Awesome

reCaptcha-V3

reCAPTCHA V3 for .NET 5.

Usage

1. Install the package.

Install-Package reCaptcha-V3 -Version 1.0.0

or

dotnet add package reCaptcha-V3 --version 1.0.0

2. Get your Site-Key and Secret-Key to use reCAPTCHA from here.

3. Add following service registrations to ConfigureServices method in Startup.cs.

services.AddRecaptcha(recaptchaOptions =>
{
  recaptchaOptions.SecretKey = "your_recaptcha_secret_key";
  recaptchaOptions.SiteKey = "your_recaptcha_site_key";
});

4. Specify reCAPTCHA tag helper in _ViewImports.cshtml as below.

//...
@addTagHelper *, ReCaptcha

5. Use the <recaptcha /> tag helper in your View. (e.g. Home/Index.cshtml)

<h5 class="display-5">Recaptcha MVC Demo</h5>
<div class="container">
    <form id="my-form" method="post" asp-action="Index">
        <div class="form-group">
            <label>Username</label>
            <input type="text" asp-for="Username"/>
        </div>
        <div class="form-group">
            <label>Password</label>
            <input type="text" asp-for="Password"/>
        </div>
        <input type="hidden" asp-for="RecaptchaToken" id="recaptcha-token" />
        
        <div class="form-group">
            <button class="btn btn-dark">
                Submit
            </button>
        </div>
    </form>
</div>

<recaptcha action-name="login" execute-method="tokenProvider"/>

<script>
    function tokenProvider(token) {
        document.getElementById("recaptcha-token").value = token;
    }
  </script>

6. After submitting the form and sending a POST request to the server, you can simply check the user is allowed to do the action or not.

private readonly IRecaptchaVerifier _recaptchaVerifier;

public SampleController(IRecaptchaVerifier recaptchaVerifier)
{
  _recaptchaVerifier = recaptchaVerifier;
}

[HttpPost]
public async Task<IActionResult> Index(RecaptchaModel model)
{
  var recaptcha = await _recaptchaVerifier.VerifyAsync(model.RecaptchaToken);

  if (recaptcha.Success && recaptcha.Score >= 0.7)
  {
    return Ok(recaptcha);
  }

  return BadRequest(new {message = "You can not proceed this action "});
}