using System;
using System.IO;
using System.Net;
using System.Text;

/// <summary>
/// 
/// </summary>
public static class HttpOAuth2
{
    /// <summary>
    /// 获取token
    /// </summary>
    /// <param name="url"></param>
    /// <param name="paras"></param>
    /// <returns></returns>
    public static string GetToken(string url, string[] paras)
    {
        try
        {
            string EndResult = "";
            string SendMessageAddress = url;
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(SendMessageAddress);
            request.Method = "POST";
            request.AllowAutoRedirect = true;
            request.ContentType = "application/x-www-form-urlencoded";
            
            string PostData = string.Format("grant_type={0}&client_id={1}&client_secret={2}", paras[0], paras[1], paras[2]);

            byte[] byteArray = Encoding.Default.GetBytes(PostData);
            request.ContentLength = byteArray.Length;
            using (Stream newStream = request.GetRequestStream())
            {
                newStream.Write(byteArray, 0, byteArray.Length);//写入参数
                newStream.Close();
            }

            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            Stream rspStream = response.GetResponseStream();
            using (StreamReader reader = new StreamReader(rspStream, Encoding.UTF8))
            {
                EndResult = reader.ReadToEnd();
                rspStream.Close();
            }
            response.Close();
            return EndResult;
        }
        catch (Exception ex)
        {
            return ex.Message;
        }
    }

    /// <summary>
    /// POST请求
    /// </summary>
    /// <param name="url"></param>
    /// <param name="data"></param>
    /// <param name="token"></param>
    /// <returns></returns>
    public static string Post(string url, string data, string token)
    {
        try
        {
            //将单引号转义成双引号
            data = data.Replace("'", "\"");
            //创建Web访问对象
            HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(url);

            // 接口慢，设置30分钟超时等待
            myRequest.Timeout = 1800000;

            //把用户传过来的数据转成“UTF-8”的字节流
            byte[] buf = System.Text.Encoding.GetEncoding("UTF-8").GetBytes(data);

            myRequest.Method = "POST";
            myRequest.ContentLength = buf.Length;
            myRequest.ContentType = "application/json;charset=UTF-8";
            //myRequest.MaximumAutomaticRedirections = 1;
            myRequest.AllowAutoRedirect = true;
            //string base64Header = Convert.ToBase64String(Encoding.UTF8.GetBytes(token));
            myRequest.Headers.Add("Authorization", "Bearer " + token);

            //发送请求
            Stream stream = myRequest.GetRequestStream();
            stream.Write(buf, 0, buf.Length);
            stream.Close();

            //获取接口返回值
            //通过Web访问对象获取响应内容
            HttpWebResponse myResponse = (HttpWebResponse)myRequest.GetResponse();
            //通过响应内容流创建StreamReader对象，因为StreamReader更高级更快
            StreamReader reader = new StreamReader(myResponse.GetResponseStream(), Encoding.UTF8);
            //string returnXml = HttpUtility.UrlDecode(reader.ReadToEnd());//如果有编码问题就用这个方法
            string returnXml = reader.ReadToEnd();//利用StreamReader就可以从响应内容从头读到尾
            reader.Close();
            myResponse.Close();
            return returnXml;
        }
        catch (Exception ex)
        {
            return ex.Message;
        }
    }
}