Umbraco-CMS/src/Umbraco.Web.Common/Attributes/PluginControllerAttribute.cs

using System;
using System.Linq;
using Microsoft.AspNetCore.Mvc;

namespace Umbraco.Cms.Web.Common.Attributes
{
    /// <summary>
    /// Indicates that a controller is a plugin controller and will be routed to its own area.
    /// </summary>
    [AttributeUsage(AttributeTargets.Class, AllowMultiple = false)]
    public class PluginControllerAttribute : AreaAttribute
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="PluginControllerAttribute"/> class.
        /// </summary>
        /// <param name="areaName"></param>
        public PluginControllerAttribute(string areaName) : base(areaName)
        {
            // validate this, only letters and digits allowed.
            if (areaName.Any(c => !char.IsLetterOrDigit(c)))
                throw new FormatException($"Invalid area name \"{areaName}\": the area name can only contains letters and digits.");

            AreaName = areaName;
        }

        /// <summary>
        /// Gets the name of the area.
        /// </summary>
        public string AreaName { get; }
    }
}