How to use socket.io with graphql subscription? - socket.io

Question

I want to make a real-time chat app by using nestjs and graphql technology. Most of tutorial uses PubSub but I don't know how to send a message to a specific client (?).
I think it is much easy to use socket.io for sending a message to a specific client by using socket id.
this example using PubSub:
Is there a way to send a message to a specific client by using PubSub? By reciving some data about sender like id.
How can I replace PubSub with Socket.io ?I am really comfortable with socket.io
App.module.ts
import { Module, MiddlewareConsumer, RequestMethod, Get } from '#nestjs/common';
import { TypeOrmModule } from '#nestjs/typeorm';
import { typeOrmConfig } from './config/typeorm.config';
import { AuthModule } from './auth/auth.module';
import { LoggerMiddleware } from './common/middlewares/logger.middleware';
import { Connection } from 'typeorm';
import { GraphQLModule } from '#nestjs/graphql';
import { join } from 'path';
import { ChatModule } from './chat/chat.module';
import { ChatService } from './chat/chat.service';
#Module({
imports: [
TypeOrmModule.forRoot(typeOrmConfig), // connect to database
GraphQLModule.forRoot({
debug: true,
playground: true,
typePaths: ['**/*.graphql'],
definitions: {
path: join(process.cwd(), 'src/graphql.ts'),
},
}),
AuthModule,
ChatModule,
],
controllers: [],
providers: [
],
})
export class AppModule {
}
Chat.module.ts
import { Module } from '#nestjs/common';
import { ChatService } from './chat.service';
import { ChatResolver } from './chat.resolver';
import { TypeOrmModule } from '#nestjs/typeorm';
import { AuthModule } from '../auth/auth.module';
import { PubSub } from 'graphql-subscriptions';
#Module({
imports: [
// Add all repository here; productRepository, ...
TypeOrmModule.forFeature( [
// repositories ...
]),
AuthModule
],
providers: [
//=> How to replace with socket.io ?
{
provide: 'PUB_SUB',
useValue: new PubSub(),
},
ChatService,
ChatResolver,
]
})
export class ChatModule {}
Chat.resolver.ts
import { Resolver, Query, Mutation, Args, Subscription } from '#nestjs/graphql';
import { PubSubEngine } from 'graphql-subscriptions';
import { Inject } from '#nestjs/common';
const PONG_EVENT_NAME = 'pong';
#Resolver('Chat')
export class ChatResolver {
constructor(
private chatService: ChatService,
#Inject('PUB_SUB')
private pubSub: PubSubEngine,
) {}
// Ping Pong
#Mutation('ping')
async ping() {
const pingId = Date.now();
//=> How to send deta to specific client by using user-id?
this.pubSub.publish(PONG_EVENT_NAME, { ['pong']: { pingId } });
return { id: pingId };
}
#Subscription(PONG_EVENT_NAME)
pong() {
//=> how to get data about sender like id?
return this.pubSub.asyncIterator(PONG_EVENT_NAME);
}
}
Chat.graphql
type Mutation {
ping: Ping
}
type Subscription {
tagCreated: Tag
clientCreated: Client
pong: Pong
}
type Ping {
id: ID
}
type Pong {
pingId: ID
}
How can replace PubSub with Socket.io?

Answer 1

I didn't find any solution or example to get client-socket from graphql subscription.
In most example they use Gateway instead of graphql pubsub. So I used GateWay to implement real-time activities and graphql for other request.