monorepo/LCU.Library.Internal.Security/LCU.Library.Internal.ApiSecurity/Attributes/ApiKeyAttribute.cs

using LCU.Library.Internal.ApiSecurity.Constants;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Filters;
using LCU.Library.Internal.ApiSecurity.Enums;
using LCU.Library.Internal.ApiSecurity.Models;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;

namespace LCU.Library.Internal.ApiSecurity.Attributes;

[AttributeUsage(validOn: AttributeTargets.Method)]
public class ApiKeyAttribute : Attribute, IAsyncActionFilter
{
    public async Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)
    {
        var apiSecurityConfiguration = context.HttpContext.RequestServices.GetRequiredService<ApiSecurityConfiguration>();
        var logger = context.HttpContext.RequestServices.GetRequiredService<ILoggerFactory>().CreateLogger(GetType().Name);

        if (apiSecurityConfiguration.ExternalApiKeySet.Any())
        {
            if (!context.HttpContext.Request.Headers.TryGetValue(HeaderKeys.ApiKey, out var extractedApiKey))
            {
                switch (apiSecurityConfiguration.ApiKeyAuthenticationFailureBehavior)
                {
                    case ApiKeyAuthenticationFailureBehavior.Warn:
                        logger.LogWarning(AuthMessages.NotProvidedMessage(HeaderKeys.ApiKey));
                        break;
                    case ApiKeyAuthenticationFailureBehavior.Error:
                        logger.LogError(AuthMessages.NotProvidedMessage(HeaderKeys.ApiKey));
                        context.Result = new ContentResult()
                        {
                            StatusCode = 401,
                            Content = AuthMessages.NotProvidedMessage(HeaderKeys.ApiKey)
                        };
                        return;
                    default:
                        throw new Exception("Invalid ApiKeyAuthenticationFailureBehavior Value");
                }
            }

            if (!context.HttpContext.Request.Headers.TryGetValue(HeaderKeys.Client, out var extractedClient))
            {
                switch (apiSecurityConfiguration.ApiKeyAuthenticationFailureBehavior)
                {
                    case ApiKeyAuthenticationFailureBehavior.Warn:
                        logger.LogWarning(AuthMessages.NotProvidedMessage(HeaderKeys.Client));
                        break;
                    case ApiKeyAuthenticationFailureBehavior.Error:
                        logger.LogError(AuthMessages.NotProvidedMessage(HeaderKeys.Client));
                        context.Result = new ContentResult()
                        {
                            StatusCode = 401,
                            Content = AuthMessages.NotProvidedMessage(HeaderKeys.Client)
                        };
                        return;
                    default:
                        throw new Exception("Invalid ApiKeyAuthenticationFailureBehavior Value");
                }
            }

            if (!string.IsNullOrWhiteSpace(extractedClient))
            {
                if (apiSecurityConfiguration.ExternalApiKeySet.TryGetValue(extractedClient, out var apiKey))
                {
                    if (!apiKey.Equals(extractedApiKey))
                    {
                        switch (apiSecurityConfiguration.ApiKeyAuthenticationFailureBehavior)
                        {
                            case ApiKeyAuthenticationFailureBehavior.Warn:
                                logger.LogWarning(AuthMessages.AuthFailureMessage(extractedClient));
                                break;
                            case ApiKeyAuthenticationFailureBehavior.Error:
                                logger.LogError(AuthMessages.AuthFailureMessage(extractedClient));
                                context.Result = new ContentResult()
                                {
                                    StatusCode = 401,
                                    Content = AuthMessages.AuthFailureMessage(extractedClient)
                                };
                                return;
                            default:
                                throw new Exception("Invalid ApiKeyAuthenticationFailureBehavior Value");
                        }
                    }

                    logger.LogInformation($"Valid auth received for Client: {extractedClient}");
                }
                else
                {
                    switch (apiSecurityConfiguration.ApiKeyAuthenticationFailureBehavior)
                    {
                        case ApiKeyAuthenticationFailureBehavior.Warn:
                            logger.LogWarning(AuthMessages.ClientNotFoundMessage());
                            break;
                        case ApiKeyAuthenticationFailureBehavior.Error:
                            logger.LogError(AuthMessages.ClientNotFoundMessage());
                            context.Result = new ContentResult()
                            {
                                StatusCode = 401,
                                Content = AuthMessages.ClientNotFoundMessage()
                            };
                            return;
                        default:
                            throw new Exception("Invalid ApiKeyAuthenticationFailureBehavior Value");
                    }
                }
            }
        }
        else
        {
            switch (apiSecurityConfiguration.ApiKeyAuthenticationFailureBehavior)
            {
                case ApiKeyAuthenticationFailureBehavior.Warn:
                    logger.LogWarning(AuthMessages.EmptyKeySetMessage("ExternalApiKeySet"));
                    break;
                case ApiKeyAuthenticationFailureBehavior.Error:
                    logger.LogError(AuthMessages.EmptyKeySetMessage("ExternalApiKeySet"));
                    context.Result = new ContentResult()
                    {
                        StatusCode = 401,
                        Content = AuthMessages.EmptyKeySetMessage("ExternalApiKeySet")
                    };
                    return;
                default:
                    throw new Exception("Invalid ApiKeyAuthenticationFailureBehavior Value");
            }
        }

        await next();
    }
}