blob: d58ea486e28a2dd1ccc7fd1262d178f66dd12c24 [file] [log] [blame]
// Copyright 2015 The Vanadium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
var debug = require('debug')('content-script:index');
var pageEventProxy = require('./event-proxy');
var random = require('../../../src/lib/random');
// Port to communicate with background js.
var backgroundPort = chrome.runtime.connect();
// We generate and send different instanceIds to the background page than those
// coming from the web app. This prevents the web app from intentionally
// colliding with instanceIds from apps on other tabs. The two maps below are
// used to map between the two instanceIds.
var backgroundToPage = {};
var pageToBackground = {};
// If the plug-in crashed, the state of the connected Vanadium instances
// are invalid. We will block any further messages.
var invalidated = false;
// Whitelist of message types to allow from the web app.
var messageTypeWhitelist = [
'auth',
'browsprCleanup',
'browsprMsg',
'createInstance'
];
if (process.env.ALLOW_INTENTIONAL_CRASH) {
messageTypeWhitelist.push('intentionallyPanic');
}
function isAllowedMessage(type) {
return messageTypeWhitelist.indexOf(type) >= 0;
}
// Forward messages from the webApp to the background page.
pageEventProxy.onAny(function(body) {
if (invalidated && !process.env.ALLOW_INTENTIONAL_CRASH) {
pageEventProxy.send('error', 'Refusing to send Vanadium message. ' +
'Plug-in crashed and page must be reloaded.');
return;
}
// 'this' is bound to event emitter2 instance, which sets 'this.event' to the
// type of the event.
var type = this.event;
debug('content script received message of type', type, 'from page:', body);
if (!isAllowedMessage(type)) {
var err = new Error('Ignoring message with unknown type: ' + type);
console.error(err);
pageEventProxy.send('error', { message: err.message });
return;
}
// Swap the instanceId with a generated one.
if (body && body.instanceId) {
var outgoingInstanceId = pageToBackground[body.instanceId] ||
random.int32();
pageToBackground[body.instanceId] = outgoingInstanceId;
backgroundToPage[outgoingInstanceId] = body.instanceId;
body.instanceId = outgoingInstanceId;
}
try {
backgroundPort.postMessage({
type: this.event,
body: body
});
} catch (err) {
pageEventProxy.send('error', 'Error posting message, ' +
'you may need to reload this tab. ' + err);
}
});
// Forward any messages from the background page to the webApp.
backgroundPort.onMessage.addListener(function(msg) {
debug('content script received message of type', msg.type,
'from background script:', msg.body);
if (msg.type === 'crash') {
// Block any future messages, as we don't currently have a way to
// be sure the response will be correct.
invalidated = true;
pageEventProxy.send('crash', msg.body);
return;
}
// Swap the instanceId with the original one.
if (msg.instanceId) {
msg.instanceId = backgroundToPage[msg.instanceId];
}
pageEventProxy.send(msg.type, msg);
});
debug('content script loaded');