Attribute that helps with verifying Impala webhooks in dot net core

Impala webhook verification - dot net core

public static class ImpalaHeaderContants
{
    public const string XImpalaSignature = "X-Impala-Signature";
}

public class ImpalaConfigDTO
{
    public string ApiKey { get; set; }

    public string WebhookSecret { get; set; }
}
    
public class ImpalaWebhookVerificationAttribute : ActionFilterAttribute
{
    public override async Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)
    {
        var config = context.HttpContext.RequestServices.GetService<IOptionsSnapshot<ImpalaConfigDTO>>().Value;
        var strContent = await context.HttpContext.Request.GetRawBodyStringAsync();
        context.HttpContext.Request.Headers.TryGetValue(ImpalaHeaderContants.XImpalaSignature, out var headers);
        var xImpalaSignature = headers.FirstOrDefault();
        var actualXImpalaSignature = GetXImpalaSignature(strContent, config.WebhookSecret);
        if (actualXImpalaSignature != xImpalaSignature)
        {
            var logger = context.HttpContext.RequestServices.GetService<ILogger<ImpalaWebhookVerificationAttribute>>();
            logger.LogWarning(string.Format("Unverified webhook call Body=[{0}] Hash=[{1}]", strContent, xImpalaSignature));
            context.Result = (context.Controller as Controller).StatusCode(403);
        }
        else
        {
            await next();
        }
   }

   private static string GetXImpalaSignature(string text, string key)
   {
        ASCIIEncoding encoding = new ASCIIEncoding();

        var textBytes = encoding.GetBytes(text);
        var keyBytes = encoding.GetBytes(key);

        byte[] hashBytes;

        using (HMACSHA256 hash = new HMACSHA256(keyBytes))
        {
            hashBytes = hash.ComputeHash(textBytes);
        }

        return BitConverter.ToString(hashBytes).Replace("-", "").ToLower();
    }
}

Make sure to configure options, something along the lines of:

services.Configure<ImpalaConfigDTO>(Configuration.GetSection("Impala:Plugin"));

Then you just put the Attribute on method or controller.