Is it possible to access Google Chrome's cache from within an extension?
I'd like to write an extension that loads a cached version of a page when the online one can't be accessed (e.g. Internet connectivity issue).
Updated: I know I could write an NPAPI plugin accessible through an extension to accomplish this but I'd rather not suffer writing one... I am after a solution without resorting to NPAPI, please.
Note: as far as I can tell, Google Chrome doesn't support this functionality (at least not out-of-the-box): I just had an episode of "no Internet access" and I was stranded...
Unfortunately, I'm 99% sure that this is impossible without using an NPAPI in your extension.
Chrome extensions are sandboxed to their own process, and can only access files within the extension's folder.
There is some support for things like chrome://favicon/. But that's about it, at least for now.
Source (Google Chrome Extensions Reference)
P.S. I just had a crazy idea. Extensions only have access to files in their folder... but Chrome stores it's cache in the Cache folder. What you might try is, copy (or move) the Cache folder into a subfolder within the extension. The extension should now be able to access the cache.
Whether this is enough to actually enable offline mode... I don't know. I do see some HTML files (and obviously a lot of images) within my Cache folder, though.
In fact, even without using an extension, I can open up the HTML files in Chrome. And because they're stored on your computer, you should be able to access them even without internet.
P.S. the Cache folder is stored at PATH-TO-CHROME/Default/Cache
P.P.S. there is a way to store an entire webpage and archive it for later use. Check out this extension:
https://chrome.google.com/extensions/detail/mpiodijhokgodhhofbcjdecpffjipkle
Just make a simple plugin manifest that calls an AJAX page which loads jQuery from CDN, and then uses it to parse all the <a> elements on the page and alter the href values to have this prefix: http://webcache.googleusercontent.com/search?q=cache:
So <a href="http://stackoverflow.com/questions/blah"> becomes:
<a href="http://webcache.googleusercontent.com/search?q=cache:http://stackoverflow.com/questions/blah">
Voilà, you are cache surfing, but you still need to get to Google. I understand this answer is a bit outside the scope of the question but still solves a lot of web connectivity issues.
I'm tempted to just go write this plugin but I bet it'd be taboo in Google's eyes, so it'd get blocked or removed rather quickly. :)
Related
I hope you can help me.
I am writing a desktop program that will run in a web browser (in HTML/CSS/javascript in case that wasn't clear). It will be entirely disconnected from the internet and obtain files and data using only FILE protocol. My question is: how can you obtain a listing of the contents of a directory referenced this way?
I've been searching for months and really turned up almost nothing! Maybe I just don't know how to search but there doesn't seem to be much information about how browsers actually deal with File protocol.
For example, when you open a directory in Chrome, it gives you a nice table with hyperlinks of all the parent directory's children. However, when you look at the source code, it's as if Chrome just magically knew exactly what files were in the directory. I feel that if I could understand how it knew that, maybe I'd be able to get somewhere...
Also, I am open to other ideas about how to get a directory listing. I've read about being able to do it with php but it requires running a server. Does anyone know if it is possible to run php code with File protocol rather than HTTP?
Thanks for reading this far and truely any information that could remove me from this standstill is appreciated!
Web Apps do not have access to the user's file system so you will not be able to do what the chrome file browser does with a web app. I believe chrome is using some sort of native code to do this.
I would recommend trying something a little more on the native-side. A chrome app will let you use html, css, javascript while also allowing you access to the file system. https://developer.chrome.com/apps/app_storage#filesystem
Another alternative is you could write some sort of native java application. That would allow you to read/write all the files you want.
When deploying a Polymer app to production, what's the recommended way to avoid requests for Polymer's source map files? The files platform.js.map and polymer.js.map weigh in at ~800K. Even if those downloads are deferred, surely there is some user impact (e.g., on mobile devices) simply spending bandwidth getting those files, isn't there?
Currently, my deployment process simply skips over the .map files, but when looking at the production site, I still see the browser trying to find them. Those requests fail with a 404, since the files aren't deployed. In theory the 404s shouldn't slow anything down, but it's still distracting to see 404s show up. It makes it look like there's a problem when in fact there isn't.
I could write a Grunt task to strip off the //# sourceMappingURL line from the associated .js files, but I was wondering if anyone has experimented with other means by which to drop the source maps. Or have people found that there is literally no impact on user experience when including those files?
I would consider it a browser bug if any browser loaded source maps when the user isn't using debug tools on the site in question. Are you noticing a significant number of requests to your source maps in your logs?
If you're using Google Chrome Devtools and want the source maps to be ignored, you can go to settings and uncheck the corresponding "Enable Javascript source maps" check box.
I want to get all the open URLs from browsers running on the device without having to develop extensions. There are two reasons I don't want to develop extensions. First for Chrome, the user has to go to the chrome store to install the extension. Second, I have to write an extension for all browsers installed.
So I started off by looking into Scripting Bridge, but turns out it doesn't work for Chrome without GUI scripting(for which users have to enable assistive devices).
So instead, I am looking into building a plugin instead. The thing though is plugins can only support certain mime types. How do I make sure my plugin is called from any webpage? Unless there is a universal mime type which is present in all webpages, I am not sure how to solve this problem.
In any case, do you guys think this is the best way to go? Or is there any other way to get URLs of all open tabs.
The only way to get a plugin to automatically be added to all pages would be with an extension, and there is no way without having the plugin be loaded in all pages to know about other pages other than the one that a given plugin instance is loaded in.
Plugins are not aware of the browser, only of the page they are inserted into (or loaded to handle, in the case of a plugin that handles a mimetype such as .pdf). see http://npapi.com/extensions for more information on the capabilities of a plugin vs an extension.
Because plugins only know about a page, though, that means that they can't find out about other pages in the same browser process, including tabs. They simply don't have any method for doing this, and that is by design; the API developers didn't want anyone to be able to have a plugin that handles a media type that could somehow tie into your banking site window in another tab without you realizing it. Of course, certain extension frameworks might allow you to find a way to do that anyway, but a plugin itself cannot.
I appreciate this question may appear broad. But it is because I am looking anywhere and everywhere for a possible solution to do something very simple.
The goal is from a web page opened in Chrome, to scan the DOM, extract specific elements and save them silently in some way that I can then access.
There is no intention for any of this to be published as an app or extension, it is simply me wanting to access my own rendered browser data and extract and store this data on my own computer. For this reason, I am currently finding Chrome's exhaustive sandboxing security frustrating and irrelevant to say the least.
I have a working Chrome Extension which extracts all of the data I want, has a list of 5 strings that I want to save and that's as far as I have gotten.
I have looked into these areas:
Existing NPAPI Plugins (could not get npapi file io to work).
Creating my own NPAPI Plugin - seems like a huge overhead and learning exercise simply to get external access to 5 strings
Every aspect of Chrome extension (and even App) apis (particularly their localstorage which is not accessible from outside the extension)
Any other thoughts?
I realise there is a solution through creating my own NPAPI plugin but I would like to believe that there is another approach that allows me to link a constructed DOM with my local system. I am open to any other option? (I have considered a Linux purely bash approach but I need to generate the DOM as though it was in my browser).
I just want to be able to access specifically extracted parts of a DOM on my local system, not write an entirely new C++ plugin to facilitate this very basic feature.
How can I tell chrome not to fetch any favicon.ico files from a webserver? For web development and debugging, I find this very annoying when I read server side logs. Loading the favicon is also bias when measuring and optimizing my page load times so I want to completely disabled it on the client side in chrome.
Look at this Chrome extension I hate your favicon, or build your own one, which utilizes webRequest module and trap all outgoing requests for favicons.
Also you could possibly set up one of ad blocking extensions to do the same job.
P.S. You can read discussion about whether to consider this as a bug, or feature in the issue 39402 at Chromium porject, I think it applies to Chrome as well. And it seems there will be no easy way to turn this behaviour off via options in the near future.