/// <summary>
/// Gets a token for executing API requests.
/// The returned token is initialized according to the configuration of the member variables of the class.
/// Ex: Authentication flow App Only or App + User.
/// </summary>
/// <returns>A token initialized according to the class parameters.</returns>
/// <remarks>This method implements tha lazy load pattern. If a token is already present, and it is not about to expire,
/// the previous token is returned.</remarks>
public async Task <AuthorizationToken> GetAADTokenForRequestsAsync()
{
// If token not initialized or near expiracy
if (_AADTokenForRequests != null && !_AADTokenForRequests.IsNearExpiracy())
{
// already initialized
return(_AADTokenForRequests);
}
// else. Initialize a new token and return it
AuthenticationResult authenticationResult = null;
if (_isTokenForUserPlusApplication)
{
// Get token for user + application credentials
authenticationResult = await _authenticationContext.AcquireTokenAsync(
_resourceUrl,
_userPlusApplicationAppId,
_userCredential);
}
else
{
// Get an access token from Azure AD using client credentials.
// ADAL includes an in memory cache, so this call will only send a message to the server
// if the cached token is expired.
authenticationResult = await _authenticationContext.AcquireTokenAsync(
_resourceUrl,
_clientCredential);
}
_AADTokenForRequests = new AuthorizationToken(authenticationResult.AccessToken,
authenticationResult.ExpiresOn.DateTime);
return(_AADTokenForRequests);
}
