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| import { Logger } from '@nestjs/common/services/logger.service';
import { loadPackage } from '@nestjs/common/utils/load-package.util';
import { randomStringGenerator } from '@nestjs/common/utils/random-string-generator.util';
import { EventEmitter } from 'events';
import { fromEvent, merge, Observable } from 'rxjs';
import { first, map, share, switchMap } from 'rxjs/operators';
import { ClientOptions, RmqOptions } from '../interfaces';
import {
DISCONNECT_EVENT,
ERROR_EVENT,
RQM_DEFAULT_IS_GLOBAL_PREFETCH_COUNT,
RQM_DEFAULT_PREFETCH_COUNT,
RQM_DEFAULT_QUEUE,
RQM_DEFAULT_QUEUE_OPTIONS,
RQM_DEFAULT_URL,
} from './../constants';
import { WritePacket } from './../interfaces';
import { ClientProxy } from './client-proxy';
let rqmPackage: any = {};
export class ClientRMQ extends ClientProxy {
protected readonly logger = new Logger(ClientProxy.name);
protected connection: Promise<any>;
protected client: any = null;
protected channel: any = null;
protected urls: string[];
protected queue: string;
protected prefetchCount: number;
protected isGlobalPrefetchCount: boolean;
protected queueOptions: any;
protected replyQueue: string;
protected responseEmitter: EventEmitter;
constructor(protected readonly options: ClientOptions['options']) {
super();
this.urls = this.getOptionsProp<RmqOptions>(this.options, 'urls') || [
RQM_DEFAULT_URL,
];
this.queue =
this.getOptionsProp<RmqOptions>(this.options, 'queue') ||
RQM_DEFAULT_QUEUE;
this.prefetchCount =
this.getOptionsProp<RmqOptions>(this.options, 'prefetchCount') ||
RQM_DEFAULT_PREFETCH_COUNT;
this.isGlobalPrefetchCount =
this.getOptionsProp<RmqOptions>(this.options, 'isGlobalPrefetchCount') ||
RQM_DEFAULT_IS_GLOBAL_PREFETCH_COUNT;
this.queueOptions =
this.getOptionsProp<RmqOptions>(this.options, 'queueOptions') ||
RQM_DEFAULT_QUEUE_OPTIONS;
loadPackage('amqplib', ClientRMQ.name);
rqmPackage = loadPackage('amqp-connection-manager', ClientRMQ.name);
}
public close(): void {
this.channel && this.channel.close();
this.client && this.client.close();
}
public consumeChannel() {
this.channel.addSetup(channel =>
channel.consume(
this.replyQueue,
msg => this.responseEmitter.emit(msg.properties.correlationId, msg),
{ noAck: true },
),
);
}
public connect(): Promise<any> {
Iif (this.client) {
return this.connection;
}
this.client = this.createClient();
this.handleError(this.client);
const connect$ = this.connect$(this.client);
this.connection = this.mergeDisconnectEvent(this.client, connect$)
.pipe(switchMap(() => this.createChannel()), share())
.toPromise();
return this.connection;
}
public createChannel(): Promise<void> {
return new Promise(resolve => {
this.channel = this.client.createChannel({
json: false,
setup: channel => this.setupChannel(channel, resolve),
});
});
}
public createClient<T = any>(): T {
return rqmPackage.connect(this.urls) as T;
}
public mergeDisconnectEvent<T = any>(
instance: any,
source$: Observable<T>,
): Observable<T> {
const close$ = fromEvent(instance, DISCONNECT_EVENT).pipe(
map(err => {
throw err;
}),
);
return merge(source$, close$).pipe(first());
}
public async setupChannel(channel: any, resolve: Function) {
await channel.assertQueue(this.queue, this.queueOptions);
await channel.prefetch(this.prefetchCount, this.isGlobalPrefetchCount);
this.replyQueue = (await channel.assertQueue('', {
exclusive: true,
})).queue;
this.responseEmitter = new EventEmitter();
this.responseEmitter.setMaxListeners(0);
this.consumeChannel();
resolve();
}
protected publish(
message: any,
callback: (packet: WritePacket) => any,
): Function {
try {
const correlationId = randomStringGenerator();
const listener = ({ content }) =>
this.handleMessage(JSON.parse(content.toString()), callback);
this.responseEmitter.on(correlationId, listener);
this.channel.sendToQueue(
this.queue,
Buffer.from(JSON.stringify(message)),
{
replyTo: this.replyQueue,
correlationId,
},
);
return () => this.responseEmitter.removeListener(correlationId, listener);
} catch (err) {
callback({ err });
}
}
public handleMessage(
packet: WritePacket,
callback: (packet: WritePacket) => any,
) {
const { err, response, isDisposed } = packet;
if (isDisposed || err) {
callback({
err,
response: null,
isDisposed: true,
});
}
callback({
err,
response,
});
}
public handleError(client: any): void {
client.addListener(ERROR_EVENT, err => this.logger.error(err));
}
}
|