/// <summary>
/// A static method that routes errors to a single centralized error-handler.
/// This method will attempt to extract a human-readable error from the response string,
/// based on the the format of the data and the error handling scheme of the service.
/// </summary>
public static ActionResult ShowErrorMessage(Office365ServiceInfo serviceInfo, string responseString)
{
string message, errorDetails;
try
{
message = serviceInfo.ParseErrorMessage(responseString);
errorDetails = responseString;
}
catch (Exception e)
{
message = "An unexpected error has occurred.";
errorDetails = "Exception when parsing response string: " + e.ToString() +
"\n\nResponse string was " + responseString;
}
return ShowErrorMessage(message, errorDetails);
}
/// <summary>
/// Send an HTTP request, with authorization. If the request fails due to an unauthorized exception,
/// this method will try to renew the access token in serviceInfo and try again.
/// </summary>
public static async Task<HttpResponseMessage> SendRequestAsync(
Office365ServiceInfo serviceInfo, HttpClient client, Func<HttpRequestMessage> requestCreator)
{
using (HttpRequestMessage request = requestCreator.Invoke())
{
request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", serviceInfo.AccessToken);
request.Headers.UserAgent.Add(new ProductInfoHeaderValue(AppPrincipalId, String.Empty));
HttpResponseMessage response = await client.SendAsync(request);
// Check if the server responded with "Unauthorized". If so, it might be a real authorization issue, or
// it might be due to an expired access token. To be sure, renew the token and try one more time:
if (response.StatusCode == HttpStatusCode.Unauthorized)
{
Office365Cache.GetAccessToken(serviceInfo.ResourceId).RemoveFromCache();
serviceInfo.AccessToken = GetAccessTokenFromRefreshToken(serviceInfo.ResourceId);
// Create and send a new request:
using (HttpRequestMessage retryRequest = requestCreator.Invoke())
{
retryRequest.Headers.Authorization = new AuthenticationHeaderValue("Bearer", serviceInfo.AccessToken);
retryRequest.Headers.UserAgent.Add(new ProductInfoHeaderValue(AppPrincipalId, String.Empty));
response = await client.SendAsync(retryRequest);
}
}
// Return either the original response, or the response from the second attempt:
return response;
}
}