refactor: move WebSocket API to an op_crate (#9026)

op_crates/websocket/01_websocket.js

@@ -0,0 +1,376 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+((window) => {
+  const core = window.Deno.core;
+
+  // provided by "deno_web"
+  const { URL } = window.__bootstrap.url;
+
+  const CONNECTING = 0;
+  const OPEN = 1;
+  const CLOSING = 2;
+  const CLOSED = 3;
+
+  function requiredArguments(
+    name,
+    length,
+    required,
+  ) {
+    if (length < required) {
+      const errMsg = `${name} requires at least ${required} argument${
+        required === 1 ? "" : "s"
+      }, but only ${length} present`;
+      throw new TypeError(errMsg);
+    }
+  }
+
+  const handlerSymbol = Symbol("eventHandlers");
+  function makeWrappedHandler(handler) {
+    function wrappedHandler(...args) {
+      if (typeof wrappedHandler.handler !== "function") {
+        return;
+      }
+      return wrappedHandler.handler.call(this, ...args);
+    }
+    wrappedHandler.handler = handler;
+    return wrappedHandler;
+  }
+  // TODO(lucacasonato) reuse when we can reuse code between web crates
+  function defineEventHandler(emitter, name) {
+    // HTML specification section 8.1.5.1
+    Object.defineProperty(emitter, `on${name}`, {
+      get() {
+        return this[handlerSymbol]?.get(name)?.handler;
+      },
+      set(value) {
+        if (!this[handlerSymbol]) {
+          this[handlerSymbol] = new Map();
+        }
+        let handlerWrapper = this[handlerSymbol]?.get(name);
+        if (handlerWrapper) {
+          handlerWrapper.handler = value;
+        } else {
+          handlerWrapper = makeWrappedHandler(value);
+          this.addEventListener(name, handlerWrapper);
+        }
+        this[handlerSymbol].set(name, handlerWrapper);
+      },
+      configurable: true,
+      enumerable: true,
+    });
+  }
+
+  class WebSocket extends EventTarget {
+    #readyState = CONNECTING;
+
+    constructor(url, protocols = []) {
+      super();
+      requiredArguments("WebSocket", arguments.length, 1);
+
+      const wsURL = new URL(url);
+
+      if (wsURL.protocol !== "ws:" && wsURL.protocol !== "wss:") {
+        throw new DOMException(
+          "Only ws & wss schemes are allowed in a WebSocket URL.",
+          "SyntaxError",
+        );
+      }
+
+      if (wsURL.hash !== "" || wsURL.href.endsWith("#")) {
+        throw new DOMException(
+          "Fragments are not allowed in a WebSocket URL.",
+          "SyntaxError",
+        );
+      }
+
+      this.#url = wsURL.href;
+
+      core.jsonOpSync("op_ws_check_permission", {
+        url: this.#url,
+      });
+
+      if (protocols && typeof protocols === "string") {
+        protocols = [protocols];
+      }
+
+      if (
+        protocols.some((x) => protocols.indexOf(x) !== protocols.lastIndexOf(x))
+      ) {
+        throw new DOMException(
+          "Can't supply multiple times the same protocol.",
+          "SyntaxError",
+        );
+      }
+
+      core.jsonOpAsync("op_ws_create", {
+        url: wsURL.href,
+        protocols: protocols.join(", "),
+      }).then((create) => {
+        if (create.success) {
+          this.#rid = create.rid;
+          this.#extensions = create.extensions;
+          this.#protocol = create.protocol;
+
+          if (this.#readyState === CLOSING) {
+            core.jsonOpAsync("op_ws_close", {
+              rid: this.#rid,
+            }).then(() => {
+              this.#readyState = CLOSED;
+
+              const errEvent = new ErrorEvent("error");
+              errEvent.target = this;
+              this.dispatchEvent(errEvent);
+
+              const event = new CloseEvent("close");
+              event.target = this;
+              this.dispatchEvent(event);
+              core.close(this.#rid);
+            });
+          } else {
+            this.#readyState = OPEN;
+            const event = new Event("open");
+            event.target = this;
+            this.dispatchEvent(event);
+
+            this.#eventLoop();
+          }
+        } else {
+          this.#readyState = CLOSED;
+
+          const errEvent = new ErrorEvent("error");
+          errEvent.target = this;
+          this.dispatchEvent(errEvent);
+
+          const closeEvent = new CloseEvent("close");
+          closeEvent.target = this;
+          this.dispatchEvent(closeEvent);
+        }
+      }).catch((err) => {
+        this.#readyState = CLOSED;
+
+        const errorEv = new ErrorEvent(
+          "error",
+          { error: err, message: err.toString() },
+        );
+        errorEv.target = this;
+        this.dispatchEvent(errorEv);
+
+        const closeEv = new CloseEvent("close");
+        closeEv.target = this;
+        this.dispatchEvent(closeEv);
+      });
+    }
+
+    get CONNECTING() {
+      return CONNECTING;
+    }
+    get OPEN() {
+      return OPEN;
+    }
+    get CLOSING() {
+      return CLOSING;
+    }
+    get CLOSED() {
+      return CLOSED;
+    }
+
+    get readyState() {
+      return this.#readyState;
+    }
+
+    #extensions = "";
+    #protocol = "";
+    #url = "";
+    #rid;
+
+    get extensions() {
+      return this.#extensions;
+    }
+    get protocol() {
+      return this.#protocol;
+    }
+
+    #binaryType = "blob";
+    get binaryType() {
+      return this.#binaryType;
+    }
+    set binaryType(value) {
+      if (value === "blob" || value === "arraybuffer") {
+        this.#binaryType = value;
+      }
+    }
+    #bufferedAmount = 0;
+    get bufferedAmount() {
+      return this.#bufferedAmount;
+    }
+
+    get url() {
+      return this.#url;
+    }
+
+    send(data) {
+      requiredArguments("WebSocket.send", arguments.length, 1);
+
+      if (this.#readyState != OPEN) {
+        throw Error("readyState not OPEN");
+      }
+
+      const sendTypedArray = (ta) => {
+        this.#bufferedAmount += ta.size;
+        core.jsonOpAsync("op_ws_send", {
+          rid: this.#rid,
+          kind: "binary",
+        }, ta).then(() => {
+          this.#bufferedAmount -= ta.size;
+        });
+      };
+
+      if (data instanceof Blob) {
+        data.slice().arrayBuffer().then((ab) =>
+          sendTypedArray(new DataView(ab))
+        );
+      } else if (
+        data instanceof Int8Array || data instanceof Int16Array ||
+        data instanceof Int32Array || data instanceof Uint8Array ||
+        data instanceof Uint16Array || data instanceof Uint32Array ||
+        data instanceof Uint8ClampedArray || data instanceof Float32Array ||
+        data instanceof Float64Array || data instanceof DataView
+      ) {
+        sendTypedArray(data);
+      } else if (data instanceof ArrayBuffer) {
+        sendTypedArray(new DataView(data));
+      } else {
+        const string = String(data);
+        const encoder = new TextEncoder();
+        const d = encoder.encode(string);
+        this.#bufferedAmount += d.size;
+        core.jsonOpAsync("op_ws_send", {
+          rid: this.#rid,
+          kind: "text",
+          text: string,
+        }).then(() => {
+          this.#bufferedAmount -= d.size;
+        });
+      }
+    }
+
+    close(code, reason) {
+      if (code && (code !== 1000 && !(3000 <= code > 5000))) {
+        throw new DOMException(
+          "The close code must be either 1000 or in the range of 3000 to 4999.",
+          "NotSupportedError",
+        );
+      }
+
+      const encoder = new TextEncoder();
+      if (reason && encoder.encode(reason).byteLength > 123) {
+        throw new DOMException(
+          "The close reason may not be longer than 123 bytes.",
+          "SyntaxError",
+        );
+      }
+
+      if (this.#readyState === CONNECTING) {
+        this.#readyState = CLOSING;
+      } else if (this.#readyState === OPEN) {
+        this.#readyState = CLOSING;
+
+        core.jsonOpAsync("op_ws_close", {
+          rid: this.#rid,
+          code,
+          reason,
+        }).then(() => {
+          this.#readyState = CLOSED;
+          const event = new CloseEvent("close", {
+            wasClean: true,
+            code,
+            reason,
+          });
+          event.target = this;
+          this.dispatchEvent(event);
+          core.close(this.#rid);
+        });
+      }
+    }
+
+    async #eventLoop() {
+      if (this.#readyState === OPEN) {
+        const message = await core.jsonOpAsync(
+          "op_ws_next_event",
+          { rid: this.#rid },
+        );
+        if (message.type === "string" || message.type === "binary") {
+          let data;
+
+          if (message.type === "string") {
+            data = message.data;
+          } else {
+            if (this.binaryType === "blob") {
+              data = new Blob([new Uint8Array(message.data)]);
+            } else {
+              data = new Uint8Array(message.data).buffer;
+            }
+          }
+
+          const event = new MessageEvent("message", {
+            data,
+            origin: this.#url,
+          });
+          event.target = this;
+          this.dispatchEvent(event);
+
+          this.#eventLoop();
+        } else if (message.type === "ping") {
+          core.jsonOpAsync("op_ws_send", {
+            rid: this.#rid,
+            kind: "pong",
+          });
+
+          this.#eventLoop();
+        } else if (message.type === "close") {
+          this.#readyState = CLOSED;
+          const event = new CloseEvent("close", {
+            wasClean: true,
+            code: message.code,
+            reason: message.reason,
+          });
+          event.target = this;
+          this.dispatchEvent(event);
+        } else if (message.type === "error") {
+          this.#readyState = CLOSED;
+
+          const errorEv = new ErrorEvent("error");
+          errorEv.target = this;
+          this.dispatchEvent(errorEv);
+
+          this.#readyState = CLOSED;
+          const closeEv = new CloseEvent("close");
+          closeEv.target = this;
+          this.dispatchEvent(closeEv);
+        }
+      }
+    }
+  }
+
+  Object.defineProperties(WebSocket, {
+    CONNECTING: {
+      value: 0,
+    },
+    OPEN: {
+      value: 1,
+    },
+    CLOSING: {
+      value: 2,
+    },
+    CLOSED: {
+      value: 3,
+    },
+  });
+
+  defineEventHandler(WebSocket.prototype, "message");
+  defineEventHandler(WebSocket.prototype, "error");
+  defineEventHandler(WebSocket.prototype, "close");
+  defineEventHandler(WebSocket.prototype, "open");
+
+  window.__bootstrap.webSocket = { WebSocket };
+})(this);

op_crates/websocket/Cargo.toml

@@ -0,0 +1,24 @@
+# Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+[package]
+name = "deno_websocket"
+version = "0.1.0"
+edition = "2018"
+description = "Implementation of WebSocket API for Deno"
+authors = ["the Deno authors"]
+license = "MIT"
+readme = "README.md"
+repository = "https://github.com/denoland/deno"
+
+[lib]
+path = "lib.rs"
+
+[dependencies]
+deno_core = { version = "0.75.0", path = "../../core" }
+http = "0.2.1"
+tokio = { version = "0.2.22", features = ["full"] }
+tokio-rustls = "0.14.1"
+tokio-tungstenite = "0.11.0"
+serde = { version = "1.0.116", features = ["derive"] }
+webpki = "0.21.3"
+webpki-roots = "=0.19.0" # Pinned to v0.19.0 to match 'reqwest'.

op_crates/websocket/README.md

@@ -0,0 +1,5 @@
+# deno_websocket
+
+This op crate implements the websocket functions of Deno.
+
+Spec: https://html.spec.whatwg.org/multipage/web-sockets.html

op_crates/websocket/lib.deno_websocket.d.ts

@@ -0,0 +1,112 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+// deno-lint-ignore-file no-explicit-any
+
+/// <reference no-default-lib="true" />
+/// <reference lib="esnext" />
+
+interface CloseEventInit extends EventInit {
+  code?: number;
+  reason?: string;
+  wasClean?: boolean;
+}
+
+declare class CloseEvent extends Event {
+  constructor(type: string, eventInitDict?: CloseEventInit);
+  /**
+   * Returns the WebSocket connection close code provided by the server.
+   */
+  readonly code: number;
+  /**
+   * Returns the WebSocket connection close reason provided by the server.
+   */
+  readonly reason: string;
+  /**
+   * Returns true if the connection closed cleanly; false otherwise.
+   */
+  readonly wasClean: boolean;
+}
+
+interface WebSocketEventMap {
+  close: CloseEvent;
+  error: Event;
+  message: MessageEvent;
+  open: Event;
+}
+
+/** Provides the API for creating and managing a WebSocket connection to a server, as well as for sending and receiving data on the connection. */
+declare class WebSocket extends EventTarget {
+  constructor(url: string, protocols?: string | string[]);
+
+  static readonly CLOSED: number;
+  static readonly CLOSING: number;
+  static readonly CONNECTING: number;
+  static readonly OPEN: number;
+
+  /**
+   * Returns a string that indicates how binary data from the WebSocket object is exposed to scripts:
+   *
+   * Can be set, to change how binary data is returned. The default is "blob".
+   */
+  binaryType: BinaryType;
+  /**
+   * Returns the number of bytes of application data (UTF-8 text and binary data) that have been queued using send() but not yet been transmitted to the network.
+   *
+   * If the WebSocket connection is closed, this attribute's value will only increase with each call to the send() method. (The number does not reset to zero once the connection closes.)
+   */
+  readonly bufferedAmount: number;
+  /**
+   * Returns the extensions selected by the server, if any.
+   */
+  readonly extensions: string;
+  onclose: ((this: WebSocket, ev: CloseEvent) => any) | null;
+  onerror: ((this: WebSocket, ev: Event | ErrorEvent) => any) | null;
+  onmessage: ((this: WebSocket, ev: MessageEvent) => any) | null;
+  onopen: ((this: WebSocket, ev: Event) => any) | null;
+  /**
+   * Returns the subprotocol selected by the server, if any. It can be used in conjunction with the array form of the constructor's second argument to perform subprotocol negotiation.
+   */
+  readonly protocol: string;
+  /**
+   * Returns the state of the WebSocket object's connection. It can have the values described below.
+   */
+  readonly readyState: number;
+  /**
+   * Returns the URL that was used to establish the WebSocket connection.
+   */
+  readonly url: string;
+  /**
+   * Closes the WebSocket connection, optionally using code as the the WebSocket connection close code and reason as the the WebSocket connection close reason.
+   */
+  close(code?: number, reason?: string): void;
+  /**
+   * Transmits data using the WebSocket connection. data can be a string, a Blob, an ArrayBuffer, or an ArrayBufferView.
+   */
+  send(data: string | ArrayBufferLike | Blob | ArrayBufferView): void;
+  readonly CLOSED: number;
+  readonly CLOSING: number;
+  readonly CONNECTING: number;
+  readonly OPEN: number;
+  addEventListener<K extends keyof WebSocketEventMap>(
+    type: K,
+    listener: (this: WebSocket, ev: WebSocketEventMap[K]) => any,
+    options?: boolean | AddEventListenerOptions,
+  ): void;
+  addEventListener(
+    type: string,
+    listener: EventListenerOrEventListenerObject,
+    options?: boolean | AddEventListenerOptions,
+  ): void;
+  removeEventListener<K extends keyof WebSocketEventMap>(
+    type: K,
+    listener: (this: WebSocket, ev: WebSocketEventMap[K]) => any,
+    options?: boolean | EventListenerOptions,
+  ): void;
+  removeEventListener(
+    type: string,
+    listener: EventListenerOrEventListenerObject,
+    options?: boolean | EventListenerOptions,
+  ): void;
+}
+
+type BinaryType = "arraybuffer" | "blob";

op_crates/websocket/lib.rs

@@ -0,0 +1,347 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+use deno_core::error::bad_resource_id;
+use deno_core::error::type_error;
+use deno_core::error::AnyError;
+use deno_core::futures::stream::SplitSink;
+use deno_core::futures::stream::SplitStream;
+use deno_core::futures::SinkExt;
+use deno_core::futures::StreamExt;
+use deno_core::serde_json::json;
+use deno_core::serde_json::Value;
+use deno_core::url;
+use deno_core::AsyncRefCell;
+use deno_core::BufVec;
+use deno_core::CancelFuture;
+use deno_core::CancelHandle;
+use deno_core::JsRuntime;
+use deno_core::OpState;
+use deno_core::RcRef;
+use deno_core::Resource;
+use deno_core::{serde_json, ZeroCopyBuf};
+
+use http::{Method, Request, Uri};
+use serde::Deserialize;
+use std::borrow::Cow;
+use std::cell::RefCell;
+use std::io::BufReader;
+use std::io::Cursor;
+use std::path::PathBuf;
+use std::rc::Rc;
+use std::sync::Arc;
+use tokio::net::TcpStream;
+use tokio_rustls::{rustls::ClientConfig, TlsConnector};
+use tokio_tungstenite::stream::Stream as StreamSwitcher;
+use tokio_tungstenite::tungstenite::Error as TungsteniteError;
+use tokio_tungstenite::tungstenite::{
+  handshake::client::Response, protocol::frame::coding::CloseCode,
+  protocol::CloseFrame, Message,
+};
+use tokio_tungstenite::{client_async, WebSocketStream};
+use webpki::DNSNameRef;
+
+pub use tokio_tungstenite; // Re-export tokio_tungstenite
+
+#[derive(Clone)]
+pub struct WsCaData(pub Vec<u8>);
+#[derive(Clone)]
+pub struct WsUserAgent(pub String);
+
+pub trait WebSocketPermissions {
+  fn check_net_url(&self, _url: &url::Url) -> Result<(), AnyError>;
+}
+
+/// For use with `op_websocket_*` when the user does not want permissions.
+pub struct NoWebSocketPermissions;
+
+impl WebSocketPermissions for NoWebSocketPermissions {
+  fn check_net_url(&self, _url: &url::Url) -> Result<(), AnyError> {
+    Ok(())
+  }
+}
+
+type MaybeTlsStream =
+  StreamSwitcher<TcpStream, tokio_rustls::client::TlsStream<TcpStream>>;
+
+type WsStream = WebSocketStream<MaybeTlsStream>;
+struct WsStreamResource {
+  tx: AsyncRefCell<SplitSink<WsStream, Message>>,
+  rx: AsyncRefCell<SplitStream<WsStream>>,
+  // When a `WsStreamResource` resource is closed, all pending 'read' ops are
+  // canceled, while 'write' ops are allowed to complete. Therefore only
+  // 'read' futures are attached to this cancel handle.
+  cancel: CancelHandle,
+}
+
+impl Resource for WsStreamResource {
+  fn name(&self) -> Cow<str> {
+    "webSocketStream".into()
+  }
+}
+
+impl WsStreamResource {}
+
+#[derive(Deserialize)]
+#[serde(rename_all = "camelCase")]
+struct CheckPermissionArgs {
+  url: String,
+}
+
+// This op is needed because creating a WS instance in JavaScript is a sync
+// operation and should throw error when permissions are not fullfiled,
+// but actual op that connects WS is async.
+pub fn op_ws_check_permission<WP>(
+  state: &mut OpState,
+  args: Value,
+  _zero_copy: &mut [ZeroCopyBuf],
+) -> Result<Value, AnyError>
+where
+  WP: WebSocketPermissions + 'static,
+{
+  let args: CheckPermissionArgs = serde_json::from_value(args)?;
+
+  state
+    .borrow::<WP>()
+    .check_net_url(&url::Url::parse(&args.url)?)?;
+
+  Ok(json!({}))
+}
+
+#[derive(Deserialize)]
+#[serde(rename_all = "camelCase")]
+struct CreateArgs {
+  url: String,
+  protocols: String,
+}
+
+pub async fn op_ws_create<WP>(
+  state: Rc<RefCell<OpState>>,
+  args: Value,
+  _bufs: BufVec,
+) -> Result<Value, AnyError>
+where
+  WP: WebSocketPermissions + 'static,
+{
+  let args: CreateArgs = serde_json::from_value(args)?;
+
+  {
+    let s = state.borrow();
+    s.borrow::<WP>()
+      .check_net_url(&url::Url::parse(&args.url)?)
+      .expect(
+        "Permission check should have been done in op_ws_check_permission",
+      );
+  }
+
+  let ws_ca_data = state.borrow().try_borrow::<WsCaData>().cloned();
+  let user_agent = state.borrow().borrow::<WsUserAgent>().0.clone();
+  let uri: Uri = args.url.parse()?;
+  let mut request = Request::builder().method(Method::GET).uri(&uri);
+
+  request = request.header("User-Agent", user_agent);
+
+  if !args.protocols.is_empty() {
+    request = request.header("Sec-WebSocket-Protocol", args.protocols);
+  }
+
+  let request = request.body(())?;
+  let domain = &uri.host().unwrap().to_string();
+  let port = &uri.port_u16().unwrap_or(match uri.scheme_str() {
+    Some("wss") => 443,
+    Some("ws") => 80,
+    _ => unreachable!(),
+  });
+  let addr = format!("{}:{}", domain, port);
+  let try_socket = TcpStream::connect(addr).await;
+  let tcp_socket = match try_socket.map_err(TungsteniteError::Io) {
+    Ok(socket) => socket,
+    Err(_) => return Ok(json!({"success": false})),
+  };
+
+  let socket: MaybeTlsStream = match uri.scheme_str() {
+    Some("ws") => StreamSwitcher::Plain(tcp_socket),
+    Some("wss") => {
+      let mut config = ClientConfig::new();
+      config
+        .root_store
+        .add_server_trust_anchors(&webpki_roots::TLS_SERVER_ROOTS);
+
+      if let Some(ws_ca_data) = ws_ca_data {
+        let reader = &mut BufReader::new(Cursor::new(ws_ca_data.0));
+        config.root_store.add_pem_file(reader).unwrap();
+      }
+
+      let tls_connector = TlsConnector::from(Arc::new(config));
+      let dnsname =
+        DNSNameRef::try_from_ascii_str(&domain).expect("Invalid DNS lookup");
+      let tls_socket = tls_connector.connect(dnsname, tcp_socket).await?;
+      StreamSwitcher::Tls(tls_socket)
+    }
+    _ => unreachable!(),
+  };
+
+  let (stream, response): (WsStream, Response) =
+    client_async(request, socket).await.map_err(|err| {
+      type_error(format!(
+        "failed to connect to WebSocket: {}",
+        err.to_string()
+      ))
+    })?;
+
+  let (ws_tx, ws_rx) = stream.split();
+  let resource = WsStreamResource {
+    rx: AsyncRefCell::new(ws_rx),
+    tx: AsyncRefCell::new(ws_tx),
+    cancel: Default::default(),
+  };
+  let mut state = state.borrow_mut();
+  let rid = state.resource_table.add(resource);
+
+  let protocol = match response.headers().get("Sec-WebSocket-Protocol") {
+    Some(header) => header.to_str().unwrap(),
+    None => "",
+  };
+  let extensions = response
+    .headers()
+    .get_all("Sec-WebSocket-Extensions")
+    .iter()
+    .map(|header| header.to_str().unwrap())
+    .collect::<String>();
+  Ok(json!({
+    "success": true,
+    "rid": rid,
+    "protocol": protocol,
+    "extensions": extensions
+  }))
+}
+
+#[derive(Deserialize)]
+#[serde(rename_all = "camelCase")]
+struct SendArgs {
+  rid: u32,
+  kind: String,
+  text: Option<String>,
+}
+
+pub async fn op_ws_send(
+  state: Rc<RefCell<OpState>>,
+  args: Value,
+  bufs: BufVec,
+) -> Result<Value, AnyError> {
+  let args: SendArgs = serde_json::from_value(args)?;
+
+  let msg = match args.kind.as_str() {
+    "text" => Message::Text(args.text.unwrap()),
+    "binary" => Message::Binary(bufs[0].to_vec()),
+    "pong" => Message::Pong(vec![]),
+    _ => unreachable!(),
+  };
+  let rid = args.rid;
+
+  let resource = state
+    .borrow_mut()
+    .resource_table
+    .get::<WsStreamResource>(rid)
+    .ok_or_else(bad_resource_id)?;
+  let mut tx = RcRef::map(&resource, |r| &r.tx).borrow_mut().await;
+  tx.send(msg).await?;
+  Ok(json!({}))
+}
+
+#[derive(Deserialize)]
+#[serde(rename_all = "camelCase")]
+struct CloseArgs {
+  rid: u32,
+  code: Option<u16>,
+  reason: Option<String>,
+}
+
+pub async fn op_ws_close(
+  state: Rc<RefCell<OpState>>,
+  args: Value,
+  _bufs: BufVec,
+) -> Result<Value, AnyError> {
+  let args: CloseArgs = serde_json::from_value(args)?;
+  let rid = args.rid;
+  let msg = Message::Close(args.code.map(|c| CloseFrame {
+    code: CloseCode::from(c),
+    reason: match args.reason {
+      Some(reason) => Cow::from(reason),
+      None => Default::default(),
+    },
+  }));
+
+  let resource = state
+    .borrow_mut()
+    .resource_table
+    .get::<WsStreamResource>(rid)
+    .ok_or_else(bad_resource_id)?;
+  let mut tx = RcRef::map(&resource, |r| &r.tx).borrow_mut().await;
+  tx.send(msg).await?;
+  Ok(json!({}))
+}
+
+#[derive(Deserialize)]
+#[serde(rename_all = "camelCase")]
+struct NextEventArgs {
+  rid: u32,
+}
+
+pub async fn op_ws_next_event(
+  state: Rc<RefCell<OpState>>,
+  args: Value,
+  _bufs: BufVec,
+) -> Result<Value, AnyError> {
+  let args: NextEventArgs = serde_json::from_value(args)?;
+
+  let resource = state
+    .borrow_mut()
+    .resource_table
+    .get::<WsStreamResource>(args.rid)
+    .ok_or_else(bad_resource_id)?;
+
+  let mut rx = RcRef::map(&resource, |r| &r.rx).borrow_mut().await;
+  let cancel = RcRef::map(resource, |r| &r.cancel);
+  let val = rx.next().or_cancel(cancel).await?;
+  let res = match val {
+    Some(Ok(Message::Text(text))) => json!({
+      "type": "string",
+      "data": text
+    }),
+    Some(Ok(Message::Binary(data))) => {
+      // TODO(ry): don't use json to send binary data.
+      json!({
+        "type": "binary",
+        "data": data
+      })
+    }
+    Some(Ok(Message::Close(Some(frame)))) => json!({
+      "type": "close",
+      "code": u16::from(frame.code),
+      "reason": frame.reason.as_ref()
+    }),
+    Some(Ok(Message::Close(None))) => json!({ "type": "close" }),
+    Some(Ok(Message::Ping(_))) => json!({"type": "ping"}),
+    Some(Ok(Message::Pong(_))) => json!({"type": "pong"}),
+    Some(Err(_)) => json!({"type": "error"}),
+    None => {
+      state.borrow_mut().resource_table.close(args.rid).unwrap();
+      json!({"type": "closed"})
+    }
+  };
+  Ok(res)
+}
+
+/// Load and execute the javascript code.
+pub fn init(isolate: &mut JsRuntime) {
+  isolate
+    .execute(
+      "deno:op_crates/websocket/01_websocket.js",
+      include_str!("01_websocket.js"),
+    )
+    .unwrap();
+}
+
+pub fn get_declaration() -> PathBuf {
+  PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("lib.deno_websocket.d.ts")
+}