Implement token-scoped cache keys

Backend/Remora.Discord.Caching.Redis/Services/RedisCacheProvider.cs

@@ -21,6 +21,8 @@
 //
 
 using System;
+using System.Security.Cryptography;
+using System.Text;
 using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
@@ -29,6 +31,7 @@
 using Microsoft.Extensions.Options;
 using Remora.Discord.Caching.Abstractions;
 using Remora.Discord.Caching.Abstractions.Services;
+using Remora.Discord.Rest;
 using Remora.Results;
 
 namespace Remora.Discord.Caching.Redis.Services;
@@ -41,16 +44,40 @@ public class RedisCacheProvider : ICacheProvider
 {
     private readonly IDistributedCache _cache;
     private readonly JsonSerializerOptions _jsonOptions;
+    private readonly string? _tokenHash;
 
     /// <summary>
     /// Initializes a new instance of the <see cref="RedisCacheProvider"/> class.
     /// </summary>
     /// <param name="cache">The redis cache.</param>
     /// <param name="jsonOptions">The JSON options.</param>
-    public RedisCacheProvider(IDistributedCache cache, IOptionsMonitor<JsonSerializerOptions> jsonOptions)
+    /// <param name="tokenStore">The token store, if one is available.</param>
+    public RedisCacheProvider
+    (
+        IDistributedCache cache,
+        IOptionsMonitor<JsonSerializerOptions> jsonOptions,
+        ITokenStore? tokenStore = null
+    )
     {
         _cache = cache;
         _jsonOptions = jsonOptions.Get("Discord");
+
+        if (tokenStore is null)
+        {
+            _tokenHash = null;
+            return;
+        }
+
+        using var hasher = SHA256.Create();
+        var hashBuilder = new StringBuilder(64);
+        var hash = hasher.ComputeHash(Encoding.UTF8.GetBytes(tokenStore.Token));
+
+        foreach (var value in hash)
+        {
+            hashBuilder.Append(value.ToString("x2"));
+        }
+
+        _tokenHash = hashBuilder.ToString();
     }
 
     /// <inheritdoc cref="ICacheProvider.CacheAsync{TInstance}"/>
@@ -77,7 +104,7 @@ public virtual async ValueTask CacheAsync<TInstance>
 
         var serialized = JsonSerializer.SerializeToUtf8Bytes(instance, _jsonOptions);
 
-        await _cache.SetAsync(key.ToCanonicalString(), serialized, options, ct);
+        await _cache.SetAsync(CreateTokenScopedKey(key), serialized, options, ct);
     }
 
     /// <inheritdoc cref="ICacheProvider.RetrieveAsync{TInstance}"/>
@@ -95,7 +122,7 @@ public virtual async ValueTask<Result<TInstance>> RetrieveAsync<TInstance>
     )
         where TInstance : class
     {
-        var keyString = key.ToCanonicalString();
+        var keyString = CreateTokenScopedKey(key);
 
         var value = await _cache.GetAsync(keyString, ct);
 
@@ -114,7 +141,7 @@ public virtual async ValueTask<Result<TInstance>> RetrieveAsync<TInstance>
     /// <inheritdoc cref="ICacheProvider.EvictAsync" />
     public async ValueTask<Result> EvictAsync(CacheKey key, CancellationToken ct = default)
     {
-        var keyString = key.ToCanonicalString();
+        var keyString = CreateTokenScopedKey(key);
 
         var existingValue = await _cache.GetAsync(keyString, ct);
 
@@ -143,7 +170,7 @@ public virtual async ValueTask<Result<TInstance>> EvictAsync<TInstance>
     )
         where TInstance : class
     {
-        var keyString = key.ToCanonicalString();
+        var keyString = CreateTokenScopedKey(key);
 
         var existingValue = await _cache.GetAsync(keyString, ct);
 
@@ -158,4 +185,13 @@ public virtual async ValueTask<Result<TInstance>> EvictAsync<TInstance>
 
         return deserialized;
     }
+
+    /// <summary>
+    /// Creates a cache key scoped to a specific token.
+    /// </summary>
+    /// <param name="key">The key.</param>
+    /// <returns>The scoped key.</returns>
+    private string CreateTokenScopedKey(CacheKey key) => _tokenHash is not null
+        ? $"{_tokenHash}:{key.ToCanonicalString()}"
+        : key.ToCanonicalString();
 }

Backend/Remora.Discord.Caching/Services/CacheService.cs

@@ -45,7 +45,11 @@ public class CacheService
     /// </summary>
     /// <param name="cacheProvider">The cache provider.</param>
     /// <param name="cacheSettings">The cache settings.</param>
-    public CacheService(ICacheProvider cacheProvider, ImmutableCacheSettings cacheSettings)
+    public CacheService
+    (
+        ICacheProvider cacheProvider,
+        ImmutableCacheSettings cacheSettings
+    )
     {
         _cacheProvider = cacheProvider;
         _cacheSettings = cacheSettings;

Backend/Remora.Discord.Rest/Caching/MemoryCacheProvider.cs

@@ -20,6 +20,8 @@
 //  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 //
 
+using System.Security.Cryptography;
+using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 using JetBrains.Annotations;
@@ -37,14 +39,33 @@ namespace Remora.Discord.Rest.Caching;
 public class MemoryCacheProvider : ICacheProvider
 {
     private readonly IMemoryCache _memoryCache;
+    private readonly string? _tokenHash;
 
     /// <summary>
     /// Initializes a new instance of the <see cref="MemoryCacheProvider"/> class.
     /// </summary>
     /// <param name="memoryCache">The memory cache.</param>
-    public MemoryCacheProvider(IMemoryCache memoryCache)
+    /// <param name="tokenStore">The token store, if one is available.</param>
+    public MemoryCacheProvider(IMemoryCache memoryCache, ITokenStore? tokenStore = null)
     {
         _memoryCache = memoryCache;
+
+        if (tokenStore is null)
+        {
+            _tokenHash = null;
+            return;
+        }
+
+        using var hasher = SHA256.Create();
+        var hashBuilder = new StringBuilder(64);
+        var hash = hasher.ComputeHash(Encoding.UTF8.GetBytes(tokenStore.Token));
+
+        foreach (var value in hash)
+        {
+            hashBuilder.Append(value.ToString("x2"));
+        }
+
+        _tokenHash = hashBuilder.ToString();
     }
 
     /// <inheritdoc cref="ICacheProvider.CacheAsync{TInstance}" />
@@ -57,7 +78,7 @@ public ValueTask CacheAsync<TInstance>
     )
         where TInstance : class
     {
-        _memoryCache.Set(key, instance, options);
+        _memoryCache.Set(CreateTokenScopedKey(key), instance, options);
 
         return default;
     }
@@ -66,7 +87,7 @@ public ValueTask CacheAsync<TInstance>
     public ValueTask<Result<TInstance>> RetrieveAsync<TInstance>(CacheKey key, CancellationToken ct = default)
         where TInstance : class
     {
-        if (_memoryCache.TryGetValue<TInstance>(key, out var instance))
+        if (_memoryCache.TryGetValue<TInstance>(CreateTokenScopedKey(key), out var instance))
         {
             return new(instance);
         }
@@ -77,25 +98,32 @@ public ValueTask<Result<TInstance>> RetrieveAsync<TInstance>(CacheKey key, Cance
     /// <inheritdoc cref="ICacheProvider.EvictAsync" />
     public ValueTask<Result> EvictAsync(CacheKey key, CancellationToken ct = default)
     {
-        if (!_memoryCache.TryGetValue(key, out _))
+        if (!_memoryCache.TryGetValue(CreateTokenScopedKey(key), out _))
         {
             return new(new NotFoundError($"The key \"{key}\" did not contain a value in cache."));
         }
 
-        _memoryCache.Remove(key);
+        _memoryCache.Remove(CreateTokenScopedKey(key));
         return new(Result.FromSuccess());
     }
 
     /// <inheritdoc cref="ICacheProvider.EvictAsync{TInstance}"/>
     public ValueTask<Result<TInstance>> EvictAsync<TInstance>(CacheKey key, CancellationToken ct = default)
         where TInstance : class
     {
-        if (!_memoryCache.TryGetValue(key, out TInstance? existingValue))
+        if (!_memoryCache.TryGetValue(CreateTokenScopedKey(key), out TInstance? existingValue))
         {
             return new(new NotFoundError($"The key \"{key}\" did not contain a value in cache."));
         }
 
-        _memoryCache.Remove(key);
+        _memoryCache.Remove(CreateTokenScopedKey(key));
         return new(existingValue);
     }
+
+    /// <summary>
+    /// Creates a cache key scoped to a specific token.
+    /// </summary>
+    /// <param name="key">The key.</param>
+    /// <returns>The scoped key.</returns>
+    private object CreateTokenScopedKey(CacheKey key) => (_tokenHash, key);
 }