How to inject javascript into Chrome DevTools itself - google-chrome-extension

Ok, so just the other day I learned that you can inspect the devtools if it is in its own window(explained here). I also learned that you can style the devtools with your own css by editing the Custom.css file in your profile on your computer(more on that here).
What I want to do is not only add css, but also javascript, via a chrome extension. I am very aware of devtools pages, but those do not do what I want. Pretty much I want to get a content script to run on the devtools inspector itself. I found one extension that does exactly this, but for the life of me I have not been able to replicate it(even when copy-pasting the code!!). The extension is the "Discover DevTools Companion extension" from Code School(on the webstore). They even explain how it works, but I still have had no luck. That was the only extension I have found that does what I want. So I guess what I'm really asking is if its just me that cannot get it to work or if others that try are having trouble also.

Usually, you cannot create a Chrome extension which injects code in a devtools page.
The "Discover DevTools Companion" extension from now on, referred to as DDC is allowed to do this, because this extension is whitelisted in the source code of Chromium: (this is no longer the case)
// Whitelist "Discover DevTools Companion" extension from Google that
// needs the ability to script DevTools pages. Companion will assist
// online courses and will be needed while the online educational programs
// are in place.
scripting_whitelist_.push_back("angkfkebojeancgemegoedelbnjgcgme");
If you want to publish an extension in the Chrome Web Store with these capabilities, give up.
If you want to create such an extension for personal / internal use, read further.
Method 1: Impersonate the DDC a whitelisted extension
The easiest way to create an extension with such permissions is to create an extension with the extension ID of a whitelisted extension (e.g. ChromeVox). This is achieved by copying the "key" key of its manifest file to your extension's manifest (see also: How to get the key?). This is a minimal example:
manifest.json
{
// WARNING: Do NOT load this extension if you use ChromeVox!
// WARNING: Do NOT load this extension if you use ChromeVox!
// WARNING: This is a REALLY BIG HAMMER.
"content_scripts": [{
"js": [ "run_as_devtools.js" ],
"matches": [ "<all_urls>" ]
}],
// This is the key for kgejglhpjiefppelpmljglcjbhoiplfn (ChromeVox)
"key": "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDEGBi/oD7Yl/Y16w3+gee/95/EUpRZ2U6c+8orV5ei+3CRsBsoXI/DPGBauZ3rWQ47aQnfoG00sXigFdJA2NhNK9OgmRA2evnsRRbjYm2BG1twpaLsgQPPus3PyczbDCvhFu8k24wzFyEtxLrfxAGBseBPb9QrCz7B4k2QgxD/CwIDAQAB",
"manifest_version": 2,
"name": "Elevated Devtools extension",
"version": "1.0"
}
run_as_devtools.js
if (location.protocol === 'chrome-devtools:') (function() {
'use strict';
// Whatever you want to do with the devtools.
})();
Note: This method is truly a hack. Since the extension shares the same ID as ChromeVox, both extensions cannot co-exist. And if Chrome decides to remove the whitelisted extension, then your permissions will evaporate.
Instead of filtering via the content script, you can also use the include_globs key to restrict the content script to devtools only.
Method 2: Modify resources.pak
I suggest to go with method 1 if possible. When method 1 fails (e.g. because the extension is no longer whitelisted), use the next method.
Get paktools.py, unpack.py and pack.py from DennisKehrig/patch_devtools (on Github).
Locate your Chrome directory containing resources.pak.
Run python2 unpack.py resources.pak, which creates a directory resources containing all files (all file names are numbers).
Locate the file containing a script which runs in the context of the developer tools. Add your desired code there.
Remove resources.pak
Run python2 pack.py resources to create the new resources.pak file.
Note: resources.pak may be replaced when Chrome is updated, so I suggest to create a script which automates my described algorithm. That shouldn't be too difficult.
If you're interested, you can look up the .pak file format in ui/base/resource/data_pack_literal.cc (description in human language).

For those googlers who end up at this page (as I did) looking for something else, this page answers the question of manipulating DevTools ITSELF - not adding jQuery to DevTools, or injecting javaScript onto a web page. For those, see here instead:
Inject jQuery into DevTools (Chrome or Firefox):
Firefox DevTools: Automatically injecting jQuery
Inject your own javascript/css onto any web page:
How to edit a website's background colors

Related

With a Manifest v3 Chrome Extension, is it possible to load an extension HTML resource file into a new tab?

With a Manifest v3 Chrome Extension, is it possible to load an extension HTML resource file into a new tab? I was thinking about providing a plugin with a larger, full-page user experience than what the popdown panel could provide. I created a page.html (just simple HTML for now, no JS or CSS) and put it in my extensions folder. I then added this to the manifest.json:
"web_accessible_resources": [
{
"resources": ["page.html"],
"matches": [ "*://*/*" ]
}
]
I reloaded the plugin and then tried navigating to this page in my browser with:
chrome://extensions/MY-EXTENSION-ID-GOES-HERE/page.html
I get an ERR_FAILED and "This site can't be reached" message.
There is no need for a web_accessible_resources in this case in the v3 manifest for this action. Just use something like the following code to open it from the service-worker.js:
chrome.tabs.create({url:chrome.runtime.getURL('page.html'),active:true});
This will automatically open something akin to...
chrome-extension://MY-EXTENSION-ID/page.html
...where MY-EXTENSION-ID is automatically filled in by chrome.runtime.getURL('page.html').
You can then reference remote and local resources in your HTML tags. For local resources, just use relative pathing. For remote resources, keep an eye on Google Chrome Extension developer policies.
Thanks goes to wOxxOm for his assistance.

How to programmatically enable flash in Chrome? [duplicate]

chrome.tabs returns undefined despite the fact I set tabs in the permissions block.
"permissions": [
"tabs",
"http://*/*",
"https://*/*"
],
"content_scripts": [
{
"matches": [
"http://*/*",
"https://*/*"
],
"js": [
"js/myScript.js"
],
"all_frames": true
}
],
But in myScript.js the following returns undefined.
chrome.tabs
As content script has its own limitations,
chrome.tabs is only available in background scripts and popup scripts.
If you wanna to use chrome.tabs then pass message from content_script to background script and play with chrome.tabs.
Content scripts have only limited access to Chrome APIs. This access does not include the API you are trying to use (e.g. chrome.tabs). If you need to use that API, you will have to do so in a background script1.
As listed in Chrome's content scripts documentation, the APIs available to a content script are [I have placed deprecated methods in strikethrough format]:
extension ( getURL , inIncognitoContext , lastError , onRequest , sendRequest )
i18n
runtime ( connect , getManifest , getURL , id , onConnect , onMessage , sendMessage )
storage
A couple of the listed APIs are deprecated and have been for some time. Those that are deprecated have moved to different locations (also listed above):
extension.onRequest ➞ runtime.onMessage
extension.sendRequest ➞ runtime.sendMessage
While not officially deprecated, extension.lastError is also available as runtime.lastError. At this point, it is usually referred to at that location:
extension.lastError ➞ runtime.lastError
Partition your extension into background scripts and content scripts
You are going to need to separate your code into what needs to be in a background script and what needs to be in content scripts, based on the capabilities available to each type of script. Content scripts have access to the DOM of the web page into which they are injected, but limited access to extension APIs. Background scripts have full access to the extension APIs, but no access to web page content. You should read the Chrome extension overview, and the pages linked from there, to get a feel for what functionality should be located in which type of script.
It is common to need to communicate between your content scripts and background scripts. To do so you can use message passing. This allows you to communicate information between the two scripts to accomplish things which are not possible using only one type of script.
For instance, in your content script, you may need information which is only available from one of the other Chrome APIs, or you need something to happen which can most appropriately (or only) be done through one of the other Chrome extension APIs. In these cases, you will need to send a message to your background script, using chrome.runtime.sendMessage(), to tell it what needs to be done, while providing enough informaiton for it to be able to do so. Your background script can then return the desired information, if any, to your content script. Alternately, you will have times when the processing will primarily be done in the background script. The background script may inject a content script, or just message an already injected script, to obtain information from a page, or make changes to the web page.
Background script means any script that is in the background context. In addition to actual background scripts, this includes popups and options pages, etc. However, the only page that you can be sure to have consistently available to receive messages from a content script are your actual background scripts defined in manifest.json. Other pages may be available at some times as a result of the user's interaction with the browser, but they are not available consistently.
This answer was moved from a duplicate question, and then modified.
https://developer.chrome.com/extensions/tabs#method-getSelected shows
getSelected
chrome.tabs.getSelected(integer windowId, function
callback)
Deprecated since Chrome 33. Please use tabs.query {active: true}.
Gets the tab that is selected in the specified window.
Maybe, you should use chrome.tabs.query in popup.js like this
chrome.tabs.query({active: true, currentWindow: true}, function(tabs){
console.log(tabs[0].url);
});
, reload your extension and check the result in the inspect element of your extension.
result image
code image
https://developer.chrome.com/extensions/tabs#type-Tab shows that
The URL the tab is displaying. This property is only present if the extension's manifest includes the "tabs" permission.(Just for remind someone forgot. I was forgot it when I just test it.)
Check this answer also https://stackoverflow.com/a/6718277/449345
This one worked for me
chrome.tabs.getSelected(null, function(tab){
console.log(tab);
});

Opening chrome extension in new tab

Is this still valid?
"app": {
"launch": {
"local_path": "window.html",
"container": "tab"
}
},
I'm using Chrome v46 and it works but I'd like to be sure it is not a bug.
I cannot see anything like this in the manifest file reference
Your manifest snippet (containing app.launch.local_path) describes a legacy packaged app. These are deprecated and not officially supported any more.
If you want to have an icon in the app launcher, then you need to create a Chrome app (if you want to host the content in the package) or a hosted app (if you want to host the content online).
If you don't want to create an app, but an extension, then you could use a browser action button to add a button to the toolbar, and then open a page in a new tab using chrome.tabs.create. Or, if your actual goal is replacing the new tab page, use chrome_url_overrides to override newtab.

Optionally inject Content Script

Content Script can be injected programatically or permanently by declaring in Extension manifest file. Programatic injection require host permission, which is generally grant by browser or page action.
In my use case, I want to inject gmail, outlook.com and yahoo mail web site without user action. I can do by declaring all of them manifest, but by doing so require all data access to those account. Some use may want to grant only outlook.com, but not gmail. Programatic injection does not work because I need to know when to inject. Using tabs permission is also require another permission.
Is there any good way to optionally inject web site?
You cannot run code on a site without the appropriate permissions. Fortunately, you can add the host permissions to optional_permissions in the manifest file to declare them optional and still allow the extension to use them.
In response to a user gesture, you can use chrome.permission.request to request additional permissions. This API can only be used in extension pages (background page, popup page, options page, ...). As of Chrome 36.0.1957.0, the required user gesture also carries over from content scripts, so if you want to, you could add a click event listener from a content script and use chrome.runtime.sendMessage to send the request to the background page, which in turn calls chrome.permissions.request.
Optional code execution in tabs
After obtaining the host permissions (optional or mandatory), you have to somehow inject the content script (or CSS style) in the matching pages. There are a few options, in order of my preference:
Use the chrome.declarativeContent.RequestContentScript action to insert a content script in the page. Read the documentation if you want to learn how to use this API.
Use the webNavigation API (e.g. chrome.webNavigation.onCommitted) to detect when the user has navigated to the page, then use chrome.tabs.executeScript to insert the content script in the tab (or chrome.tabs.insertCSS to insert styles).
Use the tabs API (chrome.tabs.onUpdated) to detect that a page might have changed, and insert a content script in the page using chrome.tabs.executeScript.
I strongly recommend option 1, because it was specifically designed for this use case. Note: This API was added in Chrome 38, but only worked with optional permissions since Chrome 39. Despite the "WARNING: This action is still experimental and is not supported on stable builds of Chrome." in the documentation, the API is actually supported on stable. Initially the idea was to wait for a review before publishing the API on stable, but that review never came and so now this API has been working fine for almost two years.
The second and third options are similar. The difference between the two is that using the webNavigation API adds an additional permission warning ("Read your browsing history"). For this warning, you get an API that can efficiently filter the navigations, so the number of chrome.tabs.executeScript calls can be minimized.
If you don't want to put this extra permission warning in your permission dialog, then you could blindly try to inject on every tab. If your extension has the permission, then the injection will succeed. Otherwise, it fails. This doesn't sound very efficient, and it is not... ...on the bright side, this method does not require any additional permissions.
By using either of the latter two methods, your content script must be designed in such a way that it can handle multiple insertions (e.g. with a guard). Inserting in frames is also supported (allFrames:true), but only if your extension is allowed to access the tab's URL (or the frame's URL if frameId is set).
I advise against using declarativeContent APIs because they're deprecated and buggy with CSS, as described by the last comment on https://bugs.chromium.org/p/chromium/issues/detail?id=708115.
Use the new content script registration APIs instead. Here's what you need, in two parts:
Programmatic script injection
There's a new contentScripts.register() API which can programmatically register content scripts and they'll be loaded exactly like content_scripts defined in the manifest:
browser.contentScripts.register({
matches: ['https://your-dynamic-domain.example.com/*'],
js: [{file: 'content.js'}]
});
This API is only available in Firefox but there's a Chrome polyfill you can use. If you're using Manifest v3, there's the native chrome.scripting.registerContentScript which does the same thing but slightly differently.
Acquiring new permissions
By using chrome.permissions.request you can add new domains on which you can inject content scripts. An example would be:
// In a content script or options page
document.querySelector('button').addEventListener('click', () => {
chrome.permissions.request({
origins: ['https://your-dynamic-domain.example.com/*']
}, granted => {
if (granted) {
/* Use contentScripts.register */
}
});
});
And you'll have to add optional_permissions in your manifest.json to allow new origins to be requested:
{
"optional_permissions": [
"*://*/*"
]
}
In Manifest v3 this property was renamed to optional_host_permissions.
I also wrote some tools to further simplify this for you and for the end user, such as
webext-domain-permission-toggle and webext-dynamic-content-scripts. They will automatically register your scripts in the next browser launches and allow the user the remove the new permissions and scripts.
Since the existing answer is now a few years old, optional injection is now much easier and is described here. It says that to inject a new file conditionally, you can use the following code:
// The lines I have commented are in the documentation, but the uncommented
// lines are the important part
//chrome.runtime.onMessage.addListener((message, callback) => {
// if (message == “runContentScript”){
chrome.tabs.executeScript({
file: 'contentScript.js'
});
// }
//});
You will need the Active Tab Permission to do this.

Loading Chrome Extension's manifest.json on a web page

I am developing a Extension-detect site that can detect whether the client has installed my extensions.
I try to load the manifest.json file so that I can know.
But when I tried, I got a:
Resources must be listed in the web_accessible_resources manifest key in order to be loaded by pages outside the extension.
So I put my website in the json, like:
"web_accessible_resources": [ "www.mysite.com/*", "mysite.com/*" ]
But it still doesn't work.
Is there anything I need to fix?
Thanks
web_accessible_resources is a list of files packed in your extension that can be requested by any webpage loaded by your users browser. So if you want to load your manifest from your site you need an entry like this:
"web_accessible_resources": [ "manifest.json" ]
However this will allow any site your users visit to discover if your extension is installed so the recommended approach is to use a content_script that adds a class to the body of all the pages on your domain. That way your sites JS can check for the class for installation but no information will be accessible to other sites.
// content_script run on your domains
document.documentElement.classList.add('ext-name-installed');
On your site you can now check to see if the extension is installed with
// Run on website to test for extension
if(document.documentElement.classList.contains('ext-name-installed')) {
// Extension is installed
}

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