c# post basic 接口

　　　　　　　　　 string url = "http://xxxxxxxxx";//地址，请反复检查地址的准确性

                string usernamePassword =  "username:password";

                byte[] bytes = Encoding.Default.GetBytes(usernamePassword);
                string str = Convert.ToBase64String(bytes);

                string ret = new RequestHelper().HttpBasicPost(url, unionid, str);

public class RequestHelper
    {

        /// <summary>
        /// 设置cookie
        /// </summary>
        private CookieContainer cookie;

        public CookieContainer Cookie
        {
            get { return cookie; }
            set { cookie = value; }
        }

        /// <summary>
        /// 是否允许重定向
        /// </summary>
        private bool allowAutoRedirect = true;
        /// <summary>
        /// 是否允许重定向(默认:true)
        /// </summary>
        public bool AllowAutoRedirect
        {
            get { return allowAutoRedirect; }
            set { allowAutoRedirect = value; }
        }

        /// <summary>
        /// contentType
        /// </summary>
        private string contentType = "application/x-www-form-urlencoded";
        /// <summary>
        /// 设置contentType(默认:application/x-www-form-urlencoded)
        /// </summary>
        public string ContentType
        {
            get { return contentType; }
            set { contentType = value; }
        }

        /// <summary>
        /// accept
        /// </summary>
        private string accept = "*/*";
        /// <summary>
        /// 设置accept(默认:*/*)
        /// </summary>
        public string Accept
        {
            get { return accept; }
            set { accept = value; }
        }

        /// <summary>
        /// 过期时间（默认：30000）
        /// </summary>
        private int timeOut = ;

        public int TimeOut
        {
            get { return timeOut; }
            set { timeOut = value; }
        }

        private string userAgent;
        /// <summary>
        ///
        /// </summary>
        public string UserAgent
        {
            get { return userAgent; }
            set { userAgent = value; }
        }
        private string acceptLanguage;
        /// <summary>
        /// 接受的语言
        /// </summary>
        public string AcceptLanguage
        {
            get { return acceptLanguage; }
            set { acceptLanguage = value; }
        }
        /// <summary>
        /// 处理POST请求
        /// </summary>
        /// <param name="url"></param>
        /// <param name="postdata"></param>
        /// <returns></returns>
        public string HttpPost(string url, string postdata)
        {
            var request = CreateWebRequest(url);
            request.Method = "POST";
            if (!string.IsNullOrWhiteSpace(postdata))
            {
                var bytesToPost = Encoding.UTF8.GetBytes(postdata);
                request.ContentLength = bytesToPost.Length;
                using (Stream requestStream = request.GetRequestStream())
                {
                    requestStream.Write(bytesToPost, , bytesToPost.Length);
                    requestStream.Close();
                }
            }
            using (var response = (HttpWebResponse)request.GetResponse())
            {
                using (var sr = new StreamReader(response.GetResponseStream()))
                {
                    var result = sr.ReadToEnd();
                    return result;
                }
            }
        }

        public string HttpBasicPost(string url, string postdata, string basic)
        {
            var request = CreateWebRequest(url);
            request.Method = "POST";
            request.Headers.Add("Authorization", "Basic " + basic);
            if (!string.IsNullOrWhiteSpace(postdata))
            {
                var bytesToPost = Encoding.UTF8.GetBytes(postdata);
                request.ContentLength = bytesToPost.Length;
                using (Stream requestStream = request.GetRequestStream())
                {
                    requestStream.Write(bytesToPost, , bytesToPost.Length);
                    requestStream.Close();
                }
            }
            using (var response = (HttpWebResponse)request.GetResponse())
            {
                using (var sr = new StreamReader(response.GetResponseStream()))
                {
                    var result = sr.ReadToEnd();
                    return result;
                }
            }
        }
        /// <summary>
        ///
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="url"></param>
        /// <param name="obj"></param>
        /// <returns></returns>
        public T HttpPost<T>(string url, object obj)
        {
            var resultStr = HttpPost(url, JsonConvert.SerializeObject(obj));
            return JsonConvert.DeserializeObject<T>(resultStr);
        }
        public T HttpPost<T>(string url, object obj, out string result, Func<string, string> serializeStrFunc = null)
        {
            var str = JsonConvert.SerializeObject(obj);
            if (serializeStrFunc != null)
            {
                str = serializeStrFunc(str);
            }
            result = HttpPost(url, str);
            return JsonConvert.DeserializeObject<T>(result);
        }
        /// <summary>
        /// post请求返回html
        /// </summary>
        /// <param name="url"></param>
        /// <param name="postDataStr"></param>
        /// <returns></returns>
        public string HttpPost(string url, Dictionary<string, string> postdata)
        {
            string postDataStr = null;
            if (postdata != null && postdata.Count > )
            {
                postDataStr = string.Join("&", postdata.Select(it => it.Key + "=" + it.Value));
            }
            return HttpPost(url, postDataStr);
        }
        /// <summary>
        /// get请求获取返回的html
        /// </summary>
        /// <param name="url">无参URL</param>
        /// <param name="querydata">参数</param>
        /// <returns></returns>
        public string HttpGet(string url, Dictionary<string, string> querydata)
        {
            if (querydata != null && querydata.Count > )
            {
                url += "?" + string.Join("&", querydata.Select(it => it.Key + "=" + it.Value));
            }
            return HttpGet(url);
        }
        /// <summary>
        /// get请求获取返回的html
        /// </summary>
        /// <param name="url"></param>
        /// <returns></returns>
        public string HttpGet(string url)
        {
            HttpWebRequest request = CreateWebRequest(url);
            request.Method = "GET";
            // response.Cookies = cookie.GetCookies(response.ResponseUri);
            using (var response = (HttpWebResponse)request.GetResponse())
            {
                using (var sr = new StreamReader(response.GetResponseStream(), Encoding.GetEncoding("utf-8")))
                {
                    var result = sr.ReadToEnd();
                    return result;
                }
            }
        }

        protected HttpWebRequest CreateWebRequest(string url)
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            //request.ContentType = "text/html;charset=UTF-8";
            request.ContentType = this.ContentType;
            if (cookie != null)
                request.CookieContainer = this.Cookie;
            if (string.IsNullOrEmpty(this.AcceptLanguage))
            {
                WebHeaderCollection myWebHeaderCollection = request.Headers;
                myWebHeaderCollection.Add("Accept-Language", this.AcceptLanguage);
            }
            request.Accept = this.Accept;
            request.UseDefaultCredentials = true;
            request.UserAgent = this.UserAgent;
            request.Timeout = this.TimeOut;
            request.AllowAutoRedirect = this.AllowAutoRedirect;
            this.SetCertificatePolicy();
            return request;
        }

        /// <summary>
        /// POST文件
        /// </summary>
        /// <param name="url"></param>
        /// <param name="file">文件路径</param>
        /// <param name="postdata"></param>
        /// <returns></returns>
        public string HttpUploadFile(string url, string file, Dictionary<string, string> postdata)
        {
            return HttpUploadFile(url, file, postdata, Encoding.UTF8);
        }
        /// <summary>
        /// POST文件
        /// </summary>
        /// <param name="url"></param>
        /// <param name="file">文件路径</param>
        /// <param name="postdata">参数</param>
        /// <param name="encoding"></param>
        /// <returns></returns>
        public string HttpUploadFile(string url, string file, Dictionary<string, string> postdata, Encoding encoding)
        {
            return HttpUploadFile(url, new string[] { file }, postdata, encoding);
        }
        /// <summary>
        /// POST文件
        /// </summary>
        /// <param name="url"></param>
        /// <param name="files">文件路径</param>
        /// <param name="postdata">参数</param>
        /// <returns></returns>
        public string HttpUploadFile(string url, string[] files, Dictionary<string, string> postdata)
        {
            return HttpUploadFile(url, files, postdata, Encoding.UTF8);
        }
        /// <summary>
        /// POST文件
        /// </summary>
        /// <param name="url"></param>
        /// <param name="files">文件路径</param>
        /// <param name="postdata">参数</param>
        /// <param name="encoding"></param>
        /// <returns></returns>
        public string HttpUploadFile(string url, string[] files, Dictionary<string, string> postdata, Encoding encoding)
        {
            string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");
            byte[] boundarybytes = Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");
            byte[] endbytes = Encoding.ASCII.GetBytes("\r\n--" + boundary + "--\r\n");

            HttpWebRequest request = CreateWebRequest(url);
            request.ContentType = "multipart/form-data; boundary=" + boundary;
            request.Method = "POST";
            request.KeepAlive = true; ;
            request.AllowAutoRedirect = this.AllowAutoRedirect;
            if (this.Cookie != null)
                request.CookieContainer = this.Cookie;
            request.Credentials = CredentialCache.DefaultCredentials;

            using (Stream stream = request.GetRequestStream())
            {
                //1.1 key/value
                string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";
                if (postdata != null)
                {
                    foreach (string key in postdata.Keys)
                    {
                        stream.Write(boundarybytes, , boundarybytes.Length);
                        string formitem = string.Format(formdataTemplate, key, postdata[key]);
                        byte[] formitembytes = encoding.GetBytes(formitem);
                        stream.Write(formitembytes, , formitembytes.Length);
                    }
                }

                //1.2 file
                string headerTemplate = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: application/octet-stream\r\n\r\n";
                byte[] buffer = new byte[];
                int bytesRead = ;
                for (int i = ; i < files.Length; i++)
                {
                    stream.Write(boundarybytes, , boundarybytes.Length);
                    string header = string.Format(headerTemplate, "file" + i, Path.GetFileName(files[i]));
                    byte[] headerbytes = encoding.GetBytes(header);
                    stream.Write(headerbytes, , headerbytes.Length);
                    using (FileStream fileStream = new FileStream(files[i], FileMode.Open, FileAccess.Read))
                    {
                        while ((bytesRead = fileStream.Read(buffer, , buffer.Length)) != )
                        {
                            stream.Write(buffer, , bytesRead);
                        }
                    }
                }

                //1.3 form end
                stream.Write(endbytes, , endbytes.Length);
            }
            //2.WebResponse
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            using (StreamReader stream = new StreamReader(response.GetResponseStream()))
            {
                return stream.ReadToEnd();
            }
        }

        /// <summary>
        /// 获得响应中的图像
        /// </summary>
        /// <param name="url"></param>
        /// <returns></returns>
        public Stream GetResponseImage(string url)
        {
            Stream stream = null;
            try
            {
                HttpWebRequest request = CreateWebRequest(url);
                request.KeepAlive = true;
                request.Method = "GET";
                HttpWebResponse res = (HttpWebResponse)request.GetResponse();
                stream = res.GetResponseStream();
                return stream;
            }
            catch
            {
                return null;
            }
        }
        /// <summary>
        /// 正则获取匹配的第一个值
        /// </summary>
        /// <param name="html"></param>
        /// <param name="pattern"></param>
        /// <returns></returns>
        private string GetStringByRegex(string html, string pattern)
        {
            Regex re = new Regex(pattern, RegexOptions.IgnoreCase);
            MatchCollection matchs = re.Matches(html);
            if (matchs.Count > )
            {
                return matchs[].Groups[].Value;
            }
            else
                return "";
        }
        /// <summary>
        /// 正则验证返回的response是否正确
        /// </summary>
        /// <param name="html">Html内容</param>
        /// <param name="pattern">正则表达式</param>
        /// <returns></returns>
        private bool VerifyResponseHtml(string html, string pattern)
        {
            Regex re = new Regex(pattern);
            return re.IsMatch(html);
        }
        //注册证书验证回调事件，在请求之前注册
        private void SetCertificatePolicy()
        {
            ServicePointManager.ServerCertificateValidationCallback
                       += RemoteCertificateValidate;
        }
        /// <summary> 
        /// 远程证书验证，固定返回true
        /// </summary> 
        private static bool RemoteCertificateValidate(object sender, X509Certificate cert,
            X509Chain chain, SslPolicyErrors error)
        {
            return true;
        }

        #region 提交方式
        /// <summary>
        /// 提交Https
        /// Post
        /// </summary>
        /// <param name="url">URL地址</param>
        /// <param name="parsStr">参数</param>
        public static string  SubmitHttpsPost(string url, string parsStr)
        {
            Encoding encode = System.Text.Encoding.UTF8;
            byte[] arrB = encode.GetBytes(parsStr);
            HttpWebRequest myReq = (HttpWebRequest)WebRequest.Create(url);
            myReq.Method = "POST";
            myReq.ContentType = "application/x-www-form-urlencoded";
            myReq.ContentLength = arrB.Length;
            Stream outStream = myReq.GetRequestStream();
            outStream.Write(arrB, , arrB.Length);
            outStream.Close();

            //接收HTTP做出的响应
            WebResponse myResp = myReq.GetResponse();
            Stream ReceiveStream = myResp.GetResponseStream();
            StreamReader readStream = new StreamReader(ReceiveStream, encode);
            Char[] read = new Char[];
            int count = readStream.Read(read, , );
            string str = null;
            while (count > )
            {
                str += new String(read, , count);
                count = readStream.Read(read, , );
            }
            readStream.Close();
            myResp.Close();

            if (!string.IsNullOrEmpty(str))
            {
                return str;
            }
            else
            {
                return "无返回值";
            }
        }

        #endregion
    }

basic请求的两点：

1、将用户名和密码进行编码

2、设置请求头request.Headers.Add("Authorization", "Basic " + basic);

post请求注意点：

要设置request.ContentLength，以及将表单内容写入请求中，不然会出现411长度错误

如果都尝试了还是404，请再次检查地址的准确性，在上面坑了一天！！！！！！！！！