I am in the process of building a Chrome extension, and for the whole thing to work the way I would like it to, I need an external JavaScript script to be able to detect if a user has my extension installed.
For example: A user installs my plugin, then goes to a website with my script on it. The website detects that my extension is installed and updates the page accordingly.
Is this possible?
Chrome now has the ability to send messages from the website to the extension.
So in the extension background.js (content.js will not work) add something like:
chrome.runtime.onMessageExternal.addListener(
function(request, sender, sendResponse) {
if (request) {
if (request.message) {
if (request.message == "version") {
sendResponse({version: 1.0});
}
}
}
return true;
});
This will then let you make a call from the website:
var hasExtension = false;
chrome.runtime.sendMessage(extensionId, { message: "version" },
function (reply) {
if (reply) {
if (reply.version) {
if (reply.version >= requiredVersion) {
hasExtension = true;
}
}
}
else {
hasExtension = false;
}
});
You can then check the hasExtension variable. The only drawback is the call is asynchronous, so you have to work around that somehow.
Edit:
As mentioned below, you'll need to add an entry to the manifest.json listing the domains that can message your addon. Eg:
"externally_connectable": {
"matches": ["*://localhost/*", "*://your.domain.com/*"]
},
2021 Update:
chrome.runtime.sendMessage will throw the following exception in console if the extension isn't installed or it's disabled.
Unchecked runtime.lastError: Could not establish connection. Receiving end does not exist
To fix this, add this validation inside the sendMessage callback
if (chrome.runtime.lastError) {
// handle error
}
I am sure there is a direct way (calling functions on your extension directly, or by using the JS classes for extensions), but an indirect method (until something better comes along):
Have your Chrome extension look for a specific DIV or other element on your page, with a very specific ID.
For example:
<div id="ExtensionCheck_JamesEggersAwesomeExtension"></div>
Do a getElementById and set the innerHTML to the version number of your extension or something. You can then read the contents of that client-side.
Again though, you should use a direct method if there is one available.
EDIT: Direct method found!!
Use the connection methods found here: https://developer.chrome.com/extensions/extension#global-events
Untested, but you should be able to do...
var myPort=chrome.extension.connect('yourextensionid_qwerqweroijwefoijwef', some_object_to_send_on_connect);
Another method is to expose a web-accessible resource, though this will allow any website to test if your extension is installed.
Suppose your extension's ID is aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa, and you add a file (say, a transparent pixel image) as test.png in your extension's files.
Then, you expose this file to the web pages with web_accessible_resources manifest key:
"web_accessible_resources": [
"test.png"
],
In your web page, you can try to load this file by its full URL (in an <img> tag, via XHR, or in any other way):
chrome-extension://aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/test.png
If the file loads, then the extension is installed. If there's an error while loading this file, then the extension is not installed.
// Code from https://groups.google.com/a/chromium.org/d/msg/chromium-extensions/8ArcsWMBaM4/2GKwVOZm1qMJ
function detectExtension(extensionId, callback) {
var img;
img = new Image();
img.src = "chrome-extension://" + extensionId + "/test.png";
img.onload = function() {
callback(true);
};
img.onerror = function() {
callback(false);
};
}
Of note: if there is an error while loading this file, said network stack error will appear in the console with no possibility to silence it. When Chromecast used this method, it caused quite a bit of controversy because of this; with the eventual very ugly solution of simply blacklisting very specific errors from Dev Tools altogether by the Chrome team.
Important note: this method will not work in Firefox WebExtensions. Web-accessible resources inherently expose the extension to fingerprinting, since the URL is predictable by knowing the ID. Firefox decided to close that hole by assigning an instance-specific random URL to web accessible resources:
The files will then be available using a URL like:
moz-extension://<random-UUID>/<path/to/resource>
This UUID is randomly generated for every browser instance and is not your extension's ID. This prevents websites from fingerprinting the extensions a user has installed.
However, while the extension can use runtime.getURL() to obtain this address, you can't hard-code it in your website.
I thought I would share my research on this.
I needed to be able to detect if a specific extension was installed for some file:/// links to work.
I came across this article here
This explained a method of getting the manifest.json of an extension.
I adjusted the code a bit and came up with:
function Ext_Detect_NotInstalled(ExtName, ExtID) {
console.log(ExtName + ' Not Installed');
if (divAnnounce.innerHTML != '')
divAnnounce.innerHTML = divAnnounce.innerHTML + "<BR>"
divAnnounce.innerHTML = divAnnounce.innerHTML + 'Page needs ' + ExtName + ' Extension -- to intall the LocalLinks extension click here';
}
function Ext_Detect_Installed(ExtName, ExtID) {
console.log(ExtName + ' Installed');
}
var Ext_Detect = function (ExtName, ExtID) {
var s = document.createElement('script');
s.onload = function () { Ext_Detect_Installed(ExtName, ExtID); };
s.onerror = function () { Ext_Detect_NotInstalled(ExtName, ExtID); };
s.src = 'chrome-extension://' + ExtID + '/manifest.json';
document.body.appendChild(s);
}
var is_chrome = navigator.userAgent.toLowerCase().indexOf('chrome') > -1;
if (is_chrome == true) {
window.onload = function () { Ext_Detect('LocalLinks', 'jllpkdkcdjndhggodimiphkghogcpida'); };
}
With this you should be able to use Ext_Detect(ExtensionName,ExtensionID) to detect the installation of any number of extensions.
Another possible solution if you own the website is to use inline installation.
if (chrome.app.isInstalled) {
// extension is installed.
}
I know this an old question but this way was introduced in Chrome 15 and so I thought Id list it for anyone only now looking for an answer.
Here is an other modern approach:
const checkExtension = (id, src, callback) => {
let e = new Image()
e.src = 'chrome-extension://'+ id +'/'+ src
e.onload = () => callback(1), e.onerror = () => callback(0)
}
// "src" must be included to "web_accessible_resources" in manifest.json
checkExtension('gighmmpiobklfepjocnamgkkbiglidom', 'icons/icon24.png', (ok) => {
console.log('AdBlock: %s', ok ? 'installed' : 'not installed')
})
checkExtension('bhlhnicpbhignbdhedgjhgdocnmhomnp', 'images/checkmark-icon.png', (ok) => {
console.log('ColorZilla: %s', ok ? 'installed' : 'not installed')
})
I used the cookie method:
In my manifest.js file I included a content script that only runs on my site:
"content_scripts": [
{
"matches": [
"*://*.mysite.co/*"
],
"js": ["js/mysite.js"],
"run_at": "document_idle"
}
],
in my js/mysite.js I have one line:
document.cookie = "extension_downloaded=True";
and in my index.html page I look for that cookie.
if (document.cookie.indexOf('extension_downloaded') != -1){
document.getElementById('install-btn').style.display = 'none';
}
You could have the extension set a cookie and have your websites JavaScript check if that cookie is present and update accordingly. This and probably most other methods mentioned here could of course be cirvumvented by the user, unless you try and have the extension create custom cookies depending on timestamps etc, and have your application analyze them server side to see if it really is a user with the extension or someone pretending to have it by modifying his cookies.
There's another method shown at this Google Groups post. In short, you could try detecting whether the extension icon loads successfully. This may be helpful if the extension you're checking for isn't your own.
Webpage interacts with extension through background script.
manifest.json:
"background": {
"scripts": ["background.js"],
"persistent": true
},
"externally_connectable": {
"matches": ["*://(domain.ext)/*"]
},
background.js:
chrome.runtime.onMessageExternal.addListener(function(msg, sender, sendResponse) {
if ((msg.action == "id") && (msg.value == id))
{
sendResponse({id : id});
}
});
page.html:
<script>
var id = "some_ext_id";
chrome.runtime.sendMessage(id, {action: "id", value : id}, function(response) {
if(response && (response.id == id)) //extension installed
{
console.log(response);
}
else //extension not installed
{
console.log("Please consider installig extension");
}
});
</script>
Your extension could interact with the website (e.g. changing variables) and your website could detect this.
But there should be a better way to do this. I wonder how Google is doing it on their extension gallery (already installed applications are marked).
Edit:
The gallery use the chrome.management.get function. Example:
chrome.management.get("mblbciejcodpealifnhfjbdlkedplodp", function(a){console.log(a);});
But you can only access the method from pages with the right permissions.
A lot of the answers here so far are Chrome only or incur an HTTP overhead penalty. The solution that we are using is a little different:
1. Add a new object to the manifest content_scripts list like so:
{
"matches": ["https://www.yoursite.com/*"],
"js": [
"install_notifier.js"
],
"run_at": "document_idle"
}
This will allow the code in install_notifier.js to run on that site (if you didn't already have permissions there).
2. Send a message to every site in the manifest key above.
Add something like this to install_notifier.js (note that this is using a closure to keep the variables from being global, but that's not strictly necessary):
// Dispatch a message to every URL that's in the manifest to say that the extension is
// installed. This allows webpages to take action based on the presence of the
// extension and its version. This is only allowed for a small whitelist of
// domains defined in the manifest.
(function () {
let currentVersion = chrome.runtime.getManifest().version;
window.postMessage({
sender: "my-extension",
message_name: "version",
message: currentVersion
}, "*");
})();
Your message could say anything, but it's useful to send the version so you know what you're dealing with. Then...
3. On your website, listen for that message.
Add this to your website somewhere:
window.addEventListener("message", function (event) {
if (event.source == window &&
event.data.sender &&
event.data.sender === "my-extension" &&
event.data.message_name &&
event.data.message_name === "version") {
console.log("Got the message");
}
});
This works in Firefox and Chrome, and doesn't incur HTTP overhead or manipulate the page.
You could also use a cross-browser method what I have used.
Uses the concept of adding a div.
in your content script (whenever the script loads, it should do this)
if ((window.location.href).includes('*myurl/urlregex*')) {
$('html').addClass('ifextension');
}
in your website you assert something like,
if (!($('html').hasClass('ifextension')){}
And throw appropriate message.
If you have control over the Chrome extension, you can try what I did:
// Inside Chrome extension
var div = document.createElement('div');
div.setAttribute('id', 'myapp-extension-installed-div');
document.getElementsByTagName('body')[0].appendChild(div);
And then:
// On web page that needs to detect extension
if ($('#myapp-extension-installed-div').length) {
}
It feels a little hacky, but I couldn't get the other methods to work, and I worry about Chrome changing its API here. It's doubtful this method will stop working any time soon.
If you're trying to detect any extension from any website,
This post helped: https://ide.hey.network/post/5c3b6c7aa7af38479accc0c7
Basically, the solution would be to simply try to get a specific file (manifest.json or an image) from the extension by specifying its path. Here's what I used. Definitely working:
const imgExists = function(_f, _cb) {
const __i = new Image();
__i.onload = function() {
if (typeof _cb === 'function') {
_cb(true);
}
}
__i.onerror = function() {
if (typeof _cb === 'function') {
_cb(false);
}
}
__i.src = _f;
__i = null;
});
try {
imgExists("chrome-extension://${CHROME_XT_ID}/xt_content/assets/logo.png", function(_test) {
console.log(_test ? 'chrome extension installed !' : 'chrome extension not installed..');
ifrm.xt_chrome = _test;
// use that information
});
} catch (e) {
console.log('ERROR', e)
}
Here is how you can detect a specific Extension installed and show a warning message.
First you need to open the manifest file of the extension by going to chrome-extension://extension_id_here_hkdppipefbchgpohn/manifest.json and look for any file name within "web_accessible_resources" section.
<div class="chromewarning" style="display:none">
<script type="text/javascript">
$.get("chrome-extension://extension_id_here_hkdppipefbchgpohn/filename_found_in_ web_accessible_resources.png").done(function () {
$(".chromewarning").show();
}).fail(function () {
// alert("failed.");
});
</script>
<p>We have detected a browser extension that conflicts with learning modules in this course.</p>
</div>
Chrome Extension Manifest v3:
const isFirefox = chrome.runtime.OnInstalledReason.CHROME_UPDATE != "chrome_update";
For FireFox, I believe chrome.runtime.OnInstalledReason.BROWSER_UPDATE will be "browser_update": https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/runtime/OnInstalledReason
I would like to make a soft integration for Subresource Integrity attributes, so be sure that I did not break the application, but only to show a warning that I need to fix some places.
Is there an option to do so?
Secure approach
If you need some kind of flexibility, then you should use a fallback mechanism - loading required resource from another URL. Probability that two different URL's will be hacked at the same time is a lot smaller compared to hacking just one resource. Fallback doesn't violate site security, because you must trust your known-good sources which you use in your code. If your resource is a Javascript - you can use a noncanonical-src attribute for a fallback too.
Insecure approach
Now, if you really, really want a user to break server and/or client security by forcing compromised resource load - at least ask a user if he/she takes responsibility by doing so. Of course this will still be a stupid thing, it's like asking "Would you like to run a virus in your computer ?". I bet nobody would like to say YES. Anyway, here is the code, which does asking these type of questions:
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/crypto-js/3.1.9-1/crypto-js.min.js"></script>
<script>
function loadResource(path) {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
var cs = CryptoJS.SHA256(this.responseText);
if (btoa(cs) == 'NjBiMTllNWRhNmE5MjM0ZmY5MjIwNjY4YTVlYzExMjVjMTU3YTI2ODUxMzI1NjE4OGVlODBmMmQyYzhkOGQzNg==' ||
confirm('Bootstrap is NOT the latest version 4.3.1, load anyway ?')
) {
var link = document.createElement('link');
link.rel = "stylesheet";
link.href = path;
document.head.appendChild(link);
}
else {
var err = document.getElementById('error');
err.title = "Component version error !";
err.innerHTML = ' ⚠️';
}
}
};
xhttp.open("GET", path, true);
xhttp.send();
}
loadResource(
//'https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css' // newest boostrap
'https://stackpath.bootstrapcdn.com/twitter-bootstrap/2.0.4/css/bootstrap-combined.min.css' // old legacy
);
</script>
DEMO
I do not recommend only displaying warnings when the SRI-Hashes don't match. When see the warning as a User, it's already too late and potentially malicious scripts were executed on your machine.
However, you can implement your desired behaviour using the ServiceWorker-API and something like <script data-integrity="xxxxxxxx">. For that, you'd want to:
Register a new ServiceWorker
Listen to the fetch event
[Client.postMessage] the targetURL to your Parent
Get script integrity hash by targetURL $('script[src=event.data.targetURL]').attr('data-integrity')
and push it into the client using Worker.postMessage
hash the response using e.G. cryptojs.sha256
match the hashes inside the worker
If the hashes match, return the response. If they don't match, return the response and use Client.postMessage again to trigger a warning.
I am very simply trying to print some content in a Windows 10 app (Universal) using HTML and JavaScript/WinJS.
ALL of the documentation says that there is a function on MSApp called getHtmlPrintDocumentSource.
I do not have this, nor can I seem to find any relevant source to see if it may have been moved. I instead have getHtmlPrintDocumentSourceAsync. This seems to be a replacement for the former, but I cannot get it to work and there is zero documentation on it as far as I can tell.
When I run the below code (which is based on the documentation but updated to be async):
function onPrintTaskRequested(printEvent) {
var printTask = printEvent.request.createPrintTask("Print Sample", function (args) {
MSApp.getHtmlPrintDocumentSourceAsync(document)
.then(function(result) {
args.setSource(result);
});
printTask.oncompleted = onPrintTaskCompleted;
});
}
result is populated with some of the print settings as I would expect, but the content property is set to 0, which I am guessing is the problem. I can't really be sure as there is no documentation for this function. I can't even run any of the dozens of pieces of example code in the documentation using `getHtmlPrintDocumentSource' because it seemingly doesn't exist anymore.
In addition to just sending document to the Async method, I have tried a couple of different variations of creating document fragments. Same results.
Probably not terribly helpful, but the message in the Windows Print Dialog that opens when executing the above code is: "Nothing was sent to print. Open a document and print again."
Any ideas?
getHtmlPrintDocumentSource is a synchronous deprecated API in Windows 10 apps. We'll work on some of the docs left behind for Windows 8 and 8.1 to clarify that.
Check out https://github.com/Microsoft/Windows-universal-samples/tree/master/Samples/Printing/js for an example of how to use getHtmlPrintDocumentSourceAsync in JavaScript.
Here is the code:
// Needs to be invoked before calling the print API
function registerForPrintContract() {
var printManager = Windows.Graphics.Printing.PrintManager.getForCurrentView();
printManager.onprinttaskrequested = onPrintTaskRequested;
console.log("Print Contract registered. Use the Print button to print.", "sample", "status");
}
// Variable to hold the document source to print
var gHtmlPrintDocumentSource = null;
// Print event handler for printing via the PrintManager API.
function onPrintTaskRequested(printEvent) {
var printTask = printEvent.request.createPrintTask("Print Sample", function (args) {
args.setSource(gHtmlPrintDocumentSource);
// Register the handler for print task completion event
printTask.oncompleted = onPrintTaskCompleted;
});
}
// Print Task event handler is invoked when the print job is completed.
function onPrintTaskCompleted(printTaskCompletionEvent) {
// Notify the user about the failure
if (printTaskCompletionEvent.completion === Windows.Graphics.Printing.PrintTaskCompletion.failed) {
console.log("Failed to print.", "sample", "error");
}
}
// Executed just before printing.
var beforePrint = function () {
// Replace with code to be executed just before printing the current document:
};
// Executed immediately after printing.
var afterPrint = function () {
// Replace with code to be executed immediately after printing the current document:
};
function printButtonHandler() {
// Optionally, functions to be executed immediately before and after printing can be configured as following:
window.document.body.onbeforeprint = beforePrint;
window.document.body.onafterprint = afterPrint;
// Get document source to print
MSApp.getHtmlPrintDocumentSourceAsync(document).then(function (htmlPrintDocumentSource) {
gHtmlPrintDocumentSource = htmlPrintDocumentSource;
// If the print contract is registered, the print experience is invoked.
Windows.Graphics.Printing.PrintManager.showPrintUIAsync();
});
}
The following code displays a proper list of available chromecast devices on my network. But when I click on the links, the application never launches. There are a couple of things that I'm quite confused about that may or may not be related to this question:
If I'm making my own custom application, what's with the DIAL parameters and why do I have to pass them? I don't want to write an app for the DIAL standard... this is MY app.
Again related to the DIAL parameters, if I search for devices with any other query other than "YouTube" (a DIAL parameter), the list always comes up blank. I suppose I shouldn't care, as long as the device is listed... but again... the app won't launch.
It should be noted that my sender app is a chrome webpage.
I'm a bit confused as to where my "appid" goes int he launch parameters,'
<html data-cast-api-enabled="true">
<body>
hi!<BR/>
<script>
var cast_api, cv_activity;
if (window.cast && window.cast.isAvailable) {
// Cast is known to be available
initializeApi();
} else {
// Wait for API to post a message to us
window.addEventListener("message", function(event) {
if (event.source == window && event.data &&
event.data.source == "CastApi" &&
event.data.event == "Hello")
{
//document.write("Initialize via message.<br/>");
initializeApi();
//document.write("Api initialized via message.");
};
});
};
initializeApi = function() {
cast_api = new cast.Api();
cast_api.addReceiverListener("YouTube", onReceiverList);
};
var g_list;
onReceiverList = function(list) {
g_list = list;
// If the list is non-empty, show a widget with
// the friendly names of receivers.
// When a receiver is picked, invoke doLaunch with the receiver.
document.write("Receivers: "+list.length+"<br/>");
var t;
for(t=0;t<list.length;t++)
document.write('found:'+list[t].name+' ' +list[t].id+'<br/>');
};
onLaunch = function(activity) {
if (activity.status == "running") {
cv_activity = activity;
// update UI to reflect that the receiver has received the
// launch command and should start video playback.
} else if (activity.status == "error") {
cv_activity = null;
}
};
function launchy(idx)
{
doLaunch(g_list[idx]);
}
doLaunch = function(receiver) {
var request = new window.cast.LaunchRequest(">>>>>what REALLY goes here?<<<<<<< ", receiver);
request.parameters = "v=abcdefg";
request.description = new window.cast.LaunchDescription();
request.description.text = "My Cat Video";
request.description.url = "http://my.website.get.your.own/chomecast/test.php";
cast_api.launch(request, onLaunch);
};
stopPlayback = function() {
if (cv_activity) {
cast_api.stopActivity(cv_activity.activityId);
}
};
</script>
</body>
</html>
The part marked "what really goes here?" is the part that I THINK is wrong... I couldn't be completely wrong. My device is white listed, I have an appid (which I thought might go in that slot)... The documentation merely says ActivityType DIAL Parmeters are valid, mandatory.
The first argument to the LaunchRequest is your App ID, the one that you have received in an email as part of whitelisting process. Also, the "YouTube" in the initialize method should also be replaced with the same App ID.
I strongly suggest you look at the sample that is on GitHub for chrome sender to see how you can send a request to load a media on a cast device.
What's the best way to debug custom User Scripts (aka Greasemonkey) in Chrome? Is there a way to enable User Script tracking in the Developer Tools?
What kind of debugging do you want? Like Alex said, user scripts will be listed in the same context as debugging the page itself. If you go to the "scripts" tab in the developer tools, you'll see a bar with a dropdown which will allow you to select the appropriate javascript file you wish to debug. Such scripts should have urls that look like chrome-extension://<hash>/<script file>.js. Those scripts will also log to the console of the page they're embedded on.
Additionally, if you want to log in the same place for all pages, you can try building your script as a full chrome extension, using the user script as a content script. Then you can send a message from your content script to your background page and log there. For example, if this were your content script:
function log(text) {
chrome.extension.sendRequest({'action' : 'log', 'text' : text}, function() {});
};
log("Content script loaded: " + window.location.href);
And this were your background page:
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<script>
function onRequest(request, sender, callback) {
if (request.action && request.action == 'log') {
console.log(request.text);
}
};
chrome.extension.onRequest.addListener(onRequest);
</script>
</body>
</html>
You would see each load of the content script in the background page's log.
i user the following function in my scripts for cross-browser GM Api compatibility:
function testGM() {
var isGM = typeof GM_getValue != 'undefined' && typeof GM_getValue('a', 'b') != 'undefined';
if(typeof(unsafeWindow) == 'undefined') { unsafeWindow = window; }
if(!isGM) { log = function(msg) { try { unsafeWindow.console.log(msg); } catch(e) {} }; } else { log = GM_log; }
if(window.opera) log = opera.postError;
setValue = isGM ? GM_setValue : function (name, value) { return localStorage.setItem(name, value) };
getValue = isGM ? GM_getValue : function(name, def){ var s = localStorage.getItem(name); return s == null ? def : s };
}
testGM();
it's not mine. it's courtesy sizzemctwizzle # userscripts.org
i only use log, getValue & setValue as of now, hence only these tree in that function.
You can also check out his guide.
Or you can checkout GIJoe's cross-browser GM Api too.
You could use a smaller script to actually inject your custom debug script into the page. At that point you will have the same access inside of developer tools as if it was actually included on the page.