Merge branch 'add-mod-build-config' into develop

17 files changed, 856 insertions, 0 deletions

diff --git a/src/SMAPI.Web/Controllers/ModsController.cs b/src/SMAPI.Web/Controllers/ModsController.cs
new file mode 100644
index 00000000..7dcfcf13
--- /dev/null
+++ b/src/SMAPI.Web/Controllers/ModsController.cs
@@ -0,0 +1,162 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text.RegularExpressions;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Caching.Memory;
+using Microsoft.Extensions.Options;
+using StardewModdingAPI.Models;
+using StardewModdingAPI.Web.Framework.ConfigModels;
+using StardewModdingAPI.Web.Framework.ModRepositories;
+
+namespace StardewModdingAPI.Web.Controllers
+{
+    /// <summary>Provides an API to perform mod update checks.</summary>
+    [Produces("application/json")]
+    [Route("api/{version:semanticVersion}/[controller]")]
+    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;
+
+        /// <summary>A regex which matches SMAPI-style semantic version.</summary>
+        private readonly string VersionRegex;
+
+
+        /*********
+        ** 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.VersionRegex = config.SemanticVersionRegex;
+
+            string version = this.GetType().Assembly.GetName().Version.ToString(3);
+            this.Repositories =
+                new IModRepository[]
+                {
+                    new ChucklefishRepository(
+                        vendorKey: config.ChucklefishKey,
+                        userAgent: string.Format(config.ChucklefishUserAgent, version),
+                        baseUrl: config.ChucklefishBaseUrl,
+                        modPageUrlFormat: config.ChucklefishModPageUrlFormat
+                    ),
+                    new GitHubRepository(
+                        vendorKey: config.GitHubKey,
+                        baseUrl: config.GitHubBaseUrl,
+                        releaseUrlFormat: config.GitHubReleaseUrlFormat,
+                        userAgent: string.Format(config.GitHubUserAgent, version),
+                        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)
+        {
+            string[] modKeysArray = modKeys?.Split(',').ToArray();
+            if (modKeysArray == null || !modKeysArray.Any())
+                return new Dictionary<string, ModInfoModel>();
+
+            return await this.PostAsync(new ModSearchModel(modKeysArray));
+        }
+
+        /// <summary>Fetch version metadata for the given mods.</summary>
+        /// <param name="search">The mod search criteria.</param>
+        [HttpPost]
+        public async Task<IDictionary<string, ModInfoModel>> PostAsync([FromBody] ModSearchModel search)
+        {
+            // sort & filter keys
+            string[] modKeys = (search?.ModKeys?.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 modKeys)
+            {
+                // 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 site key and mod ID like 'Nexus:541'.");
+                    continue;
+                }
+
+                // get matching repository
+                if (!this.Repositories.TryGetValue(vendorKey, out IModRepository repository))
+                {
+                    result[modKey] = new ModInfoModel($"There's no mod site with key '{vendorKey}'. Expected one of [{string.Join(", ", this.Repositories.Keys)}].");
+                    continue;
+                }
+
+                // fetch mod info
+                result[modKey] = await this.Cache.GetOrCreateAsync($"{repository.VendorKey}:{modID}".ToLower(), async entry =>
+                {
+                    entry.AbsoluteExpiration = DateTimeOffset.UtcNow.AddMinutes(this.CacheMinutes);
+
+                    ModInfoModel info = await repository.GetModInfoAsync(modID);
+                    if (info.Error == null && (info.Version == null || !Regex.IsMatch(info.Version, this.VersionRegex, RegexOptions.CultureInvariant | RegexOptions.IgnoreCase)))
+                        info = new ModInfoModel(info.Name, info.Version, info.Url, info.Version == null ? "Mod has no version number." : $"Mod has invalid semantic version '{info.Version}'.");
+
+                    return info;
+                });
+            }
+
+            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].Trim();
+            modID = parts[1].Trim();
+            return true;
+        }
+    }
+}
diff --git a/src/SMAPI.Web/Framework/ConfigModels/ModUpdateCheckConfig.cs b/src/SMAPI.Web/Framework/ConfigModels/ModUpdateCheckConfig.cs
new file mode 100644
index 00000000..03de639e
--- /dev/null
+++ b/src/SMAPI.Web/Framework/ConfigModels/ModUpdateCheckConfig.cs
@@ -0,0 +1,74 @@
+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; }
+
+        /// <summary>A regex which matches SMAPI-style semantic version.</summary>
+        /// <remarks>Derived from SMAPI's SemanticVersion implementation.</remarks>
+        public string SemanticVersionRegex { get; set; }
+
+        /****
+        ** Chucklefish mod site
+        ****/
+        /// <summary>The repository key for the Chucklefish mod site.</summary>
+        public string ChucklefishKey { get; set; }
+
+        /// <summary>The user agent for the Chucklefish API client, where {0} is the SMAPI version.</summary>
+        public string ChucklefishUserAgent { get; set; }
+
+        /// <summary>The base URL for the Chucklefish mod site.</summary>
+        public string ChucklefishBaseUrl { get; set; }
+
+        /// <summary>The URL for a mod page on the Chucklefish mod site excluding the <see cref="GitHubBaseUrl"/>, where {0} is the mod ID.</summary>
+        public string ChucklefishModPageUrlFormat { 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, where {0} is the SMAPI version.</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/SMAPI.Web/Framework/InternalControllerFeatureProvider.cs b/src/SMAPI.Web/Framework/InternalControllerFeatureProvider.cs
new file mode 100644
index 00000000..2c24c610
--- /dev/null
+++ b/src/SMAPI.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/SMAPI.Web/Framework/ModRepositories/BaseRepository.cs b/src/SMAPI.Web/Framework/ModRepositories/BaseRepository.cs
new file mode 100644
index 00000000..d98acd89
--- /dev/null
+++ b/src/SMAPI.Web/Framework/ModRepositories/BaseRepository.cs
@@ -0,0 +1,51 @@
+using System.Text.RegularExpressions;
+using System.Threading.Tasks;
+using StardewModdingAPI.Models;
+
+namespace StardewModdingAPI.Web.Framework.ModRepositories
+{
+    internal abstract class RepositoryBase : IModRepository
+    {
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The unique key for this vendor.</summary>
+        public string VendorKey { get; }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.</summary>
+        public abstract void Dispose();
+
+        /// <summary>Get metadata about a mod in the repository.</summary>
+        /// <param name="id">The mod ID in this repository.</param>
+        public abstract Task<ModInfoModel> GetModInfoAsync(string id);
+
+
+        /*********
+        ** Protected methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="vendorKey">The unique key for this vendor.</param>
+        protected RepositoryBase(string vendorKey)
+        {
+            this.VendorKey = vendorKey;
+        }
+
+        /// <summary>Normalise a version string.</summary>
+        /// <param name="version">The version to normalise.</param>
+        protected string NormaliseVersion(string version)
+        {
+            if (string.IsNullOrWhiteSpace(version))
+                return null;
+
+            version = version.Trim();
+            if (Regex.IsMatch(version, @"^v\d", RegexOptions.CultureInvariant | RegexOptions.IgnoreCase)) // common version prefix
+                version = version.Substring(1);
+
+            return version;
+        }
+    }
+}
diff --git a/src/SMAPI.Web/Framework/ModRepositories/ChucklefishRepository.cs b/src/SMAPI.Web/Framework/ModRepositories/ChucklefishRepository.cs
new file mode 100644
index 00000000..ed7bd60b
--- /dev/null
+++ b/src/SMAPI.Web/Framework/ModRepositories/ChucklefishRepository.cs
@@ -0,0 +1,92 @@
+using System;
+using System.Net;
+using System.Threading.Tasks;
+using HtmlAgilityPack;
+using Pathoschild.Http.Client;
+using StardewModdingAPI.Models;
+
+namespace StardewModdingAPI.Web.Framework.ModRepositories
+{
+    /// <summary>An HTTP client for fetching mod metadata from the Chucklefish mod site.</summary>
+    internal class ChucklefishRepository : RepositoryBase
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>The base URL for the Chucklefish mod site.</summary>
+        private readonly string BaseUrl;
+
+        /// <summary>The URL for a mod page excluding the base URL, where {0} is the mod ID.</summary>
+        private readonly string ModPageUrlFormat;
+
+        /// <summary>The underlying HTTP client.</summary>
+        private readonly IClient Client;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="vendorKey">The unique key for this vendor.</param>
+        /// <param name="userAgent">The user agent for the API client.</param>
+        /// <param name="baseUrl">The base URL for the Chucklefish mod site.</param>
+        /// <param name="modPageUrlFormat">The URL for a mod page excluding the <paramref name="baseUrl"/>, where {0} is the mod ID.</param>
+        public ChucklefishRepository(string vendorKey, string userAgent, string baseUrl, string modPageUrlFormat)
+            : base(vendorKey)
+        {
+            this.BaseUrl = baseUrl;
+            this.ModPageUrlFormat = modPageUrlFormat;
+            this.Client = new FluentClient(baseUrl).SetUserAgent(userAgent);
+        }
+
+        /// <summary>Get metadata about a mod in the repository.</summary>
+        /// <param name="id">The mod ID in this repository.</param>
+        public override async Task<ModInfoModel> GetModInfoAsync(string id)
+        {
+            // validate ID format
+            if (!uint.TryParse(id, out uint _))
+                return new ModInfoModel($"The value '{id}' isn't a valid Chucklefish mod ID, must be an integer ID.");
+
+            // fetch info
+            try
+            {
+                // fetch HTML
+                string html;
+                try
+                {
+                    html = await this.Client
+                        .GetAsync(string.Format(this.ModPageUrlFormat, id))
+                        .AsString();
+                }
+                catch (ApiException ex) when (ex.Status == HttpStatusCode.NotFound)
+                {
+                    return new ModInfoModel("Found no mod with this ID.");
+                }
+
+                // parse HTML
+                var doc = new HtmlDocument();
+                doc.LoadHtml(html);
+
+                // extract mod info
+                string url = new UriBuilder(new Uri(this.BaseUrl)) { Path = string.Format(this.ModPageUrlFormat, id) }.Uri.ToString();
+                string name = doc.DocumentNode.SelectSingleNode("//meta[@name='twitter:title']").Attributes["content"].Value;
+                if (name.StartsWith("[SMAPI] "))
+                    name = name.Substring("[SMAPI] ".Length);
+                string version = doc.DocumentNode.SelectSingleNode("//h1/span").InnerText;
+
+                // create model
+                return new ModInfoModel(name, this.NormaliseVersion(version), url);
+            }
+            catch (Exception ex)
+            {
+                return new ModInfoModel(ex.ToString());
+            }
+        }
+
+        /// <summary>Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.</summary>
+        public override void Dispose()
+        {
+            this.Client.Dispose();
+        }
+    }
+}
diff --git a/src/SMAPI.Web/Framework/ModRepositories/GitHubRepository.cs b/src/SMAPI.Web/Framework/ModRepositories/GitHubRepository.cs
new file mode 100644
index 00000000..174fb79a
--- /dev/null
+++ b/src/SMAPI.Web/Framework/ModRepositories/GitHubRepository.cs
@@ -0,0 +1,97 @@
+using System;
+using System.Net;
+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 : RepositoryBase
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>The URL for a Nexus Mods API query excluding the base URL, where {0} is the mod ID.</summary>
+        private readonly string ReleaseUrlFormat;
+
+        /// <summary>The underlying HTTP client.</summary>
+        private readonly IClient Client;
+
+
+        /*********
+        ** 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 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)
+            : base(vendorKey)
+        {
+            this.ReleaseUrlFormat = releaseUrlFormat;
+
+            this.Client = new FluentClient(baseUrl)
+                .SetUserAgent(userAgent)
+                .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 override async Task<ModInfoModel> GetModInfoAsync(string id)
+        {
+            // validate ID format
+            if (!id.Contains("/") || id.IndexOf("/", StringComparison.InvariantCultureIgnoreCase) != id.LastIndexOf("/", StringComparison.InvariantCultureIgnoreCase))
+                return new ModInfoModel($"The value '{id}' isn't a valid GitHub mod ID, must be a username and project name like 'Pathoschild/LookupAnything'.");
+
+            // fetch info
+            try
+            {
+                GitRelease release = await this.Client
+                    .GetAsync(string.Format(this.ReleaseUrlFormat, id))
+                    .As<GitRelease>();
+                return new ModInfoModel(id, this.NormaliseVersion(release.Tag), $"https://github.com/{id}/releases");
+            }
+            catch (ApiException ex) when (ex.Status == HttpStatusCode.NotFound)
+            {
+                return new ModInfoModel("Found no mod with this ID.");
+            }
+            catch (Exception ex)
+            {
+                return new ModInfoModel(ex.ToString());
+            }
+        }
+
+        /// <summary>Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.</summary>
+        public override 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.</summary>
+            [JsonProperty("tag_name")]
+            public string Tag { get; set; }
+        }
+    }
+}
diff --git a/src/SMAPI.Web/Framework/ModRepositories/IModRepository.cs b/src/SMAPI.Web/Framework/ModRepositories/IModRepository.cs
new file mode 100644
index 00000000..98e4c957
--- /dev/null
+++ b/src/SMAPI.Web/Framework/ModRepositories/IModRepository.cs
@@ -0,0 +1,24 @@
+using System;
+using System.Threading.Tasks;
+using StardewModdingAPI.Models;
+
+namespace StardewModdingAPI.Web.Framework.ModRepositories
+{
+    /// <summary>A repository which provides mod metadata.</summary>
+    internal interface IModRepository : IDisposable
+    {
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The unique key for this vendor.</summary>
+        string VendorKey { get; }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Get metadata about a mod in the repository.</summary>
+        /// <param name="id">The mod ID in this repository.</param>
+        Task<ModInfoModel> GetModInfoAsync(string id);
+    }
+}
diff --git a/src/SMAPI.Web/Framework/ModRepositories/NexusRepository.cs b/src/SMAPI.Web/Framework/ModRepositories/NexusRepository.cs
new file mode 100644
index 00000000..71970bec
--- /dev/null
+++ b/src/SMAPI.Web/Framework/ModRepositories/NexusRepository.cs
@@ -0,0 +1,89 @@
+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 Nexus Mods.</summary>
+    internal class NexusRepository : RepositoryBase
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>The URL for a Nexus Mods API query excluding the base URL, where {0} is the mod ID.</summary>
+        private readonly string ModUrlFormat;
+
+        /// <summary>The underlying HTTP client.</summary>
+        private readonly IClient Client;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="vendorKey">The unique key for this vendor.</param>
+        /// <param name="userAgent">The user agent for the Nexus Mods API client.</param>
+        /// <param name="baseUrl">The base URL for the Nexus Mods API.</param>
+        /// <param name="modUrlFormat">The URL for a Nexus Mods API query excluding the <paramref name="baseUrl"/>, where {0} is the mod ID.</param>
+        public NexusRepository(string vendorKey, string userAgent, string baseUrl, string modUrlFormat)
+            : base(vendorKey)
+        {
+            this.ModUrlFormat = modUrlFormat;
+            this.Client = new FluentClient(baseUrl).SetUserAgent(userAgent);
+        }
+
+        /// <summary>Get metadata about a mod in the repository.</summary>
+        /// <param name="id">The mod ID in this repository.</param>
+        public override async Task<ModInfoModel> GetModInfoAsync(string id)
+        {
+            // validate ID format
+            if (!uint.TryParse(id, out uint _))
+                return new ModInfoModel($"The value '{id}' isn't a valid Nexus mod ID, must be an integer ID.");
+
+            // fetch info
+            try
+            {
+                NexusResponseModel response = await this.Client
+                    .GetAsync(string.Format(this.ModUrlFormat, id))
+                    .As<NexusResponseModel>();
+
+                return response != null
+                    ? new ModInfoModel(response.Name, this.NormaliseVersion(response.Version), response.Url)
+                    : new ModInfoModel("Found no mod with this ID.");
+            }
+            catch (Exception ex)
+            {
+                return new ModInfoModel(ex.ToString());
+            }
+        }
+
+        /// <summary>Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.</summary>
+        public override void Dispose()
+        {
+            this.Client.Dispose();
+        }
+
+
+        /*********
+        ** Private models
+        *********/
+        /// <summary>A mod metadata response from Nexus Mods.</summary>
+        private class NexusResponseModel
+        {
+            /*********
+            ** Accessors
+            *********/
+            /// <summary>The mod name.</summary>
+            public string Name { get; set; }
+
+            /// <summary>The mod's semantic version number.</summary>
+            public string Version { get; set; }
+
+            /// <summary>The mod's web URL.</summary>
+            [JsonProperty("mod_page_uri")]
+            public string Url { get; set; }
+        }
+    }
+}
diff --git a/src/SMAPI.Web/Framework/RewriteSubdomainRule.cs b/src/SMAPI.Web/Framework/RewriteSubdomainRule.cs
new file mode 100644
index 00000000..5a56844f
--- /dev/null
+++ b/src/SMAPI.Web/Framework/RewriteSubdomainRule.cs
@@ -0,0 +1,30 @@
+using System;
+using Microsoft.AspNetCore.Rewrite;
+
+namespace StardewModdingAPI.Web.Framework
+{
+    /// <summary>Rewrite requests to prepend the subdomain portion (if any) to the path.</summary>
+    /// <remarks>Derived from <a href="https://stackoverflow.com/a/44526747/262123" />.</remarks>
+    internal class RewriteSubdomainRule : IRule
+    {
+        /// <summary>Applies the rule. Implementations of ApplyRule should set the value for <see cref="RewriteContext.Result" /> (defaults to RuleResult.ContinueRules).</summary>
+        /// <param name="context">The rewrite context.</param>
+        public void ApplyRule(RewriteContext context)
+        {
+            context.Result = RuleResult.ContinueRules;
+
+            // get host parts
+            string host = context.HttpContext.Request.Host.Host;
+            string[] parts = host.Split('.');
+
+            // validate
+            if (parts.Length < 2)
+                return;
+            if (parts.Length < 3 && !"localhost".Equals(parts[1], StringComparison.InvariantCultureIgnoreCase))
+                return;
+
+            // prepend to path
+            context.HttpContext.Request.Path = $"/{parts[0]}{context.HttpContext.Request.Path}";
+        }
+    }
+}
diff --git a/src/SMAPI.Web/Framework/VersionConstraint.cs b/src/SMAPI.Web/Framework/VersionConstraint.cs
new file mode 100644
index 00000000..be9c0918
--- /dev/null
+++ b/src/SMAPI.Web/Framework/VersionConstraint.cs
@@ -0,0 +1,15 @@
+using Microsoft.AspNetCore.Routing.Constraints;
+
+namespace StardewModdingAPI.Web.Framework
+{
+    /// <summary>Constrains a route value to a valid semantic version.</summary>
+    internal class VersionConstraint : RegexRouteConstraint
+    {
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        public VersionConstraint()
+            : base(@"^v(?>(?<major>0|[1-9]\d*))\.(?>(?<minor>0|[1-9]\d*))(?>(?:\.(?<patch>0|[1-9]\d*))?)(?:-(?<prerelease>(?>[a-z0-9]+[\-\.]?)+))?$") { }
+    }
+}
diff --git a/src/SMAPI.Web/Program.cs b/src/SMAPI.Web/Program.cs
new file mode 100644
index 00000000..eeecb791
--- /dev/null
+++ b/src/SMAPI.Web/Program.cs
@@ -0,0 +1,26 @@
+using System.IO;
+using Microsoft.AspNetCore.Hosting;
+
+namespace StardewModdingAPI.Web
+{
+    /// <summary>The main app entry point.</summary>
+    public class Program
+    {
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>The main app entry point.</summary>
+        /// <param name="args">The command-line arguments.</param>
+        public static void Main(string[] args)
+        {
+            // configure web server
+            new WebHostBuilder()
+                .UseKestrel()
+                .UseContentRoot(Directory.GetCurrentDirectory())
+                .UseIISIntegration()
+                .UseStartup<Startup>()
+                .Build()
+                .Run();
+        }
+    }
+}
diff --git a/src/SMAPI.Web/Properties/AssemblyInfo.cs b/src/SMAPI.Web/Properties/AssemblyInfo.cs
new file mode 100644
index 00000000..63f787a4
--- /dev/null
+++ b/src/SMAPI.Web/Properties/AssemblyInfo.cs
@@ -0,0 +1,4 @@
+using System.Reflection;
+
+[assembly: AssemblyTitle("StardewModdingAPI.Web")]
+[assembly: AssemblyProduct("StardewModdingAPI.Web")]
diff --git a/src/SMAPI.Web/Properties/launchSettings.json b/src/SMAPI.Web/Properties/launchSettings.json
new file mode 100644
index 00000000..3acee14d
--- /dev/null
+++ b/src/SMAPI.Web/Properties/launchSettings.json
@@ -0,0 +1,29 @@
+{
+  "iisSettings": {
+    "windowsAuthentication": false,
+    "anonymousAuthentication": true,
+    "iisExpress": {
+      "applicationUrl": "http://localhost:59482/",
+      "sslPort": 0
+    }
+  },
+  "profiles": {
+    "IIS Express": {
+      "commandName": "IISExpress",
+      "launchBrowser": true,
+      "launchUrl": "api/v1.0/mods",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    },
+    "Dewdrop": {
+      "commandName": "Project",
+      "launchBrowser": true,
+      "launchUrl": "api/v1.0/mods",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      },
+      "applicationUrl": "http://localhost:59483"
+    }
+  }
+}
diff --git a/src/SMAPI.Web/StardewModdingAPI.Web.csproj b/src/SMAPI.Web/StardewModdingAPI.Web.csproj
new file mode 100644
index 00000000..6b1d0687
--- /dev/null
+++ b/src/SMAPI.Web/StardewModdingAPI.Web.csproj
@@ -0,0 +1,26 @@
+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <TargetFramework>netcoreapp2.0</TargetFramework>
+    <GenerateAssemblyInfo>false</GenerateAssemblyInfo>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="..\..\build\GlobalAssemblyInfo.cs" Link="Properties\GlobalAssemblyInfo.cs" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="HtmlAgilityPack" Version="1.5.5" />
+    <PackageReference Include="Microsoft.AspNetCore" Version="2.0.0" />
+    <PackageReference Include="Microsoft.AspNetCore.Mvc" Version="2.0.0" />
+    <PackageReference Include="Microsoft.AspNetCore.Rewrite" Version="2.0.0" />
+    <PackageReference Include="Microsoft.AspNetCore.StaticFiles" Version="2.0.0" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Debug" Version="2.0.0" />
+    <PackageReference Include="Pathoschild.Http.FluentClient" Version="3.1.0" />
+  </ItemGroup>
+  <ItemGroup>
+    <DotNetCliToolReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Tools" Version="1.0.1" />
+  </ItemGroup>
+  <Import Project="..\SMAPI.Models\StardewModdingAPI.Models.projitems" Label="Shared" />
+
+</Project>
diff --git a/src/SMAPI.Web/Startup.cs b/src/SMAPI.Web/Startup.cs
new file mode 100644
index 00000000..eaf14983
--- /dev/null
+++ b/src/SMAPI.Web/Startup.cs
@@ -0,0 +1,70 @@
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Rewrite;
+using Microsoft.AspNetCore.Routing;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using Newtonsoft.Json;
+using StardewModdingAPI.Web.Framework;
+using StardewModdingAPI.Web.Framework.ConfigModels;
+
+namespace StardewModdingAPI.Web
+{
+    /// <summary>The web app startup configuration.</summary>
+    internal class Startup
+    {
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The web app configuration.</summary>
+        public IConfigurationRoot Configuration { get; }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="env">The hosting environment.</param>
+        public Startup(IHostingEnvironment env)
+        {
+            this.Configuration = new ConfigurationBuilder()
+                .SetBasePath(env.ContentRootPath)
+                .AddEnvironmentVariables()
+                .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
+                .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
+                .AddEnvironmentVariables()
+                .Build();
+        }
+
+        /// <summary>The method called by the runtime to add services to the container.</summary>
+        /// <param name="services">The service injection container.</param>
+        public void ConfigureServices(IServiceCollection services)
+        {
+            services
+                .Configure<ModUpdateCheckConfig>(this.Configuration.GetSection("ModUpdateCheck"))
+                .Configure<RouteOptions>(options => options.ConstraintMap.Add("semanticVersion", typeof(VersionConstraint)))
+                .AddMemoryCache()
+                .AddMvc()
+                .ConfigureApplicationPartManager(manager => manager.FeatureProviders.Add(new InternalControllerFeatureProvider()))
+                .AddJsonOptions(options =>
+                {
+                    options.SerializerSettings.Formatting = Formatting.Indented;
+                    options.SerializerSettings.NullValueHandling = NullValueHandling.Ignore;
+                });
+        }
+
+        /// <summary>The method called by the runtime to configure the HTTP request pipeline.</summary>
+        /// <param name="app">The application builder.</param>
+        /// <param name="env">The hosting environment.</param>
+        /// <param name="loggerFactory">The logger factory.</param>
+        public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
+        {
+            loggerFactory.AddConsole(this.Configuration.GetSection("Logging"));
+            loggerFactory.AddDebug();
+            app
+                .UseRewriter(new RewriteOptions().Add(new RewriteSubdomainRule())) // convert subdomain.smapi.io => smapi.io/subdomain for routing
+                .UseMvc();
+        }
+    }
+}
diff --git a/src/SMAPI.Web/appsettings.Development.json b/src/SMAPI.Web/appsettings.Development.json
new file mode 100644
index 00000000..fa8ce71a
--- /dev/null
+++ b/src/SMAPI.Web/appsettings.Development.json
@@ -0,0 +1,10 @@
+{
+  "Logging": {
+    "IncludeScopes": false,
+    "LogLevel": {
+      "Default": "Debug",
+      "System": "Information",
+      "Microsoft": "Information"
+    }
+  }
+}
diff --git a/src/SMAPI.Web/appsettings.json b/src/SMAPI.Web/appsettings.json
new file mode 100644
index 00000000..852f6f71
--- /dev/null
+++ b/src/SMAPI.Web/appsettings.json
@@ -0,0 +1,30 @@
+{
+  "Logging": {
+    "IncludeScopes": false,
+    "LogLevel": {
+      "Default": "Warning"
+    }
+  },
+  "ModUpdateCheck": {
+    "CacheMinutes": 60,
+    "SemanticVersionRegex": "^(?>(?<major>0|[1-9]\\d*))\\.(?>(?<minor>0|[1-9]\\d*))(?>(?:\\.(?<patch>0|[1-9]\\d*))?)(?:-(?<prerelease>(?>[a-z0-9]+[\\-\\.]?)+))?$",
+
+    "ChucklefishKey": "Chucklefish",
+    "ChucklefishUserAgent": "SMAPI/{0} (+https://github.com/Pathoschild/SMAPI)",
+    "ChucklefishBaseUrl": "https://community.playstarbound.com",
+    "ChucklefishModPageUrlFormat": "resources/{0}",
+
+    "GitHubKey": "GitHub",
+    "GitHubUserAgent": "SMAPI/{0} (+https://github.com/Pathoschild/SMAPI)",
+    "GitHubBaseUrl": "https://api.github.com",
+    "GitHubReleaseUrlFormat": "repos/{0}/releases/latest",
+    "GitHubAcceptHeader": "application/vnd.github.v3+json",
+    "GitHubUsername": null, /* set via environment properties */
+    "GitHubPassword": null, /* set via environment properties */
+
+    "NexusKey": "Nexus",
+    "NexusUserAgent": "Nexus Client v0.63.15",
+    "NexusBaseUrl": "http://www.nexusmods.com/stardewvalley",
+    "NexusModUrlFormat": "mods/{0}"
+  }
+}