refractor websocket again

client/javascript/ws_polyfill.js

@@ -0,0 +1,113 @@
+//class for websocket polyfill
+
+class FakeWebSocket extends EventTarget {
+  constructor(url, protocols=[], options={}) {
+    super();
+
+    this.url = url;
+    this.protocols = protocols;
+    this.options = options;
+    this.binaryType = "blob";
+
+    //legacy event handlers
+    this.onopen = () => {};
+    this.onerror = () => {};
+    this.onmessage = () => {};
+    this.onclose = () => {};
+
+    this.CONNECTING = 0;
+    this.OPEN = 1;
+    this.CLOSING = 2;
+    this.CLOSED = 3;
+    this.status = this.CONNECTING;
+
+    this.socket = null;
+    this.connect();
+  }
+
+  connect() {
+    this.socket = new CurlWebSocket(this.url, this.protocols, this.options);
+
+    this.socket.onopen = () => {
+      this.status = this.OPEN;
+      let open_event = new Event("open");
+      this.onopen(open_event);
+      this.dispatchEvent(open_event);
+    }
+
+    this.socket.onclose = () => {
+      this.status = this.CLOSED;
+      let close_event = new CloseEvent("close");
+      this.dispatchEvent(close_event);
+      this.onclose(close_event);
+    };
+
+    this.socket.onerror = (error) => {
+      this.status = this.CLOSED;
+      console.error(`websocket ${this.url} encountered an error (${error})`);
+      let error_event = new Event("error");
+      this.dispatchEvent(error_event);
+      this.onerror(error_event);
+    }
+
+    this.socket.onmessage = (data) => {
+      let converted;
+      if (typeof data === "string") {
+        converted = data;
+      }
+      else { //binary frame received as uint8array
+        if (this.binaryType == "blob") {
+          converted = new Blob(data);
+        }
+        else if (this.binaryType == "arraybuffer") {
+          converted = data.buffer;
+        }
+        else {
+          throw "invalid binaryType string";
+        }
+      }
+      
+      let msg_event = new MessageEvent("message", {data: converted});
+      this.onmessage(msg_event);
+      this.dispatchEvent(msg_event);
+    }
+  }
+
+  send(data) {
+    let is_text = typeof data === "string";
+    if (this.status === this.CONNECTING) {
+      throw new DOMException("websocket not ready yet");
+    }
+    if (this.status === this.CLOSED) {
+      return;
+    }
+
+    (async () => {
+      if (is_text) {
+        this.socket.send(data);
+      }
+      else {
+        let data_array = await data_to_array(data);
+        this.send(data_array);
+      }
+    })();
+  }
+
+  close() {
+    this.status = this.CLOSING;
+    this.socket.close();
+  }
+
+  get readyState() {
+    return this.status;
+  }
+  get bufferedAmount() {
+    return 0;
+  }
+  get protocol() {
+    return this.protocols[0] || "";
+  }
+  get extensions() {
+    return "";
+  }
+}