Provider Hosted APP with Azure & On-Premise Deployment Not able to take ClientContext

Question

I am creating Provider Hosted APP and Deploying in Azure and Consuming in my SharePoint 2013 - On Premise.

When I am using:

var spContext = SharePointContextProvider.Current.GetSharePointContext(Context);

var clientContext = spContext.CreateUserClientContextForSPHost()

It's Giving an error: Object reference not set to an instance of an object.

But when I am using:

var contextToken = TokenHelper.GetContextTokenFromRequest(Request);

var hostWeb = Request.QueryString["SPHostUrl"];

var clientContext = TokenHelper.GetClientContextWithContextToken(hostWeb, contextToken, Request.Url.Authority)

It's giving an error: The parameter 'token' cannot be a null or empty string

If I commenting all code in .cs file then APP is working fine. Its showing .aspx file data. Also when I deployed to Office 365 account I am able to take Client Context.

So how can I take ClientContext for on-premise?

I have added below code in web.config:

 <appSettings>
    <add key="ClientId" value="68150c39-ee2d-4d71-aa5d-12d06c52e29a" />
    <add key="ClientSecret" value="C7iwn79rs83sQPeP42iCSO1Oo/9nI6yUbvxJM5j1+G4=" />
  </appSettings>

Also in azure I have mentioned my Client ID and Client Secret:

Answer 1

Provider hosted apps are divided into two different categories in terms of authentication mechanism.

These are low-trust apps and high-trust apps, both use OAuth for authentication.

Low trust apps use Azure Access Control Services (ACS) in order to obtain OAuth access token, high trust apps use certificate in order to generate access token right inside the app (that's why high-trust).

For SharePoint online (Office 365) only low-trust app available. Low trust apps use ClientId and CientSecret. For on-premise by default only high-trust availiable, apps use ClientId, ClientSigningCertificatePath, ClientSigningCertificatePassword in web config. Besides it's possible to configure your on-premise farm to work in low trust and use ACS for access tokens. Besides this configuration requires O365 subscription.

Answering your question - it's not possible to easily deploy provider hosted app with high trust authentication into Azure, it will never work. You need either configure low trust or change the code inside TokenHelper.cs to make it work.

Some additional useful reading:

• Create high-trust SharePoint Add-ins
• Creating SharePoint Add-ins that use low-trust authorization
• SharePoint Low-Trust Apps for On-Premises Deployments