Middleware to intercept responses

[patrickvuarnoz]

Currently, as far as I can see, in Leaf 4 it is only possible to use middleware to intercept requests and perform actions and checks before the route gets called. It would be helpful if a middleware could also be used to intercept a response before it is sent to the client.

My current use case is logging. Logging the requests is simple with the current possibilities of the middleware. But depending on the status code of the response I also want to log the response, i.e. for all 4xx and 5xx responses, to be able to provide better support when API users contact the support about the problem. I don't want to add code for this kind of logging in all program parts where 4xx responses are sent and I don't want to replace response()->json() with a custom method for this.

I imagine something like Middleware::before() und Middleware::after() would be useful. One being called before routing happens, one after the routing before Response::send() is called. Another option would be to allow to create interceptors for responses with something like Response::onBeforeSend(function () {}).

Would it be possible to extend Leaf to be able to handle this?

[patrickvuarnoz]

For my current use case with logging I found a workaround as it is also possible to log the response AFTER it has been sent. It's not a clean solution but I'll post it here in case somebody else is having the same issue. Still, being able to not only intercept the request but also the response would be helpful. And being able to access the response properties without reflection would also be helpful (i.e. add getters for status, content, headers).

class RequestLogMiddleware extends Middleware {
  
  public function call() {
    
    // Get request data
    $method = $_SERVER['REQUEST_METHOD'] ?? 'GET';
    $uri = $_SERVER['REQUEST_URI'] ?? '/';
    
    // Build request line
    $requestLine = $method . ' ' . $uri;
    
    // Get headers
    $requestHeaders = [];
    foreach (getallheaders() as $name => $value) {
      $requestHeaders[] = $name . ': ' . $value;
    }
    
    // Get raw body
    $requestBody = file_get_contents('php://input');
    
    // Create log entry
    $log = new RequestLog();
    $log->user_id = auth()->id();
    $log->session_id = session()->id();
    $log->user_agent = request()->getUserAgent();
    $log->ip_address = request()->getIp();
    $log->request = trim($requestLine . PHP_EOL . implode(PHP_EOL, $requestHeaders) . PHP_EOL . PHP_EOL . $requestBody);
    $log->save();
    
    // Create shutdown function to track errors
    register_shutdown_function(function () use ($log) {
      
      // Get response code
      $responseCode = http_response_code();
      
      // Check response code
      if ($responseCode >= 400 && $responseCode <= 599) {
        
        // Build response line
        $responseLine = 'HTTP/1.1 ' . $responseCode . ' ' . response()::getMessageForCode($responseCode);
        
        // Get response headers
        $responseHeaders = headers_list();
        
        // Get response body (via reflection as the property on the response
        // is protected)
        $reflection = new \ReflectionClass(response());
        $property = $reflection->getProperty('content');
        $property->setAccessible(true);
        $responseBody = $property->getValue(response());
        
        // Update log entry
        $log->error = trim($responseLine . PHP_EOL . implode(PHP_EOL, $responseHeaders) . PHP_EOL . PHP_EOL . $responseBody);
        $log->save();
      }
    });
  }
}