.Net Core 跨平台实现验证码

1. 系统平台

• 服务器：Ubuntu 18.04
• 后端框架： .Net Core 2.1
• 前端： Vue

2. 项目引入ZKWeb.System.Drawing

ZXWeb.png

3. 验证码 相关环境安装

• Ubuntu 18.04

apt-get install libgdiplus
cd /usr/lib
ln -s libgdiplus.so gdiplus.dll

• Fedora 23

dnf install libgdiplus
cd /usr/lib64/
ln -s libgdiplus.so.0 gdiplus.dll

• CentOS 7

yum install autoconf automake libtool
yum install freetype-devel fontconfig libXft-devel
yum install libjpeg-turbo-devel libpng-devel giflib-devel libtiff-devel libexif-devel
yum install glib2-devel cairo-devel
git clone https://github.com/mono/libgdiplus
cd libgdiplus
./autogen.sh
make
make install
cd /usr/lib64/
ln -s /usr/local/lib/libgdiplus.so gdiplus.dll

4. 相关代码

• VierificationCodeServices.cs

using System;
using System.Collections.Generic;
using System.DrawingCore;
using System.DrawingCore.Imaging;
using System.IO;
using System.Linq;
using System.Threading.Tasks;

namespace WebApi.Common
{
    /// <summary>
    /// 验证码  add by cfl  2022-09-15
    /// </summary>
    public class VierificationCodeServices
    {
        /// <summary>
        /// 该方法用于生成指定位数的随机数
        /// </summary>
        /// <param name="VcodeNum">参数是随机数的位数</param>
        /// <returns>返回一个随机数字符串</returns>
        private static string RndNum(int VcodeNum)
        {
            //验证码可以显示的字符集合
            string Vchar = "0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,i,j,k,l,m,n,p" +
                ",q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,P,P,Q" +
                ",R,S,T,U,V,W,X,Y,Z";
            string[] VcArray = Vchar.Split(new Char[] { ',' });//拆分成数组
            string code = "";//产生的随机数
            int temp = -1;//记录上次随机数值，尽量避避免生产几个一样的随机数


            Random rand = new Random();
            //采用一个简单的算法以保证生成随机数的不同
            for (int i = 1; i < VcodeNum + 1; i++)
            {
                if (temp != -1)
                {
                    rand = new Random(i * temp * unchecked((int)DateTime.Now.Ticks));//初始化随机类
                }
                int t = rand.Next(61);//获取随机数
                if (temp != -1 && temp == t)
                {
                    return RndNum(VcodeNum);//如果获取的随机数重复，则递归调用
                }
                temp = t;//把本次产生的随机数记录起来
                code += VcArray[t];//随机数的位数加一
            }
            return code;
        }


        /// <summary>
        /// 该方法是将生成的随机数写入图像文件
        /// </summary>
        /// <param name="code">code是一个随机数</param>
        /// <param name="numbers">生成位数（默认4位）</param>
        public static MemoryStream Create(out string code, int numbers = 4)
        {
            code = RndNum(numbers);
            Bitmap Img = null;
            Graphics g = null;
            MemoryStream ms = null;
            Random random = new Random();
            //验证码颜色集合
            Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };


            //验证码字体集合
            string[] fonts = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体" };


            //定义图像的大小，生成图像的实例
            Img = new Bitmap((int)code.Length * 18, 32);


            g = Graphics.FromImage(Img);//从Img对象生成新的Graphics对象


            g.Clear(Color.White);//背景设为白色


            //在随机位置画背景点
            for (int i = 0; i < 100; i++)
            {
                int x = random.Next(Img.Width);
                int y = random.Next(Img.Height);
                g.DrawRectangle(new Pen(Color.LightGray, 0), x, y, 1, 1);
            }
            //验证码绘制在g中
            for (int i = 0; i < code.Length; i++)
            {
                int cindex = random.Next(7);//随机颜色索引值
                int findex = random.Next(5);//随机字体索引值
                Font f = new Font(fonts[findex], 15, FontStyle.Bold);//字体
                Brush b = new SolidBrush(c[cindex]);//颜色
                int ii = 4;
                if ((i + 1) % 2 == 0)//控制验证码不在同一高度
                {
                    ii = 2;
                }
                g.DrawString(code.Substring(i, 1), f, b, 3 + (i * 12), ii);//绘制一个验证字符
            }
            ms = new MemoryStream();//生成内存流对象
            Img.Save(ms, ImageFormat.Jpeg);//将此图像以Png图像文件的格式保存到流中


            //回收资源
            g.Dispose();
            Img.Dispose();
            return ms;
        }


    }
}

• 方法调用 (根据自己项目改写，核心代码就那么一段，其余都是自定义，我就不贴这么详细了)

[HttpGet]
        public ActionResult<ResponseData> GetCode()
        {
            ResponseData res = new ResponseData();
            ModelData dt = new ModelData();
            try
            {
                string code = "";
                MemoryStream ms = VierificationCodeServices.Create(out code);
               
                if (!string.IsNullOrEmpty(code))
                {
                    CodeModel codeModel = new CodeModel();
                    codeModel.Code = BizBase.Get<BizAutoCode>().NextCode("TbCode", "pkCode", 4);
                    codeModel.SCode = code.ToLower();
                    BizBase.Get<BizCode>().Add(codeModel);
                    dt.Info = codeModel.Code;
                    dt.DataList = File(ms.ToArray(), @"image/png"); ;
                }
                else
                {
                    dt.DataList = RedirectToAction("/Login/VCode?rand=" + Guid.NewGuid().ToString().Substring(1, 10), "image/jpeg");
                }
                res.ErrorCode = 0;
                res.Message = "操作成功";
                res.DataList = dt;

            }
            catch (Exception ex)
            {
                return this.ControllerExHandler(res, "GetCode", ex);
            }
            return res;
        }

5. 效果

验证码.png