Catch exceptions from streaming generators and send stream stop flag; send stop flag if RR has stopped the stream; add comments

Author: roxblnfk

src/HttpWorker.php

@@ -93,21 +93,37 @@ private function respondStream(int $status, Generator $body, array $headers = []
 
         do {
             if (!$body->valid()) {
+                // End of generator
                 $content = (string)$body->getReturn();
                 if ($endOfStream === false && $content === '') {
+                    // We don't need to send an empty frame if the stream is not ended
                     return;
                 }
                 $worker->respond(new Payload($content, $head, $endOfStream));
                 break;
             }
+
             $content = (string)$body->current();
             if ($worker->getPayload(StreamStop::class) !== null) {
                 $body->throw(new StreamStoppedException());
+
+                // RoadRunner is waiting for a Stream Stop Frame to confirm that the stream is closed
+                // and the worker doesn't hang
+                $worker->respond(new Payload(''));
                 return;
             }
+
+            // Send a chunk of data
             $worker->respond(new Payload($content, $head, false));
-            $body->next();
             $head = null;
+
+            try {
+                $body->next();
+            } catch (\Throwable) {
+                // Stop the stream if an exception is thrown from the generator
+                $worker->respond(new Payload(''));
+                return;
+            }
         } while (true);
     }
 

src/HttpWorkerInterface.php

@@ -25,8 +25,7 @@ public function waitRequest(): ?Request;
      * @param Generator<mixed, scalar|Stringable, mixed, Stringable|scalar|null>|string $body Body of response.
      *        If the body is a generator, then each yielded value will be sent as a separated stream chunk.
      *        Returned value will be sent as a last stream package.
-     *        Note: Stream response is experimental feature and isn't supported by RoadRunner yet.
-     *              But you can try to use RoadRunner 2.9-alpha to test it.
+     *        Note: Stream response is supported by RoadRunner since version 2023.3
      * @param HeadersList|array $headers An associative array of the message's headers. Each key MUST be a header name,
      *                                   and each value MUST be an array of strings for that header.
      */