
*
* @param \Illuminate\Http\Request $request
*/
private function resolveAllowedOrigin($request)
{
$allowedOrigin = static::$allowedOrigin;
// If origin is in our $allowedOriginsWhitelist
// then we send that in Access-Control-Allow-Origin
$origin = $request->headers->get('Origin');
if (in_array($origin, static::$allowedOriginsWhitelist))
{
$allowedOrigin = $origin;
}
return $allowedOrigin;
}
/**
* Take the incoming client request headers
* and return. Will be used to pass in Access-Control-Allow-Headers
*
* @param \Illuminate\Http\Request $request
*/
private function resolveAllowedHeaders($request)
{
$allowedHeaders = $request->headers->get('Access-Control-Request-Headers');
return $allowedHeaders;
}
}
Also written a blog post on this.