/// <summary>
/// Checks that an OutlookServicesClient object is available.
/// </summary>
/// <returns>The OutlookServicesClient object. </returns>
public static async Task <SharePointClient> GetSharePointClientAsync()
{
if (_sharePointClient != null && !String.IsNullOrEmpty(AuthenticationHelper.LastAuthority))
{
Debug.WriteLine("Got a SharePoint client for Files.");
return(_sharePointClient);
}
else
{
try
{
//First, look for the authority used during the last authentication.
//If that value is not populated, use CommonAuthority.
string authority = null;
if (String.IsNullOrEmpty(AuthenticationHelper.LastAuthority))
{
authority = AuthenticationHelper.CommonAuthority;
}
else
{
authority = AuthenticationHelper.LastAuthority;
}
// Create an AuthenticationContext using this authority.
AuthenticationHelper._authenticationContext = new AuthenticationContext(authority);
// Set the value of _authenticationContext.UseCorporateNetwork to true so that you
// can use this app inside a corporate intranet. If the value of UseCorporateNetwork
// is true, you also need to add the Enterprise Authentication, Private Networks, and
// Shared User Certificates capabilities in the Package.appxmanifest file.
AuthenticationHelper._authenticationContext.UseCorporateNetwork = true;
//See the Discovery Service Sample (https://github.com/OfficeDev/Office365-Discovery-Service-Sample)
//for an approach that improves performance by storing the discovery service information in a cache.
DiscoveryClient discoveryClient = new DiscoveryClient(
async() => await AuthenticationHelper.GetTokenHelperAsync(AuthenticationHelper._authenticationContext, AuthenticationHelper.DiscoveryResourceId));
// Get the specified capability ("Calendar").
CapabilityDiscoveryResult result =
await discoveryClient.DiscoverCapabilityAsync("MyFiles");
var token = await AuthenticationHelper.GetTokenHelperAsync(AuthenticationHelper._authenticationContext, result.ServiceResourceId);
// Check the token
if (String.IsNullOrEmpty(token))
{
// User cancelled sign-in
return(null);
}
else
{
_sharePointClient = new SharePointClient(
result.ServiceEndpointUri,
async() => await AuthenticationHelper.GetTokenHelperAsync(AuthenticationHelper._authenticationContext, result.ServiceResourceId));
Debug.WriteLine("Got a SharePoint client for Files.");
return(_sharePointClient);
}
}
// The following is a list of exceptions you should consider handling in your app.
// In the case of this sample, the exceptions are handled by returning null upstream.
catch (DiscoveryFailedException dfe)
{
Debug.WriteLine(dfe.Message);
}
catch (ArgumentException ae)
{
Debug.WriteLine(ae.Message);
}
AuthenticationHelper._authenticationContext.TokenCache.Clear();
return(null);
}
}
