implement SSEManager & SSEChannel

packages/server/classes/SSEChannel/index.js

@@ -0,0 +1,13 @@
+import EventEmitter from "@foxify/events"
+
+export default class SSEChannel {
+    constructor(params) {
+        this.id = params.id
+    }
+
+    eventBus = new EventEmitter()
+
+    clients = new Set()
+
+    cache = []
+}

packages/server/classes/SSEManager/index.js

@@ -0,0 +1,70 @@
+import SSEChannel from "../SSEChannel"
+
+export default class SSEManager {
+    channels = new Map()
+
+    createChannel(channelId) {
+        const channel = new SSEChannel({
+            id: channelId
+        })
+
+        this.channels.set(channelId, channel)
+
+        return channel
+    }
+
+    sendToChannel(channelId, ...args) {
+        const channel = this.channels.get(channelId)
+
+        if (!channel) {
+            throw new Error("Channel not found")
+        }
+
+        channel.cache.push(args)
+        channel.eventBus.emit("data", ...args)
+    }
+
+    connectToChannelStream = (channelId, req, res) => {
+        const channel = this.channels.get(channelId)
+
+        if (!channel) {
+            throw new OperationError(404, `Channel [${channelId}] not found`)
+        }
+
+        channel.clients.add(req)
+
+        res.setHeader("Content-Type", "text/event-stream")
+        res.setHeader("Cache-Control", "no-cache")
+        res.setHeader("Connection", "keep-alive")
+        res.status(200)
+
+        if (channel.cache.length > 0) {
+            for (const oldData of channel.cache) {
+                this.writeJSONToResponse(res, oldData)
+            }
+        }
+
+        channel.eventBus.on("data", (data) => {
+            this.writeJSONToResponse(res, data)
+        })
+
+        req.on("close", () => {
+            channel.clients.delete(req)
+
+            if (channel.clients.size === 0) {
+                this.channels.delete(channelId)
+            }
+
+            res.end()
+        })
+    }
+
+    writeJSONToResponse = (res, data) => {
+        console.log(`[SSE] Sending data >`, data)
+        res.write("data: " + JSON.stringify(data) + "\n\n")
+    }
+
+    getChannel = (channelId) => {
+        return this.channels.get(channelId)
+    }
+}