Re: Offline Web Applications status

Louis-Rémi,
We are working on a large-size HTML5 web application and are using appcache
successfully. For a large-size webapp being delivered off of a slow
network, appcache provides a huge (arguably essential) performance gain
because the client doesn't have to do a server request for everything that
is put into the appcache, whereas you still need to ping the server for
old-style cached files. (Therefore, we are using appcache today mostly for
network performance advantages versus old-style browser caching. We aren't
doing "offline" at this point. However, we are looking at taking the next
step to offline down the road.)

We found it was difficult to get working on a cross-browser basis due to
incomplete specs and browser quirks. I vote for improving what exists
today, particularly hammering out detailed spec issues and creating a
comprehensive test suite.

Jon Ferraiolo, IBM



                                                                                                        
  From:       louis-rémi BABE <lrbabe@gmail.com>                                                        
                                                                                                        
  To:         public-webapps@w3.org                                                                     
                                                                                                        
  Date:       03/23/2011 08:58 AM                                                                       
                                                                                                        
  Subject:    Offline Web Applications status                                                           
                                                                                                        
  Sent by:    public-webapps-request@w3.org                                                             
                                                                                                        





Hello Webapps working group,

I'm an intern at Mozilla Developers Engagement team and I'm currently
working on promoting Offline Web Applications.
My first task is to understand what did go wrong with the App Cache
mechanism...

## Maybe Web devs don't use App Cache because they don't understand
what it is... ##
The possibility of using Webapps offline has a great potential but its
adoption by developers didn't reach our expectations. We asked Web
developers some time ago what were their feelings regarding
application cache  (see
http://hacks.mozilla.org/2010/05/revitalizing-caching/ ) and it
appeared that the name was misleading, as they expected it to be more
of an auxiliary cache than an offline mechanism. You can find
evidences of this confusion on StackOverflow, where some people
struggle to use the application cache as a mean to boost performances
of their Websites.

## Can you see other reasons? ##
Before going back to developers or writing yet another App Cache
documentation, I wanted to have *your* feelings about this mechanism.
You might have a different impression about its adoption and be aware
of successful real-world use-cases.
You might have asked developers yourself and received a different feedback.
Maybe you feel that Web advocates are not doing a good enough job at
documenting this feature, producing demos and clarifying its nature.
Maybe you think that the problem has to do with the specification itself.
Maybe there is an evolution of the specification underway that I am
not aware of.

## Two naive questions ##
After reading a large amount of documentation, I have to admit that I
am myself confused about app cache:
Do you think it *can* be used as an auxiliary cache mechanism, and
what would be the limitations? The main problem I see is that there is
no way to white-list the referring document (e.g. index.html).
Currently, I would advocate *against* using it as an auxiliary cache.
Why isn't there any DOM API allowing a fine-grained control of the
application cache?
applicationCache.cache.add( URI );
applicationCache.cache.remove( URI );


Thank you in advance,

Louis-Rémi Babé