SendGrid RESTfulAPI-400BAD请求

Question

我正致力于与SendGrid的集成，并设法让所有的一切工作正常使用邮递员。但是，当从我的C#项目中发送请求时，我收到了一个400错误的请求错误消息，它的响应如下：

StatusCode: 400, ReasonPhrase: 'Bad Request', Version: 1.1, Content: System.Net.Http.StreamContent, Headers:
Connection: keep-alive
Access-Control-Allow-Origin: https://sendgrid.api-docs.io
Access-Control-Allow-Methods: POST
Access-Control-Allow-Headers: Authorization, Content-Type, On-behalf-of, x-sg-elas-acl
Access-Control-Max-Age: 600
X-No-CORS-Reason: https://sendgrid.com/docs/Classroom/Basics/API/cors.html
Strict-Transport-Security: max-age=600; includeSubDomains
Date: Wed, 15 Sep 2021 08:10:31 GMT
Server: nginx
Content-Length: 191
Content-Type: application/json

我已经检查了我的JSON字符串是否有效，并且模式与SendGrid的文档是一致的。

我不知道为什么我会收到一条关于CORS的错误消息，因为我没有使用浏览器或JavaScript。

有人有使用SendGrid API的Http请求的经验吗？

下面是我发送请求的C#代码。我已经尝试过PostAsJsonAsync和PostAsync，但是没有什么不同。我还尝试了与'UserAgent‘头和没有’主机‘头也有和不。

public static async Task<string> SendGridSendMailRequest(string json, string apiToken)
{
    string result = string.Empty;
    try
    {
        var content = new StringContent(json, Encoding.UTF8, "application/json");
                
        ProductHeaderValue header = new ProductHeaderValue("MyApp", System.Reflection.Assembly.GetExecutingAssembly().GetName().Version.ToString());
        ProductInfoHeaderValue user_agent = new ProductInfoHeaderValue(header);
        http_client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("*/*"));
        http_client.DefaultRequestHeaders.Host = "api.sendgrid.com";
        http_client.DefaultRequestHeaders.UserAgent.Add(user_agent);
        http_client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", apiToken);

        // HTTP POST
        //HttpResponseMessage response = await http_client.PostAsync("https://api.sendgrid.com/v3/mail/send", content);
        HttpResponseMessage response = await http_client.PostAsJsonAsync("https://api.sendgrid.com/v3/mail/send", content);

        // verification & response 
        if (response.IsSuccessStatusCode)
        {
           result = response.Content.ReadAsStringAsync().Result;
        }
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.ToString());
    }
    return result;
}

http_client是一个私有静态变量，如下所示：

private static HttpClient http_client = new HttpClient();

Answer 1

起初，我想这可能是一个问题，删除授权头，这可能发生在重定向，但问题原来是有关的TLS。当我使用.NET Framework4.5或更低版本时，我应该更早地想到这一点，因为在使用TLS版本之前，我已经被TLS版本问题刺痛了。

下面是现在工作正常的最后一个POST请求代码：

public static async Task<string> SendGridSendMailRequest(string json, string apiToken)
{
   string result = string.Empty;
   try
   {
      if (http_client == null)
      {
         var handler = new HttpClientHandler()
         {
            AllowAutoRedirect = false,
            SslProtocols = System.Security.Authentication.SslProtocols.Tls12 | System.Security.Authentication.SslProtocols.Tls11 | System.Security.Authentication.SslProtocols.Tls
         };
         http_client = new HttpClient(handler);
      }
      var content = new StringContent(json, Encoding.UTF8, "application/json");      
      http_client.BaseAddress = new Uri("https://api.sendgrid.com");
      http_client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("*/*"));
      http_client.DefaultRequestHeaders.Host = "api.sendgrid.com";
      http_client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", apiToken);
      HttpResponseMessage response = await http_client.PostAsync("/v3/mail/send", content);
      if (response.IsSuccessStatusCode)
      {
          result = response.Content.ReadAsStringAsync().Result;
      }
   }
   catch (Exception ex)
   {
      MessageBox.Show(ex.ToString());
   }
   return result;
}