• .Net Core Session验证码


    1、验证码帮助类

    namespace IdeaCore.Services.Common
    {
        public class ValidateCodeService : IValidateCodeService
        {
            private const string ValidateCodeKey = "ValidateCode";
            private const double Pi2 = 6.283185307179586476925286766559;
            private const string BackColor = "#dde3ec";
    
            /// <summary>
            /// 获取验证码的sessionkey
            /// </summary>
            /// <returns></returns>
            public string GetValidateCodeKey() {
                return ValidateCodeKey;
            }
    
            /// <summary>
            /// 生成验证码
            /// </summary>
            /// <param name="length"></param>
            /// <returns></returns>
            public string CreateValidateCode(int length)
            {
                string code = string.Empty;
    
                while (true)
                {
                    var s = (Guid.NewGuid() + "").Substring(0, 1);
                    if (s == "1" || s == "l" || s == "o" || s == "0")
                    {
    
                    }
                    else
                    {
                        code += s;
                    }
    
                    if (code.Length >= length)
                    {
                        break;
                    }
                }
                return code;
            }
    
            /// <summary>
            /// 创建验证码的图片
            /// </summary>
            /// <param name="validateCode">验证码</param>
            public byte[] CreateValidateGraphic(string validateCode)
            {
                const int fSize = 40;
                const int fWidth = fSize + 8;
    
                int imageWidth = validateCode.Length * fWidth + 4 + 8 * 2;
                const int imageHeight = fSize * 2 + 8;
    
                Color[] colors = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
                string[] fonts = { "Arial", "Georgia" };
    
                var image = new Bitmap(imageWidth, imageHeight);
                Graphics g = Graphics.FromImage(image);
                try
                {
                    g.Clear(ColorTranslator.FromHtml(BackColor));
                    var rand = new Random();
    
                    ////给背景添加随机生成的燥点
                    //Pen pen = new Pen(Color.RoyalBlue, 0);
                    //    int c = 6 * 20; //杂点数量
                    //    for (int i = 0; i < c; i++)
                    //    {
                    //        int x = rand.Next(image.Width);
                    //        int y = rand.Next(image.Height);
                    //        g.DrawRectangle(pen, x, y, 1, 1);
                    //    }
    
                    const int n1 = (imageHeight - 40 - 8 * 2);
                    const int n2 = n1 / 4;
                    const int top1 = n2;
                    const int top2 = n2 * 2;
    
                    //随机字体和颜色的验证码字符
                    for (int i = 0; i < validateCode.Length; i++)
                    {
                        int cindex = rand.Next(colors.Length - 1);
                        int findex = rand.Next(fonts.Length - 1);
    
                        var f = new Font(fonts[findex], fSize, FontStyle.Bold);
                        Brush b = new SolidBrush(colors[cindex]);
    
                        var top = i % 2 == 1 ? top2 : top1;
    
                        var left = i * fWidth;
                        if (i == 0) { left += 8; }
    
                        g.DrawString(validateCode.Substring(i, 1), f, b, left, top);
                    }
                    //
                    image = TwistImage(image, true, new Random().Next(3, 10), new Random().Next(0, 6));
    
                    var stream = new MemoryStream();
                    image.Save(stream, ImageFormat.Jpeg);
                    //输出图片流
                    return stream.ToArray();
                }
                finally
                {
                    g.Dispose();
                    image.Dispose();
                }
            }
    
    
    
            #region 产生波形滤镜效果
    
            /// <summary>
            /// 正弦曲线Wave扭曲图片(Edit By 51aspx.com)
            /// </summary>
            /// <param name="srcBmp">图片路径</param>
            /// <param name="bXDir">如果扭曲则选择为True</param>
            /// <param name="dMultValue"></param>
            /// <param name="dPhase">波形的起始相位,取值区间[0-2*PI)</param>
            /// <returns></returns>
            private static Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)
            {
                var destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);
    
                // 将位图背景填充为白色
                var graph = Graphics.FromImage(destBmp);
                graph.FillRectangle(new SolidBrush(ColorTranslator.FromHtml(BackColor)), 0, 0, destBmp.Width, destBmp.Height);
                graph.Dispose();
    
                double dBaseAxisLen = bXDir ? destBmp.Height : destBmp.Width;
    
                for (int i = 0; i < destBmp.Width; i++)
                {
                    for (int j = 0; j < destBmp.Height; j++)
                    {
                        var dx = bXDir ? (Pi2 * j) / dBaseAxisLen : (Pi2 * i) / dBaseAxisLen;
                        dx += dPhase;
                        var dy = Math.Cos(dx);
    
                        // 取得当前点的颜色
                        int nOldX = bXDir ? i + (int)(dy * dMultValue) : i;
                        int nOldY = bXDir ? j : j + (int)(dy * dMultValue);
    
                        var color = srcBmp.GetPixel(i, j);
                        if (nOldX >= 0 && nOldX < destBmp.Width
                         && nOldY >= 0 && nOldY < destBmp.Height)
                        {
                            destBmp.SetPixel(nOldX, nOldY, color);
                        }
                    }
                }
    
                return destBmp;
            }
            #endregion
        }
    }

    2、获取验证码

    /// <summary>
    /// 获取验证码
    /// </summary>
    /// <returns></returns>
    public FileContentResult GetValidateCode()
    {
        var code = _validateCodeService.CreateValidateCode(4);
        var bytes = _validateCodeService.CreateValidateGraphic(code);
        HttpContext.Session.SetString(_validateCodeService.GetValidateCodeKey(), code);
        return File(bytes, @"image/jpeg");
    }

    3、验证验证码

    /// <summary>
    /// 验证验证码
    /// </summary>
    /// <param name="code"></param>
    /// <returns></returns>
    protected bool ValidateCode(string code) {
        if (string.IsNullOrEmpty(code)) {
            return false;
        }
    
        var sessionCode = HttpContext.Session.GetString("ValidateCode");
        return sessionCode != null && sessionCode == code.Trim();
    }
  • 相关阅读:
    MySQL max_allowed_packet设置及问题
    centos 7 编译安装mysql 详细过程
    如何快速查看mysql数据文件存放路径?
    centos yum 库更新
    centos 7 ifconfig 命令找不到
    http协议
    前端那些事儿
    C++接口的定义与实现的详细过程
    List转为字符串
    spring cloud spring boot JPA 克隆对象修改属性后 无法正常的执行save方法进行保存或者更新
  • 原文地址:https://www.cnblogs.com/ideacore/p/6283218.html
Copyright © 2020-2023  润新知