Awesome

Twirp Dart Plugin

A protoc plugin for generating a twirp client suitable for web and flutter/io projects. Inspired by the Twirp typescript plugin.

Setup

The protobuf v3 compiler is required. You can get the latest precompiled binary for your system here:

https://github.com/google/protobuf/releases

Twirp Go Server (optional)

While not required for generating the client code, it is required to run the server component of the example.

go get github.com/twitchtv/twirp/protoc-gen-twirp
go get -u github.com/golang/protobuf/protoc-gen-go

Dependencies

This plugin requires 2 Dart pub dependencies. In your pubspec.yaml specify: http: ^0.11.0 requester: ">=0.0.2 <2.0.0"

Usage

go get -u github.com/apptreesoftware/protoc-gen-twirp_dart
protoc --twirp_dart_out=./example/dart_client ./example/service.proto

All generated files will be placed relative to the specified output directory for the plugin.
This is different behavior than the twirp Go plugin, which places the files relative to the input proto files.

This decision is intentional, since only client code is generated, and the destination is likely somewhere different than the server code.

Using the Twirp hashberdasher proto:

Future main(List<String> args) async {
  var service = new DefaultHaberdasher('http://localhost:8080');
  try {
    var hat = await service.makeHat(new Size()..inches = 10);
    print(hat);

    hat = await service.makeHat(new Size()..inches = -1);
    print(hat);
  } on TwirpJsonException catch (e) {
    print("${e.code} - ${e.message}");
  } catch (e) {
    print(e);
  }
}

Parameters

The plugin parameters should be added in the same manner as other protoc plugins. Key/value pairs separated by a single equal sign, and multiple parameters comma separated.

Using the Example

Run the server:

make run
go run cmd/haberdasher/main.go
 

In a new terminal run the client:

cd example/dart_client
pub get
dart main.dart