dart_web3_contract #

A type-safe wrapper for smart contract interaction. It bridges the gap between raw binary ABI data and developer-friendly Dart objects.

🚀 Features #

• Dynamic Contract Bindings: Create instance objects for any contract using its ABI and Address.
• Standard Library: High-level classes for ERC-20, ERC-721, and ERC-1155.
• Multi-call Optimized: Methods are designed to be batchable using the dart_web3_multicall package.
• Type Conversion: Automatic mapping between Solidity types and Dart primitives.

Usage Flow #

graph LR
    A[Contract Address] --> C[DeployedContract Object]
    B[Contract ABI] --> C
    C --> D[Read: call()]
    C --> E[Write: send()]
    D --> F[Parsed Result]
    E --> G[Tx Hash]

🏗️ Architecture #

graph LR
    Model[AbiDefinition] --> Factory[Contract Factory]
    Factory --> Instance[DeployedContract]
    Instance --> Read[Static Call]
    Instance --> Write[Transaction]
    
    subgraph Helpers [Included Standards]
        ERC20[ERC20Contract]
        ERC721[ERC721Contract]
    end

📚 Technical Reference #

Core Classes #

🛡️ Security Considerations #

• Decimal Precision: In ERC20Contract, always check the decimals() method result; never assume a token has 18 decimals (e.g., USDC uses 6).
• Infinite Allowance: When calling approve, consider using specific amounts rather than uint256.max unless the UX strictly requires it, to limit potential drain risk.
• Revert Handling: Always wrap contract send operations in try-catch blocks to handle custom Solidity errors (reverts).

💻 Usage #

Managing Token Allowances #

import 'package:dart_web3_contract/dart_web3_contract.dart';

void main() async {
  final dai = ERC20Contract(address: '0x...', publicClient: client);

  // Check current allowance
  final current = await dai.allowance(owner, spender);
  
  if (current < requiredAmount) {
     final tx = await dai.approve(spender, requiredAmount, walletClient: wallet);
     print('Approval sent: $tx');
  }
}

📦 Installation #

dependencies:
  dart_web3_contract: ^0.1.0