iot/projects/Infrastructure/Web/DataAnnotations/ImageCaptchaAttribute.cs

using System;
using System.ComponentModel.DataAnnotations;
using Infrastructure.Extensions;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;

namespace Infrastructure.Web.DataAnnotations
{
    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter, AllowMultiple = false)]
    public class ImageCaptchaAttribute : ValidationAttribute
    {
        protected override ValidationResult IsValid(object value, ValidationContext validationContext)
        {
            var httpContext = validationContext.GetService<IHttpContextAccessor>().HttpContext;
            var key = ImageCaptchaModel.Key;
            var captcha = value?.ToString();
            if (!string.IsNullOrEmpty(captcha))
            {
                var model = httpContext.Session.Get<ImageCaptchaModel>(key);
                if (model is null)
                {
                    return new ValidationResult("尚未发送验证码");
                }
                else
                {
                    if (DateTime.UtcNow > model.ExpireDateUtc)
                    {
                        httpContext.Session.Remove(key);
                        return new ValidationResult("验证码已过期");
                    }
                    else
                    {
                        var code = model.Captcha;
                        if (captcha == code)
                        {
                            httpContext.Session.Remove(key);
                            return null;
                        }
                        else
                        {
                            return new ValidationResult("请输入正确的验证码");
                        }
                    }
                }
            }
            else
            {
                return new ValidationResult("请输入验证码");
            }
        }
    }
}