public class HttpHelper
    {
        /// <summary>
        /// post请求
        /// </summary>
        /// <param name="url">请求地址</param>
        /// <param name="body">参数</param>
        /// <param name="headers">请求头部信息</param>
        /// <param name="callback">回调函数</param>
        /// <param name="decompress"></param>
        /// <returns></returns>
        public static async Task<string> Post(string url, object bodyObj, Dictionary<string, string> headers = null, DecompressionMethods decompress = DecompressionMethods.GZip)
        {
            var header = GetObj(headers);
            var body = JsonConvert.SerializeObject(bodyObj);
            HttpRequestMessage reqestObj = new HttpRequestMessage(HttpMethod.Post, url)
            {
                Content = new StringContent(body, Encoding.UTF8, header.ContentType)
            };
            SetHead(reqestObj.Headers, headers);

            var handler = new HttpClientHandler() { UseCookies = false, AutomaticDecompression = decompress };
            HttpClient client = new HttpClient(handler);

            //// 请求头填充数据
            EditDefaultRequestHeaders(client, header);
            var res = await client.SendAsync(reqestObj);
            var responseBody = await res.Content.ReadAsStringAsync();
            return responseBody;
        }

        /// <summary>
        /// post请求
        /// </summary>
        /// <param name="url">请求地址</param>
        /// <param name="body">参数</param>
        /// <param name="headers">请求头部信息</param>
        /// <param name="callback">回调函数</param>
        /// <param name="decompress"></param>
        /// <returns></returns>
        public static async Task<T> Post<T>(string url, object bodyObj, Dictionary<string, string> headers = null, DecompressionMethods decompress = DecompressionMethods.GZip)
        {
            var header = GetObj(headers);
            var body = JsonConvert.SerializeObject(bodyObj);
            HttpRequestMessage reqestObj = new HttpRequestMessage(HttpMethod.Post, url)
            {
                Content = new StringContent(body, Encoding.UTF8, header.ContentType)
            };
            SetHead(reqestObj.Headers, headers);

            var handler = new HttpClientHandler() { UseCookies = false, AutomaticDecompression = decompress };
            HttpClient client = new HttpClient(handler);

            //// 请求头填充数据
            EditDefaultRequestHeaders(client, header);
            var res = await client.SendAsync(reqestObj);
            var responseBody = await res.Content.ReadAsStringAsync();

            return JsonConvert.DeserializeObject<T>(responseBody); ;
        }


        /// <summary>
        /// get请求
        /// </summary>
        /// <param name="url">请求地址</param>
        /// <param name="headers">请求头部信息</param>
        /// <param name="decompress"></param>
        /// <returns></returns>
        public static async Task<string> Get(string url, Dictionary<string, string> headers = null, DecompressionMethods decompress = DecompressionMethods.GZip)
        {
            try
            {
                var header = GetObj(headers);
                var handler = new HttpClientHandler() { UseCookies = false, AutomaticDecompression = decompress };
                HttpRequestMessage req = new HttpRequestMessage(HttpMethod.Get, url);
                SetHead(req.Headers, headers);
                HttpClient client = new HttpClient(handler);
                client.DefaultRequestHeaders.Add("User-Agent", header.UserAgent);
                var res = await client.SendAsync(req);
                var str = await res.Content.ReadAsStringAsync();
                return str;

            }
            catch (Exception ex)
            {
                return ex.Message;

            }
        }

        #region 私有方法

        /// <summary>
        /// 如果存在要修改常用的请求头信息
        /// </summary>
        /// <param name="client">请求对象</param>
        /// <param name="headerObj"></param>
        private static void EditDefaultRequestHeaders(HttpClient client, HeaderObj headerObj)
        {
            if (headerObj.UserAgent.IsNotEmpty())
            {
                client.DefaultRequestHeaders.Add("User-Agent", headerObj.UserAgent);
            }
            if (headerObj.Referer.IsNotEmpty())
            {
                client.DefaultRequestHeaders.Add("Referer", headerObj.Referer);
            }
            if (headerObj.Origin.IsNotEmpty())
            {
                client.DefaultRequestHeaders.Add("Origin", headerObj.Origin);
            }
            if (headerObj.AcceptLanguage.IsNotEmpty())
            {
                client.DefaultRequestHeaders.Add("AcceptLanguage", headerObj.AcceptLanguage);
            }
            if (headerObj.Connection.IsNotEmpty())
            {
                client.DefaultRequestHeaders.Add("Connection", headerObj.Connection);
            }
            if (headerObj.Accept.IsNotEmpty())
            {
                client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue(headerObj.Accept));
            }
        }

        /// <summary>
        /// 请求头添加自定义参数
        /// </summary>
        /// <param name="headers">请求头</param>
        /// <param name="dics">请求头参数</param>
        private static void SetHead(HttpRequestHeaders headers, Dictionary<string, string> dics)
        {
            if (dics != null)
            {
                foreach (KeyValuePair<string, string> item in dics)
                {
                    if (item.Key == "Content-Type") continue;
                    if (item.Key == "Referer") continue;
                    if (item.Key == "Content-Length") continue;
                    if (item.Key == "Accept") continue;
                    if (item.Key == "Connection") continue;
                    if (item.Key == "Host") continue;

                    headers.Add(item.Key, item.Value);
                }
            }

        }
        public static Dictionary<string, string> GetHeader(string Header)
        {
            var dics = new Dictionary<string, string>();

            var headerStr = Header;
            var lines = headerStr.Split(new string[] { "\n" }, StringSplitOptions.RemoveEmptyEntries);
            foreach (var line in lines)
            {
                if (string.IsNullOrWhiteSpace(line)) continue;

                var index = line.IndexOf(":");
                if (index < 0) continue;

                var key = line.Substring(0, index);

                var val = line.Substring(index + 1, line.Length - index - 1);
                dics[key] = val.Trim().TrimEnd(';');
            }
            return dics;
        }

        /// <summary>
        /// 赋值请求头对象
        /// </summary>
        /// <param name="headers"></param>
        /// <returns></returns>
        private static HeaderObj GetObj(Dictionary<string, string> headers)
        {
            HeaderObj obj = new HeaderObj();
            if (headers != null)
            {
                if (headers.ContainsKey("Content-Type"))
                {
                    obj.ContentType = headers["Content-Type"];
                }
                if (headers.ContainsKey("Referer"))
                {
                    obj.Referer = headers["Referer"];
                }
                if (headers.ContainsKey("Connection"))
                {
                    obj.Connection = headers["Connection"];
                }
                if (headers.ContainsKey("Accept"))
                {
                    obj.Accept = headers["Accept"];
                }
                if (headers.ContainsKey("User-Agent"))
                {
                    obj.UserAgent = headers["User-Agent"];
                }
                if (headers.ContainsKey("Origin"))
                {
                    obj.Origin = headers["Origin"];
                }
                if (headers.ContainsKey("Accept-Language"))
                {
                    obj.AcceptLanguage = headers["Accept-Language"];
                }
            }

            return obj;
        }

        #endregion

    }

    class HeaderObj
    {
        public string ContentType { get; set; } = "application/json";
        public string UserAgent { get; set; }
        public string Referer { get; set; }
        public string Connection { get; set; }
        public string Origin { get; set; }
        public string AcceptLanguage { get; set; }
        public string Accept { get; set; }
    }