smoldot_provider

A light-client (smoldot) JSON-RPC provider for Dart.

getSmProvider turns a smoldot Chain into a standard, string-based JsonRpcProvider: you call it with an onMessage callback and get back a connection you send raw JSON-RPC strings to. You run your own JSON-RPC client over it. Only the light-client (smoldot) provider is supported; there is intentionally no WebSocket/other kind.

Usage

import 'dart:convert';
import 'package:smoldot_provider/smoldot_provider.dart';

final client = SmoldotClient();
await client.initialize();

// getSmProvider accepts a Chain or a Future<Chain>, so pass addChain directly.
final JsonRpcProvider provider = getSmProvider(
  client.addChain(AddChainConfig(chainSpec: westendChainSpec)),
);

// Open a connection; every inbound JSON-RPC message arrives as a raw string.
final connection = provider((message) {
  final decoded = jsonDecode(message) as Map<String, dynamic>;
  // route by `id` (responses) or `params.subscription` (notifications)
});

connection.send('{"jsonrpc":"2.0","id":1,"method":"system_chain","params":[]}');

// ... later
connection.disconnect(); // removes the chain from the smoldot client

Parachains pass potentialRelayChains; statement-store services enable AddChainConfig.statementStore:

final relay = await client.addChain(AddChainConfig(chainSpec: relaySpec));
final provider = getSmProvider(
  client.addChain(AddChainConfig(
    chainSpec: assetHubSpec,
    potentialRelayChains: [relay.chainId],
    statementStore: StatementStoreConfig(),
  )),
);

Interface

typedef JsonRpcProvider = JsonRpcConnection Function(
  void Function(String message) onMessage,
);

abstract interface class JsonRpcConnection {
  void send(String message);
  void disconnect();
}

getRawProvider(FutureOr<RawJsonRpcChain>) is the lower-level entry point: build a provider over any minimal chain surface (sendJsonRpc / nextJsonRpcResponse / close) — used by tests and custom light-client sources.

Develop

dart pub get
dart analyze
dart test               # unit tests (no native lib)
dart test --tags network  # integration vs a live chain (needs the smoldot native lib + network)