HttpRequestMessage 不会将 Cookie 添加到请求中

Question

我从控制台应用程序通过 HttpClient 发出一个简单的 POST 请求

HttpRequestMessage requestMessage = new HttpRequestMessage { Method = method };
requestMessage.Headers.Add("custom1", "c1");
requestMessage.Headers.Add("custom2", "c2");
requestMessage.Headers.Add("Cookie", "c3");
HttpClient client = new HttpClient();
using (var response = await client.SendAsync(requestMessage, cancellationToken))
using (var responseStream = await response.Content.ReadAsStreamAsync())
{
    //...
}

当我在 Fiddler 中看到请求标头时，我只看到前两个标头 - custom1 和 custom2，没有“Cookie”标头。

我使用 VS2017 和 .NET 4.7

Answer 1

您不应仅通过添加标头来添加 cookie，因为 CookieContainer 和 HttpCookie 会为您处理一些事情，例如过期、路径、域以及为 cookie 设置名称和值的正确方法。

更好的方法是使用CookieContainer。

var baseAddress = new Uri('http://localhost');

HttpRequestMessage requestMessage = new HttpRequestMessage { Method = method };
requestMessage.Headers.Add("custom1", "c1");
requestMessage.Headers.Add("custom2", "c2");
// requestMessage.Headers.Add("Cookie", "c3"); wrong way to do it

var cookieContainer = new CookieContainer();
using (var handler = new HttpClientHandler() { CookieContainer = cookieContainer })
{
   using(HttpClient client = new HttpClient(handler) { BaseAddress = baseAddress })
   {
       cookieContainer.Add(baseAddress, new Cookie("CookieName", "cookie_value"));
       using (var response = await client.SendAsync(requestMessage, cancellationToken))
       using (var responseStream = await response.Content.ReadAsStreamAsync())
       {
              // do your stuff
       }
   }
}

题外话推荐：

不要每次都创建一个新的 HttpClient 实例。这将导致所有套接字都忙。请遵循更好的方法，例如单例或HttpClientFactory。