/// <summary>
/// Builds the IEwsHttpWebRequest object for current service request with exception handling.
/// </summary>
/// <returns>An IEwsHttpWebRequest instance</returns>
protected async Task <IEwsHttpWebRequest> BuildEwsHttpWebRequest()
{
IEwsHttpWebRequest request = null;
try
{
request = this.Service.PrepareHttpWebRequest(this.GetXmlElementName());
this.Service.TraceHttpRequestHeaders(TraceFlags.EwsRequestHttpHeaders, request);
bool needSignature = this.Service.Credentials != null && this.Service.Credentials.NeedSignature;
bool needTrace = this.Service.IsTraceEnabledFor(TraceFlags.EwsRequest);
// The request might need to add additional headers
this.AddHeaders(request.Headers);
// If tracing is enabled, we generate the request in-memory so that we
// can pass it along to the ITraceListener. Then we copy the stream to
// the request stream.
if (needSignature || needTrace)
{
await this.TraceAndEmitRequest(request, needSignature, needTrace).ConfigureAwait(false);
}
else
{
await this.EmitRequest(request).ConfigureAwait(false);
}
return(request);
}
catch (WebException ex)
{
if (ex.Status == WebExceptionStatus.ProtocolError && ex.Response != null)
{
this.ProcessWebException(ex);
}
// Wrap exception if the above code block didn't throw
throw new ServiceRequestException(string.Format(Strings.ServiceRequestFailed, ex.Message), ex);
}
catch (IOException e)
{
if (request != null)
{
request.Abort();
}
// Wrap exception.
throw new ServiceRequestException(string.Format(Strings.ServiceRequestFailed, e.Message), e);
}
}
/// <summary>
/// Emits the request.
/// </summary>
/// <param name="request">The request.</param>
private void EmitRequest(IEwsHttpWebRequest request)
{
try {
using (Stream requestStream = this.GetWebRequestStream(request)) {
using (EwsServiceXmlWriter writer = new EwsServiceXmlWriter(this.Service, requestStream)) {
this.WriteToXml(writer);
}
}
} catch (Exception e) {
//FJC: We found that if the Xml generation generated an exception, then the request would be left in a
// non-usable state since the requestStream in the request wasn't fully closed?
// I'm not 100% sure I understand that part... but I found that calling .Abort on the request would force
// the request/connection to be reinitialized the next time it was used after a Xml exception.
request.Abort();
throw e;
}
}