decodeLast() — netty Function Reference

Architecture documentation for the decodeLast() function in HttpObjectDecoder.java from the netty codebase.

Function java ProtocolCodecs HTTP calls 2

Entity Profile

ProtocolCodecs→ HTTP→ decodeLast() — netty Function Reference

Dependency Diagram

graph TD
  ac7d1180_2220_c6a4_43ef_f0127601fbf9["decodeLast()"]
  6c551372_1bb2_fe27_3884_c4cc297c86ae["HttpObjectDecoder"]
  ac7d1180_2220_c6a4_43ef_f0127601fbf9 -->|defined in| 6c551372_1bb2_fe27_3884_c4cc297c86ae
  c3ede65f_ecbf_6fbd_c4d2_9a1fcb90c682["resetNow()"]
  ac7d1180_2220_c6a4_43ef_f0127601fbf9 -->|calls| c3ede65f_ecbf_6fbd_c4d2_9a1fcb90c682
  e8aadc10_5550_f709_7873_e84704f04e88["isDecodingRequest()"]
  ac7d1180_2220_c6a4_43ef_f0127601fbf9 -->|calls| e8aadc10_5550_f709_7873_e84704f04e88
  style ac7d1180_2220_c6a4_43ef_f0127601fbf9 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java lines 559–615

    @Override
    protected void decodeLast(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
        super.decodeLast(ctx, in, out);

        if (resetRequested.get()) {
            // If a reset was requested by decodeLast() we need to do it now otherwise we may produce a
            // LastHttpContent while there was already one.
            resetNow();
        }

        // Handle the last unfinished message.
        switch (currentState) {
            case READ_VARIABLE_LENGTH_CONTENT:
                if (!chunked && !in.isReadable()) {
                    // End of connection.
                    out.add(LastHttpContent.EMPTY_LAST_CONTENT);
                    resetNow();
                }
                return;
            case READ_HEADER:
                // If we are still in the state of reading headers we need to create a new invalid message that
                // signals that the connection was closed before we received the headers.
                out.add(invalidMessage(message, Unpooled.EMPTY_BUFFER,
                        new PrematureChannelClosureException("Connection closed before received headers")));
                resetNow();
                return;
            case READ_CHUNK_DELIMITER: // fall-trough
            case READ_CHUNK_FOOTER: // fall-trough
            case READ_CHUNKED_CONTENT: // fall-trough
            case READ_CHUNK_SIZE: // fall-trough
            case READ_FIXED_LENGTH_CONTENT:
                // Check if the closure of the connection signifies the end of the content.
                boolean prematureClosure;
                if (isDecodingRequest() || chunked) {
                    // The last request did not wait for a response.
                    prematureClosure = true;
                } else {
                    // Compare the length of the received content and the 'Content-Length' header.
                    // If the 'Content-Length' header is absent, the length of the content is determined by the end of
                    // the connection, so it is perfectly fine.
                    prematureClosure = contentLength > 0;
                }
                if (!prematureClosure) {
                    out.add(LastHttpContent.EMPTY_LAST_CONTENT);
                }
                resetNow();
                return;
            case SKIP_CONTROL_CHARS: // fall-trough
            case READ_INITIAL:// fall-trough
            case BAD_MESSAGE: // fall-trough
            case UPGRADED: // fall-trough
                // Do nothing
                break;
            default:
                throw new IllegalStateException("Unhandled state " + currentState);
        }
    }