HTTP/3 Bidirectional Streaming Project

This project demonstrates HTTP/3 bidirectional streaming using Netty (Java) and aioquic (Python). It features a Java server that processes incoming data packets asynchronously and slowly to demonstrate flow control and bidirectional communication, with both Java and Python client implementations.

Features

• ✅ HTTP/3 & QUIC: Full HTTP/3 bidirectional streaming.
• ✅ Cross-Language: Java Server with both Java and Python clients.
• ✅ Asynchronous Processing: Server uses a thread pool to process packets without blocking the event loop.
• ✅ JSON Communication: Structured data exchange using Jackson (Java) and json (Python).
• ✅ Flow Control: Demonstrates handling of rapid packet bursts with slow processing.

Project Structure

.
├── src/main/java/
│   ├── Http3BidirectionalStreamServer.java # Server implementation
│   ├── Http3Client.java                    # Java Client implementation
│   ├── ServerMain.java                     # Server entry point
│   ├── ClientMain.java                     # Java Client entry point
│   ├── DataPacket.java                     # Data model for packets
│   ├── AckResponse.java                    # Response model for acknowledgments
│   └── QuicTest.java                       # QUIC availability test
├── python_client.py                        # Python Client implementation
├── pyproject.toml                          # Python configuration & dependencies (Poetry)
├── build.gradle                            # Gradle build configuration
└── poetry.lock                             # Locked Python dependencies

Getting Started

Prerequisites

• Java 21 or higher.
• Python 3.10 or higher (for the Python client).
• Poetry (for Python dependency management).
• OpenSSL (to generate certificates).

1. Generate SSL Certificates

The HTTP/3 server requires an SSL certificate and private key to function. Run the following command in the project root to generate self-signed certificates:

openssl req -x509 -newkey rsa:2048 -keyout server.key -out server.crt -days 365 -nodes -subj "/CN=localhost"

This will create server.key and server.crt in your current directory.

2. Setup Python Environment

This project uses Poetry for Python dependency management (similar to Gradle for Java).

1. Install Poetry (if not already installed):

   pip install poetry

2. Install Dependencies:

   poetry install

3. Running the Server

The server starts on port 9443 using the certificates generated in step 1.

./gradlew run

4. Running the Clients

Java Client

./gradlew runClient

Python Client

poetry run python python_client.py

Implementation Details

Java Client Fixes

The Java client has been optimized for:

• Correct Pipeline Setup: Uses Http3ClientConnectionHandler and Http3.newRequestStream for proper HTTP/3 frame handling.
• Strict JSON Serialization: Uses Jackson annotations to ensure JSON compatibility between Java and Python components.
• Resilient Deserialization: Handles variations in JSON field names (e.g., isFinal vs final) gracefully.

Server Behavior

The server is designed to be "slow" by introducing a random delay (500ms - 1500ms) for each packet. This highlights the bidirectional nature of the protocol where the client can keep sending packets while waiting for individual ACKs to arrive out-of-order or delayed.

Dependencies

• Netty Incubator HTTP/3 & QUIC: For the core protocol implementation.
• Jackson Databind: For JSON processing in Java.
• aioquic: For the Python client implementation.