/**
* (c) 2013 Rob Wu <gwnRob@gmail.com>
* Released under the MIT license
* https://github.com/Rob--W/chrome-api/chrome.tabs.executeScriptInFrame
*
* Implements the chrome.tabs.executeScriptInFrame API.
* This API is similar to the chrome.tabs.executeScript method, except
* that it also recognizes the "frameId" property.
* This frameId can be obtained through the webNavigation or webRequest API.
*
* When an error occurs, chrome.runtime.lastError is set.
*
* Required permissions:
* webRequest
* webRequestBlocking
* Host permissions for the tab
*
* In addition, the following field must also be set in manifest.json:
* "web_accessible_resources": ["getFrameId"]
*/
/* globals chrome, console */
(function() {
/* jshint browser:true, maxlen:100 */
'use strict';
chrome.tabs.executeScriptInFrame = executeScript;
// This URL is used to communicate the frameId. The resource is never
// visited, so it should be a non-existent location. Do not use *, ", '
// or line breaks in the file name.
var URL_WHAT_IS_MY_FRAME_ID = chrome.extension.getURL('getFrameId');
// The callback will be called within ... ms:
// Don't set a too low value.
var MAXIMUM_RESPONSE_TIME_MS = 1000;
// Callbacks are stored here until they're invoked.
// Key = dummyUrl, value = callback function
var callbacks = {};
chrome.webRequest.onBeforeRequest.addListener(function showFrameId(details) {
// Positive integer frameId >= 0
// Since an image is used as a data transport, we add 1 to get a
// non-zero width.
var frameId = details.frameId + 1;
// Assume that the frameId fits in three bytes - which is a very
// reasonable assumption.
var width = String.fromCharCode(frameId & 0xFF, (frameId >> 8) & 0xFF);
// When frameId > 0xFFFF, use the height to convey the additional
// information. Again, add 1 to make sure that the height is non-zero.
var height = String.fromCharCode((frameId >> 16) + 1, 0);
// Convert data to base64 to avoid loss of bytes
var image = 'data:image/gif;base64,' + btoa(
// 4749 4638 3961 (GIF header)
'GIF89a' +
// Logical Screen Width (LSB)
width +
// Logical Screen Height (LSB)
height +
// "No Global Color Table follows"
'\x00' +
// Background color
'\xff' +
// No aspect information is given
'\x00' +
// (image descriptor)
// Image Separator
'\x2c' +
// Image Position (Left & Top)
'\x00\x00\x00\x00' +
// Image Width (LSB)
width +
// Image Height (LSB)
height +
// Local Color Table is not present
'\x00' +
// (End of image descriptor)
// Image data
'\x02\x02\x44\x01\x00' +
// GIF trailer
'\x3b'
);
return {redirectUrl: image};
}, {
urls: [URL_WHAT_IS_MY_FRAME_ID + '*'],
types: ['image']
}, ['blocking']);
chrome.runtime.onMessage.addListener(function(message, sender,
sendResponse) {
if (message && message.executeScriptCallback) {
var callback = callbacks[message.identifier];
if (callback) {
if (message.hello) {
clearTimeout(callback.timer);
return;
}
delete callbacks[message.identifier];
// Result within an array to be consistent with the
// chrome.tabs.executeScript API.
callback([message.evalResult]);
} else {
console.warn('Callback not found for response in tab ' +
sender.tab.id);
}
}
});
/**
* Execute content script in a specific frame.
*
* @param tabId {integer} required
* @param details.frameId {integer} required
* @param details.code {string} Code or file is required (not both)
* @param details.file {string} Code or file is required (not both)
* @param details.runAt {optional string} One of "document_start",
* "document_end", "document_idle"
* @param callback {optional function(optional result array)} When an error
* occurs, result
* is not set.
*/
function executeScript(tabId, details, callback) {
console.assert(typeof details === 'object',
'details must be an object (argument 0)');
var frameId = details.frameId;
console.assert(typeof tabId === 'number',
'details.tabId must be a number');
console.assert(typeof frameId === 'number',
'details.frameId must be a number');
var sourceType = ('code' in details ? 'code' : 'file');
console.assert(sourceType in details, 'No source code or file specified');
var sourceValue = details[sourceType];
console.assert(typeof sourceValue === 'string',
'details.' + sourceType + ' must be a string');
var runAt = details.runAt;
if (!callback) {
callback = function() {/* no-op*/};
}
console.assert(typeof callback === 'function',
'callback must be a function');
if (frameId === 0) {
// No need for heavy lifting if we want to inject the script
// in the main frame
var injectDetails = {
allFrames: false,
runAt: runAt
};
injectDetails[sourceType] = sourceValue;
chrome.tabs.executeScript(tabId, injectDetails, callback);
return;
}
var identifier = Math.random().toString(36);
if (sourceType === 'code') {
executeScriptInFrame();
} else { // sourceType === 'file'
(function() {
var x = new XMLHttpRequest();
x.open('GET', chrome.extension.getURL(sourceValue), true);
x.onload = function() {
sourceValue = x.responseText;
executeScriptInFrame();
};
x.onerror = function executeScriptResourceFetchError() {
var message = 'Failed to load file: "' + sourceValue + '".';
console.error('executeScript: ' + message);
chrome.runtime.lastError = chrome.extension.lastError =
{ message: message };
try {
callback();
} finally {
chrome.runtime.lastError = chrome.extension.lastError = undefined;
}
};
x.send();
})();
}
function executeScriptInFrame() {
callbacks[identifier] = callback;
chrome.tabs.executeScript(tabId, {
code: '(' + DETECT_FRAME + ')(' +
'window,' +
JSON.stringify(identifier) + ',' +
frameId + ',' +
JSON.stringify(sourceValue) + ')',
allFrames: true,
runAt: 'document_start'
}, function(results) {
if (results) {
callback.timer = setTimeout(executeScriptTimedOut,
MAXIMUM_RESPONSE_TIME_MS);
} else {
// Failed :(
delete callbacks[identifier];
callback();
}
});
}
function executeScriptTimedOut() {
var callback = callbacks[identifier];
if (!callback) {
return;
}
delete callbacks[identifier];
var message = 'Failed to execute script: Frame ' + frameId +
' not found in tab ' + tabId;
console.error('executeScript: ' + message);
chrome.runtime.lastError = chrome.extension.lastError =
{ message: message };
try {
callback();
} finally {
chrome.runtime.lastError = chrome.extension.lastError = undefined;
}
}
}
/**
* Code executed as a content script.
*/
var DETECT_FRAME = '' + function checkFrame(window, identifier, frameId,
code) {
var i;
if ('__executeScript_frameId__' in window) {
evalAsContentScript();
} else {
// Do NOT use new Image() because of http://crbug.com/245296
// in Chrome 27-29
i = window.document.createElement('img');
i.onload = function() {
window.__executeScript_frameId__ = (this.naturalWidth - 1) +
(this.naturalHeight - 1 << 16);
evalAsContentScript();
};
// Trigger webRequest event to get frameId
// (append extra characters to bust the cache)
i.src = 'URL_WHAT_IS_MY_FRAME_ID?' +
Math.random().toString(36).slice(-6);
}
for (i = 0 ; i < window.frames.length; ++i) {
try {
var frame = window.frames[i];
var scheme = frame.location.protocol;
if (scheme !== 'https:' && scheme !== 'http:' && scheme !== 'file:') {
checkFrame(frame, identifier, frameId, code);
}
} catch (e) {
// blocked by same origin policy, so it's not a javascript:/about:blank
// URL. chrome.tabs.executeScript will run the script for the frame.
}
}
function evalAsContentScript() {
if (window.__executeScript_frameId__ !== frameId) {
return;
}
// Send an early message to make sure that any blocking code
// in the evaluated code does not cause the time-out in the background
// page to be triggered
chrome.runtime.sendMessage({
executeScriptCallback: true,
hello: true,
identifier: identifier
});
var result = null;
try {
// jshint evil:true
result = window.eval(code);
} finally {
chrome.runtime.sendMessage({
executeScriptCallback: true,
evalResult: result,
identifier: identifier
});
}
}
}.toString().replace('URL_WHAT_IS_MY_FRAME_ID', URL_WHAT_IS_MY_FRAME_ID);
})();