This is a comment from the W3C Technical Architecture Group on the last
call working draft: "Web Storage" [1].
The HTML5 Application Cache (AppCache) [2] and Local Storage [1] both
provide client-side storage that can be used by Web Applications. Although
the interfaces are different (AppCache has an HTML interface while Local
Storage has a JavaScript API), and they do seem to have been designed with
different use cases in mind, they provide somewhat related facilities: both
cause persistent storage for an application to be created, accessed and
managed locally at the client. If, for example, the keys in Local Storage
were interpreted as URIs then Local Storage could be used to store manifest
files and Web Applications could be written to look transparently for
manifest files in either the AppCache or in Local Storage. One might also
envision common facilities for querying the size of or releasing all of the
local storage for a given application.
At the Offline Web Applications Workshop on Nov 5, 2011 [3] there was a
request for a JavaScript API for AppCache and talk about coordinating
AppCache and Local Storage.
The TAG believes it is important to consider more carefully the potential
advantages of providing a single facility to cover the use cases, of
perhaps modularizing the architecture so that some parts are shared, or if
separate facilities are indeed the best design, providing common data
access and manipulation APIs. If further careful analysis suggests that no
such integration is practical, then, at a minimum, each specification
should discuss how it is positioned with respect to the other.
Noah Mendelsohn
For the: W3C Technical Architecture Group
[1] http://www.w3.org/TR/2011/WD-webstorage-20111025/
[2] http://www.w3.org/TR/html5/offline.html#appcache
[3] http://www.w3.org/2011/web-apps-ws/
