step-03.md

Using low level starknet.dart API

In this step, you will source code generation from ABI.

To ease usage of devnet, starknet.dart provide the account0 object which represent the first predeployed account of devnet.

Create application directory

Create a new dart cli application name dart

dart create app

pubspec overrides

Create a file named pubspec_overrides.yaml in your app directory with the following content:

dependency_overrides:
  starknet:
      git:
        url: https://github.com/focustree/starknet.dart
        path: packages/starknet
  starknet_builder:
      git:
        url: https://github.com/focustree/starknet.dart
        path: packages/starknet_builder

Since starknet.dart is not yet released, you will use the latest version on github.

Replace main

Replace the app/bin/app.dart which the following content

import 'dart:convert';
import 'dart:io';
import 'package:app/app.dart' as app;

void main(List<String> arguments) async {
  final deploymentPath = arguments[0];
  final Map<String, Object?> deployment =
      jsonDecode((await File(deploymentPath).readAsString()));
  final contractAddress = deployment["address"] as String;

  print('Counter: ${(await app.getCounter(contractAddress))}');
  print('Increasing counter');
  final ok = await app.increaseCounter(contractAddress);
  print('Transaction succeeded: $ok');
  print('Counter: ${(await app.getCounter(contractAddress))}');
}

We need to implement getCounter and increaseCounter in our app/lib/app.dart

Template content of app/lib/app.dart

Future<int> getCounter(String contractAddress) async {
    return 0;
}

Future<bool> increaseCounter(String contractAddress) async {
    return true;
}

Update pubspec

Add starknet in dependencies, starknet_builder and build_runner in build_dependcies in your app/pubspec.yaml

name: app
description: A sample command-line application.
version: 1.0.0
# repository: https://github.com/my_org/my_repo

environment:
  sdk: ^3.0.5

# Add regular dependencies here.
dependencies:
  # path: ^1.8.0
  starknet:
  
dev_dependencies:
  lints: ^2.0.0
  test: ^1.21.0
  starknet_builder:
  build_runner: ^2.1.11

And then run

dart pub get

Running your app

The main is expected a JSON file containing deployment information as first argument

dart run ./app/bin/app.dart ./contracts/deployment.json

Generate source code from sierra JSON file

To generate source code from a sierra JSON file, the first step is to extract the ABI from this file.

mkdir app/lib/src

dart run ./to': dart run ./tool/bin/extract_sierra_json.dart --input ./contracts/target/dev/contracts_Counter.sierra.json --output ./app/lib/src/counter.sierra.json

You can now execute build_runner to generate a file named counter.sierra.g.dart

cd app
dart run build_runner build