session-email.md

Email captcha base session

0. Install the required nuget package

       Install-Package NCaptcha.AspNetCore.SessionEmail

1. Add Options in the appsettings.json file.

   "CaptchaEmail": {
       "UserName": "",
       "Password": "",
       "MailFromName": "",
       "MailFromAddress": "",
       "ServerHost": "",
       "ServerPort": 0,
       "UseSsl": false
   }

2. Register in DI

   public void ConfigureServices(IServiceCollection services)
   {
       services.AddSession();
       services.AddSessionBasedEmailCaptcha(Configuration.GetSection("CaptchaEmail").Bind);
   }

3. Configure the session

   public void Configure(IApplicationBuilder app)
   {
       app.UseSession();
   }

4. Add a API for sending captcha code

   public class LoginModel : PageModel
   {
       private readonly ICaptchaGenerator _captchaGenerator;
   
       public LoginModel(ICaptchaGenerator captchaGenerator)
       {
           _captchaGenerator = captchaGenerator;
       }
   
       public async Task OnPostSendCaptchaAsync() => await _captchaGenerator.GenerateCaptchaAsync();
   }

5. Validate the captcha

   public class LoginModel : PageModel
   {
       private readonly ICaptchaValidator _captchaValidator;
   
       public LoginModel(ICaptchaValidator captchaValidator)
       {
           _captchaValidator = captchaValidator;
       }
   
       public async Task<IActionResult> OnPostAsync()
       {
           if (!await _captchaValidator.ValidateAsync(Input.Captcha))
           {
               ModelState.AddModelError(nameof(InputModel.Captcha), "Invalid captcha.");
               return Page();
           }
       }
   }