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/* 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 };
|
