onPushPromiseRead() — netty Function Reference

Source Code

codec-http2/src/main/java/io/netty/handler/codec/http2/DefaultHttp2ConnectionDecoder.java lines 546–592

        @Override
        public void onPushPromiseRead(ChannelHandlerContext ctx, int streamId, int promisedStreamId,
                Http2Headers headers, int padding) throws Http2Exception {
            // A client cannot push.
            if (connection().isServer()) {
                throw connectionError(PROTOCOL_ERROR, "A client cannot push.");
            }

            Http2Stream parentStream = connection.stream(streamId);

            if (shouldIgnoreHeadersOrDataFrame(ctx, streamId, parentStream, false, "PUSH_PROMISE")) {
                return;
            }

            switch (parentStream.state()) {
              case OPEN:
              case HALF_CLOSED_LOCAL:
                  // Allowed to receive push promise in these states.
                  break;
              default:
                  // Connection error.
                  throw connectionError(PROTOCOL_ERROR,
                      "Stream %d in unexpected state for receiving push promise: %s",
                      parentStream.id(), parentStream.state());
            }

            if (!requestVerifier.isAuthoritative(ctx, headers)) {
                throw streamError(promisedStreamId, PROTOCOL_ERROR,
                        "Promised request on stream %d for promised stream %d is not authoritative",
                        streamId, promisedStreamId);
            }
            if (!requestVerifier.isCacheable(headers)) {
                throw streamError(promisedStreamId, PROTOCOL_ERROR,
                        "Promised request on stream %d for promised stream %d is not known to be cacheable",
                        streamId, promisedStreamId);
            }
            if (!requestVerifier.isSafe(headers)) {
                throw streamError(promisedStreamId, PROTOCOL_ERROR,
                        "Promised request on stream %d for promised stream %d is not known to be safe",
                        streamId, promisedStreamId);
            }

            // Reserve the push stream based with a priority based on the current stream's priority.
            connection.remote().reservePushStream(promisedStreamId, parentStream);

            listener.onPushPromiseRead(ctx, streamId, promisedStreamId, headers, padding);
        }