I got a quick question for you guys, I'm new to making Chrome Extensions and the idea I have for one I'm not sure if I can do this with an extension or not. I've been looking through the API but haven't run across something that might help. So my idea for my extension is that whoever downloads the extension will be able to set a pin code they will click the icon and it basically will lock down the browser so if someone else came to the browser they would only be able to access that one page and what it would lead to, they wouldn't be able to us the url bar or have access to the tabs unless permitted.Then the owner can press a hot key and it will ask them for there pin and will unlock the browser if need be.Or even put it in the presentation mode but not able to get out of it without a password? Is this something a chrome extension could do or am I going at this the wrong way? I noticed there are some options in the Chrome://about settings where you can compact the url bar and also make the tabs on the side bar. Any help or direction for this would be great, thanks!
You can create an options page where the extension settings are saved, and then create an option called eg DisableBrowser.
In file background.js, we monitor the onBeforeRequest event, and then check the value of variable DisableBrowser if it has true value, set the value of cancel parameter onBeforeRequest event, being equal to true when cancel is equal value to true, the request is canceled.
In short, just cancel and set equal to true and everything is rejected, ie, the browser will not open urls while the extension is installed and enabled.
Update:
The sample code below is the content of background.js file, showing how to allow only certain urls that are allowed in a list is executed successfully, and consequently all other urls will be denied and fails when opened.
// callback
var onBeforeRequestCallback = function( details ) {
// List of Urls Allowed
// You can create an array or use localStorage through options.html page,
// to save the urls allowed,
// then check and if an allowed URL, the request is not canceled, or in other words, it is permitted,
// in case of failure it is canceled and is not permitted.
if ( details.url === 'https://www.google.com/' || details.url === 'http://www.bing.com/' ) {
return {
cancel : false
};
} else {
return {
cancel : true
};
}
};
// filter
var onBeforeRequestFilter = {
urls : [
"http://*/*",
"https://*/*"
]
};
// opt_extraInfoSpec
var onBeforeRequestInfo = [
"blocking",
"requestBody"
];
// Monitors onBeforeRequest event
chrome.webRequest.onBeforeRequest.addListener( onBeforeRequestCallback, onBeforeRequestFilter, onBeforeRequestInfo );
Help Links:
options
background
onBeforeRequest
localStorage
Related
I've been attempting to write a very simple Chrome extension (manifest v3) to automatically close those annoying tabs zoom leaves open after you join a meeting.
So far I have been able to get most pages to automatically close with my extension but it simply refuses to run on certain domains, including the one I actually need it to run on: https://company-name-here.zoom.us/. I ultimately would like to set the content script matchers to just zoom but for now I have expanded it to all sites in an effort to reduce sources of error.
It is not working no matter how I attempt to load the page, be it by clicking the redirect url on a google calendar event, reloading the page manually after it has already been opened, and even manually typing out the url and hitting enter. The zoom home page suffers from the same problem but other sites such as stack overflow show the "Content script loaded" console log and close in 5 seconds as I would expect.
Please find the entire source for the extension below:
manifest.json
{
"manifest_version": 3,
"name": "Zoom Auto Closer",
"version": "1.0",
"background": {
"service_worker": "src/background.js"
},
"content_scripts": [{
"run_at": "document_start",
"matches": ["<all_urls>"],
"js": ["src/content.js"]
}]
}
src/content.js
const closeDelay = 5_000;
const closeCurrentTab = () => chrome.runtime.sendMessage('close-tab');
const main = () => {
console.log('Content script loaded');
setTimeout(closeCurrentTab, closeDelay);
};
main();
src/background.js
const closeTab = tabId => chrome.tabs.remove(tabId);
const onMessage = (message, sender) => {
console.log('Received a message:', message);
switch (message) {
case 'close-tab': return closeTab(sender.tab.id);
}
}
const main = () => {
console.log('Service worker registered');
chrome.runtime.onMessage.addListener(onMessage);
}
main();
The issue might be with the usage of <all_urls>.
Google says on the matching patterns docs:
The special pattern <all_urls> matches any URL that starts with a
permitted scheme.
And the permitted schemes are http:, https:, and file:.
I am not too familiar with Zoom, but this article suggests that zoom uses the protocol zoommtg: to launch the the desktop program, so this falls outside of what <all_urls> covers.
Edit:
Now I see that you stated that the urls start with https:// so that might invalidate what I suggested. Still might be worth trying "*://*.zoom.us/*" instead of <all_urls>.
You could try using "*://*.zoom.us/*" instead. If that doesn't work you could try ditching the content script and handling everything in the background service worker.
In the background service worker, you could add a listener for chrome.tabs.onUpdated and check the url value to see if it matches the url for a Zoom tab and close it from there. You would also need to use the Alarms API for the delay.
This method wouldn't be as efficient because it is called on every tab update (not really worth worrying about), but it is a possible workaround if you can't get the content script method to work.
I am currently writing a userscript for website A to access another the contents on website B. So I tried to use the GM_xmlhttpRequest to do it. However, a variable on B is written to the window property eg: window.var or responseContent.var.
However, when I tried to get the window.var, the output is undefined, which means the properties under the window variable cannot be read successfully. I guess the window object is refering to the website A but not website B, so the result is undefined (There is no window.var on A).
I am sure that the GM_xmlhttpRequest has successfully read the content of the website B because I have added console.log to see the response.responseText. I have also used the window.var to successfully visit that variable on website B by browser directly.
GM_xmlhttpRequest({
method: "GET",
url: url,
headers: {
referrer: "https://A.com"
},
onload: function (response) {
// console.log(response.responseText);
let responseContent = new Document();
responseContent = new DOMParser().parseFromString(response.responseText, "text/html");
let titleDiv = responseContent.querySelector("title");
if (titleDiv != null) {
if (titleDiv.innerText.includes("404")) {
console.log("404");
return;
} else {
console.log(responseContent.var);
console.log(window.var);
}
}
},
onerror: function (e) {
console.log(e);
}
});
I would like to retrieve content window.var on website B and show it on the console.log of A
Please help me solve the problem. Thank you in advance.
#wOxxOm's comments are on point. You cannot really get the executed javascript of another website like that. One way to go around it is to use <iframe> and post message, just like #wOxxOm said. But that may fail if the other website has policy against iframes.
If this userscript is just for your use, another way is to have two scripts, one for each website and have them both open in browser tabs. Then again you can use postMessage to have those two scripts communicate the information. Dirty solution for your second userscript would be to just post the variable info on regular interval:
// Userscript for website-b.com
// needs #grant for unsafe-window to get the window.var
setInterval(()=>{postMessage(unsafeWindow.var, "website-a.com");}, 1000);
That would send an update of var's value every second. It's not very elegant, but it's simple and works. For a more elegant solution, you may want to first postMessage from website a that will trigger postMessage(unsafeWindow.var, "website-a.com"). Working with that further, you will soon find yourself inventing an asynchronous communication protocol.
Alternatively, if the second website is simple, you can try to parse the value of var directly from HTML, or wherever the value is coming from. That's a preferred solution, but requires reverse-engineering on your part.
I have a google chrome extension that shares some code between it's content script and background process / popup. If it some easy and straightforward way for this code to check if it's executed as content script or not? (message passing behavior differs).
I can include additional "marker" javascript in manifest or call some chrome fnction unavailable from content script and check for exceptions - but these methods looks awkward to be. Maybe it's some easy and clean way to make this check?
To check whether or not your script is running as a content script, check if it is not being executed on a chrome-extension scheme.
if (location.protocol == 'chrome-extension:') {
// Running in the extension's process
// Background-specific code (actually, it could also be a popup/options page)
} else {
// Content script code
}
If you further want to know if you're running in a background page, use chrome.extension.getBackgroundPage()=== window. If it's true, the code is running in the background. If not, you're running in the context of a popup / options page / ...
(If you want to detect if the code is running in the context of an extension, ie not in the context of a regular web page, check if chrome.extension exists.)
Explanation of revised answer
Previously, my answer suggested to check whether background-specific APIs such as chrome.tabs were defined. Since Chrome 27 / Opera 15, this approach comes with an unwanted side-effect: Even if you don't use the method, the following error is logged to the console (at most once per page load per API):
chrome.tabs is not available: You do not have permission to access this API. Ensure that the required permission or manifest property is included in your manifest.json.
This doesn't affect your code (!!chrome.tabs will still be false), but users (developers) may get annoyed, and uninstall your extension.
The function chrome.extension.getBackgroundPage is not defined at all in content scripts, so alone it can be used to detect whether the code is running in a content script:
if (chrome.extension.getBackgroundPage) {
// background page, options page, popup, etc
} else {
// content script
}
There are more robust ways to detect each context separately in a module I wrote
function runningScript() {
// This function will return the currently running script of a Chrome extension
if (location.protocol == 'chrome-extension:') {
if (location.pathname == "/_generated_background_page.html")
return "background";
else
return location.pathname; // Will return "/popup.html" if that is the name of your popup
}
else
return "content";
}
Im making a small google chrome extension that is watching all calls a page is making. The idea is to log how a page behaves and how many external calls are made. Got everything working except the part where i need to get the source url of the page that initiates the call.
For example im going to www.stackoverflow.com in my browser, then my onbeforerequest lister kicks in and gives me all the calls. So far so good. But i still want the name of the page which is making the calls, in this case i want: "www.stackoverflow.com" and the owner of the calls.
I tried getting it from the tabs, but chrome.tabs.get uses a callback and that is not called before its all over and i got all the calls processed.
any ideas on how to get the source url?
edit
Im using this code right now, to get the url, but it keeps returning "undefined":
var contentString = "";
chrome.webRequest.onBeforeRequest.addListener(
function (details) {
var tabid = details.tabId;
var sourceurl = "N/A";
if (tabid >= 0) {
chrome.tabs.get(parseInt(tabid), function (tab) {
sourceurl = tab.url;
alert(sourceurl);
});
}
});
When doing the alert, i get undefined for every request
edit 2 - this is working for me
chrome.tabs.get(parseInt(tabid), function (tab) {
if (tab != undefined) {
alert(tab.url);
}
});
onBeforeRequest returns a TabID, then you can then use the get method of the tabs API to get a reference to the tab and thus the URL of the page.
You can use the details.initiator (see here for more details) which is supported since Chrome 63 version. Below you can see what is mentioned on Chrome APIs page about the initiator.
The origin where the request was initiated. This does not change
through redirects. If this is an opaque origin, the string 'null' will
be used.
I've been searching for examples and reference and have come up with nothing. I found a note in offscreenTab source code mentioning it cannot be instantiated from a background page (it doesn't have a tab for the offscreenTab to relate to). Elsewhere I found mention that popup also has no tie to a tab.
How do you successfully create an offscreenTab in a Chrome extension?
According to the documentation, offscreenTabs.create won't function in a background page. Although not explicitly mentioned, the API cannot be used in a Content script either. Through a simple test, it seems that the popup has the same limitation as a background page.
The only leftover option is a tab which runs in the context of a Chrome extension. The easiest way to do that is by using the following code in the background/popup:
chrome.tabs.create({url: chrome.extension.getURL('ost.htm'), active:false});
// active:false, so that the window do not jump to the front
ost.htm is a helper page, which creates the tab:
chrome.experimental.offscreenTabs.create({url: '...'}, function(offscreenTab) {
// Do something with offscreenTab.id !
});
To change the URL, use chrome.experimental.offscreenTabs.update.
offscreenTab.id is a tabId, which ought to be used with the chrome.tabs API. However, at least in Chrome 20.0.1130.1, this is not the case. All methods of the tabs API do not recognise the returned tabID.
A work-around is to inject a content script using a manifest file, eg:
{"content_scripts": {"js":["contentscript.js"], "matches":["<all_urls>"]}}
// contentscript.js:
chrome.extension.sendMessage({ .. any request .. }, function(response) {
// Do something with response.
});
Appendum to the background page:
chrome.extension.onMessage.addListener(function(message, sender, sendResponse) {
// Instead of checking for index == -1, you can also see if the ID matches
// the ID of a previously created offscreenTab
if (sender.tab && sender.tab.index === -1) {
// index is negative if the tab is invisible
// ... do something (logic) ...
sendResponse( /* .. some response .. */ );
}
});
With content scripts, you've got full access to a page's DOM. But not to the global object. You'll have to inject scripts (see this answer) if you want to run code in the context of the page.
Another API which might be useful is the chrome.webRequest API. It can be used to modify headers/abort/redirect requests. Note: It cannot be used to read or modify the response.
Currently, the offscreenTabs API is experimental. To play with it, you have to enable the experimental APIs via chrome://flags, and add "permissions":["experimental"] to your manifest file. Once it's not experimental any more, use "permissions":["offscreenTabs"].