import { isString } from '@nestjs/common/utils/shared.utils';
import * as JsonSocket from 'json-socket';
import * as net from 'net';
import { Server as NetSocket } from 'net';
import { Observable } from 'rxjs';
import {
CLOSE_EVENT,
ERROR_EVENT,
MESSAGE_EVENT,
NO_PATTERN_MESSAGE,
TCP_DEFAULT_PORT,
} from '../constants';
import { CustomTransportStrategy, PacketId, ReadPacket } from '../interfaces';
import {
MicroserviceOptions,
TcpOptions,
} from '../interfaces/microservice-configuration.interface';
import { Server } from './server';
export class ServerTCP extends Server implements CustomTransportStrategy {
private readonly port: number;
private server: NetSocket;
private isExplicitlyTerminated = false;
private retryAttemptsCount = 0;
constructor(private readonly options: MicroserviceOptions['options']) {
super();
this.port =
this.getOptionsProp<TcpOptions>(options, 'port') || TCP_DEFAULT_PORT;
this.init();
}
public listen(callback: () => void) {
this.server.listen(this.port, callback);
}
public close() {
this.isExplicitlyTerminated = true;
this.server.close();
}
public bindHandler(socket) {
const readSocket = this.getSocketInstance(socket);
readSocket.on(MESSAGE_EVENT, async msg =>
this.handleMessage(readSocket, msg),
);
}
public async handleMessage(socket, packet: ReadPacket & PacketId) {
const pattern = !isString(packet.pattern)
? JSON.stringify(packet.pattern)
: packet.pattern;
const status = 'error';
if (!this.messageHandlers[pattern]) {
return socket.sendMessage({
id: packet.id,
status,
err: NO_PATTERN_MESSAGE,
});
}
const handler = this.messageHandlers[pattern];
const response$ = this.transformToObservable(
await handler(packet.data),
) as Observable<any>;
response$ &&
this.send(response$, data =>
socket.sendMessage(Object.assign(data, { id: packet.id })),
);
}
public handleClose(): undefined | number | NodeJS.Timer {
if (
this.isExplicitlyTerminated ||
!this.getOptionsProp<TcpOptions>(this.options, 'retryAttempts') ||
this.retryAttemptsCount >=
this.getOptionsProp<TcpOptions>(this.options, 'retryAttempts')
) {
return undefined;
}
++this.retryAttemptsCount;
return setTimeout(
() => this.server.listen(this.port),
this.getOptionsProp<TcpOptions>(this.options, 'retryDelay') || 0,
);
}
private init() {
this.server = net.createServer(this.bindHandler.bind(this));
this.server.on(ERROR_EVENT, this.handleError.bind(this));
this.server.on(CLOSE_EVENT, this.handleClose.bind(this));
}
private getSocketInstance(socket): JsonSocket {
return new JsonSocket(socket);
}
}
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