微信小程序获取Access_token和页面URL生成小程序码或二维码

1、微信小程序获取Access_token：

access_token具体时效看官方文档。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Web;
using TT.Utilities;

namespace DjwzApi.Com
{
    public class WeChatApi
    {
        public static string AppID = TT.Utilities.Config.ConfigureAppConfig.GetAppSettingsKeyValue("AppID");
        public static string AppSecret = TT.Utilities.Config.ConfigureAppConfig.GetAppSettingsKeyValue("AppSecret");

        private static string Access_token = "";
        private static DateTime Expires_in_time = DateTime.Now;

        static object lockObj = new object();
        /// <summary>
        /// 获取Access_token
        /// </summary>
        /// <param name="AppID"></param>
        /// <param name="AppSecret"></param>
        /// <returns></returns>
        public static string GetAccess_token(string AppID = null, string AppSecret = null)
        {
            lock (lockObj)
            {
                if (string.IsNullOrEmpty(Access_token) || ((DateTime.Now - Expires_in_time).TotalSeconds >= -30))
                {
                    lock (lockObj)
                    {
                        Access_token = "";
                        Expires_in_time = DateTime.Now;
                        AppID = AppID ?? WeChatApi.AppID;
                        AppSecret = AppSecret ?? WeChatApi.AppSecret;

                        string url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid={0}&secret={1}";
                        url = string.Format(url, AppID, AppSecret);

                        var json = "";
                        try
                        {
                            json = TT.Utilities.Web.HttpClientUti.DoGet(url);
                        }
                        catch (Exception ex)
                        {
                            System.Threading.Tasks.Task.Factory.StartNew(() => utils.LogHelper.WriteLog(ex.Message));
                            throw new Exception("获取微信端access_token失败," + ex.Message);
                        }

                        //{"access_token":"12_TrAgGuiF64W8XPRXyFRFUK7SjzZptoa3ogS4mGKp-W-ni6dG_OoMNMbm_7q9lhYcx85xh-SNe3BUC_6Lg1H6FDMU7fUsKoG4NwN5EA-NVOCVUZg0OIdTvOmgHMgCxJQ1vWP__VvId4AJ2Bm_QYPdABAFNE","expires_in":7200}
                        dynamic obj = new { access_token = "", expires_in = 0, errcode = 0, errmsg = "" };
                        obj = TT.Utilities.Json.JsonHelper.DeserializeAnonymousType(json, obj);
                        if (obj.errcode == 0)
                        {
                            Expires_in_time = DateTime.Now.AddSeconds(obj.expires_in);
                            Access_token = obj.access_token;
                        }
                        return Access_token;
                    }
                }
                else
                {
                    return Access_token;
                }
            }
        }
    }
}

2、获取二维码

 这里实现了官网文档中提到的 接口A和接口C

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

namespace DjwzApi.Com
{
    public class WxQrcode
    {
        private const string line_color = "{"r":"0","g":"0","b":"0"}";
        /// <summary>
        /// 接口A: 生成小程序码， 适用于需要的码数量较少的业务场景 
        /// </summary>
        /// <returns></returns>
        public static string QrcodeA(string path, int width = 430, bool auto_color = false, string line_color = line_color, bool is_hyaline = false)
        {
            string url = "https://api.weixin.qq.com/wxa/getwxacode?access_token={0}";
            var ACCESS_TOKEN = WeChatApi.GetAccess_token();
            url = string.Format(url, ACCESS_TOKEN);
            var arg = new Dictionary<string, string> { 
              {"path",path},
              {"width",width.ToString()},
              //{"auto_color","false"},
              //{"line_color",line_color},
              //{"is_hyaline",is_hyaline.ToString()},
            };
            var response = TT.Utilities.Web.HttpRequest.DoPost_WebResponse(url, arg, null, 90, TT.Utilities.Web.HttpContentTypes.HttpContentTypeEnum.JSON);

            return SaveImg(response);
        }

        /// <summary>
        /// 接口C: 生成二维码， 适用于需要的码数量较少的业务场景  
        /// </summary>
        /// <returns></returns>
        public static string QrcodeC(string path, int width = 430)
        {
            string url = "https://api.weixin.qq.com/cgi-bin/wxaapp/createwxaqrcode?access_token={0}";
            var ACCESS_TOKEN = WeChatApi.GetAccess_token();
            url = string.Format(url, ACCESS_TOKEN);
            var arg = new Dictionary<string, string> { 
              {"path",path},
              {"width",width.ToString()}
            };
            var response = TT.Utilities.Web.HttpRequest.DoPost_WebResponse(url, arg, null, 90, TT.Utilities.Web.HttpContentTypes.HttpContentTypeEnum.JSON);

            return SaveImg(response);
        }


        static string SaveImg(HttpWebResponse response)
        {
            if (response.ContentType.ToLower() == "image/jpeg")
            {
                var re = TT.Utilities.Web.HttpResponse.HttpResponseStream(response);
                var bytes = TT.Utilities.StreamUti.ConveertHelper.StreamToBytes(re);
                string imgName = "ewm" + DateTime.Now.ToString("yyyyMMddhhmmss") + ".jpg";
                //文件存储相对于当前应用目录的虚拟目录
                string basePath = "/image/";
                //获取相对于应用的基目录,创建目录
                string imgPath = System.AppDomain.CurrentDomain.BaseDirectory + basePath;     //通过此对象获取文件名
                //StringHelper.CreateDirectory(imgPath);
                System.IO.File.WriteAllBytes(HttpContext.Current.Server.MapPath(basePath + imgName), bytes);//讲byte[]存储为图片
                return "/image/" + imgName;
            }
            else
            {
                //{"errcode":47001,"errmsg":"data format error hint: [Mz435a00280720]"}
                return TT.Utilities.Web.HttpResponse.HttpResponseString(response);
            }
        }
    }
}

网络请求相关：

       public static HttpWebRequest CreateHttpWebRequest(string url, int timeoutSecond = 90)
        {
            HttpWebRequest request;
            //如果是发送HTTPS请求  
            if (url.StartsWith("https", StringComparison.OrdinalIgnoreCase))
            {
                //ServicePointManager.DefaultConnectionLimit = 1000;
                ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);
                request = WebRequest.Create(url) as HttpWebRequest;
            }
            else
            {
                request = WebRequest.Create(url) as HttpWebRequest;
            }
            request.Proxy = null;
            request.ProtocolVersion = HttpVersion.Version11;
            ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls;
            request.Headers.Add(HttpRequestHeader.AcceptEncoding, "gzip,deflate");
            request.Accept = "*/*";
            request.KeepAlive = false;
            request.Timeout = timeoutSecond * 1000;
            return request;
        }

        /// <summary>
        /// 获取到HttpWebResponse对象
        /// </summary>
        /// <param name="url">url</param>
        /// <param name="dic">参数</param>
        /// <param name="headerDic">请求头参数</param>
        /// <returns></returns>
        public static HttpWebResponse DoPost_WebResponse(string url, Dictionary<string, string> dic = null, Dictionary<string, string> headerDic = null, int timeoutSecond = 90
            , HttpContentTypes.HttpContentTypeEnum contentType = HttpContentTypes.HttpContentTypeEnum.JSON)
        {
            HttpWebRequest request = CreateHttpWebRequest(url, timeoutSecond);
            request.Method = "POST";
            request.ContentType = HttpContentTypes.GetContentType(contentType);

            if (headerDic != null && headerDic.Count > 0)
            {
                foreach (var item in headerDic)
                {
                    request.Headers.Add(item.Key, item.Value);
                }
            }
            if (dic != null && dic.Count > 0)
            {
                var jsonStr = Newtonsoft.Json.JsonConvert.SerializeObject(dic);
                byte[] buffer = Encoding.UTF8.GetBytes(jsonStr);
                request.ContentLength = buffer.Length;
                try
                {
                    request.GetRequestStream().Write(buffer, 0, buffer.Length);
                }
                catch (WebException ex)
                {
                    throw ex;
                }
            }
            else
            {
                request.ContentLength = 0;
            }
            return (HttpWebResponse)request.GetResponse();
        }

  public static Stream HttpResponseStream(HttpWebResponse response)
        {
            try
            {
                return response.GetResponseStream();
            }
            catch (Exception ex)
            {
                throw new Exception("获取HttpWebResponse.GetResponseStream异常,"+ex);
            }
        }

工具类：

  public class ConveertHelper
    {
        /// <summary>
        /// Stream 转 byte[]
        /// </summary>
        /// <param name="stream"></param>
        /// <returns></returns>
        public static byte[] StreamToBytes(Stream stream)
        {
            List<byte> bytes = new List<byte>();
            int temp = stream.ReadByte();
            while (temp != -1)
            {
                bytes.Add((byte)temp);
                temp = stream.ReadByte();
            }
            return bytes.ToArray();
        }
    }

吐槽一下：官方文档对这个接口的说明不够完善，很多需要注意点没有明确，群里也有小伙伴遇到各种问题，如：返回格式没说明，错误原因不明确。

图片样式：

接口C生成的二维码：                                                                  接口A生成的小程序码：