Abstract away cache. 2 implementations: redis and memory

src/NadekoBot/Common/Attributes/Ratelimit.cs

@@ -15,22 +15,24 @@ public sealed class RatelimitAttribute : PreconditionAttribute
         Seconds = seconds;
     }
 
-    public override Task<PreconditionResult> CheckPermissionsAsync(
+    public override async Task<PreconditionResult> CheckPermissionsAsync(
         ICommandContext context,
         CommandInfo command,
         IServiceProvider services)
     {
         if (Seconds == 0)
-            return Task.FromResult(PreconditionResult.FromSuccess());
+            return PreconditionResult.FromSuccess();
 
-        var cache = services.GetRequiredService<IDataCache>();
-        var rem = cache.TryAddRatelimit(context.User.Id, command.Name, Seconds);
+        var cache = services.GetRequiredService<IBotCache>();
+        var rem = await cache.GetRatelimitAsync(
+            new($"precondition:{context.User.Id}:{command.Name}"),
+            Seconds.Seconds());
 
         if (rem is null)
-            return Task.FromResult(PreconditionResult.FromSuccess());
+            return PreconditionResult.FromSuccess();
 
         var msgContent = $"You can use this command again in {rem.Value.TotalSeconds:F1}s.";
 
-        return Task.FromResult(PreconditionResult.FromError(msgContent));
+        return PreconditionResult.FromError(msgContent);
     }
 }

src/NadekoBot/Common/Cache/BotCacheExtensions.cs

@@ -0,0 +1,46 @@
+using OneOf;
+using OneOf.Types;
+
+namespace NadekoBot.Common;
+
+public static class BotCacheExtensions
+{
+    public static async ValueTask<T?> GetOrDefaultAsync<T>(this IBotCache cache, TypedKey<T> key)
+    {
+        var result = await cache.GetAsync(key);
+        if (result.TryGetValue(out var val))
+            return val;
+
+        return default;
+    }
+    
+    private static TypedKey<byte[]> GetImgKey(Uri uri)
+        => new($"image:{uri}");
+
+    public static ValueTask SetImageDataAsync(this IBotCache c, string key, byte[] data)
+        => c.SetImageDataAsync(new Uri(key), data);
+    public static async ValueTask SetImageDataAsync(this IBotCache c, Uri key, byte[] data)
+        => await c.AddAsync(GetImgKey(key), data, expiry: TimeSpan.FromHours(48));
+
+    public static async ValueTask<OneOf<byte[], None>> GetImageDataAsync(this IBotCache c, Uri key)
+        => await c.GetAsync(GetImgKey(key));
+
+    public static async Task<TimeSpan?> GetRatelimitAsync(
+        this IBotCache c,
+        TypedKey<long> key,
+        TimeSpan length)
+    {
+        var now = DateTime.UtcNow;
+        var nowB = now.ToBinary();
+
+        var cachedValue = await c.GetOrAddAsync(key,
+            () => Task.FromResult(now.ToBinary()),
+            expiry: length);
+
+        if (cachedValue == nowB)
+            return null;
+
+        var diff = now - DateTime.FromBinary(cachedValue);
+        return length - diff;
+    }
+}

src/NadekoBot/Common/Cache/IBotCache.cs

@@ -0,0 +1,47 @@
+using OneOf;
+using OneOf.Types;
+
+namespace NadekoBot.Common;
+
+public interface IBotCache
+{
+    /// <summary>
+    /// Adds an item to the cache
+    /// </summary>
+    /// <param name="key">Key to add</param>
+    /// <param name="value">Value to add to the cache</param>
+    /// <param name="expiry">Optional expiry</param>
+    /// <param name="overwrite">Whether old value should be overwritten</param>
+    /// <typeparam name="T">Type of the value</typeparam>
+    /// <returns>Returns whether add was sucessful. Always true unless ovewrite = false</returns>
+    ValueTask<bool> AddAsync<T>(TypedKey<T> key, T value, TimeSpan? expiry = null, bool overwrite = true);
+    
+    /// <summary>
+    /// Get an element from the cache
+    /// </summary>
+    /// <param name="key">Key</param>
+    /// <typeparam name="T">Type of the value</typeparam>
+    /// <returns>Either a value or <see cref="None"/></returns>
+    ValueTask<OneOf<T, None>> GetAsync<T>(TypedKey<T> key);
+    
+    /// <summary>
+    /// Remove a key from the cache
+    /// </summary>
+    /// <param name="key">Key to remove</param>
+    /// <typeparam name="T">Type of the value</typeparam>
+    /// <returns>Whether there was item</returns>
+    ValueTask<bool> RemoveAsync<T>(TypedKey<T> key);
+
+    /// <summary>
+    /// Get the key if it exists or add a new one
+    /// </summary>
+    /// <param name="key">Key to get and potentially add</param>
+    /// <param name="createFactory">Value creation factory</param>
+    /// <param name="expiry">Optional expiry</param>
+    /// <typeparam name="T">Type of the value</typeparam>
+    /// <returns>The retrieved or newly added value</returns>
+    ValueTask<T?> GetOrAddAsync<T>(
+        TypedKey<T> key,
+        Func<Task<T?>> createFactory,
+        TimeSpan? expiry = null);
+}

src/NadekoBot/Common/Cache/MemoryBotCache.cs

@@ -0,0 +1,71 @@
+using Microsoft.Extensions.Caching.Memory;
+using OneOf;
+using OneOf.Types;
+
+// ReSharper disable InconsistentlySynchronizedField
+
+namespace NadekoBot.Common;
+
+public sealed class MemoryBotCache : IBotCache
+{
+    // needed for overwrites and Delete return value
+    private readonly object _cacheLock = new object();
+    private readonly MemoryCache _cache;
+
+    public MemoryBotCache()
+    {
+        _cache = new MemoryCache(new MemoryCacheOptions());
+    }
+
+    public ValueTask<bool> AddAsync<T>(TypedKey<T> key, T value, TimeSpan? expiry = null, bool overwrite = true)
+    {
+        if (overwrite)
+        {
+            using var item = _cache.CreateEntry(key.Key);
+            item.Value = value;
+            item.AbsoluteExpirationRelativeToNow = expiry;
+            return new(true);
+        }
+        
+        lock (_cacheLock)
+        {
+            if (_cache.TryGetValue(key.Key, out var old) && old is not null)
+                return new(false);
+            
+            using var item = _cache.CreateEntry(key.Key);
+            item.Value = value;
+            item.AbsoluteExpirationRelativeToNow = expiry;
+            return new(true);
+        }
+    }
+
+    public async ValueTask<T?> GetOrAddAsync<T>(
+        TypedKey<T> key,
+        Func<Task<T?>> createFactory,
+        TimeSpan? expiry = null)
+        => await _cache.GetOrCreateAsync(key.Key,
+            async ce =>
+            {
+                ce.AbsoluteExpirationRelativeToNow = expiry;
+                var val = await createFactory();
+                return val;
+            });
+
+    public ValueTask<OneOf<T, None>> GetAsync<T>(TypedKey<T> key)
+    {
+        if (!_cache.TryGetValue(key.Key, out var val) || val is null)
+            return new(new None());
+
+        return new((T)val);
+    }
+
+    public ValueTask<bool> RemoveAsync<T>(TypedKey<T> key)
+    {
+        lock (_cacheLock)
+        {
+            var toReturn = _cache.TryGetValue(key.Key, out var old ) && old is not null;
+            _cache.Remove(key.Key);
+            return new(toReturn);
+        }
+    }
+}

src/NadekoBot/Common/Cache/RedisBotCache.cs

@@ -0,0 +1,119 @@
+using OneOf;
+using OneOf.Types;
+using StackExchange.Redis;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace NadekoBot.Common;
+
+public sealed class RedisBotCache : IBotCache
+{
+    private static readonly Type[] _supportedTypes = new []
+    {
+        typeof(bool), typeof(int), typeof(uint), typeof(long),
+        typeof(ulong), typeof(float), typeof(double),
+        typeof(string), typeof(byte[]), typeof(ReadOnlyMemory<byte>), typeof(Memory<byte>),
+        typeof(RedisValue),
+    };
+
+    private static readonly JsonSerializerOptions _opts = new()
+    {
+        PropertyNameCaseInsensitive = true,
+        NumberHandling = JsonNumberHandling.AllowReadingFromString,
+        AllowTrailingCommas = true,
+        IgnoreReadOnlyProperties = false,
+    };
+    private readonly ConnectionMultiplexer _conn;
+
+    public RedisBotCache(ConnectionMultiplexer conn)
+    {
+        _conn = conn;
+    }
+
+    public async ValueTask<bool> AddAsync<T>(TypedKey<T> key, T value, TimeSpan? expiry = null, bool overwrite = true)
+    {
+        // if a null value is passed, remove the key
+        if (value is null)
+        {
+            await RemoveAsync(key);
+            return false;
+        }
+        
+        var db = _conn.GetDatabase();
+        RedisValue val = IsSupportedType(typeof(T)) 
+            ? RedisValue.Unbox(value)
+            : JsonSerializer.Serialize(value, _opts);
+
+        var success = await db.StringSetAsync(key.Key,
+            val,
+            expiry: expiry,
+            when: overwrite ? When.Always : When.NotExists);
+
+        return success;
+    }
+
+    public bool IsSupportedType(Type type)
+    {
+        if (type.IsGenericType)
+        {
+            var typeDef = type.GetGenericTypeDefinition();
+            if (typeDef == typeof(Nullable<>))
+                return IsSupportedType(type.GenericTypeArguments[0]);
+        }
+
+        foreach (var t in _supportedTypes)
+        {
+            if (type == t)
+                return true;
+        }
+
+        return false;
+    }
+    
+    public async ValueTask<OneOf<T, None>> GetAsync<T>(TypedKey<T> key)
+    {
+        var db = _conn.GetDatabase();
+        var val = await db.StringGetAsync(key.Key);
+        if (val == default)
+            return new None();
+
+        if (IsSupportedType(typeof(T)))
+            return (T)((IConvertible)val).ToType(typeof(T), null);
+
+        return JsonSerializer.Deserialize<T>(val.ToString(), _opts)!;
+    }
+
+    public async ValueTask<bool> RemoveAsync<T>(TypedKey<T> key)
+    {
+        var db = _conn.GetDatabase();
+
+        return await db.KeyDeleteAsync(key.Key);
+    }
+
+    public async ValueTask<T?> GetOrAddAsync<T>(TypedKey<T> key, Func<Task<T?>> createFactory, TimeSpan? expiry = null)
+    {
+        var result = await GetAsync(key);
+
+        return await result.Match<Task<T?>>(
+            v => Task.FromResult<T?>(v),
+            async _ =>
+            {
+                var factoryValue = await createFactory();
+
+                if (factoryValue is null)
+                    return default;
+                
+                await AddAsync(key, factoryValue, expiry);
+                
+                // get again to make sure it's the cached value
+                // and not the late factory value, in case there's a race condition
+                
+                var newResult = await GetAsync(key);
+
+                // it's fine to do this, it should blow up if something went wrong.
+                return newResult.Match<T?>(
+                    v => v,
+                    _ => default);
+            });
+    }
+}

src/NadekoBot/Common/Configs/BotConfig.cs

@@ -12,7 +12,7 @@ namespace NadekoBot.Common.Configs;
 public sealed partial class BotConfig : ICloneable<BotConfig>
 {
     [Comment(@"DO NOT CHANGE")]
-    public int Version { get; set; } = 2;
+    public int Version { get; set; } = 3;
 
     [Comment(@"Most commands, when executed, have a small colored line
 next to the response. The color depends whether the command
@@ -182,4 +182,4 @@ public enum ConsoleOutputType
     Normal = 0,
     Simple = 1,
     None = 2
-}
+}

src/NadekoBot/Common/Creds.cs

@@ -19,7 +19,10 @@ public sealed class Creds : IBotCredentials
     public bool UsePrivilegedIntents { get; set; }
 
     [Comment(@"The number of shards that the bot will be running on.
-Leave at 1 if you don't know what you're doing.")]
+Leave at 1 if you don't know what you're doing.
+
+note: If you are planning to have more than one shard, then you must change botCache to 'redis'.
+      Also, in that case you should be using NadekoBot.Coordinator to start the bot, and it will correctly override this value.")]
     public int TotalShards { get; set; }
 
     [Comment(   
@@ -50,8 +53,14 @@ go to https://www.patreon.com/portal -> my clients -> create client")]
 
     [Comment(@"Official cleverbot api key.")]
     public string CleverbotApiKey { get; set; }
-
-    [Comment(@"Redis connection string. Don't change if you don't know what you're doing.")]
+    
+    [Comment(@"Which cache implementation should bot use.
+'memory' - Cache will be in memory of the bot's process itself. Only use this on bots with a single shard. When the bot is restarted the cache is reset. 
+'redis' - Uses redis (which needs to be separately downloaded and installed). The cache will persist through bot restarts. You can configure connection string in creds.yml")]
+    public BotCacheImplemenation BotCache { get; set; }
+    
+    [Comment(@"Redis connection string. Don't change if you don't know what you're doing.
+Only used if botCache is set to 'redis'")]
     public string RedisOptions { get; set; }
 
     [Comment(@"Database options. Don't change if you don't know what you're doing. Leave null for default values")]
@@ -104,12 +113,12 @@ Linux default
     args: ""NadekoBot.dll -- {0}""
 Windows default
     cmd: NadekoBot.exe
-    args: {0}")]
+    args: ""{0}""")]
     public RestartConfig RestartCommand { get; set; }
 
     public Creds()
     {
-        Version = 5;
+        Version = 6;
         Token = string.Empty;
         UsePrivilegedIntents = true;
         OwnerIds = new List<ulong>();
@@ -119,6 +128,7 @@ Windows default
         Patreon = new(string.Empty, string.Empty, string.Empty, string.Empty);
         BotListToken = string.Empty;
         CleverbotApiKey = string.Empty;
+        BotCache = BotCacheImplemenation.Memory;
         RedisOptions = "localhost:6379,syncTimeout=30000,responseTimeout=30000,allowAdmin=true,password=";
         Db = new()
         {
@@ -217,4 +227,10 @@ public class GoogleApiConfig
 {
     public string SearchId { get; init; }
     public string ImageSearchId { get; init; }
+}
+
+public enum BotCacheImplemenation
+{
+    Memory,
+    Redis
 }

src/NadekoBot/Common/IBotCredentials.cs

@@ -26,6 +26,7 @@ public interface IBotCredentials
     string TwitchClientId { get; set; }
     string TwitchClientSecret { get; set; }
     GoogleApiConfig Google { get; set; }
+    BotCacheImplemenation BotCache { get; set; }
 }
 
 public class RestartConfig

src/NadekoBot/Common/ImageUrls.cs

@@ -1,9 +1,11 @@
 #nullable disable
 using NadekoBot.Common.Yml;
+using Cloneable;
 
 namespace NadekoBot.Common;
 
-public class ImageUrls
+[Cloneable]
+public partial class ImageUrls : ICloneable<ImageUrls> 
 {
     [Comment("DO NOT CHANGE")]
     public int Version { get; set; } = 3;

src/NadekoBot/Common/OneOfExtensions.cs

@@ -0,0 +1,10 @@
+using OneOf.Types;
+using OneOf;
+
+namespace NadekoBot.Common;
+
+public static class OneOfExtensions
+{
+    public static bool TryGetValue<T>(this OneOf<T, None> oneOf, out T value)
+        => oneOf.TryPickT0(out value, out _);
+}

src/NadekoBot/Common/Pokemon/SearchPokemon.cs

@@ -1,11 +1,12 @@
 #nullable disable
-using Newtonsoft.Json;
+
+using System.Text.Json.Serialization;
 
 namespace NadekoBot.Common.Pokemon;
 
 public class SearchPokemon
 {
-    [JsonProperty("num")]
+    [JsonPropertyName("num")]
     public int Id { get; set; }
 
     public string Species { get; set; }