How to Access Provider-Hosted App programmaticly

Question

I have a (working) provider hosted app that mainly acts as a REST-Service (MVC5). I want to unit test my Rest-Controllers but can't find out how to give the right credentials.

I already got the URL including crucial parameters the following way:

private string GetBaseUrl(AppInstance myApp, string hostUrl)
{
    string tokens = string.Format("SPHostUrl={0}&SPLanguage={1}&SPAppWebUrl={2}",
    Uri.EscapeDataString(hostUrl), "en-US", Uri.EscapeDataString(myApp.AppWebFullUrl));
    string url = myApp.StartPage;
    url= url.Replace("{StandardTokens}", tokens);
    string returnUrl = string.Format("{0}{{0}}?{1}", url.Split('?')[0], url.Split('?')[1]);
    return returnUrl;
}

string hostUrl="http://mySp.sharepoint.com";            
using (context = new ClientContext(hostUrl)) {
    context.Credentials = new SharePointOnlineCredentials(Username, Password);
    context.Load(context.Web);
    context.ExecuteQuery();

    var web = context.Web;

    var addInInstance = AppCatalog.GetAppInstances(context, web);
    addInInstance.Context.Load(addInInstance);
    addInInstance.Context.ExecuteQuery();

    var myApp = addInInstance.FirstOrDefault(app=>app.Title.ToLower().Contains("myApp"));
    context.Load(mydeaApp);
    context.ExecuteQuery();

    string url=string.Format(GetBaseUrl(myApp, hostUrl),"/api/users";   
    // Returns something like "localhost://443400/api/users?SPHostUrl=http%3A%2F%2F...&SPAppWebUrl=http%3A%2F%2F...&SPLanguage=en-US"
}

url contains something like "localhost://443400/api/users?SPHostUrl=http%3A%2F%2F...&SPAppWebUrl=http%3A%2F%2F...&SPLanguage=en-US"

I did all this actions just because I needed the right Request-Parameters which are automatically generated when opening the app from inside sharepoint. If I call the Url using a httpRequest

HttpWebRequest request = HttpWebRequest.CreateHttp(url);
request.Credentials=new SharePointOnlineCredentials(Username, password);
var response = (HttpWebResponse)request.GetResponse()

it just does not work as expected. My App is called, but when debugging the app I can see that the spContext is just null (which does not happen when being called from within sharepoint).

When opening the same Url in a browser where I am not logged in the behaviour is the same. So I expect that this has to do something with credentials / userpermissions.

Answer 1

SharePoint does a lot of things under the hood before calling your provider-hosted app's REST service. The most important thing - it provides a context token (if you are not familiar with OAuth/OpenId you can imagine that it's a kind of a password) to the REST service, which the service uses to establish a connection back to SharePoint (hence you can use spContext). Since most of this is done under the hood and transparently to you - you do not see it directly in code. More information about what happens when you open a provider-hosted app from SharePoint can be found here: https://msdn.microsoft.com/en-us/library/office/fp142382.aspx

Therefore unit testing a provider hosted REST app is tricky. I don't know the right way to do that, but my suggestion would be to drop the idea and instead test the logic behind your controllers.

I have also found a post in one forum which is marked as an answer on how you can access provider-hosted app pages via code (in javascript, in this case), but it's not for the faint of heart: https://social.msdn.microsoft.com/Forums/office/en-US/e010b8a3-156e-448f-9d69-ba48d0a8233f/launch-application-by-known-url?forum=appsforsharepoint