Support caching of skins to disk based on configuration variable

If a skin is downloaded it will be saved to `cache/skins` using a base64 encoded filename of the textureUrl, if allowed by setting a non 0 value for the configuration variable `cache-skins`

When reading a skin we try load it from a cache file first before trying to download it.

We don't yet expire them but do update their last modification so we know which ones have been accessed.

.gitignore

@@ -227,3 +227,4 @@ config.yml
 logs/
 public-key.pem
 locales/
+cache/

bootstrap/bukkit/src/main/java/org/geysermc/platform/bukkit/GeyserBukkitConfiguration.java

@@ -151,6 +151,11 @@ public boolean isCacheChunks() {
         return true; // We override this as with Bukkit, we have direct access to the server implementation
     }
 
+    @Override
+    public int getCacheSkins() {
+        return config.getInt("cache-skins", 0);
+    }
+
     @Override
     public boolean isAboveBedrockNetherBuilding() {
         return config.getBoolean("above-bedrock-nether-building", false);

bootstrap/bungeecord/src/main/java/org/geysermc/platform/bungeecord/GeyserBungeeConfiguration.java

@@ -150,6 +150,11 @@ public boolean isCacheChunks() {
         return config.getBoolean("cache-chunks", false);
     }
 
+    @Override
+    public int getCacheSkins() {
+        return config.getInt("cache-skins", 0);
+    }
+
     @Override
     public boolean isAboveBedrockNetherBuilding() {
         return config.getBoolean("above-bedrock-nether-building", false);

bootstrap/sponge/src/main/java/org/geysermc/platform/sponge/GeyserSpongeConfiguration.java

@@ -144,6 +144,11 @@ public boolean isCacheChunks() {
         return node.getNode("cache-chunks").getBoolean(false);
     }
 
+    @Override
+    public int getCacheSkins() {
+        return node.getNode("cache-skins").getInt(0);
+    }
+
     @Override
     public boolean isAboveBedrockNetherBuilding() {
         return node.getNode("above-bedrock-nether-building").getBoolean(false);

bootstrap/standalone/src/main/java/org/geysermc/platform/standalone/GeyserStandaloneConfiguration.java

@@ -83,6 +83,9 @@ public class GeyserStandaloneConfiguration implements GeyserConfiguration {
     @JsonProperty("cache-chunks")
     private boolean cacheChunks;
 
+    @JsonProperty(value = "cache-skins", defaultValue = "0")
+    private int cacheSkins;
+
     @JsonProperty("above-bedrock-nether-building")
     private boolean isAboveBedrockNetherBuilding;
 

bootstrap/velocity/src/main/java/org/geysermc/platform/velocity/GeyserVelocityConfiguration.java

@@ -85,9 +85,12 @@ public class GeyserVelocityConfiguration implements GeyserConfiguration {
     @JsonProperty("default-locale")
     private String defaultLocale;
 
-    @JsonProperty("cache-chunks")
+    @JsonProperty(value = "cache-chunks")
     private boolean cacheChunks;
 
+    @JsonProperty(value = "cache-skins", defaultValue = "0")
+    private int cacheSkins;
+
     @JsonProperty("above-bedrock-nether-building")
     private boolean aboveBedrockNetherBuilding;
 

connector/src/main/java/org/geysermc/connector/GeyserConfiguration.java

@@ -68,6 +68,8 @@ public interface GeyserConfiguration {
 
     boolean isCacheChunks();
 
+    int getCacheSkins();
+
     IMetricsInfo getMetrics();
 
     interface IBedrockConfiguration {

connector/src/main/java/org/geysermc/connector/utils/SkinProvider.java

@@ -39,6 +39,10 @@
 import java.net.URL;
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.attribute.FileTime;
 import java.util.Arrays;
 import java.util.Base64;
 import java.util.Map;
@@ -285,11 +289,33 @@ public static void storeEarGeometry(UUID playerID, boolean isSlim) {
     }
 
     private static Skin supplySkin(UUID uuid, String textureUrl) {
-        byte[] skin = EMPTY_SKIN.getSkinData();
+        // First see if we have a cached file
+        Path skinFile = Paths.get("cache", "skins", Base64.getEncoder().encodeToString(textureUrl.getBytes()));
         try {
-            skin = requestImage(textureUrl, null);
+            Files.setLastModifiedTime(skinFile, FileTime.fromMillis(System.currentTimeMillis()));
+            GeyserConnector.getInstance().getLogger().debug("Reading cached skin from file " + skinFile.toString() + " for " + textureUrl);
+            return new Skin(uuid, textureUrl, Files.readAllBytes(skinFile), System.currentTimeMillis(), false, false);
+        } catch (IOException ignored) {}
+
+        try {
+            byte[] skin = requestImage(textureUrl, null);
+
+            // Write cache if we are allowed
+            if (GeyserConnector.getInstance().getConfig().getCacheSkins() > 0) {
+                //noinspection ResultOfMethodCallIgnored
+                skinFile.getParent().toFile().mkdirs();
+                try {
+                    Files.write(skinFile, skin);
+                    GeyserConnector.getInstance().getLogger().debug("Writing cached skin to file " + skinFile.toString() + " for " + textureUrl);
+                } catch (IOException e) {
+                    GeyserConnector.getInstance().getLogger().error("Failed to write cached skin to file " + skinFile.toString() + " for " + textureUrl);
+                }
+            }
+
+            return new Skin(uuid, textureUrl, skin, System.currentTimeMillis(), false, false);
         } catch (Exception ignored) {} // just ignore I guess
-        return new Skin(uuid, textureUrl, skin, System.currentTimeMillis(), false, false);
+
+        return new Skin(uuid, "empty", EMPTY_SKIN.getSkinData(), System.currentTimeMillis(), false, false);
     }
 
     private static Cape supplyCape(String capeUrl, CapeProvider provider) {