grpc

What is grpc?

The grpc npm package is a Node.js library for making and handling remote procedure calls (RPC) using the gRPC framework. It allows for efficient communication between services, supports multiple programming languages, and provides features like load balancing, authentication, and more.

What are grpc's main functionalities?

Creating a gRPC Server

This code demonstrates how to create a basic gRPC server in Node.js. It loads a .proto file, defines a service, and starts the server to listen for incoming requests.

const grpc = require('grpc');
const protoLoader = require('@grpc/proto-loader');
const packageDefinition = protoLoader.loadSync('path/to/your/protofile.proto', {});
const protoDescriptor = grpc.loadPackageDefinition(packageDefinition);
const yourService = protoDescriptor.yourService;

function yourFunction(call, callback) {
  callback(null, { message: 'Hello ' + call.request.name });
}

const server = new grpc.Server();
server.addService(yourService.service, { yourFunction: yourFunction });
server.bind('127.0.0.1:50051', grpc.ServerCredentials.createInsecure());
server.start();

Creating a gRPC Client

This code demonstrates how to create a gRPC client in Node.js. It connects to a gRPC server, makes a request, and handles the response.

const grpc = require('grpc');
const protoLoader = require('@grpc/proto-loader');
const packageDefinition = protoLoader.loadSync('path/to/your/protofile.proto', {});
const protoDescriptor = grpc.loadPackageDefinition(packageDefinition);
const yourService = protoDescriptor.yourService;

const client = new yourService('localhost:50051', grpc.credentials.createInsecure());

client.yourFunction({ name: 'World' }, (error, response) => {
  if (!error) {
    console.log('Greeting:', response.message);
  } else {
    console.error(error);
  }
});

Streaming RPC

This code demonstrates how to implement a streaming RPC in a gRPC server. It handles incoming stream data and sends responses back to the client.

const grpc = require('grpc');
const protoLoader = require('@grpc/proto-loader');
const packageDefinition = protoLoader.loadSync('path/to/your/protofile.proto', {});
const protoDescriptor = grpc.loadPackageDefinition(packageDefinition);
const yourService = protoDescriptor.yourService;

function yourStreamFunction(call) {
  call.on('data', (request) => {
    console.log('Received:', request);
    call.write({ message: 'Hello ' + request.name });
  });
  call.on('end', () => {
    call.end();
  });
}

const server = new grpc.Server();
server.addService(yourService.service, { yourStreamFunction: yourStreamFunction });
server.bind('127.0.0.1:50051', grpc.ServerCredentials.createInsecure());
server.start();

Other packages similar to grpc

grpc-web

The grpc-web package allows gRPC to be used in web applications. It provides a JavaScript client library that can communicate with gRPC services from the browser. This package is useful for integrating gRPC with frontend applications, whereas the grpc package is primarily focused on server-side and backend communication.

README

Node.js gRPC Library

PREREQUISITES

• node: This requires node to be installed, version 4.0 or above. If you instead have the nodejs executable on Debian, you should install the nodejs-legacy package.

• Note: If you installed node via a package manager and the version is still less than 4.0, try directly installing it from nodejs.org.

INSTALLATION

Install the gRPC NPM package

npm install grpc

BUILD FROM SOURCE

1. Clone the grpc Git Repository.
2. Run npm install --build-from-source from the repository root.

• Note: On Windows, this might fail due to nodejs issue #4932 in which case, you will see something like the following in npm install's output (towards the very beginning):

   ..
   Building the projects in this solution one at a time. To enable parallel build, please add the "/m" switch.
   WINDOWS_BUILD_WARNING
    "..\IMPORTANT: Due to https:\github.com\nodejs\node\issues\4932, to build this library on Windows, you must first remove C:\Users\jenkins\.node-gyp\4.4.0\include\node\openssl"
    ...
    ..
  

  To fix this, you will have to delete the folder C:\Users\<username>\.node-gyp\<node_version>\include\node\openssl and retry npm install

API DOCUMENTATION

See the API Documentation.

TESTING

To run the test suite, simply run npm test in the install location.