/// <summary>
/// Performs the HTTP request.
/// </summary>
/// <returns>The server response string(UTF8 decoded).</returns>
public virtual string Request()
{
HttpWebRequest req = HttpWebRequest.Create(ConstructUri()) as HttpWebRequest;
AppendHeaders(req.Headers);
if (!string.IsNullOrEmpty(Method))
{
req.Method = Method;
}
if (!string.IsNullOrEmpty(ContentType))
{
req.ContentType = ContentType;
}
PrepareRequest(req);
// Calls GetRequestStream with a "GET" method, an exception is thrown "Cannot send a content-body with this verb-type."
if (req.Method == HttpMethod.Post)
{
using (var reqStream = req.GetRequestStream())
{
WriteBody(reqStream);
}
// ContentLength is automatically calculated.
}
WebResponse resp = null;
try
{
resp = req.GetResponse();
}
catch (WebException wex)
{
ErrorResponse errorResp;
var webResp = wex.Response as HttpWebResponse;
if (null == webResp)
throw new AMicroblogException(LocalErrorCode.NetworkUnavailable);
try
{
var responseContent = RetrieveResponse(webResp);
if (!string.IsNullOrEmpty(responseContent) && responseContent.StartsWith(Constants.XmlHeader, StringComparison.InvariantCultureIgnoreCase))
{
errorResp = XmlSerializationHelper.XmlToObject<ErrorResponse>(responseContent);
// Retrieves the error code and wraps the exception.
var errorCode = AMicroblogException.RetrieveErrorCode(errorResp.ErrorMessage);
if (!string.IsNullOrEmpty(errorCode))
errorResp.ErrorCode = int.Parse(errorCode);
}
else
{
// Handle other cases
errorResp = new ErrorResponse() { ErrorCode = (int)webResp.StatusCode, ErrorMessage = webResp.StatusDescription };
}
}
catch (Exception exx)
{
throw new AMicroblogException(LocalErrorCode.ProcessResponseErrorHandlingFailed, exx);
}
var aex = new AMicroblogException(errorResp.ErrorMessage, wex) { IsRemoteError = true, ErrorCode = errorResp.ErrorCode };
var e = new ResponseErrorEventArgs(req.RequestUri.AbsoluteUri, aex, req.Method, req.ContentType);
Environment.NotifyResponseError(e);
aex.IsHandled = e.IsHandled;
throw aex;
}
return RetrieveResponse(resp);
}
/// <summary>
/// Handles the response error event.
/// </summary>
private static void HandleResponseError(object sender, ResponseErrorEventArgs e)
{
foreach (var handler in ResponseErrorHandlers)
{
try
{
var errorCode = e.ErrorData.ErrorCode.ToString();
if (handler.ErrorCode == "*" || errorCode == handler.ErrorCode || Regex.IsMatch(errorCode, handler.ErrorCode, RegexOptions.IgnoreCase))
{
var realHandler = Activator.CreateInstance(handler.Type) as IResponseErrorHandler;
realHandler.Handle(e.ErrorData);
e.IsHandled = true;
}
}
catch
{
// Nothing to do.
}
}
}
/*
// Sample code of calling a AMicroblog API
public void Post(string status)
{
try
{
var updStatusInfo = new UpdateStatusInfo();
updStatusInfo.Status = status;
var statusInfo = AMicroblog.PostStatus(updStatusInfo);
// Further post-process against statusInfo...
}
catch (AMicroblogException aex)
{
// Handles the exception only if the exception is not handled by Unified Response Error Handling mechanism.
if (!aex.IsHandled)
{
if (aex.IsRemoteError)
{
ShowErrorMessage("Server returned an error: {0}", aex.Message);
// You can customize the error message based on aex.RemoteErrorCode.
}
else
ShowErrorMessage("Unexpected error occured: {0}", aex.Message);
}
}
catch (Exception ex)
{
ShowErrorMessage("Unexpected error occured: {0}", ex.Message);
}
}
*/
private void Environment_ResponseError(object sender, ResponseErrorEventArgs e)
{
Console.WriteLine("An error response for {0}: {1}", e.ErrorData.RequestUri, e.ErrorData.Exception.Message);
}
/// <summary>
/// Triggers the <see cref="ResponseError"/>.
/// </summary>
/// <remarks>To insure that each event handler has a chance to process the event, any exception is suspended.</remarks>
internal static void NotifyResponseError(ResponseErrorEventArgs e)
{
if (null != ResponseError)
{
var invocationList = ResponseError.GetInvocationList();
foreach (var invocation in invocationList)
{
try
{
var inv = invocation as EventHandler<ResponseErrorEventArgs>;
inv(null, e);
}
catch { }
}
}
}
