[英]how to implement Remote procedure call (RPC) in RabbitMQ using Nodejs
so i want to take a Json and parse it to Object and then implement a RPC RabbitMQ Server so that i can send the Object to the Server through RabbitMQ and there the Object will be proceed to be saved in a local Array and a universally unique id which will tell where exactly is the object stored, will be returned from that Server to the client throught the RPC. 所以我想用一个Json并将其解析为Object,然后实现一个RPC RabbitMQ Server,以便我可以通过RabbitMQ将对象发送到Server,然后该Object将继续保存在本地Array和一个通用的ID中它将告诉对象确切存储在哪里,将通过RPC从该服务器返回到客户端。
the Official Webseite shows some Implementation to RPC in RabbitMQ, here you can find their Implementration https://www.rabbitmq.com/tutorials/tutorial-six-javascript.html , in the Tutorial they send a Number and the Server will calculate Fibonacci Sequence and return the Result to the Client. 官方网站显示了RabbitMQ中RPC的一些实现,您可以在此处找到其实现https://www.rabbitmq.com/tutorials/tutorial-six-javascript.html ,在教程中,他们发送一个数字,服务器将计算斐波纳契排序并将结果返回给客户端。 instead i want to send an Object, not a Number and i want to receive the universally unique id(uuid) of that Object which i ll store in a global Array in my Program, i changed the code so that it ll send an Object and return the uuid but it didnt work.
相反,我想发送一个对象,而不是一个数字,并且我想接收该对象的通用唯一id(uuid),并将其存储在程序中的全局数组中,我更改了代码,以便它可以发送一个对象并返回uuid,但没有成功。 i ll apreciate any help from you guys
我会感谢你们的任何帮助
//this is my server_rpc.js code :
const amqp = require('amqplib/callback_api');
const uuid = require("uuid/v1");
amqp.connect('here is the url: example: localhost', (err, conn) => {
conn.createChannel( (err, ch) => {
let q = 'rpc_queue';
ch.assertQueue(q, {durable: false});
ch.prefetch(10);
console.log(' [x] Waiting RPC requests');
ch.consume(q, function reply(msg) {
console.log("corralation key is: ", msg.properties.correlationId);
let n = uuid();
console.log(" data received ",JSON.parse(JSON.stringify(msg.content.toString())));
console.log("corralation key is: ", msg.properties.correlationId);
ch.sendToQueue(msg.properties.replyTo, Buffer.from(n.toString()), {correlationId: msg.properties.correlationId});
ch.ack(msg);
});
});
}); });
// and this is my client_rpc.js code :
const amqp = require('amqplib/callback_api');
const uuid = require("uuid/v1");
const express = require("express");
let data = {
"name" : "hil01",
"region" : "weissach",
"ID" : "1",
"version" : "0.0.1"
}
amqp.connect('url: example localhost ', (err, conn) => {
conn.createChannel( (err, ch) => {
ch.assertQueue('', {exclusive: true}, (err, q) => {
var corr = generateUuid();
var newHil = JSON.stringify(data);
console.log(" [x] Requesting uuid for the registered HIL: ", newHil );
console.log("corralation key is: ", corr);
ch.consume(q.queue, function(msg) {
if(msg.properties.correlationId == corr) {
console.log(" [.] Got %s", msg.content.toString());
setTimeout(() => { conn.close(); process.exit(0) }, 100);
}
}, {noAck: true});
ch.sendToQueue('rpc_queue', Buffer.from(newHil, {correlationId: corr, replyTo: q.queue }));
});
});
}); });
//method to generate the uuid, later will be replaced with the real
uuid function
var generateUuid = () => Math.random().toString() +
Math.random().toString() + Math.random().toString() ;
when i run server_rpc, [x] waiting for requests should be printed then in a seperate cmd i run client_rpc.js then the object should be sent and the server execute and return to me the uuid back to the client. 当我运行server_rpc时,应该打印[x]等待请求,然后在单独的cmd中运行client_rpc.js,然后应发送对象,服务器执行并把uuid返回给我。
Seems what you need here is direct reply-to RPC pattern: you want to send a message and get a response. 似乎您需要的是直接答复RPC模式:您想发送消息并获得响应。
Here is documentation on RabbitMQ about direct reply-to: https://www.rabbitmq.com/direct-reply-to.html 这是RabbitMQ上有关直接回复的文档: https : //www.rabbitmq.com/direct-reply-to.html
TL;TR TL; TR
Here is an example of a client and a server, which would work from the box: 这是一个客户端和服务器的示例,它们可以在框中工作:
https://github.com/Igor-lkm/node-rabbitmq-rpc-direct-reply-to https://github.com/Igor-lkm/node-rabbitmq-rpc-direct-reply-to
What is inside 里面有什么
After installation of RabbitMQ you would have 2 files to execute: 安装RabbitMQ之后,您将有2个文件要执行:
server.js server.js
const amqp = require('amqplib');
const uuidv4 = require('uuid/v4');
const RABBITMQ = 'amqp://guest:guest@localhost:5672';
const open = require('amqplib').connect(RABBITMQ);
const q = 'example';
// Consumer
open
.then(function(conn) {
console.log(`[ ${new Date()} ] Server started`);
return conn.createChannel();
})
.then(function(ch) {
return ch.assertQueue(q).then(function(ok) {
return ch.consume(q, function(msg) {
console.log(
`[ ${new Date()} ] Message received: ${JSON.stringify(
JSON.parse(msg.content.toString('utf8')),
)}`,
);
if (msg !== null) {
const response = {
uuid: uuidv4(),
};
console.log(
`[ ${new Date()} ] Message sent: ${JSON.stringify(response)}`,
);
ch.sendToQueue(
msg.properties.replyTo,
Buffer.from(JSON.stringify(response)),
{
correlationId: msg.properties.correlationId,
},
);
ch.ack(msg);
}
});
});
})
.catch(console.warn);
client.js client.js
const amqp = require('amqplib');
const EventEmitter = require('events');
const uuid = require('uuid');
const RABBITMQ = 'amqp://guest:guest@localhost:5672';
// pseudo-queue for direct reply-to
const REPLY_QUEUE = 'amq.rabbitmq.reply-to';
const q = 'example';
// Credits for Event Emitter goes to https://github.com/squaremo/amqp.node/issues/259
const createClient = rabbitmqconn =>
amqp
.connect(rabbitmqconn)
.then(conn => conn.createChannel())
.then(channel => {
channel.responseEmitter = new EventEmitter();
channel.responseEmitter.setMaxListeners(0);
channel.consume(
REPLY_QUEUE,
msg => {
channel.responseEmitter.emit(
msg.properties.correlationId,
msg.content.toString('utf8'),
);
},
{ noAck: true },
);
return channel;
});
const sendRPCMessage = (channel, message, rpcQueue) =>
new Promise(resolve => {
const correlationId = uuid.v4();
channel.responseEmitter.once(correlationId, resolve);
channel.sendToQueue(rpcQueue, Buffer.from(message), {
correlationId,
replyTo: REPLY_QUEUE,
});
});
const init = async () => {
const channel = await createClient(RABBITMQ);
const message = { uuid: uuid.v4() };
console.log(`[ ${new Date()} ] Message sent: ${JSON.stringify(message)}`);
const respone = await sendRPCMessage(channel, JSON.stringify(message), q);
console.log(`[ ${new Date()} ] Message received: ${respone}`);
process.exit();
};
try {
init();
} catch (e) {
console.log(e);
}
You would have a result, like: 您将得到一个结果,例如:
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