Topics tutorial

Author: priviterag

javascript-nodejs/src/emit_log_topic.js

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+#!/usr/bin/env node
+
+var amqp = require('amqplib');
+var when = require('when');
+
+var conn = amqp.connect('amqp://localhost')
+conn.then(createChannel).then(null, console.warn);
+
+function createChannel(conn) {
+  return when(conn.createChannel().then(logMessage)).ensure(function() { conn.close(); });
+}
+
+function logMessage(ch) {
+  var ex = 'topic_logs';
+  var ok = ch.assertExchange(ex, 'topic', {durable: false})
+
+  return ok.then(function() {
+    var args = process.argv.slice(2);
+    var msg = args.slice(1).join(' ') || 'Hello World!';
+    var key = (args.length > 0) ? args[0] : 'anonymous.info';
+
+    ch.publish(ex, key, new Buffer(msg));
+    console.log(" [x] Sent %s:'%s'", key, msg);
+    return ch.close();
+  });
+}

javascript-nodejs/src/receive_logs_topic.js

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+#!/usr/bin/env node
+
+usage();
+
+var amqp = require('amqplib');
+var all = require('when').all;
+var conn = amqp.connect('amqp://localhost')
+var ch = conn.then(createChannel).then(null, console.warn);
+
+ch.then(function(ch) {
+  var x = ch.assertExchange('topic_logs', 'topic', {durable: false});
+  var q = x.then(function() {
+    return ch.assertQueue('', {exclusive: true});
+  });
+
+  var ok = q.then(function(qok) {
+    var queue = qok.queue;
+    var keys = process.argv.slice(2);
+
+    return all(keys.map(function(key) {
+      ch.bindQueue(queue, 'topic_logs', key);
+    })).then(function() { return queue; });
+  });
+
+  ok = ok.then(function(queue) {
+    return ch.consume(queue, logMessage, {noAck: true});
+  });
+  return ok.then(function() {
+    console.log(' [*] Waiting for logs. To exit press CTRL+C');
+  });
+
+  function logMessage(msg) {
+    console.log(" [x] %s:'%s'", msg.fields.routingKey, msg.content.toString());
+  }
+});
+
+function createChannel(conn) {
+  process.once('SIGINT', function() { conn.close(); });
+  return conn.createChannel();
+}
+
+function usage() {
+  if (process.argv.length < 3) {
+    console.log("Usage: receive_logs_topic.js binding_key [binding_key...]");
+    process.exit(1);
+  }
+}