Merge branch 'feature/update-check-api' into develop

32 files changed, 977 insertions, 334 deletions

diff --git a/.gitignore b/.gitignore
index 08d3fe47..f2d50778 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,262 +1,25 @@
-# SMAPI Specific Ignores
-StardewModdingAPI/bin/
-StardewModdingAPI/obj/
-TrainerMod/bin/
-TrainerMod/obj/
-StardewInjector/bin/
-StardewInjector/obj/
-packages/
-steamapps/
-
-*.symlink
-*.lnk
-!*.exe
-!*.dll
-
-## Ignore Visual Studio temporary files, build results, and
-## files generated by popular Visual Studio add-ons.
-
-# User-specific files
+# user-specific files
 *.suo
 *.user
 *.userosscache
 *.sln.docstates
 
-# User-specific files (MonoDevelop/Xamarin Studio)
-*.userprefs
-
-# Build results
+# build results
 [Dd]ebug/
-[Dd]ebugPublic/
 [Rr]elease/
-[Rr]eleases/
-x64/
-x86/
-bld/
 [Bb]in/
 [Oo]bj/
-[Ll]og/
 
-# Visual Studio 2015 cache/options directory
+# Visual Studio cache/options
 .vs/
-# Uncomment if you have tasks that create the project's static files in wwwroot
-#wwwroot/
-
-# MSTest test Results
-[Tt]est[Rr]esult*/
-[Bb]uild[Ll]og.*
-
-# NUNIT
-*.VisualState.xml
-TestResult.xml
-
-# Build Results of an ATL Project
-[Dd]ebugPS/
-[Rr]eleasePS/
-dlldata.c
-
-# DNX
-project.lock.json
-artifacts/
-
-*_i.c
-*_p.c
-*_i.h
-*.ilk
-*.meta
-*.obj
-*.pch
-*.pdb
-*.pgc
-*.pgd
-*.rsp
-*.sbr
-*.tlb
-*.tli
-*.tlh
-*.tmp
-*.tmp_proj
-*.log
-*.vspscc
-*.vssscc
-.builds
-*.pidb
-*.svclog
-*.scc
-
-# Chutzpah Test files
-_Chutzpah*
-
-# Visual C++ cache files
-ipch/
-*.aps
-*.ncb
-*.opendb
-*.opensdf
-*.sdf
-*.cachefile
 
-# Visual Studio profiler
-*.psess
-*.vsp
-*.vspx
-*.sap
-
-# TFS 2012 Local Workspace
-$tf/
-
-# Guidance Automation Toolkit
-*.gpState
-
-# ReSharper is a .NET coding add-in
+# ReSharper
 _ReSharper*/
 *.[Rr]e[Ss]harper
 *.DotSettings.user
 
-# JustCode is a .NET coding add-in
-.JustCode
-
-# TeamCity is a build add-in
-_TeamCity*
-
-# DotCover is a Code Coverage Tool
-*.dotCover
-
-# NCrunch
-_NCrunch_*
-.*crunch*.local.xml
-nCrunchTemp_*
-
-# MightyMoose
-*.mm.*
-AutoTest.Net/
-
-# Web workbench (sass)
-.sass-cache/
-
-# Installshield output folder
-[Ee]xpress/
-
-# DocProject is a documentation generator add-in
-DocProject/buildhelp/
-DocProject/Help/*.HxT
-DocProject/Help/*.HxC
-DocProject/Help/*.hhc
-DocProject/Help/*.hhk
-DocProject/Help/*.hhp
-DocProject/Help/Html2
-DocProject/Help/html
-
-# Click-Once directory
-publish/
-
-# Publish Web Output
-*.[Pp]ublish.xml
-*.azurePubxml
-# TODO: Comment the next line if you want to checkin your web deploy settings 
-# but database connection strings (with potential passwords) will be unencrypted
-*.pubxml
-*.publishproj
-
-# NuGet Packages
+# NuGet packages
 *.nupkg
-# The packages folder can be ignored because of Package Restore
 **/packages/*
-# except build/, which is used as an MSBuild target.
-!**/packages/build/
-# Uncomment if necessary however generally it will be regenerated when needed
-#!**/packages/repositories.config
-# NuGet v3's project.json files produces more ignoreable files
 *.nuget.props
 *.nuget.targets
-
-# Microsoft Azure Build Output
-csx/
-*.build.csdef
-
-# Microsoft Azure Emulator
-ecf/
-rcf/
-
-# Microsoft Azure ApplicationInsights config file
-ApplicationInsights.config
-
-# Windows Store app package directories and files
-AppPackages/
-BundleArtifacts/
-Package.StoreAssociation.xml
-_pkginfo.txt
-
-# Visual Studio cache files
-# files ending in .cache can be ignored
-*.[Cc]ache
-# but keep track of directories ending in .cache
-!*.[Cc]ache/
-
-# Others
-ClientBin/
-~$*
-*~
-*.dbmdl
-*.dbproj.schemaview
-*.pfx
-*.publishsettings
-node_modules/
-orleans.codegen.cs
-
-# Since there are multiple workflows, uncomment next line to ignore bower_components 
-# (https://github.com/github/gitignore/pull/1529#issuecomment-104372622)
-#bower_components/
-
-# RIA/Silverlight projects
-Generated_Code/
-
-# Backup & report files from converting an old project file
-# to a newer Visual Studio version. Backup files are not needed,
-# because we have git ;-)
-_UpgradeReport_Files/
-Backup*/
-UpgradeLog*.XML
-UpgradeLog*.htm
-
-# SQL Server files
-*.mdf
-*.ldf
-
-# Business Intelligence projects
-*.rdl.data
-*.bim.layout
-*.bim_*.settings
-
-# Microsoft Fakes
-FakesAssemblies/
-
-# GhostDoc plugin setting file
-*.GhostDoc.xml
-
-# Node.js Tools for Visual Studio
-.ntvs_analysis.dat
-
-# Visual Studio 6 build log
-*.plg
-
-# Visual Studio 6 workspace options file
-*.opt
-
-# Visual Studio LightSwitch build output
-**/*.HTMLClient/GeneratedArtifacts
-**/*.DesktopClient/GeneratedArtifacts
-**/*.DesktopClient/ModelManifest.xml
-**/*.Server/GeneratedArtifacts
-**/*.Server/ModelManifest.xml
-_Pvt_Extensions
-
-# Paket dependency manager
-.paket/paket.exe
-
-# FAKE - F# Make
-.fake/
-
-# JetBrains Rider
-.idea/
-*.sln.iml
\ No newline at end of file
diff --git a/release-notes.md b/release-notes.md
index c31d2bae..a07de71f 100644
--- a/release-notes.md
+++ b/release-notes.md
@@ -6,12 +6,15 @@ For players:
 * The console is now simpler and easier to read.
 * The console now adjusts its colors when you have a light terminal background.
 * SMAPI now detects mods which may impact game stability and shows a warning in the console.
-* Updated compatibility list.
+* SMAPI now alerts you in the console when one of your mods has a new version.
 * Renamed installer folder from `SMAPI 2.0` to `SMAPI 2.0 installer` to avoid confusion.
+* Updated compatibility list.
+* Fixed update check errors on Linux/Mac.
 
 For mod developers:
 * Added new APIs to edit, inject, and reload XNB assets loaded by the game at any time.  
   <small>_This let mods do anything previously only possible with XNB mods, plus enables new mod scenarios (e.g. seasonal textures, NPC clothing that depend on the weather or location, etc)._</small>
+* Added new manifest fields to enable automatic update checks.
 * Added new input events.  
   <small>_The new `InputEvents` combine keyboard + mouse + controller input into one event for easy handling, add metadata like the cursor position and grab tile to support click handling, and add an option to suppress input from the game to enable new scenarios like action highjacking and UI overlays._</small>
 * Added support for optional dependencies.
diff --git a/src/StardewModdingAPI.Models/ModInfoModel.cs b/src/StardewModdingAPI.Models/ModInfoModel.cs
new file mode 100644
index 00000000..44071230
--- /dev/null
+++ b/src/StardewModdingAPI.Models/ModInfoModel.cs
@@ -0,0 +1,48 @@
+using Newtonsoft.Json;
+
+namespace StardewModdingAPI.Models
+{
+    /// <summary>Generic metadata about a mod.</summary>
+    internal class ModInfoModel
+    {
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The mod name.</summary>
+        public string Name { get; }
+
+        /// <summary>The mod's semantic version number.</summary>
+        public string Version { get; }
+
+        /// <summary>The mod's web URL.</summary>
+        public string Url { get; }
+
+        /// <summary>The error message indicating why the mod is invalid (if applicable).</summary>
+        public string Error { get; }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct a valid instance.</summary>
+        /// <param name="name">The mod name.</param>
+        /// <param name="version">The mod's semantic version number.</param>
+        /// <param name="url">The mod's web URL.</param>
+        /// <param name="error">The error message indicating why the mod is invalid (if applicable).</param>
+        [JsonConstructor]
+        public ModInfoModel(string name, string version, string url, string error = null)
+        {
+            this.Name = name;
+            this.Version = version;
+            this.Url = url;
+            this.Error = error; // mainly initialised here for the JSON deserialiser
+        }
+
+        /// <summary>Construct an valid instance.</summary>
+        /// <param name="error">The error message indicating why the mod is invalid.</param>
+        public ModInfoModel(string error)
+        {
+            this.Error = error;
+        }
+    }
+}
diff --git a/src/StardewModdingAPI.Models/StardewModdingAPI.Models.projitems b/src/StardewModdingAPI.Models/StardewModdingAPI.Models.projitems
new file mode 100644
index 00000000..2465760e
--- /dev/null
+++ b/src/StardewModdingAPI.Models/StardewModdingAPI.Models.projitems
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <MSBuildAllProjects>$(MSBuildAllProjects);$(MSBuildThisFileFullPath)</MSBuildAllProjects>
+    <HasSharedItems>true</HasSharedItems>
+    <SharedGUID>2aa02fb6-ff03-41cf-a215-2ee60ab4f5dc</SharedGUID>
+  </PropertyGroup>
+  <PropertyGroup Label="Configuration">
+    <Import_RootNamespace>StardewModdingAPI.Models</Import_RootNamespace>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildThisFileDirectory)ModInfoModel.cs" />
+  </ItemGroup>
+</Project>
\ No newline at end of file
diff --git a/src/StardewModdingAPI.Models/StardewModdingAPI.Models.shproj b/src/StardewModdingAPI.Models/StardewModdingAPI.Models.shproj
new file mode 100644
index 00000000..c80517af
--- /dev/null
+++ b/src/StardewModdingAPI.Models/StardewModdingAPI.Models.shproj
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>2aa02fb6-ff03-41cf-a215-2ee60ab4f5dc</ProjectGuid>
+    <MinimumVisualStudioVersion>14.0</MinimumVisualStudioVersion>
+  </PropertyGroup>
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\CodeSharing\Microsoft.CodeSharing.Common.Default.props" />
+  <Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\CodeSharing\Microsoft.CodeSharing.Common.props" />
+  <PropertyGroup />
+  <Import Project="StardewModdingAPI.Models.projitems" Label="Shared" />
+  <Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\CodeSharing\Microsoft.CodeSharing.CSharp.targets" />
+</Project>
diff --git a/src/StardewModdingAPI.Tests/StardewModdingAPI.Tests.csproj b/src/StardewModdingAPI.Tests/StardewModdingAPI.Tests.csproj
index f3dbcdd4..41525bcb 100644
--- a/src/StardewModdingAPI.Tests/StardewModdingAPI.Tests.csproj
+++ b/src/StardewModdingAPI.Tests/StardewModdingAPI.Tests.csproj
@@ -39,8 +39,8 @@
     <Reference Include="Newtonsoft.Json, Version=8.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed, processorArchitecture=MSIL">
       <HintPath>..\packages\Newtonsoft.Json.8.0.3\lib\net45\Newtonsoft.Json.dll</HintPath>
     </Reference>
-    <Reference Include="nunit.framework, Version=3.7.1.0, Culture=neutral, PublicKeyToken=2638cd05610744eb, processorArchitecture=MSIL">
-      <HintPath>..\packages\NUnit.3.7.1\lib\net45\nunit.framework.dll</HintPath>
+    <Reference Include="nunit.framework, Version=3.8.1.0, Culture=neutral, PublicKeyToken=2638cd05610744eb, processorArchitecture=MSIL">
+      <HintPath>..\packages\NUnit.3.8.1\lib\net45\nunit.framework.dll</HintPath>
     </Reference>
     <Reference Include="System" />
   </ItemGroup>
diff --git a/src/StardewModdingAPI.Tests/packages.config b/src/StardewModdingAPI.Tests/packages.config
index 6f04e625..5fdfebdb 100644
--- a/src/StardewModdingAPI.Tests/packages.config
+++ b/src/StardewModdingAPI.Tests/packages.config
@@ -3,5 +3,5 @@
   <package id="Castle.Core" version="4.1.1" targetFramework="net45" />
   <package id="Moq" version="4.7.99" targetFramework="net45" />
   <package id="Newtonsoft.Json" version="8.0.3" targetFramework="net45" />
-  <package id="NUnit" version="3.7.1" targetFramework="net45" />
-</packages>
\ No newline at end of file
+  <package id="NUnit" version="3.8.1" targetFramework="net45" />
+</packages>
diff --git a/src/StardewModdingAPI.Web/Controllers/ModsController.cs b/src/StardewModdingAPI.Web/Controllers/ModsController.cs
new file mode 100644
index 00000000..8fc2cb51
--- /dev/null
+++ b/src/StardewModdingAPI.Web/Controllers/ModsController.cs
@@ -0,0 +1,132 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Caching.Memory;
+using Microsoft.Extensions.Options;
+using StardewModdingAPI.Web.Framework.ConfigModels;
+using StardewModdingAPI.Web.Framework.ModRepositories;
+using StardewModdingAPI.Models;
+
+namespace StardewModdingAPI.Web.Controllers
+{
+    /// <summary>Provides an API to perform mod update checks.</summary>
+    [Produces("application/json")]
+    internal class ModsController : Controller
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>The mod repositories which provide mod metadata.</summary>
+        private readonly IDictionary<string, IModRepository> Repositories;
+
+        /// <summary>The cache in which to store mod metadata.</summary>
+        private readonly IMemoryCache Cache;
+
+        /// <summary>The number of minutes update checks should be cached before refetching them.</summary>
+        private readonly int CacheMinutes;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="cache">The cache in which to store mod metadata.</param>
+        /// <param name="configProvider">The config settings for mod update checks.</param>
+        public ModsController(IMemoryCache cache, IOptions<ModUpdateCheckConfig> configProvider)
+        {
+            ModUpdateCheckConfig config = configProvider.Value;
+
+            this.Cache = cache;
+            this.CacheMinutes = config.CacheMinutes;
+
+            this.Repositories =
+                new IModRepository[]
+                {
+                    new GitHubRepository(
+                        vendorKey: config.GitHubKey,
+                        baseUrl: config.GitHubBaseUrl,
+                        releaseUrlFormat: config.GitHubReleaseUrlFormat,
+                        userAgent: config.GitHubUserAgent,
+                        acceptHeader: config.GitHubAcceptHeader,
+                        username: config.GitHubUsername,
+                        password: config.GitHubPassword
+                    ),
+                    new NexusRepository(
+                        vendorKey: config.NexusKey,
+                        userAgent: config.NexusUserAgent,
+                        baseUrl: config.NexusBaseUrl,
+                        modUrlFormat: config.NexusModUrlFormat
+                    )
+                }
+                .ToDictionary(p => p.VendorKey, StringComparer.CurrentCultureIgnoreCase);
+        }
+
+        /// <summary>Fetch version metadata for the given mods.</summary>
+        /// <param name="modKeys">The namespaced mod keys to search as a comma-delimited array.</param>
+        [HttpGet]
+        public async Task<IDictionary<string, ModInfoModel>> GetAsync(string modKeys)
+        {
+            // sort & filter keys
+            string[] modKeysArray = (modKeys?.Split(',').Select(p => p.Trim()).ToArray() ?? new string[0])
+                .Distinct(StringComparer.CurrentCultureIgnoreCase)
+                .OrderBy(p => p, StringComparer.CurrentCultureIgnoreCase)
+                .ToArray();
+
+            // fetch mod info
+            IDictionary<string, ModInfoModel> result = new Dictionary<string, ModInfoModel>(StringComparer.CurrentCultureIgnoreCase);
+            foreach (string modKey in modKeysArray)
+            {
+                // parse mod key
+                if (!this.TryParseModKey(modKey, out string vendorKey, out string modID))
+                {
+                    result[modKey] = new ModInfoModel("The mod key isn't in a valid format. It should contain the mod repository key and mod ID like 'Nexus:541'.");
+                    continue;
+                }
+
+                // get matching repository
+                if (!this.Repositories.TryGetValue(vendorKey, out IModRepository repository))
+                {
+                    result[modKey] = new ModInfoModel("There's no mod repository matching this namespaced mod ID.");
+                    continue;
+                }
+
+                // fetch mod info
+                result[modKey] = await this.Cache.GetOrCreateAsync($"{repository.VendorKey}:{modID}".ToLower(), async entry =>
+                {
+                    entry.AbsoluteExpiration = DateTimeOffset.UtcNow.AddMinutes(this.CacheMinutes);
+                    return await repository.GetModInfoAsync(modID);
+                });
+            }
+
+            return result;
+        }
+
+
+        /*********
+        ** Private methods
+        *********/
+        /// <summary>Parse a namespaced mod ID.</summary>
+        /// <param name="raw">The raw mod ID to parse.</param>
+        /// <param name="vendorKey">The parsed vendor key.</param>
+        /// <param name="modID">The parsed mod ID.</param>
+        /// <returns>Returns whether the value could be parsed.</returns>
+        private bool TryParseModKey(string raw, out string vendorKey, out string modID)
+        {
+            // split parts
+            string[] parts = raw?.Split(':');
+            if (parts == null || parts.Length != 2)
+            {
+                vendorKey = null;
+                modID = null;
+                return false;
+            }
+
+            // parse
+            vendorKey = parts[0];
+            modID = parts[1];
+            return true;
+        }
+    }
+}
diff --git a/src/StardewModdingAPI.Web/Framework/ConfigModels/ModUpdateCheckConfig.cs b/src/StardewModdingAPI.Web/Framework/ConfigModels/ModUpdateCheckConfig.cs
new file mode 100644
index 00000000..5d55ba18
--- /dev/null
+++ b/src/StardewModdingAPI.Web/Framework/ConfigModels/ModUpdateCheckConfig.cs
@@ -0,0 +1,54 @@
+namespace StardewModdingAPI.Web.Framework.ConfigModels
+{
+    /// <summary>The config settings for mod update checks.</summary>
+    public class ModUpdateCheckConfig
+    {
+        /*********
+        ** Accessors
+        *********/
+        /****
+        ** General
+        ****/
+        /// <summary>The number of minutes update checks should be cached before refetching them.</summary>
+        public int CacheMinutes { get; set; }
+
+        /****
+        ** GitHub
+        ****/
+        /// <summary>The repository key for Nexus Mods.</summary>
+        public string GitHubKey { get; set; }
+
+        /// <summary>The user agent for the GitHub API client.</summary>
+        public string GitHubUserAgent { get; set; }
+
+        /// <summary>The base URL for the GitHub API.</summary>
+        public string GitHubBaseUrl { get; set; }
+
+        /// <summary>The URL for a GitHub API latest-release query excluding the <see cref="GitHubBaseUrl"/>, where {0} is the organisation and project name.</summary>
+        public string GitHubReleaseUrlFormat { get; set; }
+
+        /// <summary>The Accept header value expected by the GitHub API.</summary>
+        public string GitHubAcceptHeader { get; set; }
+
+        /// <summary>The username with which to authenticate to the GitHub API (if any).</summary>
+        public string GitHubUsername { get; set; }
+
+        /// <summary>The password with which to authenticate to the GitHub API (if any).</summary>
+        public string GitHubPassword { get; set; }
+
+        /****
+        ** Nexus Mods
+        ****/
+        /// <summary>The repository key for Nexus Mods.</summary>
+        public string NexusKey { get; set; }
+
+        /// <summary>The user agent for the Nexus Mods API client.</summary>
+        public string NexusUserAgent { get; set; }
+
+        /// <summary>The base URL for the Nexus Mods API.</summary>
+        public string NexusBaseUrl { get; set; }
+
+        /// <summary>The URL for a Nexus Mods API query excluding the <see cref="NexusBaseUrl"/>, where {0} is the mod ID.</summary>
+        public string NexusModUrlFormat { get; set; }
+    }
+}
diff --git a/src/StardewModdingAPI.Web/Framework/InternalControllerFeatureProvider.cs b/src/StardewModdingAPI.Web/Framework/InternalControllerFeatureProvider.cs
new file mode 100644
index 00000000..2c24c610
--- /dev/null
+++ b/src/StardewModdingAPI.Web/Framework/InternalControllerFeatureProvider.cs
@@ -0,0 +1,27 @@
+using System;
+using System.Reflection;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.Controllers;
+
+namespace StardewModdingAPI.Web.Framework
+{
+    /// <summary>Discovers controllers with support for non-public controllers.</summary>
+    internal class InternalControllerFeatureProvider : ControllerFeatureProvider
+    {
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Determines if a given type is a controller.</summary>
+        /// <param name="type">The <see cref="T:System.Reflection.TypeInfo" /> candidate.</param>
+        /// <returns><code>true</code> if the type is a controller; otherwise <code>false</code>.</returns>
+        protected override bool IsController(TypeInfo type)
+        {
+            return
+                type.IsClass
+                && !type.IsAbstract
+                && (/*type.IsPublic &&*/ !type.ContainsGenericParameters)
+                && (!type.IsDefined(typeof(NonControllerAttribute))
+                && (type.Name.EndsWith("Controller", StringComparison.OrdinalIgnoreCase) || type.IsDefined(typeof(ControllerAttribute))));
+        }
+    }
+}
diff --git a/src/StardewModdingAPI.Web/Framework/ModRepositories/GitHubRepository.cs b/src/StardewModdingAPI.Web/Framework/ModRepositories/GitHubRepository.cs
new file mode 100644
index 00000000..421220de
--- /dev/null
+++ b/src/StardewModdingAPI.Web/Framework/ModRepositories/GitHubRepository.cs
@@ -0,0 +1,95 @@
+using System;
+using System.Threading.Tasks;
+using Newtonsoft.Json;
+using Pathoschild.Http.Client;
+using StardewModdingAPI.Models;
+
+namespace StardewModdingAPI.Web.Framework.ModRepositories
+{
+    /// <summary>An HTTP client for fetching mod metadata from GitHub project releases.</summary>
+    internal class GitHubRepository : IModRepository
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>The underlying HTTP client.</summary>
+        private readonly IClient Client;
+
+
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The unique key for this vendor.</summary>
+        public string VendorKey { get; }
+
+        /// <summary>The URL for a Nexus Mods API query excluding the base URL, where {0} is the mod ID.</summary>
+        public string ReleaseUrlFormat { get; }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="vendorKey">The unique key for this vendor.</param>
+        /// <param name="baseUrl">The base URL for the Nexus Mods API.</param>
+        /// <param name="releaseUrlFormat">The URL for a Nexus Mods API query excluding the <paramref name="baseUrl"/>, where {0} is the mod ID.</param>
+        /// <param name="userAgent">The user agent for the GitHub API client.</param>
+        /// <param name="acceptHeader">The Accept header value expected by the GitHub API.</param>
+        /// <param name="username">The username with which to authenticate to the GitHub API.</param>
+        /// <param name="password">The password with which to authenticate to the GitHub API.</param>
+        public GitHubRepository(string vendorKey, string baseUrl, string releaseUrlFormat, string userAgent, string acceptHeader, string username, string password)
+        {
+            this.VendorKey = vendorKey;
+            this.ReleaseUrlFormat = releaseUrlFormat;
+
+            this.Client = new FluentClient(baseUrl)
+                .SetUserAgent(string.Format(userAgent, this.GetType().Assembly.GetName().Version))
+                .AddDefault(req => req.WithHeader("Accept", acceptHeader));
+            if (!string.IsNullOrWhiteSpace(username))
+                this.Client = this.Client.SetBasicAuthentication(username, password);
+        }
+
+        /// <summary>Get metadata about a mod in the repository.</summary>
+        /// <param name="id">The mod ID in this repository.</param>
+        public async Task<ModInfoModel> GetModInfoAsync(string id)
+        {
+            try
+            {
+                GitRelease release = await this.Client
+                    .GetAsync(string.Format(this.ReleaseUrlFormat, id))
+                    .As<GitRelease>();
+
+                return new ModInfoModel(id, release.Tag, $"https://github.com/{id}/releases");
+            }
+            catch (Exception ex)
+            {
+                return new ModInfoModel(ex.ToString());
+            }
+        }
+
+        /// <summary>Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.</summary>
+        public void Dispose()
+        {
+            this.Client.Dispose();
+        }
+
+
+        /*********
+        ** Private models
+        *********/
+        /// <summary>Metadata about a GitHub release tag.</summary>
+        private class GitRelease
+        {
+            /*********
+            ** Accessors
+            *********/
+            /// <summary>The display name.</summary>
+            [JsonProperty("name")]
+            public string Name { get; set; }
+
+            /// <summary>The semantic version string.</su