gRPC Extension for LoopBack 4

Overview

The @loopback/grpc component enables LoopBack 4 as a gRPC Server. Also it provides with a gRPC decorator to define your RPC Method implementations from your Application Controllers.

Installation

Install the @loopback/grpc component in your LoopBack 4 Application.

$ npm install --save @loopback/grpc

Component Configuration

import {Application} from '@loopback/core';
import {GrpcComponent, Config} from '@loopback/grpc';
import {GreeterCtrl} from './controllers/greeter/greeter.ctrl';
// Grpc Configurations are optional.
const config: Config.Component = {
  /* Optional Configs */
};
// Pass the optional configurations
const app = new Application({
  grpc: config,
});
// Add Grpc as Component
app.component(GrpcComponent);
// Bind GreeterCtrl to the LoopBack Application
app.controller(GreeterCtrl);
// Start App
app.start();

Grpc auto-generated code

The @loopback/grpc extension provides you with auto-generated interfaces and configurations for strict development.

The extension will automatically look for proto files within your project structure, creating the corresponding typescript interfaces.

Example:

- app
| - controllers
| | - greeter
| | | - greeter.proto
| | | - greeter.ctrl.ts

Once you start your app for first time it will automatically create your typescript interfaces from the greeter.proto file.

- app
| - controllers
| | - greeter
| | | - greeter.proto
| | | - greeter.proto.ts <--- Auto-generated
| | | - greeter.ctrl.ts

Once your interfaces and configurations are created, you can start building your controller logic.

Grpc Controller

The @loopback/grpc component provides you with a handy decorator to implement GRPC Methods within your LoopBack controllers.

app/controllers/greeter/greeter.ctrl.ts

import {grpc} from '@loopback/grpc';
import {Greeter, HelloRequest, HelloReply} from '/greeter.proto';
/**
 * @class GreeterCtrl
 * @description Implements grpc proto service
 **/
export class GreeterCtrl implements Greeter.Service {
    // Tell LoopBack that this is a Service RPC implementation
    @grpc(Greeter.SayHello)
    sayHello(request: HelloRequest): HelloReply {
        return {message: 'Hello ' + request.name};
    }
}

Proto Example

app/controllers/greeter/greeter.proto

syntax = "proto3";
package greeterpackage;

service Greeter {
  // Sends a greeting
  rpc SayHello (HelloRequest) returns (HelloReply) {}
}

// The request message containing the user's name.
message HelloRequest {
  string name = 1;
}

// The response message containing the greetings
message HelloReply {
  string message = 1;
}

Contribute

Get started by either downloading this project or cloning it as follows:

$ git clone https://github.com/strongloop/loopback4-extension-grpc.git
$ cd loopback4-extension-grpc && npm install

Contributions

• Guidelines
• Join the team

Tests

run npm test from the root folder.

Todo

• Watch for proto changes.
• Server/Client Streams

Contributors

See all contributors.

License

MIT