Upload photos on facebook user account while he's offline

Question

I'm developing a server side application with ASP.NET and C# with Facebook C# SDK (http://csharpsdk.org/).

This application gets the user permission publish_stream the first time the user login then the application works on background, without user interaction.

The application will upload a custom image on user photos periodically, and posts them on user wall. I need to know if it's possible, I mean if it's possible to build an application that upload photos while he is not authenticated for the application.

In my tests, I noticed that it is possible for status with app access token, but with photos I had issues: I receive the following message:

A user access token is required to request this resource.

Thanks a lot!

Answer 1

While it is not possible to upload photos without authentication of user, nothing stops you from implementing next flow:

• authenticate the user
• extend user's access_token
• store extended access_token on your end
• upload photos using stored access_token

Answer 2

I need to know if it's possible, I mean if it's possible to build an application that upload photos while he is not authenticated for the application.

Of course this isn't possible, in order to post the photo, you have to have the permission to do so.

In my tests, I noticed that it is possible for status with app access token, but with photos I had issues: I receive the following message: A user access token is required to request this resource.

This clearly indicates you need a authentication token to do this.

You should be able to renew/extend token without user interaction if it has expired.