private static async Task <HttpResponseMessage> SendAsyncWithRetry(HttpRequestFactoryDelegate requestFactory, CancellationToken cancellationToken)
{
while (!cancellationToken.IsCancellationRequested)
{
try
{
// Call SendAsync with a new request object each time, since it's invalid to send the same request object twice.
var response = await httpClient.SendAsync(requestFactory(), cancellationToken);
if (response.IsSuccessStatusCode)
{
return(response);
}
else if (response.StatusCode != HttpStatusCode.BadGateway &&
response.StatusCode != HttpStatusCode.RequestTimeout &&
response.StatusCode != HttpStatusCode.ServiceUnavailable)
{
return(response);
}
}
catch (WebException webException)
{
if (webException.Status != WebExceptionStatus.ReceiveFailure &&
webException.Status != WebExceptionStatus.ConnectFailure &&
webException.Status != WebExceptionStatus.KeepAliveFailure)
{
throw webException;
}
}
}
;
return(null);
}
private static async Task <APIResult> CallMediaWikiAPI(string options, CancellationToken cancellationToken)
{
// Post the request to the MediaWiki API endpoint.
var uri = string.Format("{0}api.php", baseURI, options);
HttpRequestFactoryDelegate requestFactory = () =>
{
var request = new HttpRequestMessage(HttpMethod.Post, uri);
request.Content = new StringContent(options, Encoding.UTF8, "application/x-www-form-urlencoded");
return(request);
};
using (var postResponse = await SendAsyncWithRetry(requestFactory, cancellationToken))
{
// Read the response.
if (!cancellationToken.IsCancellationRequested && postResponse.IsSuccessStatusCode)
{
var responseString = await postResponse.Content.ReadAsStringAsync();
var responseDocument = new XmlDocument();
responseDocument.Load(new StringReader(responseString.TrimStart(' ', '\t', '\r', '\n')));
// Check for an API error.
var result = new APIResult();
var errorElement = responseDocument.SelectSingleNode("/error");
if (errorElement != null)
{
// Extract the API error code and description.
result.errorCode = errorElement.Attributes["code"].Value;
result.errorDescription = errorElement.Attributes["info"].Value;
result.bSuccess = false;
}
else
{
// If the API call succeeded, extract the resulting XML tree.
result.resultXML = responseDocument["api"];
result.bSuccess = true;
}
return(result);
}
else
{
// If the HTTP request failed, setup an unsuccesful result struct.
var result = new APIResult();
result.resultXML = null;
result.errorCode = postResponse.StatusCode.ToString();
result.errorDescription = postResponse.ReasonPhrase;
result.bSuccess = false;
return(result);
}
}
}
