99ditui/src/platform/ZhonTai.Admin/Tools/Captcha/SlideJigsawCaptchaTool.cs

using Newtonsoft.Json;
using System;
using System.IO;
using System.Threading.Tasks;
using System.Collections.Generic;
using SixLabors.ImageSharp;
using SixLabors.ImageSharp.Drawing.Processing;
using SixLabors.ImageSharp.Processing;
using SixLabors.ImageSharp.Formats.Png;
using SixLabors.ImageSharp.Drawing;
using SixLabors.ImageSharp.PixelFormats;
using ZhonTai.Admin.Core.Attributes;
using ZhonTai.Admin.Tools.Cache;

namespace ZhonTai.Admin.Tools.Captcha;

/// <summary>
/// 滑块拼图验证
/// </summary>
[SingleInstance]
public class SlideJigsawCaptchaTool : ICaptchaTool
{
    private readonly ICacheTool _cache;

    private readonly Random _random = new();

    public SlideJigsawCaptchaTool(ICacheTool cache)
    {
        _cache = cache;
    }

    /// <summary>
    /// 随机范围内数字
    /// </summary>
    /// <param name="startNum"></param>
    /// <param name="endNum"></param>
    /// <returns></returns>
    private int GetRandomInt(int startNum, int endNum)
    {
        return (endNum > startNum ? _random.Next(endNum - startNum) : 0) + startNum;
    }

    /// <summary>
    /// 随机生成拼图坐标
    /// </summary>
    /// <param name="originalWidth"></param>
    /// <param name="originalHeight"></param>
    /// <param name="templateWidth"></param>
    /// <param name="templateHeight"></param>
    /// <returns></returns>
    private PointModel GeneratePoint(int originalWidth, int originalHeight, int templateWidth, int templateHeight)
    {
        int widthDifference = originalWidth - templateWidth;
        int heightDifference = originalHeight - templateHeight;
        int x;
        if (widthDifference <= 0)
        {
            x = 5;
        }
        else
        {
            x = _random.Next(originalWidth - templateWidth - 100) + 100;
        }

        int y;
        if (heightDifference <= 0)
        {
            y = 5;
        }
        else
        {
            y = _random.Next(originalHeight - templateHeight - 5) + 5;
        }

        return new PointModel(x, y);
    }

    /// <summary>
    /// 随机生成干扰图坐标
    /// </summary>
    /// <param name="originalWidth"></param>
    /// <param name="originalHeight"></param>
    /// <param name="templateWidth"></param>
    /// <param name="templateHeight"></param>
    /// <param name="blockX"></param>
    /// <param name="blockY"></param>
    /// <returns></returns>
    private PointModel GenerateInterferencePoint(int originalWidth, int originalHeight, int templateWidth, int templateHeight, int blockX, int blockY)
    {
        int x;
        if (originalWidth - blockX - 5 > templateWidth * 2)
        {
            //在原扣图右边插入干扰图
            x = GetRandomInt(blockX + templateWidth + 5, originalWidth - templateWidth);
        }
        else
        {
            //在原扣图左边插入干扰图
            x = GetRandomInt(100, blockX - templateWidth - 5);
        }

        int y;
        if (originalHeight - blockY - 5 > templateHeight * 2)
        {
            //在原扣图下边插入干扰图
            y = GetRandomInt(blockY + templateHeight + 5, originalHeight - templateHeight);
        }
        else
        {
            //在原扣图上边插入干扰图
            y = GetRandomInt(5, blockY - templateHeight - 5);
        }

        return new PointModel(x, y);
    }

    private static ComplexPolygon CalcBlockShape(Image<Rgba32> templateDarkImage)
    {
        int temp = 0;
        var pathList = new List<IPath>();
        templateDarkImage.ProcessPixelRows(accessor =>
        {
            for (int y = 0; y < templateDarkImage.Height; y++)
            {
                var rowSpan = accessor.GetRowSpan(y);
                for (int x = 0; x < rowSpan.Length; x++)
                {
                    ref Rgba32 pixel = ref rowSpan[x];
                    if (pixel.A != 0)
                    {
                        if (temp == 0)
                        {
                            temp = x;
                        }
                    }
                    else
                    {
                        if (temp != 0)
                        {
                            pathList.Add(new RectangularPolygon(temp, y, x - temp, 1));
                            temp = 0;
                        }
                    }
                }
            }
        });

        return new ComplexPolygon(new PathCollection(pathList));
    }

    /// <summary>
    /// 获得验证数据
    /// </summary>
    /// <param name="captchaKey"></param>
    /// <returns></returns>
    public async Task<CaptchaOutput> GetAsync(string captchaKey)
    {
        //获取网络图片
        //var client = new HttpClient();
        //var stream = await client.GetStreamAsync("https://picsum.photos/310/155");
        //client.Dispose();

        //底图
        using var baseImage = await Image.LoadAsync<Rgba32>($@"{Directory.GetCurrentDirectory()}\wwwroot\captcha\jigsaw\backgrounds\{_random.Next(1, 6)}.jpg".ToPath());
        var randomTemplate = _random.Next(1, 7);
        //深色模板图
        using var darkTemplateImage = await Image.LoadAsync<Rgba32>($@"{Directory.GetCurrentDirectory()}\wwwroot\captcha\jigsaw\templates\{randomTemplate}\dark.png".ToPath());
        //透明模板图
        using var transparentTemplateImage = await Image.LoadAsync<Rgba32>($@"{Directory.GetCurrentDirectory()}\wwwroot\captcha\jigsaw\templates\{randomTemplate}\transparent.png".ToPath());

        int baseWidth = baseImage.Width;
        int baseHeight = baseImage.Height;
        int blockWidth = 50;
        int blockHeight = 50;

        //调整模板图大小
        darkTemplateImage.Mutate(x =>
        {
            x.Resize(blockWidth, blockHeight);
        });
        transparentTemplateImage.Mutate(x =>
        {
            x.Resize(blockWidth, blockHeight);
        });

        //新建拼图
        using var blockImage = new Image<Rgba32>(blockWidth, blockHeight);
        //新建滑块拼图
        using var sliderBlockImage = new Image<Rgba32>(blockWidth, baseHeight);

        //随机生成拼图坐标
        PointModel blockPoint = GeneratePoint(baseWidth, baseHeight, blockWidth, blockHeight);

        //根据深色模板图计算轮廓形状
        var blockShape = CalcBlockShape(darkTemplateImage);

        //生成拼图
        blockImage.Mutate(x =>
        {
            x.Clip(blockShape, p => p.DrawImage(baseImage, new Point(-blockPoint.X, -blockPoint.Y), 1));
        });
        //拼图叠加透明模板图层
        blockImage.Mutate(x => x.DrawImage(transparentTemplateImage, new Point(0, 0), 1));

        //生成滑块拼图
        sliderBlockImage.Mutate(x => x.DrawImage(blockImage, new Point(0, blockPoint.Y), 1));

        var opacity = (float)(_random.Next(70, 100) * 0.01);
        //底图叠加深色模板图
        baseImage.Mutate(x => x.DrawImage(darkTemplateImage, new Point(blockPoint.X, blockPoint.Y), opacity));
        //生成干扰图坐标
        PointModel interferencePoint = GenerateInterferencePoint(baseWidth, baseHeight, blockWidth, blockHeight, blockPoint.X, blockPoint.Y);
        //底图叠加深色干扰模板图
        baseImage.Mutate(x => x.DrawImage(darkTemplateImage, new Point(interferencePoint.X, interferencePoint.Y), opacity));

        var token = Guid.NewGuid().ToString();
        var captchaData = new CaptchaOutput
        {
            Token = token,
            Data = new SlideJigsawCaptchaDto()
            {
                BaseImage = baseImage.ToBase64String(PngFormat.Instance),
                BlockImage = sliderBlockImage.ToBase64String(PngFormat.Instance)
            }
        };

        var key = string.Format(captchaKey, token);
        await _cache.SetAsync(key, blockPoint.X);

        return captchaData;
    }

    /// <summary>
    /// 检查验证数据
    /// </summary>
    /// <param name="input"></param>
    /// <returns></returns>
    public async Task<bool> CheckAsync(CaptchaInput input)
    {
        if (input == null || input.Data.IsNull())
        {
            return false;
        }
        var key = string.Format(input.CaptchaKey, input.Token);
        if (await _cache.ExistsAsync(key))
        {
            try
            {
                var point = JsonConvert.DeserializeObject<PointModel>(input.Data);
                var x = await _cache.GetAsync<int>(key);
                if (Math.Abs(x - point.X) < 5)
                {
                    if (input.DeleteCache)
                    {
                        await _cache.DelAsync(key);
                    }
                    return true;
                }
                else
                {
                    await _cache.DelAsync(key);
                    return false;
                }
            }
            catch
            {
                await _cache.DelAsync(key);
                return false;
            }
        }
        else
        {
            return false;
        }
    }
}