WCF返回MemoryStream返回空白和状态202

Question

我的WCF服务正在代理另一个Web服务。每当我修改响应并返回内存流时，客户端都会得到一个202 Accepted。

public Stream MyMethod()
{
...
...
HttpWebResponse httpGetResponse = (HttpWebResponse)httpGetRequest.GetResponse();
var result = httpGetResponse.GetResponseStream();
//if I return "result" here, I get a 200 and Messagebody contains the contents of the stream
//return result;
//modifying content body
var txtresult = new StreamReader(result, Encoding.UTF8).ReadToEnd();
txtresult = txtresult.Replace("old text", "new text");
var stream = new MemoryStream();
stream.Write(Encoding.UTF8.GetBytes(txtresult), 0, Encoding.UTF8.GetBytes(txtresult).Length);
//same as:- new MemoryStream(Encoding.UTF8.GetBytes(txtresult));
stream.Position = 0L;
//stream.Flush();
//returns 202 - Accepted. Content body is empty
return stream;
}

基本上，我只需要修改流的内容，然后再将它们提交给客户端应用程序。我已验证编码是否正确。除此之外，我不确定自己做错了什么。请你协助

此外，接口定义如下：

[WebInvoke(Method = "GET",
BodyStyle = WebMessageBodyStyle.Bare,
UriTemplate = "teststream")]
Stream MyMethod();

Answer 1

在返回响应之前，您需要设置OutgoingResponse.ContentType并添加Content-Disposition标头，如下所示：

public Stream MyMethod()
{
...
var stream = new MemoryStream();
stream.Write(Encoding.UTF8.GetBytes(txtresult), 0, Encoding.UTF8.GetBytes(txtresult).Length);
stream.Position = 0L;
WebOperationContext.Current.OutgoingResponse.ContentType = "text/plain";
WebOperationContext.Current.OutgoingResponse.Headers.Add("Content-disposition", "inline; filename=result.txt");
return stream;
}

Answer 2

我终于解决了这个问题。由于我的服务是一个代理，我将收到的头传递到客户端，而不修改它们。在返回流之前删除内容编码标头对我来说是有效的

public Stream MyMethod()
{
...
HttpWebResponse httpGetResponse = (HttpWebResponse)httpGetRequest.GetResponse();
var result = httpGetResponse.GetResponseStream();
var txtresult = new StreamReader(result, Encoding.UTF8).ReadToEnd();
txtresult = txtresult.Replace("old text", "new text");
var stream = new MemoryStream();
stream.Write(Encoding.UTF8.GetBytes(txtresult), 0, Encoding.UTF8.GetBytes(txtresult).Length);
stream.Position = 0L;
//added this line 
WebOperationContext.Current.OutgoingResponse.Headers.Remove(HttpRequestHeader.ContentEncoding);

//now returns actual content to client
return stream;
}