阿里云API 签名机制（C#）

今天想弄个服务器监控的API，发现阿里云上面本来就提供api接口。

https://help.aliyun.com/document_detail/27208.html?spm=a2c4g.11186623.6.673.P6XLr2

https://error-center.aliyun.com/status/product/Cdn?spm=a2c69.11428812.0.0.47435e6a25YlIH

但是没有C#版的示例，很蛋疼，那就自己写呗，显示照着Java的示例改成C#的，发现那个签名好像还是计算错误了。

百度也没搜到有用的文章，最后Google.com搜索到了一个例子，完美解决了！

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;
using System.Web;

namespace DomainRequest
{
    public class RequestHelper
    {
        /// <summary>
        /// 返回值的类型，支持JSON与XML。默认为XML
        /// </summary>
        public string Format { get; set; } = "JSON";

        /// <summary>
        /// API版本号，为日期形式：YYYY-MM-DD，本版本对应为2016-05-11
        /// </summary>
        public string Version { get; } = "2014-11-11";

        /// <summary>
        /// 阿里云颁发给用户的访问服务所用的密钥ID
        /// </summary>
        public string AccessKeyId { get; set; } = "****************";

        /// <summary>
        /// 签名结果串
        /// </summary>
        public string Signature { get; set; }

        /// <summary>
        /// 签名方式，目前支持HMAC-SHA1
        /// </summary>
        public string SignatureMethod { get; } = "HMAC-SHA1";

        /// <summary>
        /// 请求的时间戳。日期格式按照ISO8601标准表示，并需要使用UTC时间。格式为YYYY-MM-DDThh:mm:ssZ例如，2015-01-09T12:00:00Z（为UTC时间2015年1月9日12点0分0秒）
        /// </summary>
        public string Timestamp { get; set; } = DateTime.UtcNow.ToString("yyyy-MM-ddTHH:mm:ssZ");

        /// <summary>
        /// 签名算法版本，目前版本是1.0
        /// </summary>
        public string SignatureVersion { get; } = "1.0";

        /// <summary>
        /// 唯一随机数，用于防止网络重放攻击。用户在不同请求间要使用不同的随机数值
        /// </summary>
        public string SignatureNonce { get; } = Guid.NewGuid().ToString();

        /// <summary>
        ///
        /// </summary>
        private readonly HttpMethod _httpMethod;

        /// <summary>
        /// 阿里云颁发给用户的访问服务所用的密钥
        /// </summary>
        private string AccessKeySecret { get; set; } = "******************";

        /// <summary>
        ///
        /// </summary>
        private readonly Dictionary<string, string> _parameters;

        public RequestHelper(HttpMethod httpMethod, Dictionary<string, string> parameters)
        {
            _httpMethod = httpMethod;
            _parameters = parameters;
        }

        private void BuildParameters()
        {
            _parameters.Add(nameof(Format), Format.ToUpper());
            _parameters.Add(nameof(Version), Version);
            _parameters.Add(nameof(AccessKeyId), AccessKeyId);
            _parameters.Add(nameof(SignatureVersion), SignatureVersion);
            _parameters.Add(nameof(SignatureMethod), SignatureMethod);
            _parameters.Add(nameof(SignatureNonce), SignatureNonce);
            _parameters.Add(nameof(Timestamp), Timestamp);
        }

        public void ComputeSignature()
        {
            BuildParameters();
            var canonicalizedQueryString = string.Join("&",
                _parameters.OrderBy(x => x.Key)
                .Select(x => PercentEncode(x.Key) + "=" + PercentEncode(x.Value)));

            var stringToSign = _httpMethod.ToString().ToUpper() + "&%2F&" + PercentEncode(canonicalizedQueryString);

            var keyBytes = Encoding.UTF8.GetBytes(AccessKeySecret + "&");
            var hmac = new HMACSHA1(keyBytes);
            var hashBytes = hmac.ComputeHash(Encoding.UTF8.GetBytes(stringToSign));
            Signature = Convert.ToBase64String(hashBytes);
            _parameters.Add(nameof(Signature), Signature);
        }

        private string PercentEncode(string value)
        {
            return UpperCaseUrlEncode(value)
                .Replace("+", "%20")
                .Replace("*", "%2A")
                .Replace("%7E", "~");
        }

        private static string UpperCaseUrlEncode(string s)
        {
            char[] temp = HttpUtility.UrlEncode(s).ToCharArray();
            for (int i = 0; i < temp.Length - 2; i++)
            {
                if (temp[i] == '%')
                {
                    temp[i + 1] = char.ToUpper(temp[i + 1]);
                    temp[i + 2] = char.ToUpper(temp[i + 2]);
                }
            }
            return new string(temp);
        }

        public string GetUrl(string url)
        {
            ComputeSignature();
            return "http://"+ url + "/?" +
                string.Join("&", _parameters.Select(x => x.Key + "=" + HttpUtility.UrlEncode(x.Value)));
        }
    }
}

调用方法：

        private static async void CheckDomain(string domain= "cdn.aliyuncs.com")
        {
            var parameters = new Dictionary<string, string>()
                {
                    {"Action", "DescribeDomainSrcFlowData"},
                };
            var request = new RequestHelper(HttpMethod.Get, parameters);
            var url = request.GetUrl(domain);
            string result;
            using (var httpClient = new HttpClient())
            {
                var response = await httpClient.GetAsync(url);
                // response.EnsureSuccessStatusCode();
                result = await response.Content.ReadAsStringAsync();
                //剩下的该干嘛干嘛
            }
        }

结果：