如何从 c# 连接到 Apple News API？

Question

我正在尝试连接到 Apple 的新闻 API。生成签名时，每个不同示例的结果都相同。但是，我不断收到此错误： {"errors":[{"code":"WRONG_SIGNATURE"}]}这是我生成身份验证标头的 c# 代码。public class Security{  public static string AuthHeader(string method, string url, object content=null)  {    var apiKeyId = "<YOUR KEY HERE...>"; //we get this value from our settings file.    var apiKeySecret = "<YOUR SECRET HERE...>"; //we get this value from our settings file.    if ( string.IsNullOrEmpty(apiKeyId) || string.IsNullOrEmpty(apiKeySecret)) return string.Empty;    var encoding = new ASCIIEncoding();    var dt = DateTime.Now.ToString(Constants.DateFormat);    var canonicalRequest = string.Format("{0}{1}{2}", method, url, dt);    var key = Convert.FromBase64String(apiKeySecret);    var hmac = new HMACSHA256(key);    var hashed = hmac.ComputeHash(encoding.GetBytes(canonicalRequest));    var signature = Convert.ToBase64String(hashed);    var authorizaton = string.Format(@"HHMAC; key={0}; signature={1}; date={2}", apiKeyId, signature, dt);    return authorizaton;  }}常量类的简短版本public static class Constants{  public static readonly string ChannelId = "<YOUR CHANNEL ID HERE...>"; //again from our settings file  public static readonly string BaseUrl = "https://news-api.apple.com";  public static readonly string DateFormat = "yyyy-MM-ddTHH:mm:ssK";    }Actions 类的简短版本（SendCommand 是执行请求的方法）public class Actions{  public static string SendCommand(string action, string method)  {    var url = $"{Constants.BaseUrl}{action}";          var authheader = Security.AuthHeader(method, url, null);    var request = (HttpWebRequest)WebRequest.Create(url);    request.Method = method;    request.Timeout = 1000;    request.Headers.Add("Authorization", authheader);    request.Accept = "application/json";    request.ContentType = "application/json";    var output = string.Empty;我正在使用 ReadChannel 方法进行测试。我也尝试过 php 和 ruby 中的示例，但没有成功。任何想法如何正确地做到这一点？