Manage Site App Permissions Programmatically?

Question

Hello,
Is it possible to manage a site's app permissions programmatically? (site settings -> site app permissions)
I am deploying a SharePoint-Hosted App to an on-premises instance of SharePoint 2013 using server object model:
SPAppInstance instance = web.LoadAndInstallApp(stream);
The app requires some permissions (Web, Read). I would like to trust the app programmatically as well.
Thank you!
Andre

Answer 1

For anyone that's interested, I came across a similar requirement. The code above is a good start, but it assumes that the app principal is already created (i.e. LookupAppPrincipal). Unfortunately, when installing an app, the app principal doesn't exist
and isn't created (unless of course it was done so manually). So, the code below is a variation of the above code, for when an app principal must first be created before being assigned permissions.
SPAppInstance appInstance = web.LoadAndInstallApp(package);
char[] separators = { '|', '@' };
string appPrincipalIdentifier = appInstance.AppPrincipalId.Split(separators)[2];SPAppPrincipalPermissionsManager permissionsManager = new SPAppPrincipalPermissionsManager(web);
SPAppPrincipalManager principalManager = SPAppPrincipalManager.GetManager(web);
List<string> endpoints = new List<string>();
endpoints.Add("<EndPoint Authority>");
SecureString secureString = new SecureString();DateTime now = DateTime.Now;SPAppPrincipalCredential credential = SPAppPrincipalCredential.CreateFromSymmetricKey(secureString, now, now);SPExternalAppPrincipalCreationParameters creationParameters = new SPExternalAppPrincipalCreationParameters(
appPrincipalIdentifier,
"<Display Name>",
endpoints,
credential
SPAppPrincipal principal = principalManager.CreateAppPrincipal(creationParameters);
permissionsManager.AddAppPrincipalToWeb(principal, SPAppPrincipalPermissionKind.FullControl