How a web application can download & store over 2GB ..
How a web application can download and store over 2GB without you even knowing it
I have been experimenting with the HTML5 offline application cache some more over the last few days, doing boundary tests in an attempt to learn more about browser behaviour in edge cases.
One of these experiments was testing the cache quota.
Two weeks ago, I blogged about generating and serving an offline application manifest using ASP.NET MVC. I reused that code to add hundreds of 7MB PDF files to the cache. [...]
I initially tried adding 1000 PDF files to the cache, but this threw an error: Chrome failed to commit the new cache to the storage, because the quota would be exceeded.
After lowering the number of files several times, I hit the sweet spot. I could add 300 PDF files to the cache without breaking it.
Looking into chrome://appcache-internals/, I can see the size of the cache being a whopping 2.2GB now for one single web application. [Screenshot]
As a user, I had no idea that the website I'm browsing is downloading a suspicious amount of data in the background. Chrome (17.0.963.83), nor any other desktop browser that I know of, warns me. I would expect the browser to ask for my permission when a website wants to download and store such an excessive amount of data on my machine.
Continued : http://jclaes.blogspot.com/2012/03/how-web-application-can-download-and.html
(Thanks to Bob P !)