How to get the client context for code in a provider-hosted add-in that is called outside of the SharePoint context.
For example, you want a page in your solution to be called directly and not from SharePoint. Reasons for this may be that you have a page in the add-in that you want to share with users and don’t want to give the full add-in url. Instead of:
http://myaddindomain.com/pages/custompage.aspx?SPHostUrl={etc}
You want something like this, without all the parameters:
http://myaddindomain.com/pages/custompage.aspx
With the former, you’ll be able to get the context with:
var context = SharePointContextProvider.Current.GetSharePointContext(Context);
Trying this without all the parameters will obviously fail and you’ll get a 401 unauthorised error.
To get a valid context this way, you’ll need to have the SharePoint host’s URL stored somewhere in the remote website. In the web.config for example.
To obtain the context, use this instead:
var hostUri = new Uri(ConfigurationManager.AppSettings["HostUrl"]);
using (var context = TokenHelper.GetS2SClientContextWithWindowsIdentity(hostUri, Request.LogonUserIdentity){
// CSOM code
}
This will create the context for the current user and you should now be able to query the SharePoint site’s content.
