feat: queue class with rabbitmq intergration (#7)

apps/api/src/Queue/Queue.ts

@@ -0,0 +1,66 @@
+import amqlib from "amqplib/callback_api";
+import { IInvoice } from "interfaces/Invoice.interface";
+import { RabbitMQ_URI } from "../Config";
+
+export interface Queues
+{
+    invoice_paid: IInvoice;
+    send_email: any;
+}
+
+export default class Queue
+{
+    private static initialized: boolean = false;
+    private static connection: amqlib.Connection | undefined;
+    private static channel: amqlib.Channel | undefined;
+
+    private static init()
+    {
+        if (this.initialized) return;
+        return new Promise((resolve) =>
+        {
+            amqlib.connect(RabbitMQ_URI, async (err, conn) =>
+            {
+                if (err) throw err;
+                this.connection = conn;
+                // @ts-ignore
+                this.channel = await conn.createChannel();
+                (["invoice_paid"] as const).forEach(async (queue) =>
+                {
+                    await this.channel?.assertQueue(queue, { durable: true });
+                });
+                this.initialized = true;
+                resolve(true);
+            });
+        });
+    }
+
+    public static async listen<K extends keyof Queues>(queue: K, callback: (message: Queues[K]) => void)
+    {
+        if (!this.initialized) await this.init();
+        this.channel?.consume(queue, async (msg) =>
+        {
+            if (msg)
+            {
+                try 
+                {
+                    const message = JSON.parse(msg.content.toString());
+                    callback(message);
+                    this.channel?.ack(msg);
+                }
+                catch (err)
+                {
+                    console.error(err);
+                }
+            }
+        }, { noAck: false });
+    }
+
+    public static async send<K extends keyof Queues>(queue: K, json: Queues[K] extends Array<infer U> ? U : never)
+    {
+        if (!this.initialized) await this.init();
+        const data = JSON.stringify(json);
+        this.channel?.sendToQueue(queue, Buffer.from(data));
+    }
+
+}