将安全验证码存储在 Redis 中

Question

我有一个 WebApi 项目。由于项目需要，注册用户时需要一个图形验证码。有什么有用的建议吗？另外，如何结合Redis将其存储在Redis中。像这样，但是我需要的是数字和4位数字。谢谢您的时间。 enter image description here

Answer 1

我根据你的需要写了一个Demo，你可以参考一下。

首先我使用Bitmap库生成图形验证码，代码如下：

public class VerifyCodeHelper
    {
        public static Bitmap CreateVerifyCode(out string code)
        {
            //Create a Bitmap object and draw
            Bitmap bitmap = new Bitmap(200, 60);
            Graphics graph = Graphics.FromImage(bitmap);
            graph.FillRectangle(new SolidBrush(Color.White), 0, 0, 200, 60);
            Font font = new Font(FontFamily.GenericSerif, 48, FontStyle.Bold, GraphicsUnit.Pixel);
            Random r = new Random();
            string letters = "0123456789";

            StringBuilder sb = new StringBuilder();

            //Add random 4 numbers
            for (int x = 0; x < 4; x++)
            {
                string letter = letters.Substring(r.Next(0, letters.Length - 1), 1);
                sb.Append(letter);
                graph.DrawString(letter, font, new SolidBrush(Color.Black), x * 38, r.Next(0, 15));
            }
            code = sb.ToString();

            //Confuse the background
            Pen linePen = new Pen(new SolidBrush(Color.Black), 2);
            for (int x = 0; x < 6; x++)
                graph.DrawLine(linePen, new Point(r.Next(0, 199), r.Next(0, 59)), new Point(r.Next(0, 199), r.Next(0, 59)));
            return bitmap;
        }

    }

然后创建控制器调用API生成图形验证码。然后配置Redis：

Package Manager:
Install-Package Microsoft.Extensions.Caching.StackExchangeRedis

要集成 Redis 功能，请在启动文件中配置“AddStackExchangeRedisCache()”服务。

services.AddStackExchangeRedisCache(options => {
 options.Configuration = "localhost:6379";
});

然后将 IDistributedCache 接口注入我们的端点控制器。

然后将_distributedCache.SetString接收到的4位随机数存入数据库，全部代码如下：

[ApiController]
    public class VerifyCodeController : Controller
    {

        private readonly IDistributedCache _distributedCache;

        public VerifyCodeController(IDistributedCache distributedCache)
        {
            _distributedCache = distributedCache;
        }

        [Route("get_captcha")]
        public Object VerifyCode()
        {
            string code = "";
            Bitmap bitmap = VerifyCodeHelper.CreateVerifyCode(out code);
           _distributedCache.SetString("code",code);

            base.HttpContext.Session.SetString("CheckCode",code);
            MemoryStream stream = new MemoryStream();
            bitmap.Save(stream, ImageFormat.Gif);
            return File(stream.ToArray(), "image/gif");
        }

    }

整体 Startup.cs 配置如下。如果调用 API 时出错，请记得仔细检查这些配置：

 public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {

            services.AddStackExchangeRedisCache(options => {
                options.Configuration = "localhost:6379";
            });

            services.AddControllers();

            services.AddDistributedMemoryCache();
            services.AddSession(options => {
                options.IdleTimeout = TimeSpan.FromMinutes(1);
            });
            // Add framework services.
            services.AddMvc();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseHttpsRedirection();
            
            app.UseRouting();

            app.UseAuthorization();
            app.UseStaticFiles();
            app.UseSession();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
        }
    }

最终结果：

生成的图形验证码：

Redis 数据：