RTC Sender C++ Library

A C++ library for WebRTC-based real-time robot control and monitoring. This library provides a framework for bidirectional communication between robots and control interfaces using WebRTC technology.

Overview

The rtc_sender library is the core component that enables WebRTC communication for robot platforms. It provides:

• WebRTC Client Management: Automated peer connection setup and management
• Data Channel Handlers: Bidirectional data communication for control commands and telemetry
• Media Track Handlers: Video streaming capabilities for camera feeds and other media sources
• Signaling Server: WebSocket-based signaling for WebRTC connection establishment

Library Structure

BA-GCS-rtc-sender/
├── include/rtc_sender/              # Public API headers
│   ├── handlers/
│   │   ├── data_channel/            # Data channel communication
│   │   └── media_track/             # Media streaming
│   ├── logger/                      # Logging utilities
│   ├── observers/                   # WebRTC event observers
│   └── websocket/                   # WebSocket client
├── src/                             # Implementation files
├── cmake/                           # CMake configuration for third party dependencies
├── third_party/                     # WebRTC setting & build scripts
└── test/                            # Unit tests (currently websocket client and logging related tests only)

Installation

For detailed WebRTC setup instructions, see docs/Installation.md.

Core Dependencies

• C++17 or later
• WebRTC - Google WebRTC library for peer-to-peer communication
• OpenSSL - For secure WebSocket connections
• OpenCV - Image processing and conversion
• JsonCpp - JSON data parsing
• cpprestsdk - HTTP/WebSocket client library
• fmt - Modern C++ formatting library

Integration Guide

The rtc_sender library uses the PIMPL (Pointer to Implementation) pattern to hide implementation details and minimize dependencies for client code. This means you only need to link against rtc_sender - all underlying dependencies (WebRTC, cpprestsdk, OpenSSL, etc.) are automatically handled internally.

1. Add Library to Your Project

Add the library as a subdirectory in your CMakeLists.txt:

# Set the path to rtc-sender-cpp-lib
set(RTC_SENDER_PATH "/path/to/ai-gcs-robot/rtc-sender-cpp-lib")
 
# Add the library subdirectory
add_subdirectory(${RTC_SENDER_PATH} ${CMAKE_BINARY_DIR}/cmake-build-debug)

2. Link Against the Library

For your executable or library that uses rtc_sender:

# Create your executable
add_executable(your_robot_app src/main.cpp)
 
# Link against rtc_sender library only
target_link_libraries(your_robot_app
        rtc_sender              # All dependencies are handled internally
)

Note: Thanks to the PIMPL pattern implementation, you don't need to explicitly link against WebRTC, cpprestsdk, OpenSSL, or other internal dependencies. The rtc_sender library manages all these dependencies internally.

3. Include Headers

rtc_sender.h is the main header file that includes all necessary components:

#include "rtc_sender.h"

Basic Usage Example

1. Create WebRTC Client

#include "rtc_sender.h"
 
// Configure client
rtc_sender::RobotWebRTCClientFactory factory(
    "robot_id_123",           // robot ID
    "user_id_456",            // user ID  
    "ws://localhost:8080",    // WebSocket signaling server
    "turn:server.com:3478",   // TURN server URL
    "username",               // TURN username
    "password"                // TURN password
);
 
// Create client instance
auto webrtc_client = factory.Create();

2. Register Custom Handlers and Start

// Create handlers
auto control_channel = std::make_shared<RobotControlChannel>();
auto camera_track = std::make_shared<CameraMediaTrack>();
 
// Register with client
webrtc_client->AddDataChannelHandler(control_channel);
webrtc_client->AddMediaTrackHandler(camera_track);
 
// Start the client
webrtc_client->StartSignalingServer();
 
// Cleanup
webrtc_client->ShuttingDown();

For comprehensive implementation guidance and examples:

• Implementation Guide

ROS Integration

For ROS1/ROS2 integration examples, see the examples directory:

• ROS1 Example: husky_ros1
• ROS2 Example: husky_ros2

Library Components

Core Classes

• **RobotWebRTCClient**: Main WebRTC client interface
• **RobotWebRTCClientFactory**: Factory for creating client instances

Handlers

• **DataChannelReceivable<T>**: Template for receiving typed data
• **DataChannelSendable**: Base class for sending data
• **MediaTrackHandler**: Base class for media streaming

Utilities

• **LogService**: Centralized logging system
• **WebSocketClient**: Wrapper for WebSocket communication
• **ClientStateManager**: Connection state management for RobotWebRTCClient

License

This project follows the same license as the parent BA-GCS-Robot repository.

Install

mkdir build && cd build
cmake ..
make
sudo make install