Support custom path for installed extensions (#1940)

* feat: the more you fuck around the more you learn
* feat: backwards compatible static file loading
* refactor: update paths for extension files
* refactor: var renaming
* doc: update `LNBITS_EXTENSIONS_PATH` documentation
* fix: default folder install
* feat: install ext without external path
* doc: `PYTHONPATH` no longer required
* fix: add warnings
* fix: missing path
* refactor: re-order statements
* fix: hardcoded path separator

---------

Co-authored-by: dni ⚡ <office@dnilabs.com>

lnbits/app.py

@@ -9,6 +9,7 @@ import sys
 import traceback
 from hashlib import sha256
 from http import HTTPStatus
+from pathlib import Path
 from typing import Callable, List
 
 from fastapi import FastAPI, HTTPException, Request
@@ -96,6 +97,8 @@ def create_app() -> FastAPI:
     app.add_middleware(InstalledExtensionMiddleware)
     app.add_middleware(ExtensionsRedirectMiddleware)
 
+    register_custom_extensions_path()
+
     # adds security middleware
     add_ip_block_middleware(app)
     add_ratelimit_middleware(app)
@@ -229,9 +232,7 @@ def check_installed_extension_files(ext: InstallableExtension) -> bool:
     if ext.has_installed_version:
         return True
 
-    zip_files = glob.glob(
-        os.path.join(settings.lnbits_data_folder, "extensions", "*.zip")
-    )
+    zip_files = glob.glob(os.path.join(settings.lnbits_data_folder, "zips", "*.zip"))
 
     if f"./{str(ext.zip_path)}" not in zip_files:
         ext.download_archive()
@@ -267,6 +268,25 @@ def register_routes(app: FastAPI) -> None:
             logger.error(f"Could not load extension `{ext.code}`: {str(e)}")
 
 
+def register_custom_extensions_path():
+    if settings.has_default_extension_path:
+        return
+    default_ext_path = os.path.join("lnbits", "extensions")
+    if os.path.isdir(default_ext_path) and len(os.listdir(default_ext_path)) != 0:
+        logger.warning(
+            "You are using a custom extensions path, "
+            + "but the default extensions directory is not empty. "
+            + f"Please clean-up the '{default_ext_path}' directory."
+        )
+        logger.warning(
+            f"You can move the existing '{default_ext_path}' directory to: "
+            + f" '{settings.lnbits_extensions_path}/extensions'"
+        )
+
+    sys.path.append(str(Path(settings.lnbits_extensions_path, "extensions")))
+    sys.path.append(str(Path(settings.lnbits_extensions_path, "upgrades")))
+
+
 def register_new_ext_routes(app: FastAPI) -> Callable:
     # Returns a function that registers new routes for an extension.
     # The returned function encapsulates (creates a closure around)
@@ -303,7 +323,10 @@ def register_ext_routes(app: FastAPI, ext: Extension) -> None:
     if hasattr(ext_module, f"{ext.code}_static_files"):
         ext_statics = getattr(ext_module, f"{ext.code}_static_files")
         for s in ext_statics:
-            app.mount(s["path"], s["app"], s["name"])
+            static_dir = Path(
+                settings.lnbits_extensions_path, "extensions", *s["path"].split("/")
+            )
+            app.mount(s["path"], StaticFiles(directory=static_dir), s["name"])
 
     if hasattr(ext_module, f"{ext.code}_redirect_paths"):
         ext_redirects = getattr(ext_module, f"{ext.code}_redirect_paths")