UserSubscriptions.cs

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using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
 
using HotChocolate;
using HotChocolate.Execution;
using HotChocolate.Types;
using HotChocolate.Types.Relay;
 
using Tgstation.Server.Host.GraphQL.Types;
using Tgstation.Server.Host.Security;
 
namespace Tgstation.Server.Host.GraphQL.Subscriptions
{
    [ExtendObjectType(typeof(Subscription))]
    [GraphQLDescription(Subscription.GraphQLDescription)]
    public sealed class UserSubscriptions
    {
        const string UserUpdatedTopic = "UserUpdated";
 
        public static IEnumerable<string> UserUpdatedTopics(long userId)
        {
            yield return UserUpdatedTopic;
            yield return SpecificUserUpdatedTopic(userId);
        }
 
        static string SpecificUserUpdatedTopic(long userId)
            => $"{UserUpdatedTopic}.{userId}";
 
        public ValueTask<ISourceStream<User>> UserUpdatedStream(
            [ID(nameof(User))] long? userId,
            [Service] ITopicEventReceiver receiver,
            CancellationToken cancellationToken)
        {
            ArgumentNullException.ThrowIfNull(receiver);
            var topic = userId.HasValue ? SpecificUserUpdatedTopic(userId.Value) : UserUpdatedTopic;
            return receiver.SubscribeAsync<User>(topic, cancellationToken);
        }
 
        [Subscribe(With = nameof(UserUpdatedStream))]
        public User UserUpdated([EventMessage] User user)
        {
            ArgumentNullException.ThrowIfNull(user);
            return user;
        }
 
        public ValueTask<ISourceStream<User>> CurrentUserUpdatedStream(
            [Service] ITopicEventReceiver receiver,
            [Service] IAuthenticationContext authenticationContext,
            CancellationToken cancellationToken)
        {
            ArgumentNullException.ThrowIfNull(receiver);
            ArgumentNullException.ThrowIfNull(authenticationContext);
            return receiver.SubscribeAsync<User>(SpecificUserUpdatedTopic(Models.ModelExtensions.Require(authenticationContext.User, user => user.Id)), cancellationToken);
        }
 
        [Subscribe(With = nameof(CurrentUserUpdatedStream))]
        public User CurrentUserUpdated([EventMessage] User user)
        {
            ArgumentNullException.ThrowIfNull(user);
 
            return user;
        }
    }
}