This package has framework agnostic Cross-Origin Resource Sharing (CORS) implementation. It is complaint with PSR-7 HTTP message interfaces.
Why this package?
- Implementation is based on latest CORS specification.
- Works with PSR-7 HTTP message interfaces.
- Supports debug mode with PSR-3 Logger Interface.
- Flexible, modular and extensible solution.
- High code quality. 100% test coverage.
- Free software license Apache 2.0.
The package is designed to be used as a middleware. Typical usage
use Neomerx\Cors\Analyzer;
use Psr\Http\Message\RequestInterface;
use Neomerx\Cors\Contracts\AnalysisResultInterface;
class CorsMiddleware
{
/**
* Handle an incoming request.
*
* @param RequestInterface $request
* @param Closure $next
*
* @return mixed
*/
public function handle(RequestInterface $request, Closure $next)
{
$cors = Analyzer::instance($this->getCorsSettings())->analyze($request);
switch ($cors->getRequestType()) {
case AnalysisResultInterface::ERR_NO_HOST_HEADER:
case AnalysisResultInterface::ERR_ORIGIN_NOT_ALLOWED:
case AnalysisResultInterface::ERR_METHOD_NOT_SUPPORTED:
case AnalysisResultInterface::ERR_HEADERS_NOT_SUPPORTED:
// return 4XX HTTP error
return ...;
case AnalysisResultInterface::TYPE_PRE_FLIGHT_REQUEST:
$corsHeaders = $cors->getResponseHeaders();
// return 200 HTTP with $corsHeaders
return ...;
case AnalysisResultInterface::TYPE_REQUEST_OUT_OF_CORS_SCOPE:
// call next middleware handler
return $next($request);
default:
// actual CORS request
$response = $next($request);
$corsHeaders = $cors->getResponseHeaders();
// add CORS headers to Response $response
...
return $response;
}
}
}
Analyzer accepts settings in Analyzer::instance($settings)
which must implement AnalysisStrategyInterface
. You can use default implementation \Neomerx\Cors\Strategies\Settings
to set the analyzer up.
For example,
use Neomerx\Cors\Strategies\Settings;
$settings = (new Settings())
->setServerOrigin('https', 'api.example.com', 443)
->setPreFlightCacheMaxAge(0)
->setCredentialsSupported()
->setAllowedOrigins(['https://www.example.com', ...]) // or enableAllOriginsAllowed()
->setAllowedMethods(['GET', 'POST', 'DELETE', ...]) // or enableAllMethodsAllowed()
->setAllowedHeaders(['X-Custom-Header', ...]) // or enableAllHeadersAllowed()
->setExposedHeaders(['X-Custom-Header', ...])
->disableAddAllowedMethodsToPreFlightResponse()
->disableAddAllowedHeadersToPreFlightResponse()
->enableCheckHost();
$cors = Analyzer::instance($settings)->analyze($request);
Settings could be cached which improves performance. If you already have settings configured as in the example above you can get internal settings state as
/** @var array $dataToCache */
$dataToCache = $settings->getData();
Cached state should be used as
$settings = (new Settings())->setData($dataFromCache);
$cors = Analyzer::instance($settings)->analyze($request);
composer require sankaest/neomerx-cors-psr7
Debug logging will provide a detailed step-by-step description of how requests are handled. In order to activate it a PSR-3 compatible Logger should be set to Analyzer
.
/** @var \Psr\Log\LoggerInterface $logger */
$logger = ...;
$analyzer = Analyzer::instance($settings);
$analyzer->setLogger($logger)
$cors = $analyzer->analyze($request);
There are many possible strategies for handling cross and same origin requests which might and might not depend on data from requests.
This built-in strategy Settings
implements simple settings identical for all requests (same list of allowed origins, same allowed methods for all requests and etc).
However you can customize such behaviour. For example you can send different sets of allowed methods depending on request. This might be helpful when you have some kind of Access Control System and wish to differentiate response based on request (for example on its origin). You can either implement AnalysisStrategyInterface
from scratch or override methods in Settings
class if only a minor changes are needed to Settings
. The new strategy could be sent to Analyzer
constructor or Analyzer::instance
method could be used for injection.
Example
class CustomMethodsSettings extends Settings
{
public function getRequestAllowedMethods(RequestInterface $request): string
{
// An external Access Control System could be used to determine
// which methods are allowed for this request.
return ...;
}
}
$cors = Analyzer::instance(new CustomMethodsSettings())->analyze($request);
composer test
Do not hesitate to check issues or post a new one.
If you have spotted any compliance issues with the CORS Recommendation please post an issue. Pull requests for documentation and code improvements (PSR-2, tests) are welcome.
This package is using Semantic Versioning.
Apache License (Version 2.0). Please see License File for more information.