[Client SDK] Add catalog client (loic-sharma#321)

Add the low level catalog resource client. Part of loic-sharma#308

src/BaGet.Core/Metadata/DatabasePackageMetadataService.cs

@@ -5,7 +5,6 @@
 using System.Threading.Tasks;
 using BaGet.Core.Entities;
 using BaGet.Core.Mirror;
-using BaGet.Core.ServiceIndex;
 using BaGet.Protocol;
 using NuGet.Versioning;
 
@@ -130,25 +129,25 @@ private RegistrationIndexPageItem ToRegistrationIndexPageItem(Package package) =
 
         private IReadOnlyList<DependencyGroupItem> ToDependencyGroups(Package package)
         {
-            var groups = new List<DependencyGroupItem>();
-
-            var targetFrameworks = package.Dependencies.Select(d => d.TargetFramework).Distinct();
-
-            foreach (var target in targetFrameworks)
-            {
-                // A package may have no dependencies for a target framework. This is represented
-                // by a single dependency item with a null "Id" and "VersionRange".
-                var groupId = $"https://api.nuget.org/v3/catalog0/data/2015.02.01.06.24.15/{package.Id}.{package.Version}.json#dependencygroup/{target}";
-                var dependencyItems = package.Dependencies
-                    .Where(d => d.TargetFramework == target)
-                    .Where(d => d.Id != null && d.VersionRange != null)
-                    .Select(d => new DependencyItem($"{groupId}/{d.Id}", d.Id, d.VersionRange))
-                    .ToList();
-
-                groups.Add(new DependencyGroupItem(groupId, target, dependencyItems));
-            }
-
-            return groups;
+            return package.Dependencies
+                .GroupBy(d => d.TargetFramework)
+                .Select(group => new DependencyGroupItem
+                {
+                    TargetFramework = group.Key,
+
+                    // A package that supports a target framework but does not have dependencies while on
+                    // that target framework is represented by a fake dependency with a null "Id" and "VersionRange".
+                    // This fake dependency should not be included in the output.
+                    Dependencies = group
+                        .Where(d => d.Id != null && d.VersionRange != null)
+                        .Select(d => new DependencyItem
+                        {
+                            Id = d.Id,
+                            Range = d.VersionRange
+                        })
+                        .ToList()
+                })
+                .ToList();
         }
     }
 }

src/BaGet.Protocol/BaGet.Protocol.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
@@ -9,7 +9,7 @@
 
   <ItemGroup>
     <PackageReference Include="Newtonsoft.Json" Version="11.0.2" />
-    <PackageReference Include="NuGet.Versioning" Version="$(NuGetPackageVersion)" />
+    <PackageReference Include="NuGet.Protocol" Version="$(NuGetPackageVersion)" />
     <PackageReference Include="System.Text.Encodings.Web" Version="4.5.0" />
   </ItemGroup>
 

src/BaGet.Protocol/Catalog/CatalogClient.cs

@@ -0,0 +1,67 @@
+using System;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace BaGet.Protocol.Internal
+{
+    public class CatalogClient : ICatalogResource
+    {
+        private readonly HttpClient _httpClient;
+        private readonly string _catalogUrl;
+
+        public CatalogClient(HttpClient httpClient, string catalogUrl)
+        {
+            _httpClient = httpClient ?? throw new ArgumentNullException(nameof(httpClient));
+            _catalogUrl = catalogUrl ?? throw new ArgumentNullException(nameof(catalogUrl));
+        }
+
+        public async Task<CatalogIndex> GetIndexAsync(CancellationToken cancellationToken = default)
+        {
+            var response = await _httpClient.DeserializeUrlAsync<CatalogIndex>(_catalogUrl, cancellationToken);
+
+            return response.GetResultOrThrow();
+        }
+
+        public async Task<CatalogPage> GetPageAsync(string pageUrl, CancellationToken cancellationToken = default)
+        {
+            var response = await _httpClient.DeserializeUrlAsync<CatalogPage>(pageUrl, cancellationToken);
+
+            return response.GetResultOrThrow();
+        }
+
+        public async Task<PackageDeleteCatalogLeaf> GetPackageDeleteLeafAsync(string leafUrl, CancellationToken cancellationToken = default)
+        {
+            return await GetAndValidateLeafAsync<PackageDeleteCatalogLeaf>(
+                CatalogLeafType.PackageDelete,
+                leafUrl,
+                cancellationToken);
+        }
+
+        public async Task<PackageDetailsCatalogLeaf> GetPackageDetailsLeafAsync(string leafUrl, CancellationToken cancellationToken = default)
+        {
+            return await GetAndValidateLeafAsync<PackageDetailsCatalogLeaf>(
+                CatalogLeafType.PackageDetails,
+                leafUrl,
+                cancellationToken);
+        }
+
+        private async Task<T> GetAndValidateLeafAsync<T>(
+            CatalogLeafType type,
+            string leafUrl,
+            CancellationToken cancellationToken) where T : CatalogLeaf
+        {
+            var result = await _httpClient.DeserializeUrlAsync<T>(leafUrl, cancellationToken);
+            var leaf = result.GetResultOrThrow();
+
+            if (leaf.Type != type)
+            {
+                throw new ArgumentException(
+                    $"The leaf type found in the document does not match the expected '{type}' type.",
+                    nameof(type));
+            }
+
+            return leaf;
+        }
+    }
+}

src/BaGet.Protocol/Catalog/CatalogIndex.cs

@@ -0,0 +1,24 @@
+using System;
+using System.Collections.Generic;
+using Newtonsoft.Json;
+
+namespace BaGet.Protocol
+{
+    /// <summary>
+    /// The catalog index is the entry point for the catalog resource.
+    /// Use this to discover catalog pages, which in turn can be used to discover catalog leafs.
+    /// See: https://docs.microsoft.com/en-us/nuget/api/catalog-resource#catalog-index
+    /// Based off: https://github.com/NuGet/NuGet.Services.Metadata/blob/64af0b59c5a79e0143f0808b39946df9f16cb2e7/src/NuGet.Protocol.Catalog/Models/CatalogIndex.cs
+    /// </summary>
+    public class CatalogIndex
+    {
+        [JsonProperty("commitTimeStamp")]
+        public DateTimeOffset CommitTimestamp { get; set; }
+
+        [JsonProperty("count")]
+        public int Count { get; set; }
+
+        [JsonProperty("items")]
+        public List<CatalogPageItem> Items { get; set; }
+    }
+}

src/BaGet.Protocol/Catalog/CatalogLeaf.cs

@@ -0,0 +1,37 @@
+using System;
+using BaGet.Protocol.Internal;
+using Newtonsoft.Json;
+
+namespace BaGet.Protocol
+{
+    /// <summary>
+    /// A catalog leaf. Represents a single package event.
+    /// Leafs can be discovered from a <see cref="CatalogPage"/>.
+    /// See: https://docs.microsoft.com/en-us/nuget/api/catalog-resource#catalog-leaf
+    /// Based off: https://github.com/NuGet/NuGet.Services.Metadata/blob/64af0b59c5a79e0143f0808b39946df9f16cb2e7/src/NuGet.Protocol.Catalog/Models/CatalogLeaf.cs
+    /// </summary>
+    public class CatalogLeaf : ICatalogLeafItem
+    {
+        [JsonProperty("@id")]
+        public string Url { get; set; }
+
+        [JsonProperty("@type")]
+        [JsonConverter(typeof(CatalogLeafTypeConverter))]
+        public CatalogLeafType Type { get; set; }
+
+        [JsonProperty("catalog:commitId")]
+        public string CommitId { get; set; }
+
+        [JsonProperty("catalog:commitTimeStamp")]
+        public DateTimeOffset CommitTimestamp { get; set; }
+
+        [JsonProperty("id")]
+        public string PackageId { get; set; }
+
+        [JsonProperty("published")]
+        public DateTimeOffset Published { get; set; }
+
+        [JsonProperty("version")]
+        public string PackageVersion { get; set; }
+    }
+}

src/BaGet.Protocol/Catalog/CatalogLeafItem.cs

@@ -0,0 +1,30 @@
+using System;
+using BaGet.Protocol.Internal;
+using Newtonsoft.Json;
+
+namespace BaGet.Protocol
+{
+    /// <summary>
+    /// An item in a <see cref="CatalogPage"/> that references a <see cref="CatalogLeaf"/>.
+    /// See: https://docs.microsoft.com/en-us/nuget/api/catalog-resource#catalog-item-object-in-a-page
+    /// Based off: https://github.com/NuGet/NuGet.Services.Metadata/blob/64af0b59c5a79e0143f0808b39946df9f16cb2e7/src/NuGet.Protocol.Catalog/Models/CatalogLeafItem.cs
+    /// </summary>
+    public class CatalogLeafItem : ICatalogLeafItem
+    {
+        [JsonProperty("@id")]
+        public string Url { get; set; }
+
+        [JsonProperty("@type")]
+        [JsonConverter(typeof(CatalogLeafItemTypeConverter))]
+        public CatalogLeafType Type { get; set; }
+
+        [JsonProperty("commitTimeStamp")]
+        public DateTimeOffset CommitTimestamp { get; set; }
+
+        [JsonProperty("nuget:id")]
+        public string PackageId { get; set; }
+
+        [JsonProperty("nuget:version")]
+        public string PackageVersion { get; set; }
+    }
+}

src/BaGet.Protocol/Catalog/CatalogLeafType.cs

@@ -0,0 +1,19 @@
+namespace BaGet.Protocol
+{
+    /// <summary>
+    /// The type of a <see cref="CatalogLeaf"/>.
+    /// Based off: https://github.com/NuGet/NuGet.Services.Metadata/blob/64af0b59c5a79e0143f0808b39946df9f16cb2e7/src/NuGet.Protocol.Catalog/Models/CatalogLeafType.cs
+    /// </summary>
+    public enum CatalogLeafType
+    {
+        /// <summary>
+        /// The <see cref="CatalogLeaf"/> represents the snapshot of a package's metadata.
+        /// </summary>
+        PackageDetails = 1,
+
+        /// <summary>
+        /// The <see cref="CatalogLeaf"/> represents a package that was deleted.
+        /// </summary>
+        PackageDelete = 2,
+    }
+}