构建API

前言

过程，如图：

第一步创建一个帮助类，类里面提供了加密、组装Url等方法，代码如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.IO;
using System.Net;
using System.Security.Cryptography;
using System.Text; 

namespace APIClient.Content
{
    public class WebHelper
    {

        #region 获得客户端时间+ public static int GetTimeZ(DateTime time)
        public static int GetTimeZ(DateTime time)
        {
            var startTime = TimeZone.CurrentTimeZone.ToLocalTime(new DateTime(1970, 1, 1));
            return (int)(time - startTime).TotalSeconds;
        }
        #endregion

        #region 加密key+private string CreateSign(Dictionary<string, string> paramList, string appKey)
        public static string CreateSign(Dictionary<string, string> paramList, string appKey)
        {
            var str = paramList.OrderBy(c => c.Key).Aggregate(string.Empty, (current, item) => current + item.Value);
            return MD5(str + appKey).ToLower();//调用MD5
        }
        #endregion

        #region 执行HTTP GET请求+ public static string DoGet(string url, IDictionary<string, string> parameters)
        public static string DoGet(string url, IDictionary<string, string> parameters)
        {
            if (parameters != null && parameters.Count > 0)
            {
                if (url.Contains("?"))
                {
                    url = url + "&" + BuildPostDate(parameters); //调用BuildPostDate
                }
                else
                {
                    url = url + "?" + BuildPostDate(parameters);
                }
            }

            HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
            req.Method = "GET";
            req.KeepAlive = true;
            req.UserAgent = "ADCSDK";
            req.ContentType = "application/x-www-form-urlencoded;charset=utf-8";
            HttpWebResponse rsp = (HttpWebResponse)req.GetResponse();
            Encoding encoding = Encoding.GetEncoding(rsp.CharacterSet);
            return GetResponseAsString(rsp, encoding); //调用GetResponseAsString
        }

        #endregion

        #region MD5加密+ public static string MD5(string input)
        /// <summary>
        /// MD5加密 （添加命名空间；using System.Security.Cryptography;）
        /// </summary>
        /// <param name="input">输入字符串</param>
        /// <returns>加密后的字符串</returns>
        public static string MD5(string input)
        {
            if (string.IsNullOrEmpty(input))
            {
                return string.Empty;
            }

            var md5 = new MD5CryptoServiceProvider();
            var inputBytes = Encoding.UTF8.GetBytes(input);
            var outPutbytes = md5.ComputeHash(inputBytes);
            return BitConverter.ToString(outPutbytes).Replace("-", "");
        }
        #endregion

        #region 组装普通文本请求参数+ private static string BuildPostDate(IDictionary<string, string> parameters)
        private static string BuildPostDate(IDictionary<string, string> parameters)
        {
            StringBuilder postDate = new StringBuilder();
            bool hasParam = false;
            IEnumerator<KeyValuePair<string, string>> dem = parameters.GetEnumerator();
            while (dem.MoveNext())
            {
                string name = dem.Current.Key;
                string value = dem.Current.Value;
                if (!string.IsNullOrEmpty(name) && !string.IsNullOrEmpty(value))
                {
                    if (hasParam)
                    {
                        postDate.Append("&");
                    }
                    postDate.Append(name);
                    postDate.Append("=");
                    postDate.Append(Uri.EscapeDataString(value));
                    hasParam = true;
                }
            }
            return postDate.ToString();
        }
        #endregion

        #region 把响应流转换为文本+ private static string GetResponseAsString(HttpWebResponse rsp, Encoding encoding)
        private static string GetResponseAsString(HttpWebResponse rsp, Encoding encoding)
        {
            StringBuilder result = new StringBuilder();
            Stream stream = null;
            StreamReader reader = null;

            try
            {
                stream = rsp.GetResponseStream();
                reader = new StreamReader(stream, encoding);
                var buffer = new char[256];
                int readBytes;
                while ((readBytes = reader.Read(buffer, 0, buffer.Length)) > 0)
                {
                    result.Append(buffer, 0, readBytes);
                }
            }
            finally
            {
                if (reader != null) reader.Close();
                if (stream != null) stream.Close();
                if (rsp != null) rsp.Close();
            }
            return result.ToString();
        }
        #endregion


    }
}

第二步服务器端创建一个API（参数协商定义），代码如下：

 public ActionResult Reg(int productId, string version, string source, string userName, string timeZ, string sign)
        {
            if (string.IsNullOrEmpty(version))
                return Content("productId");
            if (string.IsNullOrEmpty(version))
                return Content("version");
            if (string.IsNullOrEmpty(version))
                return Content("source");
            if (string.IsNullOrEmpty(version))
                return Content("userName");
            if (string.IsNullOrEmpty(version))
                return Content("timeZ");
            if (string.IsNullOrEmpty(version))
                return Content("sign1");

            var dict = new Dictionary<string, string>
                           {
                               {"productId", productId.ToString()},
                               {"version", version},
                               {"source", source},
                               {"userName", userName},
                               {"timeZ", timeZ},
                           };

            var checkSign =WebHelper.CreateSign(dict, "zz680000f7-6834");//sign 是数据库中一个key，这里是为了方便，应当是根据productId值从数据库中取出相应的key与程序传过来的key比较
                
            if (sign.ToLower() != checkSign.ToLower())
            {
                return Content("sign2");
            }
            //调用接口之后还应当在数据库中插入一条日志数据
            return Content("1");
        } 

第三步应用程序创建一个方法，请求API，代码如下：

 public ActionResult List()
        {
            RegTest();
            return View();
        }
        //参数
        private const string APIUrl = "http://localhost:4023/APISever/";
        private const int ProductId = 3;
        private const string AppKey = "zz680000f7-68341";//680000f7-6834-4b5f-8534-70cea7fd641b

        //注册接口
        public void RegTest()
        {
            var url = string.Format("{0}reg", APIUrl);
            var dict = new Dictionary<string, string>
                           {
                                {"productId", ProductId.ToString()},
                               {"version", "1.0.0.1"},
                               {"source", "lg"},
                               {"userName", "zlzl"},
                               {"timeZ",WebHelper.GetTimeZ(DateTime.Now).ToString()},//调用GetTimeZ
                           };

            dict["sign"] =WebHelper.CreateSign(dict, AppKey);//调用CreateSign

            var result = WebHelper.DoGet(url, dict);//调用DoGet
            Response.Write(string.Format("注册接口测试结果：{0}",result));
        }