I'm choosing a platform for distributed MP3 player. Its basic functionality will be:

• authenticate itself and query central server (through HTTP request to asmx web service)
• get list of approved MP3s in some JSON
• download those MP3s to local disc
• play downloaded files (not stream, player must work also without temporary connection to server)

I'm thinking about HTML5 based player. But I'm not sure about new HTML5's File object capatibilities. Is possible to download and store huge (GBs) amount of mp3 data to local disc and access it purely in HTML5/js?

Didn't I miss something? Are there some other gaps? Customer need as multi-platform player as possible, so quick work in WPF C# is last choice.

• web-services
• html5
• mp3
• local-storage

I would look into the HTML5 File API, or a chrome extension (Allows infinite store with Web SQL DBs).

The file API spec is here:

http://dev.w3.org/2009/dap/file-system/pub/FileSystem/

Basically all other storage mechanisms have a hard limit on most browsers, even though Web SQL is spec'd to allow you to specify max db size in your app.