Add Support for WebRTC set-up in py-libp2p

[seetadev]

Description

Adding WebRTC set-up support to py-libp2p would enhance its capabilities by enabling peer-to-peer connections in browsers and other environments where direct network access may be restricted. This feature would complement existing transports like QUIC and TCP, making py-libp2p more versatile for real-time communication and decentralized applications.

Motivation

WebRTC is a critical transport layer for enabling efficient peer-to-peer communication, especially in environments where NAT traversal and real-time low-latency connections are essential. Many applications, such as decentralized chat systems, collaborative tools, and private-to-private networks, depend on WebRTC for seamless operation.

Implementing WebRTC in py-libp2p would also align with the existing capabilities of other libp2p implementations (e.g., js-libp2p and go-libp2p), further enhancing cross-platform interoperability.

Current Implementation

1. Integration with a WebRTC Library: Utilize an existing Python WebRTC library such as aiortc to handle the WebRTC signaling, media, and data channels.

2. Signaling Protocol: Define a signaling protocol that integrates seamlessly with libp2p's transport layer.

3. NAT Traversal: Ensure proper handling of NAT traversal using Autonat, Circuit Relay, Hole Punching or using existing protocols like STUN and TURN.

4. Transport Implementation: Implement WebRTC as a libp2p transport, adhering to libp2p's transport interface.

5. Testing and Documentation: Provide unit tests, integration tests, and comprehensive documentation to ensure reliability and ease of use.

Acceptance Criteria:

A functional WebRTC transport is added to py-libp2p.

The WebRTC transport is interoperable with other libp2p implementations that support WebRTC.

Proper handling of signaling, NAT traversal, and peer discovery.

Clear documentation and examples for developers to utilize the feature.

Benefits:

Broader applicability of py-libp2p in browser-based and restricted network environments.

Improved interoperability with other libp2p implementations.

Expanded use cases for real-time communication and decentralized applications.

References:

WebRTC Documentation

aiortc Python Library

js-libp2p WebRTC Example

libp2p Transport Interface

Potential Challenges:

Ensuring stable NAT traversal across different environments.

Managing compatibility with existing WebRTC implementations in go-libp2p and js-libp2p.

Performance optimization for high-throughput use cases.

Are you planning to do it yourself in a pull request ?

Maybe

[seetadev]

@Nkovaturient : As discussed, would like you to work on this issue and keep us posted on your progress. Share a draft pull request to help us review as you progress on adding Support for webrtc

[Nkovaturient]

@seetadev Roger that!

[Nkovaturient]

@seetadev created a PR with initial setup and config, kindly guide ahead!

[seetadev]

@Nkovaturient : Wonderful to learn that you have taken the initial steps. Please use trio as shared by @pacrob

Thanks for organizing the initial PR. Here's a breakdown of the proposed implementation steps for full WebRTC set-up support in py-libp2p, aligned with libp2p's transport interface and signaling patterns:

Phase 1: Validate the initial Setup

• Created WebRTCTransport class scaffold under libp2p/transport/
• Registered the transport for future integration into the switch
• Added config placeholders for signaling and peer connection management

Phase 2: Signaling Mechanism

WebRTC requires a signaling step to exchange SDP offers/answers and ICE candidates. Two options for moving forward:

Option 1: WebSocket Signaling (simpler, short-term)

• Standalone signaling server (via WebSockets)
• Peers exchange messages like offer, answer, and ice-candidate
• Each peer identifies itself using peer_id or multiaddr

Option 2: Native libp2p Signaling (preferred, long-term)

• Implement a signaling protocol over libp2p streams
  e.g., /libp2p/webrtc/signal/1.0.0
• Exchange SDP and ICE messages directly via established libp2p connections

Phase 3: Transport Integration

• Use aiortc for WebRTC support in Python. You would have to switch to trio instead of asyncio.
• Build out WebRTCTransport to:
  • Set up RTCPeerConnection
  • Manage connection lifecycle (offer/answer, ICE negotiation)
  • Send/receive bytes over a data channel
• Conform to libp2p.transport.base.BaseTransport

Phase 4: Testing & Debugging

• Local: loopback test between two Python peers
• Browser ↔ Python peer (optional stretch goal)
• Add logs for signaling steps, ICE state, and connection health
• Prepare minimal integration tests for CI

Steps after an MVP version of Webrtc is ready

• Add support for /webrtc/ multiaddrs
• Optional TURN/STUN support via aiortc config
• Connect to switch with secure channel upgrades (Noise/SECIO)

[Nkovaturient]

Sure, will update you soon @seetadev

[Nkovaturient]

@seetadev kindly review. I have enhanced and implemented the further steps, #557

[seetadev]

@Nkovaturient : You're getting really close—great work so far. When you have a chance, try to resolve the remaining mypy mismatches and the .rst formatting issue. Once that's cleared up, I'll ping @pacrob so we can review everything together and discuss the next steps. Appreciate the effort you're putting into this!

[Nkovaturient]

sure, working on resolving this build issues and correct implementation.
will update you soon!