deepkit-rabbit-module.ts

#!/usr/bin/env ts-node-script
import 'reflect-metadata';
import { Application, onServerMainBootstrap } from '@deepkit/framework';
import { injectable, InjectorContext } from '@deepkit/injector';
import { t } from '@deepkit/type';
import { AppModule, AppModuleConfig } from '@deepkit/app';
import { ClassType } from '@deepkit/core';
import { eventDispatcher } from '@deepkit/event';

type Options = { exchange: string, routingKey: string, queue: string };

const mappedClasses = new Map<ClassType, Options & { property: string }>();

function rabbitSubscribe(options: Options) {
    return (target: any, property: string) => {
        mappedClasses.set(target.constructor, { ...options, property });
    };
}

const rabbitConfig = new AppModuleConfig({
    exchanges: t.array({ name: t.string, type: t.string }).optional,
    uri: t.string.description('The URI in format of amqp://rabbitmq:rabbitmq@localhost:5672')
});

class ConnectionConfig extends rabbitConfig.slice(['uri']) {
}

@injectable()
class ConnectionManager {
    constructor(
        private config: ConnectionConfig,
        private injector: InjectorContext,
    ) {
    }

    connect() {
        //establish connection using this.config.uri

        //register callbacks
        for (const [classType, options] of mappedClasses) {
            const service = this.injector.get(classType);

            // service[options.property] is the function callback
        }
    }
}

@injectable()
class BootstrapListener {
    constructor(private connectionManager: ConnectionManager) {
    }

    @eventDispatcher.listen(onServerMainBootstrap)
    onBoostrap() {
        this.connectionManager.connect();
    }
}

const rabbitModule = new AppModule({
    config: rabbitConfig,
    listeners: [BootstrapListener],
    providers: [ConnectionManager],
}, 'rabbit').forRoot();



//------- here is the user code of the module


@injectable()
export class MessagingService {
    @rabbitSubscribe({
        exchange: 'exchange1',
        routingKey: 'subscribe-route',
        queue: 'subscribe-queue',
    })
    public async pubSubHandler(msg: {}) {
        console.log(`Received message: ${JSON.stringify(msg)}`);
    }
}

Application.create({
    providers: [MessagingService],
    imports: [
        rabbitModule.configure({
            uri: 'amqp://rabbitmq:rabbitmq@localhost:5672'
        })
    ]
}).run();