AuthenticationContext.cs

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using System;
using System.Linq;
 
using Tgstation.Server.Api.Rights;
using Tgstation.Server.Host.Models;
 
namespace Tgstation.Server.Host.Security
{
    sealed class AuthenticationContext : IAuthenticationContext, IDisposable
    {
        public bool Valid { get; private set; }
 
        public User User => user ?? throw InvalidContext();
 
        public PermissionSet PermissionSet => permissionSet ?? throw InvalidContext();
 
        public InstancePermissionSet? InstancePermissionSet { get; private set; }
 
        public ISystemIdentity? SystemIdentity { get; private set; }
 
        public DateTimeOffset SessionExpiry => sessionExpiry ?? throw InvalidContext();
 
        public string SessionId => sessionId ?? throw InvalidContext();
 
        User? user;
 
        PermissionSet? permissionSet;
 
        DateTimeOffset? sessionExpiry;
 
        string? sessionId;
 
        public AuthenticationContext()
        {
        }
 
        static InvalidOperationException InvalidContext()
            => new("AuthenticationContext is invalid!");
 
        public void Dispose() => SystemIdentity?.Dispose();
 
        public void Initialize(
            User user,
            DateTimeOffset sessionExpiry,
            string sessionId,
            InstancePermissionSet? instanceUser,
            ISystemIdentity? systemIdentity)
        {
            ArgumentNullException.ThrowIfNull(user);
            ArgumentNullException.ThrowIfNull(sessionId);
            if (systemIdentity == null && user.SystemIdentifier != null)
                throw new ArgumentNullException(nameof(systemIdentity));
 
            permissionSet = user.PermissionSet
                ?? user.Group!.PermissionSet
                ?? throw new ArgumentException("No PermissionSet provider", nameof(user));
            this.user = user;
            InstancePermissionSet = instanceUser;
            SystemIdentity = systemIdentity;
            this.sessionId = sessionId;
            this.sessionExpiry = sessionExpiry;
 
            Valid = true;
        }
 
        public ulong GetRight(RightsType rightsType)
        {
            var isInstance = RightsHelper.IsInstanceRight(rightsType);
 
            if (User == null)
                throw new InvalidOperationException("Authentication context has no user!");
 
            if (isInstance && InstancePermissionSet == null)
                return 0;
            var rightsEnum = RightsHelper.RightToType(rightsType);
 
            // use the api versions because they're the ones that contain the actual properties
            var typeToCheck = isInstance ? typeof(InstancePermissionSet) : typeof(PermissionSet);
 
            var nullableType = typeof(Nullable<>);
            var nullableRightsType = nullableType.MakeGenericType(rightsEnum);
 
            var prop = typeToCheck.GetProperties().Where(x => x.PropertyType == nullableRightsType && x.CanRead).First();
 
            var right = prop.GetMethod!.Invoke(
                isInstance
                    ? InstancePermissionSet
                    : PermissionSet,
                Array.Empty<object>())
                ?? throw new InvalidOperationException("A user right was null!");
 
            return (ulong)right;
        }
    }
}