https://rcoedo.com/blog/2019/01/18/node-js-grpc-services-in-style

dynamic-proto-loading.js

const protoLoader = require("@grpc/proto-loader");

const proto = protoLoader.loadSync(path.join(__dirname, "..", "greeter.proto"));
const definition = grpc.loadPackageDefinition(proto);

Examples for "Node.js gRPC Services in Style"

This gist contains the examples for the article "Node.js gRPC Service in Style".

- https://medium.com/trabe/node-js-grpc-services-in-style-222389be991a
- https://rcoedo.com/blog/2019/01/18/node-js-grpc-services-in-style

greeter.proto

syntax= "proto3";

service HelloWorldService {
  rpc GreetMe (GreetRequest) returns (GreetReply) {}
}

message GreetRequest {
  string name = 1;
}

message GreetReply {
  string reply = 1;
}

grpc-service-definition.js

const grpc = require("@grpc/grpc-js");

const greetMe = (call, callback) => {
  callback(null, { reply: `Hey ${call.request.name}!` });
};

const server = new grpc.Server();

server.addService(definition.GreeterService.service, { greetMe });

grpc-service-example-1.js

const path = require("path");
const grpc = require("@grpc/grpc-js");
const protoLoader = require("@grpc/proto-loader");

const proto = protoLoader.loadSync(path.join(__dirname, "..", "greeter.proto"));
const definition = grpc.loadPackageDefinition(proto);

const greetMe = (call, callback) => {
  callback(null, { reply: `Hey ${call.request.name}!` });
};

const server = new grpc.Server();

server.addService(definition.GreeterService.service, { greetMe });

server.bindAsync("0.0.0.0:50051", grpc.ServerCredentials.createInsecure(), port => {
  server.start();
});

grpc-service-start.js

server.bindAsync("0.0.0.0:50051", grpc.ServerCredentials.createInsecure(), port => {
  server.start();
});

handler-2-middleware.js

// Before
const greetMe = (call, callback) => {
  callback(null, { reply: `Hey ${call.request.name}!` });
};

// After
const greetMe = async (ctx, next) => {
  ctx.res = { reply: `Hey ${ctx.req.name}` };
  await next();
};

mali-service-1.js

const path = require("path");
const Mali = require("mali");

const greetMe = async (ctx, next) => {
  ctx.res = { reply: `Hey ${ctx.req.name}!` };
  await next();
};

const app = new Mali(path.join(__dirname, "..", "greeter.proto"));

app.use({ greetMe });

app.start("0.0.0.0:50051");

mali-service-2.js

const path = require("path");
const Mali = require("mali");

const greetMe = async (ctx, next) => {
  ctx.res = { reply: `Hey ${ctx.req.name}!` };
  await next();
};

const logRequest = async (ctx, next) => {
  const start = new Date();

  await next();

  const ms = new Date() - start;
  console.log(`[${start.toLocaleString()}] Request ${ctx.name} took ${ms}ms`);
};

const app = new Mali(path.join(__dirname, "..", "greeter.proto"));

app.use(logRequest);
app.use({ greetMe });

app.start("0.0.0.0:50051");

mali-service-middleware-1.js

async (ctx, next) => {
  // Do some stuff, maybe.
  // cascade through the rest of the middleware chain
  await next();
  // Do more stuff, or not. ¯\_(ツ)_/¯
}

mali-service-middleware-2.js

async (ctx, next) => {
  const start = new Date();
  
  await next();
  
  const ms = new Date() - start;
  console.log(`[${start.toLocaleString()}] Request ${ctx.name} took ${ms}ms`);
}