mirror of https://github.com/grpc/grpc-node.git
Merge pull request #2487 from murgatroid99/example_metadata
Add metadata example
This commit is contained in:
Michael Lumish
GitHub
commit
9322f0cf54
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# Metadata example
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This example shows how to set and read metadata in RPC headers and trailers.
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## Start the server
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```
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node server.js
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```
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## Run the client
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```
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node client.js
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```
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/*
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*
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* Copyright 2023 gRPC authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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const grpc = require('@grpc/grpc-js');
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const protoLoader = require('@grpc/proto-loader');
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const parseArgs = require('minimist');
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const PROTO_PATH = __dirname + '/../protos/echo.proto';
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const packageDefinition = protoLoader.loadSync(
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PROTO_PATH,
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{keepCase: true,
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longs: String,
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enums: String,
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defaults: true,
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oneofs: true
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});
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const echoProto = grpc.loadPackageDefinition(packageDefinition).grpc.examples.echo;
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const STREAMING_COUNT = 10;
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function unaryCallWithMetadata(client, message) {
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return new Promise((resolve, reject) => {
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console.log('--- unary ---');
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const requestMetadata = new grpc.Metadata();
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requestMetadata.set('timestamp', new Date().toISOString());
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const call = client.unaryEcho({message}, requestMetadata, (error, value) => {
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if (error) {
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console.log(`Received error ${error}`);
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return;
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}
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console.log('Response:');
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console.log(`- ${JSON.stringify(value)}`);
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});
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call.on('metadata', metadata => {
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const timestamps = metadata.get('timestamp');
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if (timestamps.length > 0) {
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console.log('timestamp from header:');
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for (const [index, value] of timestamps.entries()) {
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console.log(` ${index}. ${value}`);
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}
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} else {
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console.error("timestamp expected but doesn't exist in header");
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}
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const locations = metadata.get('location');
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if (locations.length > 0) {
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console.log('location from header:');
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for (const [index, value] of locations.entries()) {
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console.log(` ${index}. ${value}`);
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}
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} else {
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console.error("location expected but doesn't exist in header");
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}
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});
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call.on('status', status => {
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const timestamps = status.metadata.get('timestamp');
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if (timestamps.length > 0) {
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console.log('timestamp from trailer:');
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for (const [index, value] of timestamps.entries()) {
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console.log(` ${index}. ${value}`);
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}
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} else {
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console.error("timestamp expected but doesn't exist in trailer");
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}
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resolve();
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});
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});
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}
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function serverStreamingWithMetadata(client, message) {
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return new Promise((resolve, reject) => {
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console.log('--- server streaming ---');
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const requestMetadata = new grpc.Metadata();
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requestMetadata.set('timestamp', new Date().toISOString());
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const call = client.serverStreamingEcho({message}, requestMetadata);
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call.on('metadata', metadata => {
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const timestamps = metadata.get('timestamp');
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if (timestamps.length > 0) {
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console.log('timestamp from header:');
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for (const [index, value] of timestamps.entries()) {
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console.log(` ${index}. ${value}`);
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}
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} else {
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console.error("timestamp expected but doesn't exist in header");
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}
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const locations = metadata.get('location');
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if (locations.length > 0) {
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console.log('location from header:');
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for (const [index, value] of locations.entries()) {
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console.log(` ${index}. ${value}`);
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}
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} else {
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console.error("location expected but doesn't exist in header");
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}
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});
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call.on('data', value => {
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console.log(`Received response ${JSON.stringify(value)}`);
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});
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call.on('status', status => {
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const timestamps = status.metadata.get('timestamp');
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if (timestamps.length > 0) {
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console.log('timestamp from trailer:');
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for (const [index, value] of timestamps.entries()) {
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console.log(` ${index}. ${value}`);
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}
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} else {
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console.error("timestamp expected but doesn't exist in trailer");
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}
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resolve();
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});
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call.on('error', error => {
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console.log(`Received error ${error}`);
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});
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});
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}
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function clientStreamingWithMetadata(client, message) {
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return new Promise((resolve, reject) => {
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console.log('--- client streaming ---');
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const requestMetadata = new grpc.Metadata();
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requestMetadata.set('timestamp', new Date().toISOString());
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const call = client.clientStreamingEcho(requestMetadata, (error, value) => {
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if (error) {
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console.log(`Received error ${error}`);
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return;
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}
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console.log('Response:');
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console.log(`- ${JSON.stringify(value)}`);
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});
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call.on('metadata', metadata => {
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const timestamps = metadata.get('timestamp');
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if (timestamps.length > 0) {
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console.log('timestamp from header:');
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for (const [index, value] of timestamps.entries()) {
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console.log(` ${index}. ${value}`);
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}
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} else {
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console.error("timestamp expected but doesn't exist in header");
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}
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const locations = metadata.get('location');
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if (locations.length > 0) {
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console.log('location from header:');
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for (const [index, value] of locations.entries()) {
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console.log(` ${index}. ${value}`);
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}
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} else {
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console.error("location expected but doesn't exist in header");
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}
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});
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call.on('status', status => {
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const timestamps = status.metadata.get('timestamp');
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if (timestamps.length > 0) {
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console.log('timestamp from trailer:');
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for (const [index, value] of timestamps.entries()) {
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console.log(` ${index}. ${value}`);
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}
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} else {
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console.error("timestamp expected but doesn't exist in trailer");
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}
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resolve();
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});
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for (let i = 0; i < STREAMING_COUNT; i++) {
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call.write({message});
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}
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call.end();
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});
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}
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function bidirectionalWithMetadata(client, message) {
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return new Promise((resolve, reject) => {
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console.log('--- bidirectional ---');
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const requestMetadata = new grpc.Metadata();
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requestMetadata.set('timestamp', new Date().toISOString());
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const call = client.bidirectionalStreamingEcho(requestMetadata);
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call.on('metadata', metadata => {
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const timestamps = metadata.get('timestamp');
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if (timestamps.length > 0) {
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console.log('timestamp from header:');
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for (const [index, value] of timestamps.entries()) {
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console.log(` ${index}. ${value}`);
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}
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} else {
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console.error("timestamp expected but doesn't exist in header");
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}
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const locations = metadata.get('location');
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if (locations.length > 0) {
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console.log('location from header:');
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for (const [index, value] of locations.entries()) {
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console.log(` ${index}. ${value}`);
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}
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} else {
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console.error("location expected but doesn't exist in header");
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}
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});
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call.on('data', value => {
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console.log(`Received response ${JSON.stringify(value)}`);
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});
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call.on('status', status => {
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const timestamps = status.metadata.get('timestamp');
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if (timestamps.length > 0) {
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console.log('timestamp from trailer:');
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for (const [index, value] of timestamps.entries()) {
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console.log(` ${index}. ${value}`);
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}
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} else {
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console.error("timestamp expected but doesn't exist in trailer");
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}
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resolve();
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});
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call.on('error', error => {
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console.log(`Received error ${error}`);
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});
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for (let i = 0; i < STREAMING_COUNT; i++) {
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call.write({message});
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}
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call.end();
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});
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}
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function asyncWait(ms) {
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return new Promise((resolve, reject) => {
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setTimeout(resolve, ms);
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});
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}
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const message = 'this is examples/metadata';
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async function main() {
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let argv = parseArgs(process.argv.slice(2), {
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string: 'target',
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default: {target: 'localhost:50052'}
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});
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const client = new echoProto.Echo(argv.target, grpc.credentials.createInsecure());
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await unaryCallWithMetadata(client, message);
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await asyncWait(1000);
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await serverStreamingWithMetadata(client, message);
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await asyncWait(1000);
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await clientStreamingWithMetadata(client, message);
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await asyncWait(1000);
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await bidirectionalWithMetadata(client, message);
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client.close();
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}
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main();
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@ -0,0 +1,156 @@
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/*
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*
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* Copyright 2023 gRPC authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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const grpc = require('@grpc/grpc-js');
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const protoLoader = require('@grpc/proto-loader');
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const PROTO_PATH = __dirname + '/../protos/echo.proto';
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const packageDefinition = protoLoader.loadSync(
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PROTO_PATH,
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{keepCase: true,
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longs: String,
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enums: String,
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defaults: true,
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oneofs: true
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});
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const echoProto = grpc.loadPackageDefinition(packageDefinition).grpc.examples.echo;
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const STREAMING_COUNT = 10;
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function unaryEcho(call, callback) {
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console.log('--- UnaryEcho ---');
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const incomingTimestamps = call.metadata.get('timestamp');
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if (incomingTimestamps.length > 0) {
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console.log('Timestamp from metadata:');
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for (const [index, value] of incomingTimestamps.entries()) {
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console.log(` ${index}. ${value}`);
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}
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}
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const outgoingHeaders = new grpc.Metadata();
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outgoingHeaders.set('location', 'MTV');
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outgoingHeaders.set('timestamp', new Date().toISOString());
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call.sendMetadata(outgoingHeaders);
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const outgoingTrailers = new grpc.Metadata();
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outgoingTrailers.set('timestamp', new Date().toISOString());
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console.log(`Request received ${JSON.stringify(call.request)}, sending echo`);
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callback(null, call.request, outgoingTrailers);
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}
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function serverStreamingEcho(call) {
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console.log('--- ServerStreamingEcho ---');
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const incomingTimestamps = call.metadata.get('timestamp');
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if (incomingTimestamps.length > 0) {
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console.log('Timestamp from metadata:');
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for (const [index, value] of incomingTimestamps.entries()) {
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console.log(` ${index}. ${value}`);
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}
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}
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const outgoingHeaders = new grpc.Metadata();
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outgoingHeaders.set('location', 'MTV');
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outgoingHeaders.set('timestamp', new Date().toISOString());
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call.sendMetadata(outgoingHeaders);
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console.log(`Request received ${JSON.stringify(call.request)}`);
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for (let i = 0; i < STREAMING_COUNT; i++) {
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console.log(`Echo message ${JSON.stringify(call.request)}`);
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call.write(call.request);
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}
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const outgoingTrailers = new grpc.Metadata();
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outgoingTrailers.set('timestamp', new Date().toISOString());
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call.end(outgoingTrailers);
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}
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function clientStreamingEcho(call, callback) {
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console.log('--- ClientStreamingEcho ---');
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const incomingTimestamps = call.metadata.get('timestamp');
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if (incomingTimestamps.length > 0) {
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console.log('Timestamp from metadata:');
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for (const [index, value] of incomingTimestamps.entries()) {
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console.log(` ${index}. ${value}`);
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}
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}
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const outgoingHeaders = new grpc.Metadata();
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outgoingHeaders.set('location', 'MTV');
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outgoingHeaders.set('timestamp', new Date().toISOString());
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call.sendMetadata(outgoingHeaders);
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let lastReceivedMessage = '';
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call.on('data', value => {
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console.log(`Received request ${JSON.stringify(value)}`);
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lastReceivedMessage = value.message;
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});
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call.on('end', () => {
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const outgoingTrailers = new grpc.Metadata();
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outgoingTrailers.set('timestamp', new Date().toISOString());
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callback(null, {message: lastReceivedMessage}, outgoingTrailers);
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});
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}
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function bidirectionalStreamingEcho(call) {
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console.log('--- BidirectionalStreamingEcho ---');
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const incomingTimestamps = call.metadata.get('timestamp');
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if (incomingTimestamps.length > 0) {
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console.log('Timestamp from metadata:');
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for (const [index, value] of incomingTimestamps.entries()) {
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console.log(` ${index}. ${value}`);
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}
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}
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const outgoingHeaders = new grpc.Metadata();
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outgoingHeaders.set('location', 'MTV');
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outgoingHeaders.set('timestamp', new Date().toISOString());
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call.sendMetadata(outgoingHeaders);
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call.on('data', value => {
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console.log(`Request received ${JSON.stringify(value)}, sending echo`);
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call.write(value);
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});
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call.on('end', () => {
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const outgoingTrailers = new grpc.Metadata();
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outgoingTrailers.set('timestamp', new Date().toISOString());
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call.end(outgoingTrailers);
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});
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}
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const serviceImplementation = {
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unaryEcho,
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serverStreamingEcho,
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clientStreamingEcho,
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bidirectionalStreamingEcho
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};
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function main() {
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const argv = parseArgs(process.argv.slice(2), {
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string: 'port',
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default: {port: '50052'}
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});
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const server = new grpc.Server();
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server.addService(echoProto.Echo.service, serviceImplementation);
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server.bindAsync(`0.0.0.0:${argv.port}`, grpc.ServerCredentials.createInsecure(), () => {
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server.start();
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});
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}
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main();
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@ -0,0 +1,45 @@
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/*
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*
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* Copyright 2018 gRPC authors.
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*
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||||
* 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.
|
||||
*
|
||||
*/
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syntax = "proto3";
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option go_package = "google.golang.org/grpc/examples/features/proto/echo";
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package grpc.examples.echo;
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// EchoRequest is the request for echo.
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message EchoRequest {
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string message = 1;
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}
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// EchoResponse is the response for echo.
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message EchoResponse {
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string message = 1;
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}
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// Echo is the echo service.
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service Echo {
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// UnaryEcho is unary echo.
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rpc UnaryEcho(EchoRequest) returns (EchoResponse) {}
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// ServerStreamingEcho is server side streaming.
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rpc ServerStreamingEcho(EchoRequest) returns (stream EchoResponse) {}
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// ClientStreamingEcho is client side streaming.
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rpc ClientStreamingEcho(stream EchoRequest) returns (EchoResponse) {}
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// BidirectionalStreamingEcho is bidi streaming.
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rpc BidirectionalStreamingEcho(stream EchoRequest) returns (stream EchoResponse) {}
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}
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