ASP.NET Web API ActionFilter示例

public class AuthenticationFilter : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext context)
    {
        // 验证用户身份
        bool isAuthenticated = AuthenticateUser(context.HttpContext.User.Identity.Name);
        if (!isAuthenticated)
        {
            context.Result = new UnauthorizedResult(context.HttpContext);
        }
    }
}

public class AuthorizationFilter : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext context)
    {
        // 检查用户是否拥有特定权限
        bool hasPermission = CheckPermission(context.HttpContext.User.Identity.Name);
        if (!hasPermission)
        {
            context.Result = new ForbidResult(context.HttpContext);
        }
    }
}

public class LoggingFilter : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext context)
    {
        // 记录 API 调用日志
        Log.Debug("API called: {0}", context.HttpContext.Request.Method);
        base.OnActionExecuting(context);
    }
}

public class DataTransformationFilter : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext context)
    {
        // 对请求数据进行转换和验证
        string data = context.HttpContext.Request.Body.AsString();
        bool isValidData = ValidateData(data);
        if (!isValidData)
        {
            context.Result = new BadRequestResult(context.HttpContext);
        }
    }
}