C#滑动验证码拼图验证功能实现(SlideCaptcha)

目录

• 使用背景：
• 实现分析：
• 后端代码：
• 准备：
• 使用：
• 前端代码：
• 结语：

使用背景：

关于滑动验证码的使用场所还是非常多的，如：调取短信接口之前，和 注册请求之前 或者 频繁会调用的接口都需要加这个拼图验证。这里先上一下效果图吧（心中无码，自然高清）。

话不多说，开撸！

实现分析：

滑动验证码的逻辑也很简单。大概说一下：

　　1，服务器生成主图+附图（从主图裁剪下来的不需要管y坐标）并且存储X坐标；

　　2，前端传入本地X坐标到服务器。

　　3，服务器进行计算存储X坐标和本地X坐标相差值；

　　4，验证相差值是否在 0-2 之间，判断 true | false

后端代码：

准备：

增加SlideCaptcha文件夹，并且增加Captcha.cs CaptchaModel.cs Config.cs ImgFormat.cs 4个文件。分别是：验证，验证实体，配置和图片生成类。代码如下：

Captcha.cs　

using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;
using System.Net;

namespace SliderCaptcha.NET
{
    public class Captcha
    {
        public static Captcha64Model GenerateBase64()
        {
            CaptchaModel model = Captcha.Generate();
            if (model != null)
            {
                return new Captcha64Model()
                {
                    X = model.X,
                    Y = model.Y,
                    Background = ImageToBase64(model.Background,ImageFormat.Jpeg),
                    Slide = ImageToBase64(model.Slide, ImageFormat.Png)
                };
            }
            else
            {
                return null;
            }
        }

        /// <summary>
        /// 生成验证码
        /// </summary>
        /// <returns></returns>
        public static CaptchaModel Generate()
        {
            Bitmap image = BgImage();
            if (image != null)
            {
                int l = Config.l;
                int d = Config.d;
                int width = image.Width;
                int height = image.Height;
                int x = RandomNext(width / 3, width - d - l - 10);//初始x
                int y = RandomNext(10 + d, height - l - 10); ;//初始y
                GraphicsPath path = GetSliderPath(x, y);
                Graphics g = GetGraphics(image);

                //水印
                if (Config.showWatermark)
                {
                    Font font = new Font("宋体", 12, FontStyle.Bold);
                    SizeF size = g.MeasureString(Config.watermarkText, font);
                    Point Plogo = new Point((int)(width - size.Width - 5), (int)(height - size.Height - 5));
                    Color color = image.GetPixel(Plogo.X, Plogo.Y);
                    SolidBrush bru = new SolidBrush(AntiColor(color));
                    g.DrawString(Config.watermarkText, font, bru, Plogo);
                }

                Pen pen = new Pen(Color.FromArgb(200, 255, 255, 255), 2);
                g.DrawPath(pen, path);
                Image slider = CaptureSlider(image, path, x, width, height);
                SolidBrush brush = new SolidBrush(Color.FromArgb(100, 255, 255, 255));
                g.FillPath(brush, path);
                g.Save();
                g.Dispose();
                return new CaptchaModel()
                {
                    X = x,
                    Y = y,
                    Background = image,
                    Slide = slider
                };
            }
            return null;
        }

        /// <summary>
        /// 获取图片Graphics
        /// </summary>
        /// <param name="image"></param>
        /// <returns></returns>
        private static Graphics GetGraphics(Image image)
        {
            Graphics g = Graphics.FromImage(image);
            g.SmoothingMode = SmoothingMode.HighQuality;
            g.CompositingQuality = CompositingQuality.HighQuality;
            g.InterpolationMode = InterpolationMode.High;
            return g;
        }

        /// <summary>
        /// 获取滑块path
        /// </summary>
        private static GraphicsPath GetSliderPath(int x, int y)
        {
            int l = Config.l;
            int r = Config.r;
            int b = Config.b;
            int c = Config.c;
            int d = Config.d;
            int blod = Config.blod;
            GraphicsPath path = new GraphicsPath(FillMode.Winding);
            Point Pa = new Point(x, y);
            Point Pb = new Point(x + l / 2 - b, y - c + blod);
            Point Pd = new Point(x + l, y);
            Point Pe = new Point(Pd.X + c - blod, y + l / 2 - b);
            Point Pg = new Point(Pd.X, y + l);
            Point Ph = new Point(x, y + l);
            Point Pj = new Point(x + c - blod, Pe.Y);
            path.AddLine(Pa, Pb);
            path.AddArc(x + l / 2 - r, y - d, d, d, 130f, 280f);
            path.AddLines(new Point[] { Pd, Pe });
            path.AddArc(x + l, y + l / 2 - r, d, d, 220f, 280f);
            path.AddLines(new Point[] { Pg, Ph });
            path.AddArc(x, y + l / 2 - r, d, d, 140f, -280f);
            path.AddLine(Pj, Pa);
            return path;
        }

        /// <summary>
        /// 获取滑块区域
        /// </summary>
        /// <param name="image"></param>
        /// <param name="path"></param>
        /// <param name="x"></param>
        /// <param name="width"></param>
        /// <param name="height"></param>
        /// <returns></returns>
        private static Image CaptureSlider(Image image, GraphicsPath path, int x, int width, int height)
        {
            Bitmap concave = new Bitmap(image.Width, image.Height);
            Graphics g = GetGraphics(concave);
            TextureBrush brush = new TextureBrush(image);
            g.Clear(Color.Transparent);
            g.FillPath(brush, path);
            g.Dispose();
            return CaptureImage(concave, x, height);
        }

        /// <summary>
        /// 裁剪图片
        /// </summary>
        /// <param name="fromImage"></param>
        /// <param name="offsetX"></param>
        /// <param name="width"></param>
        /// <param name="height"></param>
        /// <returns></returns>
        private static Image CaptureImage(Image fromImage, int offsetX, int height)
        {
            int width = Config.l + Config.d + Config.blod;
            Bitmap bitmap = new Bitmap(width, height);
            Graphics g = GetGraphics(bitmap);
            g.DrawImage(fromImage, 0, 0, new Rectangle(offsetX, 0, width, height), GraphicsUnit.Pixel);
            g.Dispose();
            return bitmap;
        }

        /// <summary>
        /// 生成随机数
        /// </summary>
        /// <param name="min"></param>
        /// <param name="max"></param>
        /// <returns></returns>
        private static int RandomNext(int min, int max)
        {
            Random random = new Random(Guid.NewGuid().GetHashCode());
            return random.Next(min, max);
        }

        /// <summary>
        /// 取反色
        /// </summary>
        /// <param name="color"></param>
        /// <returns></returns>
        public static Color AntiColor(Color color)
        {
            if (color.R > 128 && color.G > 128 && color.B > 128)
            {
                return Color.Black;
            }
            else
            {
                return Color.White;
            }
        }

        /// <summary>
        /// 获取背景图
        /// </summary>
        /// <returns></returns>
        private static Bitmap BgImage()
        {
            WebClient web = new WebClient();
            int num = RandomNext(1, 20);
            Stream stream = web.OpenRead($"http://00x1.com/images/Pic/{num}.jpg");
            Bitmap bitmap = (Bitmap)Image.FromStream(stream);
            return bitmap;
        }

        /// <summary>
        /// base64转图片
        /// </summary>
        /// <param name="base64string"></param>
        /// <returns></returns>
        public static Bitmap Base64ToImage(string base64string)
        {
            byte[] b = Convert.FromBase64String(base64string);
            MemoryStream ms = new MemoryStream(b);
            Bitmap bitmap = new Bitmap(ms);
            return bitmap;
        }

        /// <summary>
        /// 图片转base64
        /// </summary>
        /// <param name="image"></param>
        /// <returns></returns>
        public static string ImageToBase64(Image image, ImageFormat format)
        {
            if (image == null) return string.Empty;
            string strbaser64 = "";
            try
            {
                string head = "";
                string formatName = ImgFormat.NameFromGuid(format);
                head = $"data:image/{formatName.ToLower()};base64,";
                MemoryStream ms = new MemoryStream();
                image.Save(ms, format);
                byte[] arr = new byte[ms.Length];
                ms.Position = 0;
                ms.Read(arr, 0, (int)ms.Length);
                ms.Close();
                strbaser64 = head+Convert.ToBase64String(arr);
            }
            catch (Exception)
            {
                throw new Exception("Something wrong during convert!");
            }
            return strbaser64;
        }

    }
}

CaptchaModel.cs　　　　　

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Text;

namespace SliderCaptcha.NET
{
    public class CaptchaModel
    {
        public int X { get; set; }
        public int Y { get; set; }
        public Image Background { get; set; }
        public Image Slide { get; set; }
    }
    public class Captcha64Model
    {
        public int X { get; set; }
        public int Y { get; set; }
        public string Background { get; set; }
        public string Slide { get; set; }
    }
}

using System;
namespace SliderCaptcha.NET
{
    public class Config
    {
        /// <summary>
        /// 矩形宽
        /// </summary>
        public static int l = 42;
        /// <summary>
        /// 圆形半径
        /// </summary>
        public static int r = 9;
        /// <summary>
        /// 圆形直径
        /// </summary>
        public static int d = r * 2;
        /// <summary>
        /// 计算圆形与矩形交接三角形边
        /// </summary>
        public static int a = (int)(r * Math.Sin(Math.PI * (50 / 180f)));
        public static int b = (int)(r * Math.Cos(Math.PI * (50 / 180f)));
        public static int c = r - a;
        /// <summary>
        /// 滑块边框
        /// </summary>
        public static int blod = 2;
        /// <summary>
        /// 水印
        /// </summary>
        public static string watermarkText = "SC.NET";
        /// <summary>
        /// 是否显示水印
        /// </summary>
        public static bool showWatermark = true;
    }
}

using System;
using System.Collections.Generic;
using System.Drawing.Imaging;

namespace SliderCaptcha.NET
{
    public class ImgFormat
    {
        private static Dictionary<string, string> Formats = new Dictionary<string, string>() {
                            {"b96b3caa-0728-11d3-9d7b-0000f81ef32e","MemoryBmp"},
                            {"b96b3cab-0728-11d3-9d7b-0000f81ef32e","Bmp"},
                            {"b96b3cac-0728-11d3-9d7b-0000f81ef32e","Emf"},
                            {"b96b3cad-0728-11d3-9d7b-0000f81ef32e","Wmf"},
                            {"b96b3cae-0728-11d3-9d7b-0000f81ef32e","Jpeg"},
                            {"b96b3caf-0728-11d3-9d7b-0000f81ef32e","Png"},
                            {"b96b3cb0-0728-11d3-9d7b-0000f81ef32e","Gif"},
                            {"b96b3cb1-0728-11d3-9d7b-0000f81ef32e","Tiff"},
                            {"b96b3cb2-0728-11d3-9d7b-0000f81ef32e","Exif"},
                            {"b96b3cb5-0728-11d3-9d7b-0000f81ef32e","Icon"}
        };

        public static ImageFormat FormatFromGuid(ImageFormat format)
        {
            return FormatFromGuid(format.Guid);
        }
        public static ImageFormat FormatFromGuid(Guid guid)
        {
            return FormatFromGuid(guid.ToString());
        }
        public static ImageFormat FormatFromGuid(string guid)
        {
            if (Formats.ContainsKey(guid))
            {
                string name = Formats[guid];
                ImageFormat format = null;
                switch (name)
                {
                    case "MemoryBmp":
                        format = ImageFormat.MemoryBmp;
                        break;
                    case "Bmp":
                        format = ImageFormat.Bmp;
                        break;
                    case "Emf":
                        format = ImageFormat.Emf;
                        break;
                    case "Wmf":
                        format = ImageFormat.Wmf;
                        break;
                    case "Gif":
                        format = ImageFormat.Gif;
                        break;
                    case "Jpeg":
                        format = ImageFormat.Jpeg;
                        break;
                    case "Png":
                        format = ImageFormat.Png;
                        break;
                    case "Tiff":
                        format = ImageFormat.Tiff;
                        break;
                    case "Exif":
                        format = ImageFormat.Exif;
                        break;
                    case "Icon":
                        format = ImageFormat.Icon;
                        break;
                }
                return format;
            }
            else
            {
                return null;
            }
        }

        public static string NameFromGuid(ImageFormat format)
        {
            return NameFromGuid(format.Guid);
        }
        public static string NameFromGuid(Guid guid)
        {
            return NameFromGuid(guid.ToString());
        }
        public static string NameFromGuid(string guid)
        {
            if (Formats.ContainsKey(guid))
            {
                return Formats[guid];
            }
            else
            {
                return string.Empty;
            }
        }
    }
}

使用：

这里用的是asp.net mvc 的框架，用的是api接口，前后端分离供前端使用。具体使用根据个人需求，可以是接口调用亦可以是项目调用。

呼声如果很高的话，考虑出一个winfrom版本的滑动验证码~（滑稽）

[HttpGet]
        public IHttpActionResult GetCaptcha()
        {
            Captcha64Model model = Captcha.GenerateBase64();
            CacheHelper.Cache.SetCache("sliderX", model.X);
            Hashtable ht = new Hashtable();
            ht.Add("background", model.Background);
            ht.Add("slider", model.Slide);
            ht.Add("sliderXXXXX", model.X);
            return Json(ht);
        }

        /// <summary>
        /// 检查验证
        /// </summary>
        /// <param name="x"></param>
        /// <returns></returns>
        [HttpPost]
        public IHttpActionResult CheckCaptcha([FromBody] int x = 0)
        {
            Hashtable hs = new Hashtable();
            string Mess = "";
            int Code = 0;
            var session = CacheHelper.Cache.GetCache("sliderX");
            if (session == null)
            {
                Mess = "请刷新验证码";
                Code = 500;
                goto block;
            }
            string sliderXStr = session?.ToString();// as string
            int sliderX = Convert.ToInt32(sliderXStr);
            int difX = sliderX - x;
            if (difX >= 0 - Config.blod && difX <= Config.blod)
            {
                Mess = "success";
                Code = 0;
            }
            else
            {
                session = null;
                Mess = "错误";
                Code = 500;
            }
        block:
            hs.Add("Mess", Mess);
            hs.Add("Code", Code);
            return Json(hs);
        }

前端代码：

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
    <title>Splide Captcha</title>
    <style>
        * {
            -webkit-user-select: none;
            -moz-user-select: none;
            -ms-user-select: none;
            user-select: none;
        }

        .sc-captcha {
            width: 300px;
            margin: 100px auto;
        }

        .sc_net_panel {
            padding: 10px;
        }

            .sc_net_panel > div {
                position: relative;
            }

        .bg_slider {
            position: absolute;
            left: 0;
            top: 0;
        }

        .bg_refresh {
            position: absolute;
            right: 5px;
            top: 5px;
            background: #808080;
            color: #fff;
            border-radius: 3px;
            width: 16px;
            line-height: 16px;
            text-align: center;
            cursor: pointer;
        }

        .sc_net_slider_icon {
            position: absolute;
            left: 0;
            top: 0;
            height: 37px;
            text-align: center;
            border-radius: 5px;
            border: #808080 1px solid;
            width: 37px;
            line-height: 37px;
            cursor: pointer;
        }

            .sc_net_slider_icon:hover {
                color: #fff;
                background: #1991fa;
            }

        .sc_net_slider_text {
            position: absolute;
            left: 0;
            top: 0;
            text-align: center;
            width: 280px;
            color: #45494c;
            border: #808080 1px solid;
            border-radius: 5px;
            line-height: 35px;
            height: 37px;
            cursor: default;
        }

        .sc_net_slider_area {
            position: absolute;
            left: 0;
            top: 0;
            height: 37px;
        }
    </style>
    <script src="E:\porject\碚煜Api\ByzkApi\Scripts\jquery-3.4.1.js"></script>
    <script src="E:\porject\碚煜Api\ByzkApi\Scripts\jquery-3.4.1.min.js"></script>
</head>
<body>
    <div>
        <div class="sc-captcha">
            <div class="sc_net_panel">
                <div class="sc_net_bg">
                    <div class="sc_net_bgimg">
                    </div>
                    <div class="bg_refresh" onclick="loadCaptcha()" title="刷新">↻</div>
                </div>
            </div>
            <div class="sc_net_panel">
                <div class="sc_net_slider">
                    <div class="sc_net_slider_text">向右拖动滑块填充拼图</div>
                    <div class="sc_net_slider_area"></div>
                    <div class="sc_net_slider_icon">➞</div>
                </div>
            </div>
        </div>
    </div>
</body>

<script>
    loadCaptcha();
    function loadCaptcha() {
        $.ajax({
            url: "http://192.168.1.216:5500/api/TestApi/GetCaptcha",
            type: "Get",
            dataType: "JSON",
            success: function (json) {
                var bg = createCanvas(280, 155);
                bg.className = 'bg_img';
                bg_slider = createCanvas(62, 155);
                bg_slider.className = 'bg_slider';
                CanvasSetImage(bg, json.background);
                CanvasSetImage(bg_slider, json.slider);
                var doc = document.getElementsByClassName("sc_net_bgimg")[0];
                doc.innerHTML = "";
                doc.appendChild(bg);
                doc.appendChild(bg_slider);

                console.log(json.modelX);
            }
        })
    }

    function createCanvas(width, height) {
        var canvas = document.createElement('canvas');
        canvas.width = width;
        canvas.height = height;
        return canvas;
    };

    function CanvasSetImage(_canvas, base64) {
        //获取2d画布对象
        var ctx = _canvas.getContext("2d");
        //创建图片标签
        var _img = document.createElement("img");
        //设置图片地址
        _img.src = base64;
        //ctx.fillRect(0, 0, _canvas.clientWidth, _canvas.clientHeight);
        //ctx.fillStyle = 'rgba(255, 255, 255, 0)';
        _img.onload = function () {
            ctx.drawImage(_img, 0, 0);
        }
        /*           ctx.drawImage(_img, 10, 10);*/
    }

    function getByClassName0(className) {
        return document.getElementsByClassName(className)[0];
    };

    var slider = getByClassName0("sc_net_slider_icon");
    var text = getByClassName0("sc_net_slider_text");
    var area = getByClassName0("sc_net_slider_area");
    var bg_slider;
    slider.addEventListener('mousedown', handleDragStart);
    slider.addEventListener('touchstart', handleDragStart);
    document.addEventListener('mousemove', handleDragMove);
    document.addEventListener('touchmove', handleDragMove);
    document.addEventListener('mouseup', handleDragEnd);
    document.addEventListener('touchend', handleDragEnd);
    document.addEventListener('mousedown', function () { return false; });
    document.addEventListener('touchstart', function () { return false; });
    var originX, originY, trail = [],
        isMouseDown = false;

    var isOk = false;

    function handleDragStart(e) {
        console.log("handleDragStart");
        if (isOk) return;
        originX = e.clientX || e.touches[0].clientX;
        originY = e.clientY || e.touches[0].clientY;
        isMouseDown = true;
    };

    function handleDragMove(e) {
        if (!isMouseDown) return false;
        var eventX = e.clientX || e.touches[0].clientX;
        var eventY = e.clientY || e.touches[0].clientY;
        var moveX = eventX - originX;
        var moveY = eventY - originY;
        if (moveX >= 0 && moveX <= 243) {
            slider.style.left = moveX + "px";
            bg_slider.style.left = moveX / 243 * 218 + "px";
        }
    };

    function handleDragEnd(e) {
        if (!isMouseDown)
            return false
        isMouseDown = false
        var eventX = e.clientX || e.changedTouches[0].clientX
        if (eventX == originX)
            return false

        //获取前端的x坐标；
        var a = $(".bg_slider");
        var localX = a[0].offsetLeft;

        $.ajax({
            url: "http://192.168.1.216:5500/api/TestApi/CheckCaptcha?x=" + localX,
            type: "Post",
            dataType: "JSON",
            success: function (res) {
                alert(res.Mess);
            }
        })
    };
</script>
</html>

结语：

到这里基本上就已经完成了，以上前端地址更换成自己的接口即可。正常业务 验证码是很频发的一个操作并且是多用户。所以缓存存储的时候也需要注意一下。

到此这篇关于C#滑动验证码拼图验证功能实现的文章就介绍到这了,更多相关C#滑动验证码拼图验证内容请搜索我们以前的文章或继续浏览下面的相关文章希望大家以后多多支持我们！