Fix some bugs with message delivery

src/util/Socket.ts

@@ -0,0 +1,107 @@
+import WebSocket from "isomorphic-ws"
+import {EventBus} from "./EventBus"
+import {Deferred, defer} from "./Deferred"
+
+export class Socket {
+  ws?: WebSocket
+  url: string
+  ready?: Deferred<void>
+  timeout?: NodeJS.Timeout
+  queue: string[]
+  bus: EventBus
+  status: string
+  _onOpen: (e: any) => void
+  _onMessage: (e: any) => void
+  _onClose: (e: any) => void
+  static STATUS = {
+    NEW: "new",
+    PENDING: "pending",
+    CLOSED: "closed",
+    READY: "ready",
+  }
+  constructor(url: string) {
+    this.ws = undefined
+    this.url = url
+    this.ready = undefined
+    this.timeout = undefined
+    this.queue = []
+    this.bus = new EventBus()
+    this.status = Socket.STATUS.NEW
+
+    this._onOpen = e => {
+      this.status = Socket.STATUS.READY
+      this.ready?.resolve()
+    }
+
+    this._onMessage = e => {
+      this.queue.push(e.data as string)
+
+      if (!this.timeout) {
+        this.handleMessagesAsync()
+      }
+    }
+
+    this._onClose = e => {
+      this.disconnect()
+      this.ready?.reject()
+      this.status = Socket.STATUS.CLOSED
+    }
+  }
+  async connect() {
+    if ([Socket.STATUS.NEW, Socket.STATUS.CLOSED].includes(this.status)) {
+      if (this.ws) {
+        console.error("Attempted to connect when already connected", this)
+      }
+
+      this.ready = defer()
+      this.ws = new WebSocket(this.url)
+      this.status = Socket.STATUS.PENDING
+
+      this.ws.addEventListener("open", this._onOpen)
+      this.ws.addEventListener("message", this._onMessage)
+      this.ws.addEventListener("close", this._onClose)
+    }
+
+    await this.ready?.catch(() => null)
+  }
+  disconnect() {
+    if (this.ws) {
+      this.ws.close()
+      this.ws.removeEventListener("open", this._onOpen)
+      this.ws.removeEventListener("message", this._onMessage)
+      this.ws.removeEventListener("error", this._onClose)
+      this.ws.removeEventListener("close", this._onClose)
+      this.ws = undefined
+    }
+  }
+  handleMessages() {
+    for (const json of this.queue.splice(0, 10)) {
+      let message
+      try {
+        message = JSON.parse(json)
+      } catch (e) {
+        continue
+      }
+
+      this.bus.emit('message', this.url, message)
+    }
+
+    if (this.queue.length > 0) {
+      this.handleMessagesAsync()
+    } else {
+      this.timeout = undefined
+    }
+  }
+  handleMessagesAsync() {
+    this.timeout = setTimeout(() => this.handleMessages(), 10) as NodeJS.Timeout
+  }
+  send(message: any) {
+    if (this.status === Socket.STATUS.READY) {
+      if (this.ws?.readyState !== 1) {
+        console.warn("Send attempted before socket was ready", this)
+      }
+
+      this.ws?.send(JSON.stringify(message))
+    }
+  }
+}