feat(WebSocket): Add Pub/Sub feature

[hayatosc]

relate to #3230

Desctiption

This PR will allow us to use Publish/Subscribe messaging model on WebSocket like Bun can do natively.

Demo

Bun

Bun has own Pub/Sub API.

import { Hono } from 'hono'
import { createBunWebSocket } from 'hono/bun'
import type { ServerWebSocket } from 'bun'

const app = new Hono()
const { upgradeWebSocket, websocket } =
  createBunWebSocket<ServerWebSocket>()

app.get(
  '/ws',
  upgradeWebSocket((c) => {
    return {
      onMessage(event, ws) {
        ws.subscribe('chatroom')
        server.publish('Hello!')
      }
    }
  })
)

const server = Bun.serve({
  fetch: app.fetch,
  websocket,
})

Other runtimes

Other runtimes such as Deno will get minimal PubSub class.

import { Hono } from 'hono'
import { upgradeWebSocket } from 'hono/deno'
import { WSPubSub } from 'hono/websocket'

const app = new Hono()
const pubsub = new WSPubSub()

app.get(
  '/ws',
  upgradeWebSocket(pubsub, (c) => {
    return {
      onMessage(event, ws) {
        ws.subscribe('chatroom')
        pubsub.publish('Hello!')
      }
    }
  })
)

I don't know this method of implementation will accept all people. So if you have the opinion, please comment.

The author should do the following, if applicable

• [ ] Add tests
• [ ] Run tests
• [ ] bun run format:fix && bun run lint:fix to format the code
• [ ] Add TSDoc/JSDoc to document the code

[hayatosc]

How do you think, @yusukebe @nakasyou ?

I think the implementation of Other runtime may have a more good solution.

[nakasyou]

It looks very good to me. I like it.

I have an idea. How about like that?:

const chatroom1 = new PubSub()
app.get(
  '/ws',
  upgradeWebSocket((c) => {
    return {
      onMessage(event, ws) {
        chatroom1.publish('Hello World')
      },
      pubSub: chatroom1
    }
  })
)

I think it's more extendable.

And in my opinion, I think we have to avoid extending WSContext and WSEvents for each runtime. I have no idea to implement it, but I think it should be made clear that the API is runtime-specific.

[hayatosc]

@nakasyou

It looks very good to me. I like it.

I have an idea. How about like that?:

const chatroom1 = new PubSub()
app.get(
  '/ws',
  upgradeWebSocket((c) => {
    return {
      onMessage(event, ws) {
        chatroom1.publish('Hello World')
      },
      pubSub: chatroom1
    }
  })
)

I think it's more extendable.

And in my opinion, I thinkwe have to avoid extending WSContext and WSEvents for each runtime. I have no idea to implement it, but I think it should be made clear that the API is runtime-specific.

Hmm. Your opinion was not bad for me.

However, most of actual use cases need multiple topics, so there is a risk that the completed code will become complicated.

app.get(
  '/ws/:id',
  upgradeWebSocket((c) => {
    return {
      onMessage(event, ws) {
        const { id } = c.req.param()
        pubsub.subscribe(`chatroom-${id}`) // we want to do this
      }
    }
  })
)

Individually, also in the context of code compatibility, I feel we should follow Bun's Pub/Sub API as possible.

[nakasyou]

@hayatosc

However, most of actual use cases need multiple topics, so there is a risk that the completed code will become complicated.

I agree with you. So, what do you think about that?

// Bun
const {
  upgradeWebSocket, 
  websocket,
  pubSub // Provides pubSub instance for Bun
} = createBunWebSocket<ServerWebSocket>()
app.get(
  '/ws/:id',
  upgradeWebSocket((c) => {
    const { id } = c.req.param()
    return {
      onOpen(_evt, ws) {
        ws.subscribe(`chatroom-${id}`) // Use received `pubSub`
      },
      onMessage(event, ws) {
        pubsub.publish(`chatroom-${id}`, event.data)
      },
      pubSub
    }
  })
)

// Other runtimes
const pubSub = new PubSub()
app.get(
  '/ws/:id',
  upgradeWebSocket((c) => {
    const { id } = c.req.param()
    return {
      onOpen(_evt, ws) {
        ws.subscribe(`chatroom-${id}`) // Use received `pubSub`
      },
      onMessage(event, ws) {
        pubsub.publish(`chatroom-${id}`, event.data)
      },
      pubSub
    }
  })
)

In this idea, users can switch runtime easier. And it doesn't extends WSContext and WSEvents for only Bun.