如何使用 HttpClient 发出 OPTIONS 请求答案

【问题标题】：how to make an OPTIONS request with HttpClient如何使用 HttpClient 发出 OPTIONS 请求
【发布时间】：2019-04-19 20:04:41
【问题描述】：

如何使用 System.Net.Http.HttpClient 发送 OPTIONS 请求

HttpClient 的公开方法

删除异步
GetAsync
后异步
PutAsync
其他人也很少.....

我期待一个 OptionsAsync

   switch (httpMethod) {
      case HTTP_METHODS.DELETE:
       {
        httpResponseMessage = httpClient.DeleteAsync(uri).Result;
        break;
       }
      case HTTP_METHODS.GET:
       {
        httpResponseMessage = httpClient.GetAsync(uri).Result;
        break;
       }
      case HTTP_METHODS.POST:
       {
        httpResponseMessage = httpClient.PostAsync(uri, httpContent).Result;
        break;
       }
      case HTTP_METHODS.PUT:
       {
        httpResponseMessage = httpClient.PutAsync(uri, httpContent).Result;
        break;
       }
      case HTTP_METHODS.OPTION:
       {
        //not sure what method to call on httpclient here to make Options request
        httpResponseMessage = httpClient.PutAsync(uri, httpContent).Result;
        if (httpResponseMessage.Headers.Contains("X-CSRF-TOKEN")) {
         IEnumerable < string > headerValues = httpResponseMessage.Headers.GetValues("X-CSRF-TOKEN");
         csrfToken = headerValues.FirstOrDefault();
        }
        break;
       } 
     }

【问题讨论】：

你看过这个吗：stackoverflow.com/questions/6660019/…

标签： c# http dotnet-httpclient

【解决方案1】：

这种方法没有包装器（例如OPTIONS 和HEAD），但您可以像这些包装器一样使用SendAsync：

var request = new HttpRequestMessage(HttpMethod.Options, "url");
var result = await _httpClient.SendAsync(request);

【讨论】：

【解决方案2】：

为了获得预期的响应，您必须确保在请求中设置“Origin”标头，如下所示：

using var client = new HttpClient();
var message = new HttpRequestMessage(HttpMethod.Options, "url");
message.Headers.Add("Origin", "http://example.com");
var response = await client.SendAsync(message);

【讨论】：