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| import { Type } from '@nestjs/common/interfaces/type.interface';
import { isFunction } from '@nestjs/common/utils/shared.utils';
import { ApplicationConfig } from '@nestjs/core/application-config';
import { MetadataScanner } from '@nestjs/core/metadata-scanner';
import { from as fromPromise, Observable, of, Subject } from 'rxjs';
import { distinctUntilChanged, mergeAll } from 'rxjs/operators';
import { GATEWAY_OPTIONS, PORT_METADATA } from './constants';
import { WsContextCreator } from './context/ws-context-creator';
import { InvalidSocketPortException } from './exceptions/invalid-socket-port.exception';
import {
GatewayMetadataExplorer,
MessageMappingProperties,
} from './gateway-metadata-explorer';
import { NestGateway } from './interfaces/nest-gateway.interface';
import { ObservableSocketServer } from './interfaces/observable-socket-server.interface';
import { SocketServerProvider } from './socket-server-provider';
export class WebSocketsController {
private readonly metadataExplorer = new GatewayMetadataExplorer(
new MetadataScanner(),
);
constructor(
private readonly socketServerProvider: SocketServerProvider,
private readonly config: ApplicationConfig,
private readonly contextCreator: WsContextCreator,
) {}
public hookGatewayIntoServer(
instance: NestGateway,
metatype: Type<any>,
module: string,
) {
const options = Reflect.getMetadata(GATEWAY_OPTIONS, metatype) || {};
const port = Reflect.getMetadata(PORT_METADATA, metatype) || 0;
if (!Number.isInteger(port)) {
throw new InvalidSocketPortException(port, metatype);
}
this.subscribeObservableServer(instance, options, port, module);
}
public subscribeObservableServer(
instance: NestGateway,
options: any,
port: number,
module: string,
) {
const nativeMessageHandlers = this.metadataExplorer.explore(instance);
const messageHandlers = nativeMessageHandlers.map(
({ callback, message }) => ({
message,
callback: this.contextCreator.create(instance, callback, module),
}),
);
const observableServer = this.socketServerProvider.scanForSocketServer(
options,
port,
);
this.hookServerToProperties(instance, observableServer.server);
this.subscribeEvents(instance, messageHandlers, observableServer);
}
public subscribeEvents(
instance: NestGateway,
subscribersMap: MessageMappingProperties[],
observableServer: ObservableSocketServer,
) {
const { init, disconnect, connection, server } = observableServer;
const adapter = this.config.getIoAdapter();
this.subscribeInitEvent(instance, init);
this.subscribeConnectionEvent(instance, connection);
this.subscribeDisconnectEvent(instance, disconnect);
const handler = this.getConnectionHandler(
this,
instance,
subscribersMap,
disconnect,
connection,
);
adapter.bindClientConnect(server, handler);
}
public getConnectionHandler(
context: WebSocketsController,
instance: NestGateway,
subscribersMap: MessageMappingProperties[],
disconnect: Subject<any>,
connection: Subject<any>,
) {
const adapter = this.config.getIoAdapter();
return (...args: any[]) => {
const [client] = args;
connection.next(args);
context.subscribeMessages(subscribersMap, client, instance);
const disconnectHook = adapter.bindClientDisconnect;
disconnectHook &&
disconnectHook.call(adapter, client, _ => disconnect.next(client));
};
}
public subscribeInitEvent(instance: NestGateway, event: Subject<any>) {
if (instance.afterInit) {
event.subscribe(instance.afterInit.bind(instance));
}
}
public subscribeConnectionEvent(instance: NestGateway, event: Subject<any>) {
if (instance.handleConnection) {
event
.pipe(distinctUntilChanged())
.subscribe((args: any[]) => instance.handleConnection(...args));
}
}
public subscribeDisconnectEvent(instance: NestGateway, event: Subject<any>) {
if (instance.handleDisconnect) {
event
.pipe(distinctUntilChanged())
.subscribe(instance.handleDisconnect.bind(instance));
}
}
public subscribeMessages<T = any>(
subscribersMap: MessageMappingProperties[],
client: T,
instance: NestGateway,
) {
const adapter = this.config.getIoAdapter();
const handlers = subscribersMap.map(({ callback, message }) => ({
message,
callback: callback.bind(instance, client),
}));
adapter.bindMessageHandlers(client, handlers, data =>
fromPromise(this.pickResult(data)).pipe(mergeAll()),
);
}
public async pickResult(
defferedResult: Promise<any>,
): Promise<Observable<any>> {
const result = await defferedResult;
if (result && isFunction(result.subscribe)) {
return result;
}
Iif (result instanceof Promise) {
return fromPromise(result);
}
return of(result);
}
private hookServerToProperties(instance: NestGateway, server) {
for (const propertyKey of this.metadataExplorer.scanForServerHooks(
instance,
)) {
Reflect.set(instance, propertyKey, server);
}
}
}
|