I am trying to wrap my head around my options when it comes to SharePoint Apps, and I am hoping that you guys can help clear this up for me.
I want to create a separate Web Application that is not SharePoint that will gather information from an existing SharePoint farm and also write information to a separate SQL Server DB. This web app will also need to be surfaced within the existing SharePoint farm.
From what I have read, I believe that I am looking to develop a Provider Hosted App on my own IIS Web Application. This will allow me to write server side code if necessary, but will allow me to gain access to the SharePoint farm via the CSOM. I have then found that there are 2 ways that I can authenticate with the SharePoint farm. I can use ACS or I can configure a High Trust App.
Assuming that this is correct (please let me know if it is not), My concern is the authentication. I would prefer not to involve Azure (and thus ACS) as we don't have a subscription, but it looks like the other High Trust App scenario is only intended for internal on-premise situations. Are there any other options if I am developing this App for a public facing site?
Any help that you can provide is GREATLY appreciated!