Offline support

[sumnerevans]

One of the primary goals was to make sure that the offline usage was good.

• Convert the can_* functions to be not dependent on the ping state.

• Get rid of can_service_requests and instead use ping state and initial_sync.

• Use the GTA can_* only, because the caching adapter should basically inherit from that.

• Disable certain features that require being online.

  • Refresh buttons
  • Download all buttons
  • Edit button on Playlists
  • Disable all network requests
    • Get rid of the constant ping.
    • Use exponential backoff on ping after a network failure.
  • Make rows unselectable and not sensitive https://stackoverflow.com/questions/12783444/making-rows-in-a-gtk-treeview-unselectable#26755941
  • Don't play songs that require streaming
  • If there are no songs in the queue that can be played, show a non-modal error.
  • Indication that data was not retrievable: https://developer.gnome.org/hig/stable/empty-placeholder.html.en

• Need to be able to detect being offline.

  • Listen on DBUS for network updates from NetworkManager (Deferred to Listen to changes to the active connection over DBus/NM #96)
  • Poll periodically to see if we have a connection.

• Invalidations should not be destructive. That way, we can just use the previous values when we are unable to fetch.

• The UI should have some indication of being offline. Maybe just something in the header or maybe in the dropdown, not sure.

• Albums browsing needs to be refactored. In online mode, we can just use the server function, but in offline mode:

  • When random is selected, just grab a random sample of the downloaded albums.
  • When genre is selected, iterate though the local albums for albums of the genre.
  • When year is selected, find all albums in the year range.
  • When alphabetical is selected, sort all of the albums according to the secondary sort param.

• Search (two ideas here: combine offline and online results always, or use two different searches when in offline/online modes)

[sumnerevans]

marked this issue as related to #133

[sumnerevans]

closed via merge request !40

[sumnerevans]

marked this issue as related to #221