DNTCaptcha.Core is a captcha generator and validator for ASP.NET Core applications.
To install DNTCaptcha.Core, run the following command in the Package Manager Console:
PM> Install-Package DNTCaptcha.Core
You can also view the package page on NuGet.
- After installing the DNTCaptcha.Core package, add the following definition to the _ViewImports.cshtml file:
@addTagHelper *, DNTCaptcha.Core- Then to use it, add its new tag-helper to your view:
For bootstrap-3:
<dnt-captcha asp-captcha-generator-max="9000"
asp-captcha-generator-min="1"
asp-captcha-generator-language="English"
asp-captcha-generator-display-mode="NumberToWord"
asp-use-relative-urls="true"
asp-placeholder="Security code as a number"
asp-validation-error-message="Please enter the security code as a number."
asp-font-name="Tahoma"
asp-font-size="20"
asp-fore-color="#333333"
asp-back-color="#ccc"
asp-text-box-class="text-box single-line form-control col-md-4"
asp-text-box-template="<div class='input-group col-md-4'><span class='input-group-addon'><span class='glyphicon glyphicon-lock'></span></span>{0}</div>"
asp-validation-message-class="text-danger"
asp-refresh-button-class="glyphicon glyphicon-refresh btn-sm"
asp-use-noise="false"
/>For bootstrap-4 (you will need to npm install components-font-awesome for the missing font-glyphs too):
<dnt-captcha asp-captcha-generator-max="9000"
asp-captcha-generator-min="1"
asp-captcha-generator-language="English"
asp-captcha-generator-display-mode="NumberToWord"
asp-use-relative-urls="true"
asp-placeholder="Security code as a number"
asp-validation-error-message="Please enter the security code as a number."
asp-font-name="Tahoma"
asp-font-size="20"
asp-fore-color="#333333"
asp-back-color="#ccc"
asp-text-box-class="text-box form-control"
asp-text-box-template="<div class='input-group'><span class='input-group-prepend'><span class='input-group-text'><i class='fas fa-lock'></i></span></span>{0}</div>"
asp-validation-message-class="text-danger"
asp-refresh-button-class="fas fa-redo btn-sm"
asp-use-noise="false"
/>- To register its default providers, call
services.AddDNTCaptcha();method in your Startup class.
using DNTCaptcha.Core;
namespace DNTCaptcha.TestWebApp
{
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
// options.UseSessionStorageProvider() // -> It doesn't rely on the server or client's times. Also it's the safest one.
// options.UseMemoryCacheStorageProvider() // -> It relies on the server's times. It's safer than the CookieStorageProvider.
options.UseCookieStorageProvider() // -> It relies on the server and client's times. It's ideal for scalability, because it doesn't save anything in the server's memory.
// .UseDistributedCacheStorageProvider() // --> It's ideal for scalability using `services.AddStackExchangeRedisCache()` for instance.
// .UseDistributedSerializationProvider()
// Don't set this line (remove it) to use the installed system's fonts (FontName = "Tahoma").
// Or if you want to use a custom font, make sure that font is present in the wwwroot/fonts folder and also use a good and complete font!
.UseCustomFont(Path.Combine(_env.WebRootPath, "fonts", "IRANSans(FaNum)_Bold.ttf")) // This is optional.
.AbsoluteExpiration(minutes: 7)
.ShowThousandsSeparators(false)
.WithEncryptionKey("This is my secure key!")
.InputNames(// This is optional. Change it if you don't like the default names.
new DNTCaptchaComponent
{
CaptchaHiddenInputName = "DNTCaptchaText",
CaptchaHiddenTokenName = "DNTCaptchaToken",
CaptchaInputName = "DNTCaptchaInputText"
})
.Identifier("dntCaptcha")// This is optional. Change it if you don't like its default name.
;
}- Now you can add the
ValidateDNTCaptchaattribute to your action method to verify the entered security code:
[HttpPost, ValidateAntiForgeryToken]
[ValidateDNTCaptcha(ErrorMessage = "Please enter the security code as a number.",
CaptchaGeneratorLanguage = Language.English,
CaptchaGeneratorDisplayMode = DisplayMode.NumberToWord)]
public IActionResult Index([FromForm]AccountViewModel data)
{
if (ModelState.IsValid) // If `ValidateDNTCaptcha` fails, it will set a `ModelState.AddModelError`.
{
//TODO: Save data
return RedirectToAction(nameof(Thanks), new { name = data.Username });
}
return View();
}Or you can use the IDNTCaptchaValidatorService directly:
namespace DNTCaptcha.TestWebApp.Controllers
{
public class HomeController : Controller
{
private readonly IDNTCaptchaValidatorService _validatorService;
private readonly DNTCaptchaOptions _captchaOptions;
public HomeController(IDNTCaptchaValidatorService validatorService, IOptions<DNTCaptchaOptions> options)
{
_validatorService = validatorService;
_captchaOptions = options == null ? throw new ArgumentNullException(nameof(options)) : options.Value;
}
[HttpPost, ValidateAntiForgeryToken]
public IActionResult Login2([FromForm]AccountViewModel data)
{
if (!_validatorService.HasRequestValidCaptchaEntry(Language.English, DisplayMode.SumOfTwoNumbersToWords))
{
this.ModelState.AddModelError(_captchaOptions.CaptchaComponent.CaptchaInputName, "Please enter the security code as a number.");
return View(nameof(Index));
}
//TODO: Save data
return RedirectToAction(nameof(Thanks), new { name = data.Username });
}Samples:
Different supported DisplayModes:
| DisplayMode | Output |
|---|---|
| NumberToWord |  |
| ShowDigits |  |
| SumOfTwoNumbers |  |
| SumOfTwoNumbersToWords |  |
- This library uses unobtrusive Ajax library for the refresh button. Make sure you have included its related scripts too:
- Add required files using the NPM. To do it add package.json file and then run the
npm installcommand - It's better to bundle the installed dependencies using
dotnet bundlebundleconfig.json - Or you can download it from: https://github.com/aspnet/jquery-ajax-unobtrusive/releases
- Add required files using the NPM. To do it add package.json file and then run the
Please follow the DNTCaptcha.TestWebApp sample for more details.
It's possible to use this captcha with Angular 4.3+ apps too. Here is a sample to demonstrate it:
Find all currently supported languages here. To add new language, kindly contribute by editing the following files:
To run this project on non-Windows-based operating systems, you will need to install libgdiplus too:
-
Ubuntu 16.04 and above: - apt-get install libgdiplus - cd /usr/lib - ln -s libgdiplus.so gdiplus.dll
-
Fedora 23 and above: - dnf install libgdiplus - cd /usr/lib64/ - ln -s libgdiplus.so.0 gdiplus.dll
-
CentOS 7 and above: - yum install autoconf automake libtool - yum install freetype-devel fontconfig libXft-devel - yum install libjpeg-turbo-devel libpng-devel giflib-devel libtiff-devel libexif-devel - yum install glib2-devel cairo-devel - git clone https://github.com/mono/libgdiplus - cd libgdiplus - ./autogen.sh - make - make install - cd /usr/lib64/ - ln -s /usr/local/lib/libgdiplus.so libgdiplus.so
-
Docker - RUN apt-get update \
&& apt-get install -y libgdiplus -
MacOS - brew install mono-libgdiplus
After installing the [Mono MDK](http://www.mono-project.com/download/#download-mac), Copy Mono MDK Files: - /Library/Frameworks/Mono.framework/Versions/4.6.2/lib/libgdiplus.0.dylib - /Library/Frameworks/Mono.framework/Versions/4.6.2/lib/libgdiplus.0.dylib.dSYM - /Library/Frameworks/Mono.framework/Versions/4.6.2/lib/libgdiplus.dylib - /Library/Frameworks/Mono.framework/Versions/4.6.2/lib/libgdiplus.la And paste them to: /usr/local/lib