private static void HandleFailure(TwitterAPIEndpoint endpoint, UserRateLimitInfo userStatus, AuthenticationType?authTypeUsed, HttpResponseMessage response)
{
if (!response.IsSuccessStatusCode)
{
if (authTypeUsed.Value == AuthenticationType.Application)
{
RateLimitCache.Get[endpoint].Update(RateLimitCache.Get[endpoint].Limit - 1);
}
else
{
userStatus?.Update(userStatus.Limit - 1);
}
}
}
private static void UpdateRateLimits(TwitterAPIEndpoint endpoint, UserRateLimitInfo userStatus, AuthenticationType?authTypeUsed, HttpResponseMessage response)
{
if (response.Headers.TryGetValues("x-rate-limit-remaining", out IEnumerable <string> remaining) &&
response.Headers.TryGetValues("x-rate-limit-reset", out IEnumerable <string> reset))
{
if (int.TryParse(remaining.FirstOrDefault(), out int limitRemaining) &&
double.TryParse(reset.FirstOrDefault(), out double secondsUntilReset))
{
if (authTypeUsed.Value == AuthenticationType.Application)
{
RateLimitCache.Get[endpoint].Update(limitRemaining, UntilEpochSeconds(secondsUntilReset));
}
else
{
userStatus?.Update(limitRemaining, UntilEpochSeconds(secondsUntilReset));
}
}
}
}
private static bool UseUserAuth(AuthenticationType authType, string token, UserRateLimitInfo userStatus)
{
return(userStatus != null && userStatus.Available && token != null &&
(authType == AuthenticationType.User || authType == AuthenticationType.Both));
}
private static bool UseApplicationAuth(AuthenticationType authType, string token, AppRateLimitInfo appStatus, UserRateLimitInfo userStatus)
{
return(appStatus.Available &&
(authType == AuthenticationType.Application ||
(authType == AuthenticationType.Both && (null == token || !userStatus.Available))));
}
private static bool TryAuthorize(HttpRequestMessage request, IConfiguration config, AuthenticationType authType, string token, string tokenSecret, AppRateLimitInfo appStatus, UserRateLimitInfo userStatus, out AuthenticationType?used)
{
if (UseApplicationAuth(authType, token, appStatus, userStatus))
{
AddBearerAuth(config, request);
used = AuthenticationType.Application;
}
else if (UseUserAuth(authType, token, userStatus))
{
AddUserAuth(config, request, token, tokenSecret);
used = AuthenticationType.User;
}
else
{
used = null;
return(false);
}
return(true);
}
/// <summary>
/// Attempts to authenticate a call to the Twitter API with the given query string and authentication info. Updates rate limits if applicable.
/// </summary>
/// <param name="config"></param>
/// <param name="authType"></param>
/// <param name="endpoint"></param>
/// <param name="query"></param>
/// <param name="token"></param>
/// <param name="tokenSecret"></param>
/// <param name="userStatus"></param>
/// <returns></returns>
internal static async Task <string> GetResponse(IConfiguration config, AuthenticationType authType, TwitterAPIEndpoint endpoint,
string query, string token, string tokenSecret, UserRateLimitInfo userStatus)
{
// Yep, that's a lot of parameters.
AppRateLimitInfo appStatus = RateLimitCache.Get[endpoint];
if (!appStatus.Available)
{
throw new Exception($"Endpoint {endpoint} currently unavailable due to rate limits. Time until reset: {appStatus.UntilReset}");
}
appStatus.ResetIfNeeded();
try
{
using (var client = new HttpClient())
using (var request = new HttpRequestMessage(HttpMethod(endpoint), GetUri(endpoint, query)))
{
if (!TryAuthorize(request, config, authType, token, tokenSecret, appStatus, userStatus, out AuthenticationType? authTypeUsed))
{
throw new Exception($"Unable to authenticate Twitter API call of type {authType}, endpoint {endpoint}.");
}
using (HttpResponseMessage response = await client.SendAsync(request, HttpCompletionOption.ResponseContentRead))
{
HandleFailure(endpoint, userStatus, authTypeUsed, response);
response.EnsureSuccessStatusCode();
UpdateRateLimits(endpoint, userStatus, authTypeUsed, response);
return(await response.Content.ReadAsStringAsync());
}
}
}
catch (Exception ex)
{
throw new Exception($"Twitter API call failed: {ex.Message}");
}
}