Change fallback system

core/src/main/java/org/geysermc/geyser/network/UpstreamPacketHandler.java

@@ -282,7 +282,7 @@ public class UpstreamPacketHandler extends LoggingPacketHandler {
                 // TODO: Proper pack checking - could be that the remote url is offline, the pack changed, or.. something?
                 GeyserImpl.getInstance().getLogger().warning("Received ResourcePackChunkRequestPacket for URL pack " + urlPackCodec.url());
 
-                WebUtils.checkRemotePackUrl(urlPackCodec.url());
+                WebUtils.checkUrlAndDownloadRemotePack(urlPackCodec.url());
             }
         }
 

core/src/main/java/org/geysermc/geyser/pack/url/GeyserUrlPackCodec.java

@@ -27,6 +27,7 @@ package org.geysermc.geyser.pack.url;
 
 import lombok.Getter;
 import org.checkerframework.checker.nullness.qual.NonNull;
+import org.geysermc.geyser.GeyserImpl;
 import org.geysermc.geyser.api.pack.ResourcePack;
 import org.geysermc.geyser.api.pack.UrlPackCodec;
 import org.geysermc.geyser.pack.path.GeyserPathPackCodec;
@@ -39,7 +40,7 @@ public class GeyserUrlPackCodec extends UrlPackCodec {
     private final String url;
     private final String contentKey;
     @Getter
-    private final GeyserPathPackCodec fallback;
+    private GeyserPathPackCodec fallback;
 
     public GeyserUrlPackCodec(String url) throws IllegalArgumentException {
         this(url, "");
@@ -48,31 +49,49 @@ public class GeyserUrlPackCodec extends UrlPackCodec {
     public GeyserUrlPackCodec(String url, String contentKey) throws IllegalArgumentException {
         this.url = url;
         this.contentKey = contentKey;
-        try {
-            this.fallback = new GeyserPathPackCodec(ResourcePackLoader.downloadPack(url).get());
-        } catch (Exception e) {
-            throw new IllegalArgumentException("Unable to download pack from " + url, e);
-        }
     }
 
     @Override
     public byte @NonNull [] sha256() {
+        if (this.fallback == null) {
+            throw new IllegalStateException("Fallback pack not initialized! Needs to be created first.");
+        }
         return fallback.sha256();
     }
 
     @Override
     public long size() {
+        if (this.fallback == null) {
+            throw new IllegalStateException("Fallback pack not initialized! Needs to be created first.");
+        }
         return fallback.size();
     }
 
     @Override
     public @NonNull SeekableByteChannel serialize(@NonNull ResourcePack resourcePack) throws IOException {
+        if (this.fallback == null) {
+            throw new IllegalStateException("Fallback pack not initialized! Needs to be created first.");
+        }
         return fallback.serialize(resourcePack);
     }
 
     @Override
     @NonNull
     public ResourcePack create() {
+        if (this.fallback == null) {
+            try {
+                this.fallback = new GeyserPathPackCodec(ResourcePackLoader.downloadPack(url).whenComplete((pack, throwable) -> {
+                    if (throwable != null) {
+                        GeyserImpl.getInstance().getLogger().error("Failed to download pack from " + url, throwable);
+                        if (GeyserImpl.getInstance().getConfig().isDebugMode()) {
+                            throwable.printStackTrace();
+                        }
+                    }
+                }).join());
+            } catch (Exception e) {
+                throw new IllegalArgumentException("Unable to download pack from " + url, e);
+            }
+        }
         return ResourcePackLoader.loadDownloadedPack(this);
     }
 

core/src/main/java/org/geysermc/geyser/registry/loader/ResourcePackLoader.java

@@ -230,16 +230,20 @@ public class ResourcePackLoader implements RegistryLoader<Path, Map<String, Reso
     }
 
     public static CompletableFuture<@Nullable Path> downloadPack(String url) throws IllegalArgumentException {
-        CompletableFuture<Path> future = WebUtils.checkRemotePackUrl(url);
-        AtomicReference<Path> pathAtomicReference = new AtomicReference<>();
+        CompletableFuture<Path> future = WebUtils.checkUrlAndDownloadRemotePack(url);
         future.whenCompleteAsync((cachedPath, throwable) -> {
-            if (cachedPath == null || throwable != null) {
+            if (cachedPath == null) {
+                return;
+            }
+
+            if (throwable != null) {
+                GeyserImpl.getInstance().getLogger().error("Failed to download resource pack " + url, throwable);
                 return;
             }
 
             // Check if the pack is a .zip or .mcpack file
             if (!PACK_MATCHER.matches(cachedPath)) {
-                throw new IllegalArgumentException("Invalid pack! Not a .zip or .mcpack file.");
+                throw new IllegalArgumentException("Invalid pack format! Not a .zip or .mcpack file.");
             }
 
             try {
@@ -258,10 +262,7 @@ public class ResourcePackLoader implements RegistryLoader<Path, Map<String, Reso
             } catch (IOException e) {
                 throw new IllegalArgumentException(GeyserLocale.getLocaleStringLog("geyser.resource_pack.broken", url), e);
             }
-
-            pathAtomicReference.set(cachedPath);
         });
-
-        return future.thenApplyAsync(x -> pathAtomicReference.get());
+        return future;
     }
 }

core/src/main/java/org/geysermc/geyser/util/WebUtils.java

@@ -105,19 +105,25 @@ public class WebUtils {
      * @param url The URL to check
      * @return Path to the downloaded pack file
      */
-    public static CompletableFuture<@Nullable Path> checkRemotePackUrl(String url) {
+    public static CompletableFuture<@Nullable Path> checkUrlAndDownloadRemotePack(String url) {
         return CompletableFuture.supplyAsync(() -> {
             try {
                 HttpURLConnection con = (HttpURLConnection) new URL(url).openConnection();
                 con.setRequestProperty("User-Agent", "Geyser-" + GeyserImpl.getInstance().getPlatformType().toString() + "/" + GeyserImpl.VERSION);
                 int size = con.getContentLength();
                 String type = con.getContentType();
-                InputStream in = con.getInputStream();
 
-                if (size < 1 || !type.equals("application/zip")) {
-                    GeyserImpl.getInstance().getLogger().error("Invalid resource pack: " + url + " (" + type + ", " + size + " bytes)");
-                    //return null;
+                if (size <= 0) {
+                    GeyserImpl.getInstance().getLogger().error(String.format("Invalid size from remote pack URL: %s (size: %d)", url, size));
+                    return null;
                 }
+
+                if (type == null || !type.equals("application/zip")) {
+                    GeyserImpl.getInstance().getLogger().error(String.format("Invalid application type from remote pack URL: %s (type: %s)", url, type));
+                    return null;
+                }
+
+                InputStream in = con.getInputStream();
                 Path fileLocation = GeyserImpl.getInstance().getBootstrap().getConfigFolder().resolve("cache").resolve("remote_packs").resolve(url.hashCode() + ".zip");
                 Files.copy(in, fileLocation, StandardCopyOption.REPLACE_EXISTING);