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 have a problem with my Service Worker.
I'm currently implementing offline functionality with an offline.html site to be shown in case of network failure. I have implemented Navigation Preloads as described here: https://developers.google.com/web/updates/2017/02/navigation-preload#activating_navigation_preload
Here is my install EventListener were skipWaiting() and initialize new cache
const version = 'v.1.2.3'
const CACHE_NAME = '::static-cache'
const urlsToCache = ['index~offline.html', 'favicon-512.png']
self.addEventListener('install', function(event) {
self.skipWaiting()
event.waitUntil(
caches
.open(version + CACHE_NAME)
.then(function(cache) {
return cache.addAll(urlsToCache)
})
.then(function() {
console.log('WORKER: install completed')
})
)
})
Here is my activate EventListener were I feature-detect navigationPreload and enable it. Afterwards I check for old caches and delete them
self.addEventListener('activate', event => {
console.log('WORKER: activated')
event.waitUntil(
(async function() {
// Feature-detect
if (self.registration.navigationPreload) {
// Enable navigation preloads!
console.log('WORKER: Enable navigation preloads')
await self.registration.navigationPreload.enable()
}
})().then(
caches.keys().then(function(cacheNames) {
cacheNames.forEach(function(cacheName) {
if (cacheName !== version + CACHE_NAME) {
caches.delete(cacheName)
console.log(cacheName + ' CACHE deleted')
}
})
})
)
)
})
This is my fetch eventListener
self.addEventListener('fetch', event => {
const { request } = event
// Always bypass for range requests, due to browser bugs
if (request.headers.has('range')) return
event.respondWith(
(async function() {
// Try to get from the cache:
const cachedResponse = await caches.match(request)
if (cachedResponse) return cachedResponse
try {
const response = await event.preloadResponse
if (response) return response
// Otherwise, get from the network
return await fetch(request)
} catch (err) {
// If this was a navigation, show the offline page:
if (request.mode === 'navigate') {
console.log('Err: ',err)
console.log('Request: ', request)
return caches.match('index~offline.html')
}
// Otherwise throw
throw err
}
})()
)
})
Now my Problem:
On my local machine on localhost everything just works as it should. If network is offline the index~offline.html page is delivered to the user. If I deploy to my test server everything works as well as expected, except for a strange error-message in Chrome on normal browsing(not offline mode):
The service worker navigation preload request failed with network error: net::ERR_INTERNET_DISCONNECTED.
I logged the error and the request to get more information
Error:
DOMException: The service worker navigation preload request failed with a network error.
Request:
Its strange because somehow index.html is requested no matter which site is loaded.
Additional Information this is happening in Chrome 89, in chrome 88 everything seems fine(I checked in browserstack). I just saw there was a change in pwa offline detection in Chrome 89...
https://developer.chrome.com/blog/improved-pwa-offline-detection/
anybody has an idea what the problem might be?
Update
I rebuild the problem here so everybody can check it out: https://dreamy-leavitt-bd4f0e.netlify.app/
This error is directly caused by the improved pwa offline detection you linked to:
https://developer.chrome.com/blog/improved-pwa-offline-detection/
The browser fakes an offline context and tries to request the start_url of your manifest, e.g. the index.html specified in your https://dreamy-leavitt-bd4f0e.netlify.app/site.webmanifest
This is to make sure that your service worker is actually returning a valid 200 response in this situation, i.e. the valid cached response for your index~offline.html page.
The error you're asking about specifically is from the await event.preloadResponse part and it apparently can't be suppressed.
The await fetch call produces a similar error but that can be suppressed, just don't console.log in the catch section.
Hopefully chrome won't show this error from preload responses in future when doing offline pwa detection as it's needlessly confusing.
I have set up a Node.js app where I use sessions and store them in MySQL. When using MemoryStorage, redirections work fine, but when using MySQL, req.session doesn't update until you reload or you move to a different page, and I'm forced to replace every single res.redirect('/...') by res.render() of that same page to display anything in req.session immediately.
I've tried using both return res.redirect() and not, as well as using setTimeout, neither work. I can't figure it out and I need sessions to be stored in DB
router.get('/student-sign-up', function (req, res, next) {
res.render('student/signUp', {
title: 'Sign up',
errors: req.session.errors
});
req.session.errors = null; //to flush them on reload
}).post('/student-sign-up', function (req, res, next) {
//Some form checks
let errors = req.validationErrors();
if (errors) {
req.session.errors = errors;
req.session.signUpSuccess = false;
return res.redirect('/student-sign-up');
}
//...
}
The above should redirect to the same page, and display the error (I use Handlebars as my view engine) if there were one, but it simply redirects, and if you refresh manually or submit a faulty from again, then it displays it. Same thing for logins (both success not going into the platform's home, and failure not showing errors either). It's like everything's lagging behind by 1 step...
OK, I found the solution. According to the express-session docs, all I had to do was force a save and then redirect, as so:
req.session.save((err) => {
if (err) {
req.locals.error = err;
return res.redirect('/');
}
return res.redirect('/next-section');
});
I'll leave this here for anyone that might have the same issue!
After months of working without any trouble, now when trying to make login, this error appears. The code shown is simplified, when it arrives at "Parse.User.logIn" is when the error happens. There are some similar questions here, but all of them are related to CORS, and I don´t know how or where to make something like the line below:
Access-Control-Expose-Headers: x-parse-job-status-id
CODE:
$scope.signin = function () {
var email = $scope.login.email;
var pass = $scope.login.pass;
Parse.User.logIn(email, pass, {
success: function (user) {
Stuff after successful login
}
});
},
error: function (user, error) {
stuff after unsuccessful login
}
});
}
}
Any help would be appreciated.
Fix can be found here. We tried it and worked like a charm 👍
https://github.com/parse-community/Parse-SDK-JS/issues/622
Edit:
Solution (can be found in link)
"I believe you're using the unpkg version:
https://unpkg.com/parse/dist/parse.js, and the minified production version is at https://unpkg.com/parse/dist/parse.min.js.
Which is automatically pointing to the latest release, you should use:
https://unpkg.com/parse#1.11.1/dist/parse.js
As you are now pointing to the SDK v2.0 which contains that issue."
Why is navigator.clipboard always undefined in the following snippet?
var clipboard = navigator.clipboard;
if (clipboard == undefined) {
console.log('clipboard is undefined');
} else {
clipboard.writeText('stuff to write').then(function() {
console.log('Copied to clipboard successfully!');
}, function() {
console.error('Unable to write to clipboard. :-(');
});
}
More on the clipboard API can be found here.
Chrome Version: 68.0.3440.106.
I'm sure this was working at some point, but no longer is. It's confusing because this table suggests that the Clipboard API is implemented in Chrome (has been for some time), but this table of specific API methods suggests that none of the methods of the API is supported??
This requires a secure origin — either HTTPS or localhost (or disabled by running Chrome with a flag). Just like for ServiceWorker, this state is indicated by the presence or absence of the property on the navigator object.
https://developers.google.com/web/updates/2018/03/clipboardapi
This is noted in the spec with [SecureContext] on the interface: https://w3c.github.io/clipboard-apis/#dom-navigator-clipboard
You can check the state of window.isSecureContext to learn if that's the reason a feature is unavailable. Secure contexts | MDN
And yes, you should set up HSTS to make sure HTTP redirects to HTTPS.
you can write an all-in-one wrapper function.
if in secure context (https) : use navigator clipboard api
if not : use the 'out of viewport hidden text area' trick
// return a promise
function copyToClipboard(textToCopy) {
// navigator clipboard api needs a secure context (https)
if (navigator.clipboard && window.isSecureContext) {
// navigator clipboard api method'
return navigator.clipboard.writeText(textToCopy);
} else {
// text area method
let textArea = document.createElement("textarea");
textArea.value = textToCopy;
// make the textarea out of viewport
textArea.style.position = "fixed";
textArea.style.left = "-999999px";
textArea.style.top = "-999999px";
document.body.appendChild(textArea);
textArea.focus();
textArea.select();
return new Promise((res, rej) => {
// here the magic happens
document.execCommand('copy') ? res() : rej();
textArea.remove();
});
}
}
use :
copyToClipboard("I'm going to the clipboard !")
.then(() => console.log('text copied !'))
.catch(() => console.log('error'));
ps : do not try it in a repl like jsfiddle/copeden/...
Try this:
if (typeof (navigator.clipboard) == 'undefined') {
console.log('navigator.clipboard');
var textArea = document.createElement("textarea");
textArea.value = linkToGo;
textArea.style.position = "fixed"; //avoid scrolling to bottom
document.body.appendChild(textArea);
textArea.focus();
textArea.select();
try {
var successful = document.execCommand('copy');
var msg = successful ? 'successful' : 'unsuccessful';
toastr.info(msg);
} catch (err) {
toastr.warning('Was not possible to copy te text: ', err);
}
document.body.removeChild(textArea)
return;
}
navigator.clipboard.writeText(linkToGo).then(function () {
toastr.info(`successful!`);
}, function (err) {
toastr.warning('unsuccessful!', err);
});
In localhost, the clipboard is blocked by the chrome browser. You check this by going to the following path
Chrome > settings > privacy and Security > site settings > View permissions and data stored across sites then click on your localhost URL which will mentation on the page and check the permission of the clipboard
A minimal solution for copying tooltips when HTTPS is not yet available and the solution with document.execCommand('copy') does not work.
But it requires that the user selects and copies by hand what is displayed in the alert.
function copyToClipboard(text) {
if(navigator.clipboard) {
navigator.clipboard.writeText(text);
}
else{
alert(text);
}
}
This solutions works at the moment (it includes cross browser support, error handling + clean up).
https://stackoverflow.com/a/33928558/318380
you can use :
change the :
navigator.clipboard.writeText("Content")
to :
navigator['clipboard'].writeText("Content") instead.