grpc-node/examples/metadata/server.js

/*
 *
 * Copyright 2023 gRPC authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

const grpc = require('@grpc/grpc-js');
const protoLoader = require('@grpc/proto-loader');
const parseArgs = require('minimist');

const PROTO_PATH = __dirname + '/../protos/echo.proto';

const packageDefinition = protoLoader.loadSync(
  PROTO_PATH,
  {keepCase: true,
   longs: String,
   enums: String,
   defaults: true,
   oneofs: true
  });
const echoProto = grpc.loadPackageDefinition(packageDefinition).grpc.examples.echo;

const STREAMING_COUNT = 10;

function unaryEcho(call, callback) {
  console.log('--- UnaryEcho ---');
  const incomingTimestamps = call.metadata.get('timestamp');
  if (incomingTimestamps.length > 0) {
    console.log('Timestamp from metadata:');
    for (const [index, value] of incomingTimestamps.entries()) {
      console.log(` ${index}. ${value}`);
    }
  }

  const outgoingHeaders = new grpc.Metadata();
  outgoingHeaders.set('location', 'MTV');
  outgoingHeaders.set('timestamp', new Date().toISOString());
  call.sendMetadata(outgoingHeaders);

  const outgoingTrailers = new grpc.Metadata();
  outgoingTrailers.set('timestamp', new Date().toISOString());

  console.log(`Request received ${JSON.stringify(call.request)}, sending echo`);
  callback(null, call.request, outgoingTrailers);
}

function serverStreamingEcho(call) {
  console.log('--- ServerStreamingEcho ---');
  const incomingTimestamps = call.metadata.get('timestamp');
  if (incomingTimestamps.length > 0) {
    console.log('Timestamp from metadata:');
    for (const [index, value] of incomingTimestamps.entries()) {
      console.log(` ${index}. ${value}`);
    }
  }

  const outgoingHeaders = new grpc.Metadata();
  outgoingHeaders.set('location', 'MTV');
  outgoingHeaders.set('timestamp', new Date().toISOString());
  call.sendMetadata(outgoingHeaders);

  console.log(`Request received ${JSON.stringify(call.request)}`);
  for (let i = 0; i < STREAMING_COUNT; i++) {
    console.log(`Echo message ${JSON.stringify(call.request)}`);
    call.write(call.request);
  }

  const outgoingTrailers = new grpc.Metadata();
  outgoingTrailers.set('timestamp', new Date().toISOString());
  call.end(outgoingTrailers);
}

function clientStreamingEcho(call, callback) {
  console.log('--- ClientStreamingEcho ---');
  const incomingTimestamps = call.metadata.get('timestamp');
  if (incomingTimestamps.length > 0) {
    console.log('Timestamp from metadata:');
    for (const [index, value] of incomingTimestamps.entries()) {
      console.log(` ${index}. ${value}`);
    }
  }

  const outgoingHeaders = new grpc.Metadata();
  outgoingHeaders.set('location', 'MTV');
  outgoingHeaders.set('timestamp', new Date().toISOString());
  call.sendMetadata(outgoingHeaders);

  let lastReceivedMessage = '';
  call.on('data', value => {
    console.log(`Received request ${JSON.stringify(value)}`);
    lastReceivedMessage = value.message;
  });
  call.on('end', () => {
    const outgoingTrailers = new grpc.Metadata();
    outgoingTrailers.set('timestamp', new Date().toISOString());
    callback(null, {message: lastReceivedMessage}, outgoingTrailers);
  });
}

function bidirectionalStreamingEcho(call) {
  console.log('--- BidirectionalStreamingEcho ---');
  const incomingTimestamps = call.metadata.get('timestamp');
  if (incomingTimestamps.length > 0) {
    console.log('Timestamp from metadata:');
    for (const [index, value] of incomingTimestamps.entries()) {
      console.log(` ${index}. ${value}`);
    }
  }

  const outgoingHeaders = new grpc.Metadata();
  outgoingHeaders.set('location', 'MTV');
  outgoingHeaders.set('timestamp', new Date().toISOString());
  call.sendMetadata(outgoingHeaders);

  call.on('data', value => {
    console.log(`Request received ${JSON.stringify(value)}, sending echo`);
    call.write(value);
  });
  call.on('end', () => {
    const outgoingTrailers = new grpc.Metadata();
    outgoingTrailers.set('timestamp', new Date().toISOString());
    call.end(outgoingTrailers);
  });
}

const serviceImplementation = {
  unaryEcho,
  serverStreamingEcho,
  clientStreamingEcho,
  bidirectionalStreamingEcho
};

function main() {
  const argv = parseArgs(process.argv.slice(2), {
    string: 'port',
    default: {port: '50052'}
  });
  const server = new grpc.Server();
  server.addService(echoProto.Echo.service, serviceImplementation);
  server.bindAsync(`0.0.0.0:${argv.port}`, grpc.ServerCredentials.createInsecure(), (err, port) => {
    if (err != null) {
      return console.error(err);
    }
    console.log(`gRPC listening on ${port}`)
  });
}

main();