zongzhilinglan/GDZZ.Core/Captcha/General/GeneralCaptcha.cs

using Furion.DependencyInjection;
using Microsoft.Extensions.Caching.Memory;
using System;
using System.ComponentModel.DataAnnotations;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Text;

namespace GDZZ.Core;

/// <summary>
/// 常规验证码
/// </summary>
public class GeneralCaptcha : IGeneralCaptcha, ITransient 
{
    private readonly IMemoryCache _memoryCache;

    public GeneralCaptcha(IMemoryCache memoryCache)
    {
        _memoryCache = memoryCache;
    }

    /// <summary>
    /// 生成验证码图片
    /// </summary>
    /// <param name="length"></param>
    /// <returns></returns>
    public string CreateCaptchaImage(int length = 4)
    {
        return Convert.ToBase64String(Draw(length));
    }

    private string GenerateRandom(int length)
    {
        var chars = new StringBuilder();
        // 验证码的字符集，去掉了一些容易混淆的字符 
        char[] character = { '2', '3', '4', '5', '6', '8', '9', 'a', 'b', 'd', 'e', 'f', 'h', 'k', 'm', 'n', 'r', 'x', 'y', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'R', 'S', 'T', 'W', 'X', 'Y' };
        Random rnd = new Random();
        // 生成验证码字符串 
        for (int i = 0; i < length; i++)
        {
            chars.Append(character[rnd.Next(character.Length)]);
        }
        return chars.ToString();
    }

    private byte[] Draw(int length = 4)
    {
        int codeW = 110;
        int codeH = 36;
        int fontSize = 22;

        // 颜色列表，用于验证码、噪线、噪点 
        Color[] color = { Color.Black, Color.Red, Color.Blue, Color.Green, Color.Orange, Color.Brown, Color.Brown, Color.DarkBlue };
        // 字体列表，用于验证码 
        string[] fonts = new[] { "Times New Roman", "Verdana", "Arial", "Gungsuh", "Impact" };

        var code = GenerateRandom(length); // 随机字符串集合

        using (Bitmap bmp = new Bitmap(codeW, codeH))
        using (Graphics g = Graphics.FromImage(bmp))
        using (MemoryStream ms = new MemoryStream())
        {
            g.Clear(Color.White);
            Random rnd = new Random();
            // 画噪线 
            for (int i = 0; i < 1; i++)
            {
                int x1 = rnd.Next(codeW);
                int y1 = rnd.Next(codeH);
                int x2 = rnd.Next(codeW);
                int y2 = rnd.Next(codeH);
                var clr = color[rnd.Next(color.Length)];
                g.DrawLine(new Pen(clr), x1, y1, x2, y2);
            }

            // 画验证码字符串                 
            string fnt;
            Font ft;
            for (int i = 0; i < code.Length; i++)
            {
                fnt = fonts[rnd.Next(fonts.Length)];
                ft = new Font(fnt, fontSize);
                var clr = color[rnd.Next(color.Length)];
                g.DrawString(code[i].ToString(), ft, new SolidBrush(clr), (float)i * 24 + 2, (float)0);
            }

            // 缓存验证码正确集合
            var cacheOptions = new MemoryCacheEntryOptions().SetSlidingExpiration(TimeSpan.FromSeconds(30));
            _memoryCache.Set(CommonConst.CACHE_KEY_CODE + Guid.NewGuid().ToString("N"), code, cacheOptions);

            // 将验证码图片写入内存流
            bmp.Save(ms, ImageFormat.Png);
            return ms.ToArray();
        }
    }

    /// <summary>
    /// 验证码验证
    /// </summary>
    /// <param name="input"></param>
    /// <returns></returns>
    public dynamic CheckCode(GeneralCaptchaInput input)
    {
        var res = new ClickWordCaptchaResult();

        var code = _memoryCache.Get(CommonConst.CACHE_KEY_CODE + input.Token);
        if (code == null)
        {
            res.repCode = "6110";
            res.repMsg = "验证码已失效，请重新获取";
            return res;
        }
        if (input.CaptchaCode != (string)code)
        {
            res.repCode = "6112";
            res.repMsg = "验证码错误";
            return res;
        }

        _memoryCache.Remove(CommonConst.CACHE_KEY_CODE + input.Token);
        res.repCode = "0000";
        res.repMsg = "验证成功";
        return res;
    }
}