Cache full version manifests

.gitignore

@@ -1,2 +1,2 @@
 versions/
-*.cache
+cache/

build.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 import hashlib
-from typing import Any, Literal, NotRequired, TypedDict
+from typing import Any, Callable, Literal, NotRequired, TypeVar, TypedDict
 from pathlib import Path
 import urllib.request
 import json
@@ -69,23 +69,25 @@ class VersionManifest(TypedDict):
     versions: list[Version]
 
 
-def load_version_manifest(version: Version):
-    # Download new manifest
-    with urllib.request.urlopen(version["url"]) as url:
-        data: VersionManifestFull = json.load(url)
-    return data
+T = TypeVar('T')
 
 
-def load_manifest(reload: bool = False, max_age: timedelta = timedelta(hours=1)):
-    manifest_cache = "manifest.cache"
-    # Load cached manifest
+def load_json(url: str) -> Any:
+    with urllib.request.urlopen(url) as request:
+        return json.load(request)
+
+
+cache_path = Path("cache")
+
+
+def load_cached_json(url: str, cache_file: Path, loader: Callable[[str], T] = load_json, max_age: timedelta = timedelta(days=1), reload: bool = False) -> T:
     if reload:
-        print("Forced manifest reload.")
+        print(f"Forced cache reload for {cache_file}!")
     else:
         try:
-            with open(manifest_cache, "rb") as f:
+            with open(cache_file, "rb") as f:
                 time: datetime
-                data: VersionManifest
+                data: T
                 (time, data) = pickle.load(f)
             cache_age = datetime.now() - time
             if cache_age <= max_age:
@@ -93,19 +95,26 @@ def load_manifest(reload: bool = False, max_age: timedelta = timedelta(hours=1))
                 return data
             print(f"Cache is older than {max_age} and will be reloaded.")
         except FileNotFoundError:
-            print("No cached manifest found!")
+            print(f"File {cache_file} not cached, will be reloaded!")
 
-    # Download new manifest
-    with urllib.request.urlopen("https://launchermeta.mojang.com/mc/game/version_manifest.json") as url:
-        data: VersionManifest = json.load(url)
+    data = loader(url)
 
-    # Save manifest to cache
-    with open(manifest_cache, "wb") as f:
+    # Save to cache
+    cache_file.parent.mkdir(parents=True, exist_ok=True)
+    with open(cache_file, "wb") as f:
         pickle.dump((datetime.now(), data), f)
 
     return data
 
 
+def load_version_manifest(version: Version, reload: bool = False) -> VersionManifestFull:
+    return load_cached_json(version["url"], cache_path / f"manifest_{version['id']}.cache", reload=reload)
+
+
+def load_manifest(reload: bool = False) -> VersionManifest:
+    return load_cached_json("https://launchermeta.mojang.com/mc/game/version_manifest.json", cache_path / "manifest.cache", reload=reload)
+
+
 BUF_SIZE = 65536