Objective-c：NSURLConnection sendSynchronousRequest被赋予415不支持的媒体类型错误和Soap请求

Question

我正在尝试使NSURLConnection与WCF * .svc基于soap的服务（不是REST）同步，并且我在httpResponse对象上不断收到 415 Media type not supported error 。我相信我正在使用正确的内容类型和 SOAPAction 设置标题，如 Fiddler 所示。我还用WebRequest编写了一个.net应用程序，我用相同的肥皂从它获得200状态OK响应。任何人都可以告诉我我哪里出错或者我错过了什么。我用我的Objective-c代码打开了ARC。谢谢你......

-(void) GetJSONResponse_soap: (NSString *) PReqURL
{
  NSLog(@"URL sent: %@", PReqURL);  
  NSMutableString *sRequest = [[NSMutableString alloc] init];

  //creating soap request
  [sRequest appendString:@"<?xml version=\"1.0\" encoding=\"utf-8\"?>"];
  [sRequest appendString:@"<s:Envelope xmlns:s=\"http://schemas.xmlsoap.org/soap/envelope/\">"];
  [sRequest appendString:@"<s:Body>"];
  [sRequest appendString:@"<GetJSONStrFromPrm xmlns=\"WCFJSON\">"];
  [sRequest appendString:@"<Prm>Whatever</Prm>"];
  [sRequest appendString:@"</GetJSONStrFromPrm>"];
  [sRequest appendString:@"</s:Body>"];
  [sRequest appendString:@"</s:Envelope>"];

  NSURL *reqURL = [NSURL URLWithString:PReqURL];
  //request
  NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:reqURL];

  [request addValue:@"WCFJSON/IJSONStrService/GetJSONStrFromPrm"  forHTTPHeaderField:@"SOAPAction"]; 
  [request addValue:@"text/xml; charset:utf-8" forHTTPHeaderField:@"Content-Type"];
  [request setHTTPMethod:@"POST"];
  [request setHTTPBody:[sRequest dataUsingEncoding:NSUTF8StringEncoding]];

  NSLog(@"\n\nRequest Xml: %@ \n\n", sRequest);

  NSURLResponse *theResponse = NULL;
  NSError *theError;

  //Connection start
  NSData *LcReceivedData = [NSURLConnection sendSynchronousRequest:request  returningResponse:&theResponse error:&theError];  

  //received string
  NSString *ResponseStr = [[NSString alloc] initWithData:LcReceivedData encoding:NSUTF8StringEncoding];
  NSLog(@"\n\nResponse: %@", ResponseStr);

  //response string which in this case seems to be 415
  NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)theResponse;
  long statusCode = [httpResponse statusCode];
  NSLog(@"\n\nStatus Code: %ld",statusCode);
  NSLog(@"\n\nError: %@", [theError localizedDescription]);

}