Install cache manifest

[mvl22]

Need the HTML5 cache manifest installed, so that download times are reduced.

http://diveintohtml5.org/offline.html
has some useful pointers.

[annapowellsmith]

Actually (having read up on this previously) it doesn't work quite like that - basically it only has any effect at all if you're offline.

(Caching while online is dependent on our cache-control headers, so we should make sure we're using them correctly.)

With cache-manifest, when the user is offline, you can configure it either to show them the cached file, or a fallback file that is only used while offline.

I think if our users are offline, we should not actually show them anything except their saved routes as text - because showing them anything else is likely to be misleading - they will think they are offline.

I've created cyclestreets/mobileweb#4 as a ticket for a new, special offline version of CycleStreets that only shows saved routes as text.

(I looked into caching map tiles, but the browser cache is generally only about 2MB so we wouldn't be able to cache a meaningful number. )

[annapowellsmith]

s/they will think they are offline/they will think they are online/ above!

[mvl22]

Closing this as basically the manifest stuff wasn't what I thought it was.

Shame though - it would be a useful HTML5 feature if caching could be explicitly set via a manifest!

[mvl22]

Reopening this as it sounds like HTML5 AppCache does actually make this possible:

http://blogs.msdn.com/b/ie/archive/2011/09/27/building-offline-experiences-with-html5-appcache-and-indexeddb.aspx
http://msdn.microsoft.com/en-us/ie/hh272905.aspx#_HTML5AppCache