using System.Web;

/// <summary>

/// 公共帮助类

/// </summary>

public class Common {

    private HttpContext Context { get; set; }

    public static string OpenId = "Openid";

    public static string access_token = "access_token";

    #region 构造函数

    /// <summary>

    /// 构造函数

    /// </summary>

    /// <param name="Context"></param>

    public Common(HttpContext context)

    {

        this.Context = context;

    }

    #endregion

    #region 通过code换取AccessToken

    /// <summary>

    /// 通过code换取AccessToken

    /// </summary>

    public void GetOpenidAndAccessToken()

    {

        if (!string.IsNullOrEmpty(Context.Request.QueryString["code"]))

        {

            //获取code码，以获取openid和access_token

            string code = Context.Request.QueryString["code"];

            GetOpenidAndAccessTokenFromCode(code);

        }

        else

        {

            //构造网页授权获取code的URL

            string host = Context.Request.Url.Host;

            string path = Context.Request.Path;

            string redirect_uri = HttpUtility.UrlEncode("http://" + host + path);

            WxPayData data = new WxPayData();

            data.SetValue("appid",

WxPayConfig.APPID);

            data.SetValue("redirect_uri", redirect_uri);

            data.SetValue("response_type", "code");

            data.SetValue("scope", "snsapi_base");

            data.SetValue("state", "STATE" + "#wechat_redirect");

            string url = "https://open.weixin.qq.com/connect/oauth2/authorize?" + data.ToUrl();

            try

            {

                //触发微信返回code码

                Context.Response.Redirect(url);//Redirect函数会抛出ThreadAbortException异常，不用处理这个异常

            }

            catch (System.Threading.ThreadAbortException ex)

            {

            }

        }

    }

    #endregion

    #region 通过用户授权获取AccessToken和OpenId

    /// <summary>

    /// 通过用户授权获取AccessToken和OpenId

    /// </summary>

    /// <param name="code"></param>

    public void GetOpenidAndAccessTokenFromCode(string code)

    {

        try

        {

            //构造获取openid及access_token的url

            WxPayData data = new WxPayData();

            data.SetValue("appid",

WxPayConfig.APPID);

            data.SetValue("secret",

WxPayConfig.APPSECRET);

            data.SetValue("code",

code);

            data.SetValue("grant_type", "authorization_code");

            string url = "https://api.weixin.qq.com/sns/oauth2/access_token?" + data.ToUrl();

            //请求url以获取数据

            string result = HttpService.Get(url);

            //保存access_token，用于收货地址获取

            JsonData jd = JsonMapper.ToObject(result);

            access_token = (string)jd["access_token"];

            //获取用户openid

            OpenId = (string)jd["openid"];

        }

        catch (Exception ex)

        {

            throw new WxPayException(ex.ToString());

        }

    }

    #endregion

    #region 获取OpenId

    /// <summary>

    /// 获取OpenId

    /// </summary>

    /// <param name="postStr"></param>

    /// <returns></returns>

    public string GetOpenId()

    {

        Common common = new Common(Context);

        common.GetOpenidAndAccessToken();

        return OpenId;

    }

    #endregion

}