3 files changed, 294 insertions, 0 deletions
diff --git a/remote/server/README b/remote/server/README
new file mode 100644
index 0000000000..00184130d3
--- /dev/null
+++ b/remote/server/README
@@ -0,0 +1,8 @@
+These files provide functionality for serving and responding to HTTP
+requests, and handling WebSocket connections.  For this we rely on
+httpd.js and the chrome-only WebSocket.createServerWebSocket function.
+
+Generally speaking, this is all held together with a piece of string.
+It is a known problem that we do not have a high-quality HTTPD
+implementation in central, and we’d like to move away from using
+any of this code.
diff --git a/remote/server/WebSocketHandshake.jsm b/remote/server/WebSocketHandshake.jsm
new file mode 100644
index 0000000000..3037738c66
--- /dev/null
+++ b/remote/server/WebSocketHandshake.jsm
@@ -0,0 +1,198 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+var EXPORTED_SYMBOLS = ["WebSocketHandshake"];
+
+// This file is an XPCOM service-ified copy of ../devtools/server/socket/websocket-server.js.
+
+const CC = Components.Constructor;
+
+const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
+const { XPCOMUtils } = ChromeUtils.import(
+  "resource://gre/modules/XPCOMUtils.jsm"
+);
+
+const { executeSoon } = ChromeUtils.import("chrome://remote/content/Sync.jsm");
+
+XPCOMUtils.defineLazyGetter(this, "WebSocket", () => {
+  return Services.appShell.hiddenDOMWindow.WebSocket;
+});
+
+const CryptoHash = CC(
+  "@mozilla.org/security/hash;1",
+  "nsICryptoHash",
+  "initWithString"
+);
+const threadManager = Cc["@mozilla.org/thread-manager;1"].getService();
+
+// TODO(ato): Merge this with httpd.js so that we can respond to both HTTP/1.1
+// as well as WebSocket requests on the same server.
+
+/**
+ * Write a string of bytes to async output stream
+ * and return promise that resolves once all data has been written.
+ * Doesn't do any UTF-16/UTF-8 conversion.
+ * The string is treated as an array of bytes.
+ */
+function writeString(output, data) {
+  return new Promise((resolve, reject) => {
+    const wait = () => {
+      if (data.length === 0) {
+        resolve();
+        return;
+      }
+
+      output.asyncWait(
+        stream => {
+          try {
+            const written = output.write(data, data.length);
+            data = data.slice(written);
+            wait();
+          } catch (ex) {
+            reject(ex);
+          }
+        },
+        0,
+        0,
+        threadManager.currentThread
+      );
+    };
+
+    wait();
+  });
+}
+
+/** Write HTTP response (array of strings) to async output stream. */
+function writeHttpResponse(output, response) {
+  const s = response.join("\r\n") + "\r\n\r\n";
+  return writeString(output, s);
+}
+
+/**
+ * Process the WebSocket handshake headers and return the key to be sent in
+ * Sec-WebSocket-Accept response header.
+ */
+function processRequest({ requestLine, headers }) {
+  const method = requestLine.split(" ")[0];
+  if (method !== "GET") {
+    throw new Error("The handshake request must use GET method");
+  }
+
+  const upgrade = headers.get("upgrade");
+  if (!upgrade || upgrade.toLowerCase() !== "websocket") {
+    throw new Error(
+      `The handshake request has incorrect Upgrade header: ${upgrade}`
+    );
+  }
+
+  const connection = headers.get("connection");
+  if (
+    !connection ||
+    !connection
+      .split(",")
+      .map(t => t.trim())
+      .includes("Upgrade")
+  ) {
+    throw new Error("The handshake request has incorrect Connection header");
+  }
+
+  const version = headers.get("sec-websocket-version");
+  if (!version || version !== "13") {
+    throw new Error(
+      "The handshake request must have Sec-WebSocket-Version: 13"
+    );
+  }
+
+  // Compute the accept key
+  const key = headers.get("sec-websocket-key");
+  if (!key) {
+    throw new Error(
+      "The handshake request must have a Sec-WebSocket-Key header"
+    );
+  }
+
+  return { acceptKey: computeKey(key) };
+}
+
+function computeKey(key) {
+  const str = `${key}258EAFA5-E914-47DA-95CA-C5AB0DC85B11`;
+  const data = Array.from(str, ch => ch.charCodeAt(0));
+  const hash = new CryptoHash("sha1");
+  hash.update(data, data.length);
+  return hash.finish(true);
+}
+
+/**
+ * Perform the server part of a WebSocket opening handshake
+ * on an incoming connection.
+ */
+async function serverHandshake(request, output) {
+  try {
+    // Check and extract info from the request
+    const { acceptKey } = processRequest(request);
+
+    // Send response headers
+    await writeHttpResponse(output, [
+      "HTTP/1.1 101 Switching Protocols",
+      "Upgrade: websocket",
+      "Connection: Upgrade",
+      `Sec-WebSocket-Accept: ${acceptKey}`,
+    ]);
+  } catch (error) {
+    // Send error response in case of error
+    await writeHttpResponse(output, ["HTTP/1.1 400 Bad Request"]);
+    throw error;
+  }
+}
+
+async function createWebSocket(transport, input, output) {
+  const transportProvider = {
+    setListener(upgradeListener) {
+      // onTransportAvailable callback shouldn't be called synchronously
+      executeSoon(() => {
+        upgradeListener.onTransportAvailable(transport, input, output);
+      });
+    },
+  };
+
+  return new Promise((resolve, reject) => {
+    const socket = WebSocket.createServerWebSocket(
+      null,
+      [],
+      transportProvider,
+      ""
+    );
+    socket.addEventListener("close", () => {
+      input.close();
+      output.close();
+    });
+
+    socket.onopen = () => resolve(socket);
+    socket.onerror = err => reject(err);
+  });
+}
+
+/** Upgrade an existing HTTP request from httpd.js to WebSocket. */
+async function upgrade(request, response) {
+  // handle response manually, allowing us to send arbitrary data
+  response._powerSeized = true;
+
+  const { transport, input, output } = response._connection;
+
+  const headers = new Map();
+  for (let [key, values] of Object.entries(request._headers._headers)) {
+    headers.set(key, values.join("\n"));
+  }
+  const convertedRequest = {
+    requestLine: `${request.method} ${request.path}`,
+    headers,
+  };
+  await serverHandshake(convertedRequest, output);
+
+  return createWebSocket(transport, input, output);
+}
+
+const WebSocketHandshake = { upgrade };
diff --git a/remote/server/WebSocketTransport.jsm b/remote/server/WebSocketTransport.jsm
new file mode 100644
index 0000000000..611000f07b
--- /dev/null
+++ b/remote/server/WebSocketTransport.jsm
@@ -0,0 +1,88 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This is an XPCOM service-ified copy of ../devtools/shared/transport/websocket-transport.js.
+
+"use strict";
+
+var EXPORTED_SYMBOLS = ["WebSocketTransport"];
+
+const { EventEmitter } = ChromeUtils.import(
+  "resource://gre/modules/EventEmitter.jsm"
+);
+
+function WebSocketTransport(socket) {
+  EventEmitter.decorate(this);
+
+  this.active = false;
+  this.hooks = null;
+  this.socket = socket;
+}
+
+WebSocketTransport.prototype = {
+  ready() {
+    if (this.active) {
+      return;
+    }
+
+    this.socket.addEventListener("message", this);
+    this.socket.addEventListener("close", this);
+
+    this.active = true;
+  },
+
+  send(object) {
+    this.emit("send", object);
+    if (this.socket) {
+      this.socket.send(JSON.stringify(object));
+    }
+  },
+
+  startBulkSend() {
+    throw new Error("Bulk send is not supported by WebSocket transport");
+  },
+
+  close() {
+    if (!this.socket) {
+      return;
+    }
+    this.emit("close");
+    this.active = false;
+
+    this.socket.removeEventListener("message", this);
+    this.socket.removeEventListener("close", this);
+    this.socket.close();
+    this.socket = null;
+
+    if (this.hooks) {
+      this.hooks.onClosed();
+      this.hooks = null;
+    }
+  },
+
+  handleEvent(event) {
+    switch (event.type) {
+      case "message":
+        this.onMessage(event);
+        break;
+      case "close":
+        this.close();
+        break;
+    }
+  },
+
+  onMessage({ data }) {
+    if (typeof data !== "string") {
+      throw new Error(
+        "Binary messages are not supported by WebSocket transport"
+      );
+    }
+
+    const object = JSON.parse(data);
+    this.emit("packet", object);
+    if (this.hooks) {
+      this.hooks.onPacket(object);
+    }
+  },
+};