osu/osu.Game/Database/UserLookupCache.cs

// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
// See the LICENCE file in the repository root for full licence text.

using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using JetBrains.Annotations;
using osu.Game.Online.API.Requests;
using osu.Game.Online.API.Requests.Responses;

namespace osu.Game.Database
{
    public class UserLookupCache : OnlineLookupCache<int, APIUser, GetUsersRequest>
    {
        /// <summary>
        /// Perform an API lookup on the specified user, populating a <see cref="APIUser"/> model.
        /// </summary>
        /// <param name="userId">The user to lookup.</param>
        /// <param name="token">An optional cancellation token.</param>
        /// <returns>The populated user, or null if the user does not exist or the request could not be satisfied.</returns>
        [ItemCanBeNull]
        public Task<APIUser> GetUserAsync(int userId, CancellationToken token = default) => LookupAsync(userId, token);

        /// <summary>
        /// Perform an API lookup on the specified users, populating a <see cref="APIUser"/> model.
        /// </summary>
        /// <param name="userIds">The users to lookup.</param>
        /// <param name="token">An optional cancellation token.</param>
        /// <returns>The populated users. May include null results for failed retrievals.</returns>
        public Task<APIUser[]> GetUsersAsync(int[] userIds, CancellationToken token = default) => LookupAsync(userIds, token);

        protected override GetUsersRequest CreateRequest(IEnumerable<int> ids) => new GetUsersRequest(ids.ToArray());

        protected override IEnumerable<APIUser> RetrieveResults(GetUsersRequest request) => request.Response?.Users;
    }
}