我试图将安慰消息发布到某个主题，然后在订阅服务器中接收到该消息之后，订阅服务器通过事件将该消息发送到我的应用程序的另一部分，以进行进一步处理。所有这些都是在一个node.js进程中发生的。我知道这可能是做事的最佳做法，因此可以随时向我指出更好的方向。我知道不是事件，我可以使用消息队列，但我想看看事件是否会导致这种情况发生。
我有以下文件：
server.js ：服务器初始化代码
TopicPublisher.js ：向主题发布安慰消息
TopicSubscriber.js ：订阅一个安慰性主题以使用消息，然后发出带有消息内容的事件
SocketWrapper.js ：接收TopicSubscriber.js发出的事件并进行进一步处理
function initServer() {
const express = require('express'),
app = express(),
server = require('http').createServer(app);
io = require('socket.io')(server);
const SocketWrapper = require('./SocketWrapper');
let sockets = new Set();
//This example emits to individual sockets (track by sockets Set above).
//Could also add sockets to a "room" as well using socket.join('roomId')
//https://socket.io/docs/server-api/#socket-join-room-callback
app.use(express.static(__dirname + '/dist'));
/*
everytime there is a new connection, there is a new socket
*/
io.on('connection', socket => {
sockets.add(socket);
//add socket to heartbeatGenerator as well
socketWrapper.sockets.add(socket);
console.log(`Socket ${socket.id} added`);
socket.on('clientdata', data => {
console.log(data);
});
if (!socketWrapper.started) {
socketWrapper.start();
}
socket.on('disconnect', () => {
console.log(`Deleting socket: ${socket.id}`);
sockets.delete(socket);
console.log(`Remaining sockets: ${sockets.size}`);
});
});
server.listen(8080);
console.log('Visit http://localhost:8080 in your browser');
}
initServer();
//1000ms to ensure async behaviors perform in a sync manner
require('./solace/TopicSubscriber', 1000);
//1500ms to ensure async behaviors perform in a sync manner
setTimeout(() => { require('./solace/TopicPublisher');}, 1500);
我知道setTimeout()的方法很hack ..只是试图使该版本正常工作。
const solace = require('solclientjs').debug; // logging supported
const eventEmitter = require('../EventEmitter');
const fs = require('fs');
const path = require('path');
// Initialize factory with the most recent API defaults
const factoryProps = new solace.SolclientFactoryProperties();
factoryProps.profile = solace.SolclientFactoryProfiles.version10;
solace.SolclientFactory.init(factoryProps);
// enable logging to JavaScript console at WARN level
// NOTICE: works only with ('solclientjs').debug
solace.SolclientFactory.setLogLevel(solace.LogLevel.WARN);
const TopicSubscriber = function (solaceModule, topicName) {
'use strict';
const solace = solaceModule;
const subscriber = {};
subscriber.session = null;
subscriber.topicName = topicName;
subscriber.subscribed = false;
// Logger
subscriber.log = function (line) {
const now = new Date();
const time = [('0' + now.getHours()).slice(-2), ('0' + now.getMinutes()).slice(-2),
('0' + now.getSeconds()).slice(-2)];
const timestamp = '[' + time.join(':') + '] ';
console.log(timestamp + line);
};
subscriber.log('\n*** Subscriber to topic "' + subscriber.topicName + '" is ready to connect ***');
// main function
subscriber.run = function (argv) {
subscriber.connect(argv);
};
// Establishes connection to Solace message router
subscriber.connect = function (argv) {
if (subscriber.session !== null) {
subscriber.log('Already connected and ready to subscribe.');
return;
}
// extract params
if (argv.length < 3) { // expecting 3 real arguments
subscriber.log('Cannot connect: expecting all arguments' +
' <protocol://host[:port]> <client-username>@<message-vpn> <client-password>.\n' +
'Available protocols are ws://, wss://, http://, https://, tcp://, tcps://');
process.exit();
}
const hosturl = argv[0];
subscriber.log('Connecting to Solace message router using url: ' + hosturl);
const usernamevpn = argv[1];
const username = usernamevpn.split('@')[0];
subscriber.log('Client username: ' + username);
const vpn = usernamevpn.split('@')[1];
subscriber.log('Solace message router VPN name: ' + vpn);
const pass = argv[2];
// create session
try {
subscriber.session = solace.SolclientFactory.createSession({
// solace.SessionProperties
url: hosturl,
vpnName: vpn,
userName: username,
password: pass,
});
} catch (error) {
subscriber.log(error.toString());
}
// define session event listeners
subscriber.session.on(solace.SessionEventCode.UP_NOTICE, function (sessionEvent) {
subscriber.log('=== Successfully connected and ready to subscribe. ===');
subscriber.subscribe();
});
subscriber.session.on(solace.SessionEventCode.CONNECT_FAILED_ERROR, function (sessionEvent) {
subscriber.log('Connection failed to the message router: ' + sessionEvent.infoStr +
' - check correct parameter values and connectivity!');
});
subscriber.session.on(solace.SessionEventCode.DISCONNECTED, function (sessionEvent) {
subscriber.log('Disconnected.');
subscriber.subscribed = false;
if (subscriber.session !== null) {
subscriber.session.dispose();
subscriber.session = null;
}
});
subscriber.session.on(solace.SessionEventCode.SUBSCRIPTION_ERROR, function (sessionEvent) {
subscriber.log('Cannot subscribe to topic: ' + sessionEvent.correlationKey);
});
subscriber.session.on(solace.SessionEventCode.SUBSCRIPTION_OK, function (sessionEvent) {
if (subscriber.subscribed) {
subscriber.subscribed = false;
subscriber.log('Successfully unsubscribed from topic: ' + sessionEvent.correlationKey);
} else {
subscriber.subscribed = true;
subscriber.log('Successfully subscribed to topic: ' + sessionEvent.correlationKey);
subscriber.log('=== Ready to receive messages. ===');
}
});
// define message event listener
subscriber.session.on(solace.SessionEventCode.MESSAGE, function (message) {
subscriber.log('Received message: "' + message.getBinaryAttachment() + '", details:\n' +
message.dump());
//TODO: where the event emitting occurs
const eventStatus = eventEmitter.emit('heartbeat-msg', message.getBinaryAttachment());
console.log(`eventStatus: ${eventStatus}`);
});
// connect the session
try {
subscriber.session.connect();
} catch (error) {
subscriber.log(error.toString());
}
};
// Subscribes to topic on Solace message router
subscriber.subscribe = function () {
if (subscriber.session !== null) {
if (subscriber.subscribed) {
subscriber.log('Already subscribed to "' + subscriber.topicName
+ '" and ready to receive messages.');
} else {
subscriber.log('Subscribing to topic: ' + subscriber.topicName);
try {
subscriber.session.subscribe(
solace.SolclientFactory.createTopicDestination(subscriber.topicName),
true, // generate confirmation when subscription is added successfully
subscriber.topicName, // use topic name as correlation key
10000 // 10 seconds timeout for this operation
);
} catch (error) {
subscriber.log(error.toString());
}
}
} else {
subscriber.log('Cannot subscribe because not connected to Solace message router.');
}
};
subscriber.exit = function () {
subscriber.unsubscribe();
subscriber.disconnect();
setTimeout(function () {
process.exit();
}, 1000); // wait for 1 second to finish
};
// Unsubscribes from topic on Solace message router
subscriber.unsubscribe = function () {
if (subscriber.session !== null) {
if (subscriber.subscribed) {
subscriber.log('Unsubscribing from topic: ' + subscriber.topicName);
try {
subscriber.session.unsubscribe(
solace.SolclientFactory.createTopicDestination(subscriber.topicName),
true, // generate confirmation when subscription is removed successfully
subscriber.topicName, // use topic name as correlation key
10000 // 10 seconds timeout for this operation
);
} catch (error) {
subscriber.log(error.toString());
}
} else {
subscriber.log('Cannot unsubscribe because not subscribed to the topic "'
+ subscriber.topicName + '"');
}
} else {
subscriber.log('Cannot unsubscribe because not connected to Solace message router.');
}
};
// Gracefully disconnects from Solace message router
subscriber.disconnect = function () {
subscriber.log('Disconnecting from Solace message router...');
if (subscriber.session !== null) {
try {
subscriber.session.disconnect();
} catch (error) {
subscriber.log(error.toString());
}
} else {
subscriber.log('Not connected to Solace message router.');
}
};
return subscriber;
};
const connectionArgs = []; //not provided for security reasons
subscriber.run(connectionArgs);
process.on('SIGINT', function () {
'use strict';
subscriber.exit();
});
搜索字符串//TODO: where the event emitting occurs以找到代码的相关部分。
const TopicPublisher = function (solaceModule, topicName) {
'use strict';
const solace = solaceModule;
const publisher = {};
publisher.session = null;
publisher.topicName = topicName;
// Logger
publisher.log = function (line) {
const now = new Date();
const time = [('0' + now.getHours()).slice(-2), ('0' + now.getMinutes()).slice(-2),
('0' + now.getSeconds()).slice(-2)];
const timestamp = '[' + time.join(':') + '] ';
console.log(timestamp + line);
};
publisher.log('\n*** Publisher to topic "' + publisher.topicName + '" is ready to connect ***');
// main function
publisher.run = function (argv) {
publisher.connect(argv);
};
// Establishes connection to Solace message router
publisher.connect = function (argv) {
if (publisher.session !== null) {
publisher.log('Already connected and ready to publish.');
return;
}
// extract params
if (argv.length < 3) { // expecting 3 real arguments
publisher.log('Cannot connect: expecting all arguments' +
' <protocol://host[:port]> <client-username>@<message-vpn> <client-password>.\n' +
'Available protocols are ws://, wss://, http://, https://, tcp://, tcps://');
process.exit();
}
const hosturl = argv[0];
publisher.log('Connecting to Solace message router using url: ' + hosturl);
const usernamevpn = argv[1];
const username = usernamevpn.split('@')[0];
publisher.log('Client username: ' + username);
const vpn = usernamevpn.split('@')[1];
publisher.log('Solace message router VPN name: ' + vpn);
const pass = argv[2];
// create session
try {
publisher.session = solace.SolclientFactory.createSession({
// solace.SessionProperties
url: hosturl,
vpnName: vpn,
userName: username,
password: pass,
});
} catch (error) {
publisher.log(error.toString());
}
// define session event listeners
publisher.session.on(solace.SessionEventCode.UP_NOTICE, function (sessionEvent) {
publisher.log('=== Successfully connected and ready to publish messages. ===');
publisher.publish();
publisher.exit();
});
publisher.session.on(solace.SessionEventCode.CONNECT_FAILED_ERROR, function (sessionEvent) {
publisher.log('Connection failed to the message router: ' + sessionEvent.infoStr +
' - check correct parameter values and connectivity!');
});
publisher.session.on(solace.SessionEventCode.DISCONNECTED, function (sessionEvent) {
publisher.log('Disconnected.');
if (publisher.session !== null) {
publisher.session.dispose();
publisher.session = null;
}
});
// connect the session
try {
publisher.session.connect();
} catch (error) {
publisher.log(error.toString());
}
};
// Publishes one message
publisher.publish = function () {
if (publisher.session !== null) {
//NOTE: where to change sample message
const messageText = 'SOM: 0';
const message = solace.SolclientFactory.createMessage();
message.setDestination(solace.SolclientFactory.createTopicDestination(publisher.topicName));
message.setBinaryAttachment(messageText);
message.setDeliveryMode(solace.MessageDeliveryModeType.DIRECT);
publisher.log('Publishing message "' + messageText + '" to topic "' + publisher.topicName + '"...');
try {
publisher.session.send(message);
publisher.log('Message published.');
} catch (error) {
publisher.log(error.toString());
}
} else {
publisher.log('Cannot publish because not connected to Solace message router.');
}
};
publisher.exit = function () {
publisher.disconnect();
//setTimeout(function () {
// process.exit();
//}, 1000); // wait for 1 second to finish
};
// Gracefully disconnects from Solace message router
publisher.disconnect = function () {
publisher.log('Disconnecting from Solace message router...');
if (publisher.session !== null) {
try {
publisher.session.disconnect();
} catch (error) {
publisher.log(error.toString());
}
} else {
publisher.log('Not connected to Solace message router.');
}
};
return publisher;
};
const solace = require('solclientjs').debug; // logging supported
const fs = require('fs');
// Initialize factory with the most recent API defaults
const factoryProps = new solace.SolclientFactoryProperties();
factoryProps.profile = solace.SolclientFactoryProfiles.version10;
solace.SolclientFactory.init(factoryProps);
// enable logging to JavaScript console at WARN level
// NOTICE: works only with ('solclientjs').debug
solace.SolclientFactory.setLogLevel(solace.LogLevel.WARN);
// create the publisher, specifying the name of the subscription topic
const publisher = new TopicPublisher(solace, 'tutorial/topic');
//TODO: remove single service approach?
const connectionArgs = []; //removed for security reasons
publisher.run(connectionArgs);
const eventEmitter = require('./EventEmitter');
class SocketWrapper {
constructor(ECNs) {
this.started = false;
this.ECNs = ECNs;
this.sockets = new Set();
}
start() {
console.log('starting socketWrapper');
this.started = true;
if (!this.sockets.size) {
this.started = false;
console.log(`Dashboard service stopped.`);
}
//TODO: create event listener
eventEmitter.on('heartbeat-msg', (msg) => {
console.log('in eventEmitter.on');
const ecnStatus = this.parseMessage(msg);
for (const s of this.sockets) {
console.log(`Emitting value: ${ecnStatus['ECN']}:${ecnStatus['status']}`);
s.emit(ecnStatus['ECN'],
{
'ECN': ecnStatus['ECN'],
'status': ecnStatus['status']
}
);
}
});
}
//let's say message comes in as:
//<ECN>: <status>
parseMessage(msg) {
//TODO: return {ECN: <ECN>, status: <status>}
const res = msg.split(':');
return {
'ECN': res[0],
'status': res[1]
}
}
}
module.exports = SocketWrapper;
搜索字符串//TODO: create event listener以获取代码的相关部分。
预期：
$ node server.js
Visit http://localhost:8080 in your browser
[12:11:36]
*** Subscriber to topic "tutorial/topic" is ready to connect ***
[12:11:36] Connecting to Solace message router using url: ws://soluatph1v.wellsfargo.net
[12:11:36] Client username: etrade
[12:11:36] Solace message router VPN name: REMOVED
[12:11:36] === Successfully connected and ready to subscribe. ===
[12:11:36] Subscribing to topic: tutorial/topic
[12:11:36] Successfully subscribed to topic: tutorial/topic
[12:11:36] === Ready to receive messages. ===
[12:11:37]
*** Publisher to topic "tutorial/topic" is ready to connect ***
[12:11:37] Connecting to Solace message router using url: REMOVED
[12:11:37] Client username: REMOVED
[12:11:37] Solace message router VPN name: REMOVED
[12:11:37] === Successfully connected and ready to publish messages. ===
[12:11:37] Publishing message "SOM: 0" to topic "tutorial/topic"...
[12:11:37] Message published.
[12:11:37] Disconnecting from Solace message router...
[12:11:37] Disconnected.
[12:11:37] Received message: "SOM: 0", details:
Destination: [Topic tutorial/topic]
Class Of Service: COS1
DeliveryMode: DIRECT
Binary Attachment: len=6
53 4f 4d 3a 20 30 SOM:.0
in eventEmitter.on
eventStatus: true
我要寻找的是文本的最后两行，以证明事件处理有效。
实际：
$ node server.js
Visit http://localhost:8080 in your browser
[12:11:36]
*** Subscriber to topic "tutorial/topic" is ready to connect ***
[12:11:36] Connecting to Solace message router using url: ws://soluatph1v.wellsfargo.net
[12:11:36] Client username: etrade
[12:11:36] Solace message router VPN name: REMOVED
[12:11:36] === Successfully connected and ready to subscribe. ===
[12:11:36] Subscribing to topic: tutorial/topic
[12:11:36] Successfully subscribed to topic: tutorial/topic
[12:11:36] === Ready to receive messages. ===
[12:11:37]
*** Publisher to topic "tutorial/topic" is ready to connect ***
[12:11:37] Connecting to Solace message router using url: REMOVED
[12:11:37] Client username: REMOVED
[12:11:37] Solace message router VPN name: REMOVED
[12:11:37] === Successfully connected and ready to publish messages. ===
[12:11:37] Publishing message "SOM: 0" to topic "tutorial/topic"...
[12:11:37] Message published.
[12:11:37] Disconnecting from Solace message router...
[12:11:37] Disconnected.
[12:11:37] Received message: "SOM: 0", details:
Destination: [Topic tutorial/topic]
Class Of Service: COS1
DeliveryMode: DIRECT
Binary Attachment: len=6
53 4f 4d 3a 20 30 SOM:.0
eventStatus: false
答案 0 :(得分：0)
解决了这个问题。
结合我错过的事情：
1.我从未与服务器建立套接字连接，因此从未调用socketWrapper.start()。
2.在SocketWrapper.js中进行一些原始测试时；即：发出事件并在该文件中声明侦听器。.我注意到在发出事件后 声明了侦听器。由于node.js的异步特性，因此确保事情同步是很重要的。