Sitepoint.AltchaCaptcha 1.0.0

Sitepoint.AltchaCaptcha

Sitepoint.AltchaCaptcha is a lightweight community C# integration package for the ALTCHA proof-of-work CAPTCHA system.

It provides:

• A self-contained client widget (static assets)
• A typed service layer for communicating with a self-hosted ALTCHA backend
• Simple dependency injection registration for .NET / Umbraco 13 applications

Features

• Works with Umbraco 13 and any .NET 8 web app
• Built-in options pattern (IOptions<T>)
• Optional HTTP client for server-side verification
• Ships with the ALTCHA widget JS + CSS
• Minimal dependencies (only standard .NET abstractions)

Installation

Add the NuGet package:

dotnet add package Sitepoint.AltchaCaptcha

Configuration

In your Program.cs:

builder.Services.AddAltchaCaptcha(options =>
{
    options.ApiKey = builder.Configuration["SitepointCaptcha:ApiKey"]!;
    options.SiteKey = builder.Configuration["SitepointCaptcha:SiteKey"]!;
    options.VerifyChallengeUrl = builder.Configuration["SitepointCaptcha:VerifyUrl"]!;
});

Usage

In a Razor view or partial:

<script src="/altcha-widget.js" type="module"></script>

<form method="post" asp-action="Submit">
    <altcha-widget challengeurl="https://localhost:5000//captcha/generate/<siteKey>"></
    <altcha-widget>
        <button type="submit">Submit</button>
</form>

Verification Example

In your controller:

public class ContactController : Controller
{
    private readonly ICaptchaValidationService _captchaValidationService;

    public ContactController(ICaptchaValidationService captchaValidationService) => _captchaValidationService = captchaValidationService;

    [HttpPost]
    public async Task<IActionResult> Submit(ContactFormModel model)
    {
       
        if (!ModelState.IsValid)
        {
            return CurrentUmbracoPage();
        }

        var validationResult = await _captchaValidationService.ValidateAsync(HttpContext.Request.Form["altcha"]);

        if (!validationResult.IsValid)
        {
            TempData["CaptchaNotValid"] = true;
            return CurrentUmbracoPage();
        }

        TempData["FormSubmitted"] = true;
        return RedirectToCurrentUmbracoPage();
    }
}

License

This package is licensed under the MIT License (see LICENSE file).

Portions of this software are derived from the ALTCHA project and the Ixnas.AltchaNet C# library, both licensed under MIT.

About

This package is developed and maintained by Site Point as a community C# integration layer for self-hosted ALTCHA deployments.