File attachments?

[xiiihopeestheim]

Does anyone have a good idea on how to associate File attachments to EntityData for offline use in mobile apps? For example I would like to attach pictures/pdf that can also be viewed offline once pulled from the remote table

[adrianhall]

This is something I've been thinking about working on. It's a totally separate product though.

1. Create a FileAttachments table. Associate each entity in your EntityData to FileAttachments however you wish - it's up to you to maintain this. Each entity in the FileAttachments table corresponds to a file in Azure blob storage. This can be provided as a custom repository on the server side that just works with Azure blob storage.
2. Synchronize the FileAttachments table as normal. (Might be best to have a non-transmitted field in the FileAttachments table that tells you whether the file has been downloaded yet).
3. Hook into the SynchronizationProgress event handler (on the DatasyncClient) - whenever there is a new FileAttachments synchronization event, handle it - for deletions, you can just delete the file; for update/create, you can add the file reference to a queue. (Ensure the queue is persisted so you can restart downloads when the app starts)
4. Have a separate downloader queue processor (which you kick off when the app starts) that downloads files in the queue to an on-device location. (Don't forget to update that non-transmitted field in the FileAttachments table)
5. Write an extension method to the IOfflineTable class that basically is "GetFileReferenceAsync(string id)" to get an appropriate file reference for your platform.

It's definitely doable and it's definitely a lot of work.

[xiiihopeestheim]

I understand, that explanation makes complete sense.