simplify single-instance deployment and make MongoDB server optional

docs/release-notes.md

@@ -8,12 +8,16 @@
 * For the web UI:
   * Updated web framework to improve site performance and reliability.
   * Added GitHub licenses to mod compatibility list.
+  * Internal changes to improve performance and reliability.
 
 * For modders:
   * Added `Multiplayer.PeerConnected` event.
   * Simplified paranoid warnings in the log and reduced their log level.
   * Fixed asset propagation for Gil's portraits.
 
+* For SMAPI developers:
+  * When deploying web services to a single-instance app, the MongoDB server can now be replaced with in-memory storage.
+
 ## 3.5
 Released 27 April 2020 for Stardew Valley 1.4.1 or later.
 

docs/technical/web.md

@@ -340,9 +340,20 @@ short url | → | target page
 A local environment lets you run a complete copy of the web project (including cache database) on
 your machine, with no external dependencies aside from the actual mod sites.
 
-1. Enter the Nexus credentials in `appsettings.Development.json` . You can leave the other
+1. Edit `appsettings.Development.json` and set these options:
-   credentials empty to default to fetching data anonymously, and storing data in-memory and
+
-   on disk.
+   property name | description
+   ------------- | -----------
+   `NexusApiKey` | [Your Nexus API key](https://www.nexusmods.com/users/myaccount?tab=api#personal_key).
+
+   Optional settings:
+
+   property name               | description
+   --------------------------- | -----------
+   `AzureBlobConnectionString` | The connection string for the Azure Blob storage account. Defaults to using the system's temporary file folder if not specified.
+   `GitHubUsername`<br />`GitHubPassword` | The GitHub credentials with which to query GitHub release info. Defaults to anonymous requests if not specified.
+   `Storage`                   | How to storage cached wiki/mod data. `InMemory` is recommended in most cases, or `MongoInMemory` to test the MongoDB storage code. See [production environment](#production-environment) for more info on `Mongo`.
+
 2. Launch `SMAPI.Web` from Visual Studio to run a local version of the site.
 
 ### Production environment
@@ -355,19 +366,15 @@ accordingly.
 
 Initial setup:
 
-1. Launch an empty MongoDB server (e.g. using [MongoDB Atlas](https://www.mongodb.com/cloud/atlas))
+1. Create an Azure Blob storage account for uploaded files.
-   for mod data.
+2. Create an Azure App Services environment running the latest .NET Core on Linux or Windows.
-2. Create an Azure Blob storage account for uploaded files.
+3. Add these application settings in the new App Services environment:
-3. Create an Azure App Services environment running the latest .NET Core on Linux or Windows.
-4. Add these application settings in the new App Services environment:
 
    property name                   | description
    ------------------------------- | -----------------
    `ApiClients.AzureBlobConnectionString` | The connection string for the Azure Blob storage account created in step 2.
    `ApiClients.GitHubUsername`<br />`ApiClients.GitHubPassword` | The login credentials for the GitHub account with which to fetch release info. If these are omitted, GitHub will impose much stricter rate limits.
    `ApiClients:NexusApiKey`        | The [Nexus API authentication key](https://github.com/Pathoschild/FluentNexus#init-a-client).
-   `MongoDB:ConnectionString`      | The connection string for the MongoDB instance.
-   `MongoDB:Database`              | The MongoDB database name (e.g. `smapi` in production or `smapi-edge` in testing environments).
 
    Optional settings:
 
@@ -378,6 +385,23 @@ Initial setup:
    `Site:BetaBlurb`                | If `Site:BetaEnabled` is true and there's a beta version of SMAPI in its GitHub releases, this is shown on the beta download button as explanatory subtext.
    `Site:SupporterList`            | A list of Patreon supports to credit on the download page.
 
+To enable distributed servers:
+
+1. Launch an empty MongoDB server (e.g. using [MongoDB Atlas](https://www.mongodb.com/cloud/atlas))
+   for mod data.
+2. Add these application settings in the App Services environment:
+
+   property name                   | description
+   ------------------------------- | -----------------
+   `Storage:Mode`                  | Set to `Mongo`.
+   `Storage:ConnectionString`      | Set to the connection string for the MongoDB instance.
+
+   Optional settings:
+
+   property name                   | description
+   ------------------------------- | -----------------
+   `Storage:Database`              | Set to the MongoDB database name (defaults to `smapi`).
+
 To deploy updates:
 1. [Deploy the web project from Visual Studio](https://docs.microsoft.com/en-us/visualstudio/deployment/quickstart-deploy-to-azure).
 2. If the MongoDB schema changed, delete the MongoDB database. (It'll be recreated automatically.)

src/SMAPI.Web/Framework/Caching/Mods/IModCacheRepository.cs

@@ -4,7 +4,7 @@ using StardewModdingAPI.Web.Framework.ModRepositories;
 
 namespace StardewModdingAPI.Web.Framework.Caching.Mods
 {
-    /// <summary>Encapsulates logic for accessing the mod data cache.</summary>
+    /// <summary>Manages cached mod data.</summary>
     internal interface IModCacheRepository : ICacheRepository
     {
         /*********

src/SMAPI.Web/Framework/Caching/Mods/ModCacheMemoryRepository.cs

@@ -0,0 +1,89 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using StardewModdingAPI.Toolkit.Framework.UpdateData;
+using StardewModdingAPI.Web.Framework.ModRepositories;
+
+namespace StardewModdingAPI.Web.Framework.Caching.Mods
+{
+    /// <summary>Manages cached mod data in-memory.</summary>
+    internal class ModCacheMemoryRepository : BaseCacheRepository, IModCacheRepository
+    {
+        /*********
+        ** Fields
+        *********/
+        /// <summary>The cached mod data indexed by <c>{site key}:{ID}</c>.</summary>
+        private readonly IDictionary<string, CachedMod> Mods = new Dictionary<string, CachedMod>(StringComparer.InvariantCultureIgnoreCase);
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Get the cached mod data.</summary>
+        /// <param name="site">The mod site to search.</param>
+        /// <param name="id">The mod's unique ID within the <paramref name="site"/>.</param>
+        /// <param name="mod">The fetched mod.</param>
+        /// <param name="markRequested">Whether to update the mod's 'last requested' date.</param>
+        public bool TryGetMod(ModRepositoryKey site, string id, out CachedMod mod, bool markRequested = true)
+        {
+            // get mod
+            if (!this.Mods.TryGetValue(this.GetKey(site, id), out mod))
+                return false;
+
+            // bump 'last requested'
+            if (markRequested)
+            {
+                mod.LastRequested = DateTimeOffset.UtcNow;
+                mod = this.SaveMod(mod);
+            }
+
+            return true;
+        }
+
+        /// <summary>Save data fetched for a mod.</summary>
+        /// <param name="site">The mod site on which the mod is found.</param>
+        /// <param name="id">The mod's unique ID within the <paramref name="site"/>.</param>
+        /// <param name="mod">The mod data.</param>
+        /// <param name="cachedMod">The stored mod record.</param>
+        public void SaveMod(ModRepositoryKey site, string id, ModInfoModel mod, out CachedMod cachedMod)
+        {
+            string key = this.GetKey(site, id);
+            cachedMod = this.SaveMod(new CachedMod(site, id, mod));
+        }
+
+        /// <summary>Delete data for mods which haven't been requested within a given time limit.</summary>
+        /// <param name="age">The minimum age for which to remove mods.</param>
+        public void RemoveStaleMods(TimeSpan age)
+        {
+            DateTimeOffset minDate = DateTimeOffset.UtcNow.Subtract(age);
+
+            string[] staleKeys = this.Mods
+                .Where(p => p.Value.LastRequested < minDate)
+                .Select(p => p.Key)
+                .ToArray();
+
+            foreach (string key in staleKeys)
+                this.Mods.Remove(key);
+        }
+
+        /// <summary>Save data fetched for a mod.</summary>
+        /// <param name="mod">The mod data.</param>
+        public CachedMod SaveMod(CachedMod mod)
+        {
+            string key = this.GetKey(mod.Site, mod.ID);
+            return this.Mods[key] = mod;
+        }
+
+
+        /*********
+        ** Private methods
+        *********/
+        /// <summary>Get a cache key.</summary>
+        /// <param name="site">The mod site.</param>
+        /// <param name="id">The mod ID.</param>
+        public string GetKey(ModRepositoryKey site, string id)
+        {
+            return $"{site}:{id.Trim()}".ToLower();
+        }
+    }
+}

src/SMAPI.Web/Framework/Caching/Mods/ModCacheMongoRepository.cs

@@ -5,8 +5,8 @@ using StardewModdingAPI.Web.Framework.ModRepositories;
 
 namespace StardewModdingAPI.Web.Framework.Caching.Mods
 {
-    /// <summary>Encapsulates logic for accessing the mod data cache.</summary>
+    /// <summary>Manages cached mod data in MongoDB.</summary>
-    internal class ModCacheRepository : BaseCacheRepository, IModCacheRepository
+    internal class ModCacheMongoRepository : BaseCacheRepository, IModCacheRepository
     {
         /*********
         ** Fields
@@ -20,7 +20,7 @@ namespace StardewModdingAPI.Web.Framework.Caching.Mods
         *********/
         /// <summary>Construct an instance.</summary>
         /// <param name="database">The authenticated MongoDB database.</param>
-        public ModCacheRepository(IMongoDatabase database)
+        public ModCacheMongoRepository(IMongoDatabase database)
         {
             // get collections
             this.Mods = database.GetCollection<CachedMod>("mods");
@@ -29,6 +29,7 @@ namespace StardewModdingAPI.Web.Framework.Caching.Mods
             this.Mods.Indexes.CreateOne(new CreateIndexModel<CachedMod>(Builders<CachedMod>.IndexKeys.Ascending(p => p.ID).Ascending(p => p.Site)));
         }
 
+
         /*********
         ** Public methods
         *********/
@@ -75,10 +76,6 @@ namespace StardewModdingAPI.Web.Framework.Caching.Mods
             this.Mods.DeleteMany(p => p.LastRequested < minDate);
         }
 
-
-        /*********
-        ** Private methods
-        *********/
         /// <summary>Save data fetched for a mod.</summary>
         /// <param name="mod">The mod data.</param>
         public CachedMod SaveMod(CachedMod mod)
@@ -94,6 +91,10 @@ namespace StardewModdingAPI.Web.Framework.Caching.Mods
             return mod;
         }
 
+
+        /*********
+        ** Private methods
+        *********/
         /// <summary>Normalize a mod ID for case-insensitive search.</summary>
         /// <param name="id">The mod ID.</param>
         public string NormalizeId(string id)

src/SMAPI.Web/Framework/Caching/Wiki/IWikiCacheRepository.cs

@@ -5,7 +5,7 @@ using StardewModdingAPI.Toolkit.Framework.Clients.Wiki;
 
 namespace StardewModdingAPI.Web.Framework.Caching.Wiki
 {
-    /// <summary>Encapsulates logic for accessing the wiki data cache.</summary>
+    /// <summary>Manages cached wiki data.</summary>
     internal interface IWikiCacheRepository : ICacheRepository
     {
         /*********

src/SMAPI.Web/Framework/Caching/Wiki/WikiCacheMemoryRepository.cs

@@ -0,0 +1,54 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Linq.Expressions;
+using StardewModdingAPI.Toolkit.Framework.Clients.Wiki;
+
+namespace StardewModdingAPI.Web.Framework.Caching.Wiki
+{
+    /// <summary>Manages cached wiki data in-memory.</summary>
+    internal class WikiCacheMemoryRepository : BaseCacheRepository, IWikiCacheRepository
+    {
+        /*********
+        ** Fields
+        *********/
+        /// <summary>The saved wiki metadata.</summary>
+        private CachedWikiMetadata Metadata;
+
+        /// <summary>The cached wiki data.</summary>
+        private CachedWikiMod[] Mods = new CachedWikiMod[0];
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Get the cached wiki metadata.</summary>
+        /// <param name="metadata">The fetched metadata.</param>
+        public bool TryGetWikiMetadata(out CachedWikiMetadata metadata)
+        {
+            metadata = this.Metadata;
+            return metadata != null;
+        }
+
+        /// <summary>Get the cached wiki mods.</summary>
+        /// <param name="filter">A filter to apply, if any.</param>
+        public IEnumerable<CachedWikiMod> GetWikiMods(Expression<Func<CachedWikiMod, bool>> filter = null)
+        {
+            return filter != null
+                ? this.Mods.Where(filter.Compile())
+                : this.Mods.ToArray();
+        }
+
+        /// <summary>Save data fetched from the wiki compatibility list.</summary>
+        /// <param name="stableVersion">The current stable Stardew Valley version.</param>
+        /// <param name="betaVersion">The current beta Stardew Valley version.</param>
+        /// <param name="mods">The mod data.</param>
+        /// <param name="cachedMetadata">The stored metadata record.</param>
+        /// <param name="cachedMods">The stored mod records.</param>
+        public void SaveWikiData(string stableVersion, string betaVersion, IEnumerable<WikiModEntry> mods, out CachedWikiMetadata cachedMetadata, out CachedWikiMod[] cachedMods)
+        {
+            this.Metadata = cachedMetadata = new CachedWikiMetadata(stableVersion, betaVersion);
+            this.Mods = cachedMods = mods.Select(mod => new CachedWikiMod(mod)).ToArray();
+        }
+    }
+}

src/SMAPI.Web/Framework/Caching/Wiki/WikiCacheMongoRepository.cs

@@ -7,17 +7,17 @@ using StardewModdingAPI.Toolkit.Framework.Clients.Wiki;
 
 namespace StardewModdingAPI.Web.Framework.Caching.Wiki
 {
-    /// <summary>Encapsulates logic for accessing the wiki data cache.</summary>
+    /// <summary>Manages cached wiki data in MongoDB.</summary>
-    internal class WikiCacheRepository : BaseCacheRepository, IWikiCacheRepository
+    internal class WikiCacheMongoRepository : BaseCacheRepository, IWikiCacheRepository
     {
         /*********
         ** Fields
         *********/
         /// <summary>The collection for wiki metadata.</summary>
-        private readonly IMongoCollection<CachedWikiMetadata> WikiMetadata;
+        private readonly IMongoCollection<CachedWikiMetadata> Metadata;
 
         /// <summary>The collection for wiki mod data.</summary>
-        private readonly IMongoCollection<CachedWikiMod> WikiMods;
+        private readonly IMongoCollection<CachedWikiMod> Mods;
 
 
         /*********
@@ -25,21 +25,21 @@ namespace StardewModdingAPI.Web.Framework.Caching.Wiki
         *********/
         /// <summary>Construct an instance.</summary>
         /// <param name="database">The authenticated MongoDB database.</param>
-        public WikiCacheRepository(IMongoDatabase database)
+        public WikiCacheMongoRepository(IMongoDatabase database)
         {
             // get collections
-            this.WikiMetadata = database.GetCollection<CachedWikiMetadata>("wiki-metadata");
+            this.Metadata = database.GetCollection<CachedWikiMetadata>("wiki-metadata");
-            this.WikiMods = database.GetCollection<CachedWikiMod>("wiki-mods");
+            this.Mods = database.GetCollection<CachedWikiMod>("wiki-mods");
 
             // add indexes if needed
-            this.WikiMods.Indexes.CreateOne(new CreateIndexModel<CachedWikiMod>(Builders<CachedWikiMod>.IndexKeys.Ascending(p => p.ID)));
+            this.Mods.Indexes.CreateOne(new CreateIndexModel<CachedWikiMod>(Builders<CachedWikiMod>.IndexKeys.Ascending(p => p.ID)));
         }
 
         /// <summary>Get the cached wiki metadata.</summary>
         /// <param name="metadata">The fetched metadata.</param>
         public bool TryGetWikiMetadata(out CachedWikiMetadata metadata)
         {
-            metadata = this.WikiMetadata.Find("{}").FirstOrDefault();
+            metadata = this.Metadata.Find("{}").FirstOrDefault();
             return metadata != null;
         }
 
@@ -48,8 +48,8 @@ namespace StardewModdingAPI.Web.Framework.Caching.Wiki
         public IEnumerable<CachedWikiMod> GetWikiMods(Expression<Func<CachedWikiMod, bool>> filter = null)
         {
             return filter != null
-                ? this.WikiMods.Find(filter).ToList()
+                ? this.Mods.Find(filter).ToList()
-                : this.WikiMods.Find("{}").ToList();
+                : this.Mods.Find("{}").ToList();
         }
 
         /// <summary>Save data fetched from the wiki compatibility list.</summary>
@@ -63,11 +63,11 @@ namespace StardewModdingAPI.Web.Framework.Caching.Wiki
             cachedMetadata = new CachedWikiMetadata(stableVersion, betaVersion);
             cachedMods = mods.Select(mod => new CachedWikiMod(mod)).ToArray();
 
-            this.WikiMods.DeleteMany("{}");
+            this.Mods.DeleteMany("{}");
-            this.WikiMods.InsertMany(cachedMods);
+            this.Mods.InsertMany(cachedMods);
 
-            this.WikiMetadata.DeleteMany("{}");
+            this.Metadata.DeleteMany("{}");
-            this.WikiMetadata.InsertOne(cachedMetadata);
+            this.Metadata.InsertOne(cachedMetadata);
         }
     }
 }

src/SMAPI.Web/Framework/ConfigModels/MongoDbConfig.cs

@@ -1,25 +0,0 @@
-namespace StardewModdingAPI.Web.Framework.ConfigModels
-{
-    /// <summary>The config settings for mod compatibility list.</summary>
-    internal class MongoDbConfig
-    {
-        /*********
-        ** Accessors
-        *********/
-        /// <summary>The MongoDB connection string.</summary>
-        public string ConnectionString { get; set; }
-
-        /// <summary>The database name.</summary>
-        public string Database { get; set; }
-
-
-        /*********
-        ** Public method
-        *********/
-        /// <summary>Get whether a MongoDB instance is configured.</summary>
-        public bool IsConfigured()
-        {
-            return !string.IsNullOrWhiteSpace(this.ConnectionString);
-        }
-    }
-}

src/SMAPI.Web/Framework/ConfigModels/StorageConfig.cs

@@ -0,0 +1,18 @@
+namespace StardewModdingAPI.Web.Framework.ConfigModels
+{
+    /// <summary>The config settings for cache storage.</summary>
+    internal class StorageConfig
+    {
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The storage mechanism to use.</summary>
+        public StorageMode Mode { get; set; }
+
+        /// <summary>The connection string for the storage mechanism, if applicable.</summary>
+        public string ConnectionString { get; set; }
+
+        /// <summary>The database name for the storage mechanism, if applicable.</summary>
+        public string Database { get; set; }
+    }
+}

src/SMAPI.Web/Framework/ConfigModels/StorageMode.cs

@@ -0,0 +1,15 @@
+namespace StardewModdingAPI.Web.Framework.ConfigModels
+{
+    /// <summary>Indicates a storage mechanism to use.</summary>
+    internal enum StorageMode
+    {
+        /// <summary>Store data in a hosted MongoDB instance.</summary>
+        Mongo,
+
+        /// <summary>Store data in an in-memory MongoDB instance. This is useful for testing MongoDB storage locally, but will likely fail when deployed since it needs permission to open a local port.</summary>
+        MongoInMemory,
+
+        /// <summary>Store data in-memory. This is suitable for local testing or single-instance servers, but will cause issues when distributed across multiple servers.</summary>
+        InMemory
+    }
+}

src/SMAPI.Web/Startup.cs

@@ -67,12 +67,13 @@ namespace StardewModdingAPI.Web
                 .Configure<BackgroundServicesConfig>(this.Configuration.GetSection("BackgroundServices"))
                 .Configure<ModCompatibilityListConfig>(this.Configuration.GetSection("ModCompatibilityList"))
                 .Configure<ModUpdateCheckConfig>(this.Configuration.GetSection("ModUpdateCheck"))
-                .Configure<MongoDbConfig>(this.Configuration.GetSection("MongoDB"))
+                .Configure<StorageConfig>(this.Configuration.GetSection("Storage"))
                 .Configure<SiteConfig>(this.Configuration.GetSection("Site"))
                 .Configure<RouteOptions>(options => options.ConstraintMap.Add("semanticVersion", typeof(VersionConstraint)))
                 .AddLogging()
                 .AddMemoryCache();
-            MongoDbConfig mongoConfig = this.Configuration.GetSection("MongoDB").Get<MongoDbConfig>();
+            StorageConfig storageConfig = this.Configuration.GetSection("Storage").Get<StorageConfig>();
+            StorageMode storageMode = storageConfig.Mode;
 
             // init MVC
             services
@@ -82,44 +83,66 @@ namespace StardewModdingAPI.Web
             services
                 .AddRazorPages();
 
-            // init MongoDB
+            // init storage
-            services.AddSingleton<MongoDbRunner>(_ => !mongoConfig.IsConfigured()
+            switch (storageMode)
-                ? MongoDbRunner.Start()
-                : throw new InvalidOperationException("The MongoDB connection is configured, so the local development version should not be used.")
-            );
-            services.AddSingleton<IMongoDatabase>(serv =>
             {
-                // get connection string
+                case StorageMode.InMemory:
-                string connectionString = mongoConfig.IsConfigured()
+                    services.AddSingleton<IModCacheRepository>(new ModCacheMemoryRepository());
-                    ? mongoConfig.ConnectionString
+                    services.AddSingleton<IWikiCacheRepository>(new WikiCacheMemoryRepository());
-                    : serv.GetRequiredService<MongoDbRunner>().ConnectionString;
+                    break;
 
-                // get client
+                case StorageMode.Mongo:
-                BsonSerializer.RegisterSerializer(new UtcDateTimeOffsetSerializer());
+                case StorageMode.MongoInMemory:
-                return new MongoClient(connectionString).GetDatabase(mongoConfig.Database);
+                    {
-            });
+                        // local MongoDB instance
-            services.AddSingleton<IModCacheRepository>(serv => new ModCacheRepository(serv.GetRequiredService<IMongoDatabase>()));
+                        services.AddSingleton<MongoDbRunner>(_ => storageMode == StorageMode.MongoInMemory
-            services.AddSingleton<IWikiCacheRepository>(serv => new WikiCacheRepository(serv.GetRequiredService<IMongoDatabase>()));
+                            ? MongoDbRunner.Start()
+                            : throw new NotSupportedException($"The in-memory MongoDB runner isn't available in storage mode {storageMode}.")
+                        );
+
+                        // MongoDB
+                        services.AddSingleton<IMongoDatabase>(serv =>
+                        {
+                            BsonSerializer.RegisterSerializer(new UtcDateTimeOffsetSerializer());
+                            return new MongoClient(this.GetMongoDbConnectionString(serv, storageConfig))
+                                .GetDatabase(storageConfig.Database);
+                        });
+
+                        // repositories
+                        services.AddSingleton<IModCacheRepository>(serv => new ModCacheMongoRepository(serv.GetRequiredService<IMongoDatabase>()));
+                        services.AddSingleton<IWikiCacheRepository>(serv => new WikiCacheMongoRepository(serv.GetRequiredService<IMongoDatabase>()));
+                    }
+                    break;
+
+                default:
+                    throw new NotSupportedException($"Unhandled storage mode '{storageMode}'.");
+            }
 
             // init Hangfire
             services
-                .AddHangfire(config =>
+                .AddHangfire((serv, config) =>
                 {
                     config
                         .SetDataCompatibilityLevel(CompatibilityLevel.Version_170)
                         .UseSimpleAssemblyNameTypeSerializer()
                         .UseRecommendedSerializerSettings();
 
-                    if (mongoConfig.IsConfigured())
+                    switch (storageMode)
                     {
-                        config.UseMongoStorage(MongoClientSettings.FromConnectionString(mongoConfig.ConnectionString), $"{mongoConfig.Database}-hangfire", new MongoStorageOptions
+                        case StorageMode.InMemory:
-                        {
+                            config.UseMemoryStorage();
-                            MigrationOptions = new MongoMigrationOptions(MongoMigrationStrategy.Drop),
+                            break;
-                            CheckConnection = false // error on startup takes down entire process
+
-                        });
+                        case StorageMode.MongoInMemory:
+                        case StorageMode.Mongo:
+                            string connectionString = this.GetMongoDbConnectionString(serv, storageConfig);
+                            config.UseMongoStorage(MongoClientSettings.FromConnectionString(connectionString), $"{storageConfig.Database}-hangfire", new MongoStorageOptions
+                            {
+                                MigrationOptions = new MongoMigrationOptions(MongoMigrationStrategy.Drop),
+                                CheckConnection = false // error on startup takes down entire process
+                            });
+                            break;
                     }
-                    else
-                        config.UseMemoryStorage();
                 });
 
             // init background service
@@ -140,6 +163,7 @@ namespace StardewModdingAPI.Web
                     baseUrl: api.ChucklefishBaseUrl,
                     modPageUrlFormat: api.ChucklefishModPageUrlFormat
                 ));
+
                 services.AddSingleton<ICurseForgeClient>(new CurseForgeClient(
                     userAgent: userAgent,
                     apiUrl: api.CurseForgeBaseUrl
@@ -229,6 +253,20 @@ namespace StardewModdingAPI.Web
             settings.NullValueHandling = NullValueHandling.Ignore;
         }
 
+        /// <summary>Get the MongoDB connection string for the given storage configuration.</summary>
+        /// <param name="services">The service provider.</param>
+        /// <param name="storageConfig">The storage configuration</param>
+        /// <exception cref="NotSupportedException">There's no MongoDB instance in the given storage mode.</exception>
+        private string GetMongoDbConnectionString(IServiceProvider services, StorageConfig storageConfig)
+        {
+            return storageConfig.Mode switch
+            {
+                StorageMode.Mongo => storageConfig.ConnectionString,
+                StorageMode.MongoInMemory => services.GetRequiredService<MongoDbRunner>().ConnectionString,
+                _ => throw new NotSupportedException($"There's no MongoDB instance in storage mode {storageConfig.Mode}.")
+            };
+        }
+
         /// <summary>Get the redirect rules to apply.</summary>
         private RewriteOptions GetRedirectRules()
         {

src/SMAPI.Web/appsettings.Development.json

@@ -17,7 +17,8 @@
         "NexusApiKey": null
     },
 
-    "MongoDB": {
+    "Storage": {
+        "Mode": "MongoInMemory",
         "ConnectionString": null,
         "Database": "smapi-edge"
     },

src/SMAPI.Web/appsettings.json

@@ -49,7 +49,8 @@
         "PastebinBaseUrl": "https://pastebin.com/"
     },
 
-    "MongoDB": {
+    "Storage": {
+        "Mode": "InMemory",
         "ConnectionString": null,
         "Database": "smapi"
     },