Http Server未返回响应的内容编码标头

问题描述

我正在使用http客户端发出HttpWebRequest请求

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(requestString);
request.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;
request.Method = "GET"; 
request.BeginGetResponse(new AsyncCallback(GetResponseCallback),request);

public void GetResponseCallback(IAsyncResult asynchronousResult)
{
    HttpWebResponse response = null;
    HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;

    response = (HttpWebResponse)request.EndGetResponse(asynchronousResult);

    Console.WriteLine(response.Headers["content-encoding"]);
            
    if (response.StatusCode == HttpStatusCode.OK || response.StatusCode == HttpStatusCode.Moved)
    {   
        Stream inputStream = response.GetResponseStream();
        StreamReader stream = new StreamReader(inputStream);
        string responseString = stream.ReadToEnd(); 
    }
}

在Apache设置下，gzip压缩已启用并正常工作，因为从chrome浏览器向同一url请求时，我可以在响应标题中看到content-encoding。请参阅所附的屏幕截图。

但是当我使用上面提供的代码content-encoding发出相同的请求时，标头中存在键，但其值为空字符串。

为什么我的响应标题中缺少content-encoding值？ 这是响应头字符串

Headers = {Connection: keep-alive  vary: Accept-Encoding  content-encoding:   Access-Control-Allow-Origin: *  Content-Length: 36954  Content-Type: text/html; charset=UTF-8  Date: Fri,18 Sep 2020 11:31:25 GMT  Server: Nginx/1.10.2  X-Powered-By: PHP/5.3.3    }

解决方法

如果其他任何人遇到相同的问题。 就我而言，问题就在这里

request.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;

我将其更改为

request.Headers.Add(HttpRequestHeader.AcceptEncoding,"gzip,deflate");

这对我来说很奇怪，因为我的项目.Net版本是4.7.1 但是现在它可以正常工作了。