RecaptchaDotnet

A simple, easy to use library for Google Recaptcha verification in .net apps specially ASP.NET Core.

Build Status

Installation

With dotnet cli

dotnet add package RecaptchaDotnet

---

Or with nuget package manager console

Install-Package RecaptchaDotnet

How to use

Configure services

In yuour Startup.cs's ConfigureServices method add the following

public void ConfigureServices(IServiceCollection services) 
{
    services.AddRecaptcha(config => 
    {
        // your secret code from google
        config.Secret = "YOUR_SECRET_CODE";
        
        //configure reaction to unsuccessful verifications
        config.InvalidRecaptchaResponseMode = InvalidRecaptchaResponseMode.ReturnBadRequest;
    })
}

Recaptcha Attribute

Add ReCaptchaAttribute to your actions or controllers to enable recaptcha for it

[ApiController]
[Route("[controller]/[action]")]
public class AccountController : Controller
{
    ...

    [HttpPost]
    [AllowAnonymous]
    [ServiceFilter(typeof(ReCaptchaAttribute))]
    public async Task<IActionResult> Login([FromBody] LoginViewModel model)
    {
        ...
    }
}

Recaptcha Middleware

You can also use Recaptcha Middleware to enable recaptcha for every request

public void Configure(IApplicationBuilder app) 
{
    // Add this before Useing mvc and Authentication middlewares
    app.UseRecaptcha();

    app.UseAuthentication();
    app.UseMvcWithDefaultRoute();
}

Client Side

All you need to do is to add a Header with name Recaptcha with the verification code that Google Recaptcha generates for the user after interaction of user.