Add User subscriptions without event senders

src/Tgstation.Server.Host/GraphQL/Subscriptions/UserSubscriptions.cs

@@ -0,0 +1,93 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+
+using HotChocolate;
+using HotChocolate.Execution;
+using HotChocolate.Subscriptions;
+using HotChocolate.Types;
+
+using Tgstation.Server.Api.Rights;
+using Tgstation.Server.Host.GraphQL.Types;
+using Tgstation.Server.Host.Models.Transformers;
+using Tgstation.Server.Host.Security;
+
+namespace Tgstation.Server.Host.GraphQL.Subscriptions
+{
+	/// <summary>
+	/// Subscriptions for <see cref="User"/>.
+	/// </summary>
+	[ExtendObjectType(typeof(Subscription))]
+	public sealed class UserSubscriptions
+	{
+		/// <summary>
+		/// The name of the topic for when any user is updated.
+		/// </summary>
+		const string UserUpdatedTopic = "UserUpdated";
+
+		/// <summary>
+		/// Get the names of the topics to send to when a <see cref="Models.User"/> is updated.
+		/// </summary>
+		/// <param name="userId">The <see cref="Api.Models.EntityId.Id"/> of the updated <see cref="Models.User"/>.</param>
+		/// <returns>An <see cref="IEnumerable{T}"/> of topic <see cref="string"/>s.</returns>
+		public static IEnumerable<string> UserUpdatedTopics(long userId)
+		{
+			yield return UserUpdatedTopic;
+			yield return SpecificUserUpdatedTopic(userId);
+		}
+
+		/// <summary>
+		/// The name of the topic for when a specific <see cref="Models.User"/> is updated.
+		/// </summary>
+		/// <param name="userId">The <see cref="Api.Models.EntityId.Id"/> of the updated <see cref="Models.User"/>.</param>
+		/// <returns>The topic <see cref="string"/>.</returns>
+		static string SpecificUserUpdatedTopic(long userId)
+			=> $"{UserUpdatedTopic}.{userId}";
+
+		/// <summary>
+		/// Receive an update for all <see cref="User"/> changes.
+		/// </summary>
+		/// <param name="user">The <see cref="Models.User"/> received from the publisher.</param>
+		/// <returns>The updated <see cref="User"/>.</returns>
+		[Subscribe]
+		[TgsGraphQLAuthorize(AdministrationRights.ReadUsers)]
+		public User UserUpdated([EventMessage] Models.User user)
+		{
+			ArgumentNullException.ThrowIfNull(user);
+
+			return ((Models.IApiTransformable<Models.User, User, UserGraphQLTransformer>)user).ToApi();
+		}
+
+		/// <summary>
+		/// <see cref="ISourceStream"/> for <see cref="CurrentUserUpdated(Models.User)"/>.
+		/// </summary>
+		/// <param name="receiver">The <see cref="ITopicEventReceiver"/>.</param>
+		/// <param name="authenticationContext">The <see cref="IAuthenticationContext"/> for the request.</param>
+		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
+		/// <returns>A <see cref="ValueTask{TResult}"/> resulting in a <see cref="ISourceStream{TMessage}"/> of the <see cref="SessionInvalidationReason"/> for the <paramref name="authenticationContext"/>.</returns>
+		public ValueTask<ISourceStream<Models.User>> CurrentUserUpdatedStream(
+			[Service] ITopicEventReceiver receiver,
+			[Service] IAuthenticationContext authenticationContext,
+			CancellationToken cancellationToken)
+		{
+			ArgumentNullException.ThrowIfNull(receiver);
+			ArgumentNullException.ThrowIfNull(authenticationContext);
+			return receiver.SubscribeAsync<Models.User>(SpecificUserUpdatedTopic(Models.ModelExtensions.Require(authenticationContext.User, user => user.Id)), cancellationToken);
+		}
+
+		/// <summary>
+		/// Receive an update to the logged in <see cref="User"/> when it is changed.
+		/// </summary>
+		/// <param name="user">The <see cref="Models.User"/> received from the publisher.</param>
+		/// <returns>The updated <see cref="User"/>.</returns>
+		[Subscribe]
+		[TgsGraphQLAuthorize]
+		public User CurrentUserUpdated([EventMessage] Models.User user)
+		{
+			ArgumentNullException.ThrowIfNull(user);
+
+			return ((Models.IApiTransformable<Models.User, User, UserGraphQLTransformer>)user).ToApi();
+		}
+	}
+}