gRPC + JSON in Node.js

grpc.js

const process = require('process');
const grpc = require('@grpc/grpc-js');

/**
 * $ node grpc.js server
 *
 * Server listening { port: 9001 }
 * Received { request: { message: 'Hello Server!' } }
 *
 * $ node grpc.js client
 *
 * Received { response: { message: 'Hello Client!' } }
 */
const [command] = process.argv.slice(2);

const serialize = value => Buffer.from(JSON.stringify(value));
const deserialze = buffer => JSON.parse(buffer.toString());

if (command === 'client') {
    const client = new grpc.Client('localhost:9001', grpc.credentials.createInsecure());

    client.waitForReady(Infinity, error => {
        if (error) {
            console.log(error);
            process.exit(1);
        }
        const requestBody = {
            message: 'Hello Server!'
        };
        client.makeUnaryRequest(
            '/sayHello',
            serialize,
            deserialze,
            requestBody,
            (error, response) => {
                if (error) {
                    console.error(error);
                    process.exit(1);
                }
                console.log('Received', { response });
            }
        );
    });
}

if (command === 'server') {
    const server = new grpc.Server();
    server.addService({
        sayHello: {
            path: '/sayHello',
            requestStream: false,
            responseStream: false,
            requestSerialize: serialize,
            responseSerialize: serialize,
            requestDeserialize: deserialze,
            responseDeserialize: deserialze
        }
    }, {
        sayHello: (call, callback) => {
            const { request } = call;
            console.log('Received', {
                request
            });
            return callback(null, {
                message: 'Hello Client!'
            });
        }
    });
    server.bindAsync('0.0.0.0:9001', grpc.ServerCredentials.createInsecure(), (error, port) => {
        if (error) {
            console.error(error);
            process.exit(1);
        }
        server.start();
        console.log('Server listening', { port });
    });
}