I want to clear all the data except for some sites where I don't want to be unregistered.
How can I do that with Firefox or its addon?
Related
I have integrated Akamai caching in my production web application for which I have provided extensions (HTML, CSS..) which needs to be cached. But after integrating, on production I am getting white screen for 2-3 seconds as soon as I launch application in browser. Not sure why.
Note: If application files are being cached by browser than it does not take time to launch nor it shows white screen. But once you clear browser cache, Akamai should deliver files from its cache quickly.
Any inputs would be appreciated. Thanks in advance!
Akamai have special headers you can use in requests to determine if you're getting cache hits with them or if you're flowing all the way to your site, here's a couple of links to get you started with them:
https://community.akamai.com/community/web-performance/blog/2015/03/31/using-akamai-pragma-headers-to-investigate-or-troubleshoot-akamai-content-delivery
https://community.akamai.com/videos/1227
There's even chrome extensions that will add the headers for you, there's one example in the second link but I prefer this one:
https://chrome.google.com/webstore/detail/akamai-debug-headers/lcfphdldglgaodelggpckakfficpeefj?hl=en
Once we open a link in a new tab in Firefox, the data corresponding to that web page(static or dynamic) gets stored in Browser Cache. Then, when we switches at that tab again, it extracts data of that page from Cache(not requesting from the server of that site) and paints it at the frame buffer of the screen.
I want to know that how Firefox fetches this data in correct sequence?
What kind of mapping does the Firefox uses to extract the page data from its Cache?
Firefox (like any other browser) uses heuristics to decide when and what to cache. This is assuming no caching information is included in the resources. When no caching information is provided, Firefox might still decide to cache the files for certain period of time.
If you want to avoid Firefox to cache your resources altogether, you must include the following response header on your resources:
Cache-Control:no-cache, no-store
Now, the exact algorithm that Firefox uses to fetch from cache I don't think is public. Maybe somebody from Mozilla is able to answer this.
I help maintain several Wordpress-based websites that publish news and reference information.
We have been working hard to make pages at the websites load as fast as possible.
One of the things we've done is implement very long "max-age" times in the "cache-control" http headers for most of our static files, such as images and css files.
The particular cache-control setting we're using is "public, max-age=31536000". 31,536,000 seconds is 365 days.
The upside is that this setting does, in fact, cause the static files to be cached as visitors browse through different pages of our sites.
But here's the rub. This cache-control setting doesn't do much for us across browser sessions. Even though the setting is supposed to tell the browser "cache this file for an entire year", if a visitor to our site shuts down their browser, then starts it up just five minutes later and comes back to our site, the browser insists on re-loading all the static files, even though it still has them in its cache.
I've checked this carefully in Firefox, viewing the headers with Live HTTP Headers. But I can also qualitatively see the same thing happening in other browsers.
Apparently, browsers insist on re-loading all content for a website if the content hasn't been loaded once during the current browser session.
So ... Is there any way we can "politely suggest" to browsers that they always load cached content from the cache, even if the browser hasn't been to our site during the current browser session?
Check the ETag, Expires, and Last-Modified headers as well.
You need an Expires header, and sometimes ETag and Last-Modified can defeat caching.
Background
I'm building an app that links recent
web pages you've visited together.
To do this, I need to get the HTML
for recent URLs using Cocoa.
Right now, I'm using an invisible
WebView to do this.
As I understand it, if the URL isn't
in the cache for my app, this is
hitting web servers.
What I want
The chances are high that the URL I'm grabbing has already been cached by Safari as the page has already been visited.
I want my app to check Safari's cache for the URL first. If it's there, it should just use this data. If not, it should hit the web server and store the page in my app's cache.
I don't really want to have to parse the cache.db file from Safari using sqlite3 - I've no idea if this format will stay the same. I'm after something simpler and more high level.
What I've tried
I know that you can set up your own NSURLCache using the method initWithMemoryCapacity:diskCapacity:diskPath: but I don't want to try pointing this to the Safari cache in case it screws up Safari by writing to it.
Is there an easy, high level way of sharing the Safari cache?
UPDATE
Aha. I've just realised there may be a way to do this I've been missing.
I could make a new instance of NSURLCache with initWithMemoryCapacity:diskCapacity:diskPath:, point it at the Safari cache, then specify a cache policy of NSURLRequestReturnCacheDataDontLoad for the URL Request when loading the page.
When this fails, I could just try and load the page as normal. I'll try this out and update the question when I know more.
To be honest, you just can't do this.
Firstly, I'm pretty certain -[NSURLCache initWithMemoryCapacity:diskCapacity:diskPath:] won't work as you expect. It will instead blow away the old cache file to create its own; potentially highly upsetting Safari.
Secondly NSURLCache is a composite cache. That is, it caches data first in memory, and then moves it out to disk at some point. So even if you could properly access Safari's cache file (which you can't) you'd only be able to access the older cached data; not the most recent.
After running the YSlow plugin on a site, I saw that one of the recommendations was to add far future expires headers to the scripts, stylesheets, and images.
I asked a different question about how to set this up in IIS, but I am actually just curious about how each browser behaves.
I have read that IE will cache items per browsing session, so once you reopen the site after closing the browser, it will need to reload all of the content. I believe that Firefox will go ahead and set a expiration date on its own. I have also heard that IE does not cache at all when connecting over HTTPS. I am not sure if these are at all accurate, though, and was wondering if someone could clear up any misconceptions I may have. Thanks!
You are right about Firefox setting its own expiration date. See the second item in this blog post:
http://blog.httpwatch.com/2008/10/15/two-important-differences-between-firefox-and-ie-caching/
IE, like Firefox, can cache HTTPS based content. However, you need to set Cache-Control: public for persistent caching across browser sessions in Firefox. See Tip #3 in this blog post:
http://blog.httpwatch.com/2009/01/15/https-performance-tuning/