Add bindings for ISteamRemoteStorage/GetCollectionDetails endpoint.

src/SteamWebAPI2/Interfaces/ISteamRemoteStorage.cs

@@ -1,13 +1,17 @@
 using Steam.Models;
+using SteamWebAPI2.Models;
 using SteamWebAPI2.Utilities;
 using System.Threading.Tasks;
+using System.Collections.Generic;
 
 namespace SteamWebAPI2.Interfaces
 {
-    using System.Collections.Generic;
-
     public interface ISteamRemoteStorage
     {
+        Task<ISteamWebResponse<IReadOnlyCollection<CollectionDetail>>> GetCollectionDetails(ulong collectionId);
+
+        Task<ISteamWebResponse<IReadOnlyCollection<CollectionDetail>>> GetCollectionDetails(IList<ulong> collectionId);
+
         Task<ISteamWebResponse<IReadOnlyCollection<PublishedFileDetailsModel>>> GetPublishedFileDetailsAsync(uint itemCount, IList<ulong> publishedFileIds);
 
         Task<ISteamWebResponse<IReadOnlyCollection<PublishedFileDetailsModel>>> GetPublishedFileDetailsAsync(IList<ulong> publishedFileIds);

src/SteamWebAPI2/Interfaces/SteamRemoteStorage.cs

@@ -29,6 +29,51 @@ public SteamRemoteStorage(IMapper mapper, ISteamWebRequest steamWebRequest, ISte
                 : steamWebInterface;
         }
 
+        /// <summary>
+        /// Retrieves the list of items in the provided collection.
+        /// </summary>
+        /// <param name="collectionId">The collection's ID.</param>
+        /// <returns>A collection of the details of each collection or <c>null</c> if the request failed.</returns>
+        public async Task<ISteamWebResponse<IReadOnlyCollection<CollectionDetail>>> GetCollectionDetails(ulong collectionId) => await GetCollectionDetails(new List<ulong> { collectionId });
+
+        /// <summary>
+        /// Retrieves the list of items in the provided collections.
+        /// </summary>
+        /// <param name="collectionIds">The list of IDs of collections for which to retrieve details.</param>
+        /// <returns>A collection of the details of each collection or <c>null</c> if the request failed.</returns>
+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="collectionIds"/> is null.</exception>
+        /// <exception cref="ArgumentOutOfRangeException">Thrown when <paramref name="collectionIds"/> is empty.</exception>
+        public async Task<ISteamWebResponse<IReadOnlyCollection<CollectionDetail>>> GetCollectionDetails(IList<ulong> collectionIds)
+        {
+            if (collectionIds == null)
+                throw new ArgumentNullException(nameof(collectionIds));
+
+            if (!collectionIds.Any())
+                throw new ArgumentOutOfRangeException(nameof(collectionIds), $"{nameof(collectionIds)} is empty.");
+
+            IList<SteamWebRequestParameter> parameters = new List<SteamWebRequestParameter>();
+
+            parameters.AddIfHasValue(collectionIds.Count, "collectioncount");
+
+            for (int i = 0; i < collectionIds.Count; ++i)
+                parameters.AddIfHasValue(collectionIds[i], $"publishedfileids[{i}]");
+
+            try
+            {
+                var steamWebResponse = await steamWebInterface.PostAsync<CollectionDetailsResponseContainer>("GetCollectionDetails", 1, parameters);
+
+                var steamWebResponseModel = mapper.Map<
+                    ISteamWebResponse<CollectionDetailsResponseContainer>,
+                    ISteamWebResponse<IReadOnlyCollection<CollectionDetail>>>(steamWebResponse);
+
+                return steamWebResponseModel;
+            }
+            catch (HttpRequestException)
+            {
+                return null;
+            }
+        }
+
         /// <summary>
         /// Retrieves information about published files such as workshop items and screenshots.
         /// </summary>

src/SteamWebAPI2/Mappings/SteamRemoteStorageProfile.cs

@@ -36,6 +36,8 @@ public SteamRemoteStorageProfile()
             CreateMap<UGCFileDetailsResultContainer, UGCFileDetailsModel>().ConvertUsing((src, dest, context) =>
                 context.Mapper.Map<UGCFileDetails, UGCFileDetailsModel>(src.Result)
             );
+            CreateMap<CollectionDetailsResponseContainer, IReadOnlyCollection<CollectionDetail>>().ConvertUsing((src, dest, context) => 
+                context.Mapper.Map<IReadOnlyCollection<CollectionDetail>>(src.Response.CollectionDetails));
         }
     }
 }

src/SteamWebAPI2/Mappings/SteamWebResponseProfile.cs

@@ -62,6 +62,7 @@ public SteamWebResponseProfile()
             CreateSteamWebResponseMap<PublishedFileDetailsResultContainer, IReadOnlyCollection<PublishedFileDetailsModel>>();
             CreateSteamWebResponseMap<PublishedFileDetailsResultContainer, PublishedFileDetailsModel>();
             CreateSteamWebResponseMap<UGCFileDetailsResultContainer, UGCFileDetailsModel>();
+            CreateSteamWebResponseMap<CollectionDetailsResponseContainer, IReadOnlyCollection<CollectionDetail>>();
             CreateSteamWebResponseMap<PlayerSummaryResultContainer, PlayerSummaryModel>();
             CreateSteamWebResponseMap<PlayerSummaryResultContainer, IReadOnlyCollection<PlayerSummaryModel>>();
             CreateSteamWebResponseMap<FriendsListResultContainer, IReadOnlyCollection<FriendModel>>();

src/SteamWebAPI2/Models/CollectionDetailsResponseContainer.cs

@@ -0,0 +1,47 @@
+using Newtonsoft.Json;
+using System.Collections.Generic;
+
+namespace SteamWebAPI2.Models
+{
+    public class CollectionDetailsResponseContainer
+    {
+        [JsonProperty("response")]
+        public CollectionDetailsResponse Response { get; set; }
+    }
+
+    public class CollectionDetailsResponse
+    {
+        [JsonProperty("result")]
+        public uint Result { get; set; }
+
+        [JsonProperty("resultcount")]
+        public uint ResultCount { get; set; }
+
+        [JsonProperty("collectiondetails")]
+        public IList<CollectionDetail> CollectionDetails { get; set; }
+    }
+
+    public class CollectionDetail
+    {
+        [JsonProperty("publishedfileid")]
+        public string PublishedFileId { get; set; }
+
+        [JsonProperty("result")]
+        public uint Result { get; set; }
+
+        [JsonProperty("children")]
+        public IList<CollectionDetailItem> Children { get; set; }
+    }
+
+    public class CollectionDetailItem
+    {
+        [JsonProperty("publishedfileid")]
+        public string PublishedFileId { get; set; }
+
+        [JsonProperty("sortorder")]
+        public uint SortOrder { get; set; }
+
+        [JsonProperty("filetype")]
+        public uint FileType { get; set; }
+    }
+}