dart_web3_provider #

The connectivity gateway for the Dart Web3 SDK. It provides a standardized interface for sending JSON-RPC requests to blockchain nodes via various transport protocols.

🚀 Features #

• JSON-RPC 2.0 Compliant: Full support for the standard batching and error specifications.
• Transport Flexibility: Implementations for HTTP, with hooks for WebSockets and custom IPC.
• Advanced Middleware: Inject custom logic for request signing, rate limiting, or verbose logging.
• Fail-over Capability: (Planned) Logic to automatically switch between RPC endpoints.

Usage Flow #

sequenceDiagram
    participant A as Application
    participant I as Interceptor
    participant P as Provider
    participant N as Network
    A->>I: request(method, params)
    I->>P: process()
    P->>N: json-rpc via HTTP
    N-->>P: response
    P-->>I: parse
    I-->>A: result

🏗️ Architecture #

graph TD
    App[App Logic] --> Request[JsonRpcRequest]
    Request --> Provider[RpcProvider Interface]
    
    subgraph Transports [Transport Stack]
        Http[HttpProvider]
        WS[WebSocketProvider]
    end
    
    Provider --> Transports
    Transports --> Network[Public/Private RPC Node]

📚 Technical Reference #

Core Classes #

🛡️ Security Considerations #

• SSL/TLS: Always use https:// or wss:// for production RPC endpoints to prevent MITM attacks.
• Sensitive Data in Headers: When using custom auth headers, ensure the provider instance is not exposed to untrusted parts of the application.
• Rate Limit Handling: Implement exponential backoff in middleware to handle 429 Too Many Requests gracefully.

💻 Usage #

Provider with Logging Interceptor #

import 'package:dart_web3_provider/dart_web3_provider.dart';

class LoggerInterceptor extends RpcInterceptor {
  @override
  void onRequest(JsonRpcRequest request) {
    print('RPC Call: ${request.method}');
  }
}

void main() async {
  final provider = HttpProvider('https://mainnet.infura.io/v3/...')
    ..addInterceptor(LoggerInterceptor());
    
  final block = await provider.request('eth_blockNumber', []);
  print('Result: $block');
}

📦 Installation #

dependencies:
  dart_web3_provider: ^0.1.0