Add GET /internal/files. (#4295)

* Create internal route table.

* List files.

* Add GET /internal/files.

Retrieves list of files in models, output, and user directories.

* Refactor file names.

* Use typing_extensions for Python 3.8

* Fix tests.

* Remove print statements.

* Update README.

* Add output and user to valid directory test.

* Add missing type hints.

server.py

@@ -29,6 +29,8 @@ from app.frontend_management import FrontendManager
 from app.user_manager import UserManager
 from model_filemanager import download_model, DownloadModelStatus
 from typing import Optional
+from api_server.routes.internal.internal_routes import InternalRoutes
+
 
 class BinaryEventTypes:
     PREVIEW_IMAGE = 1
@@ -72,6 +74,7 @@ class PromptServer():
         mimetypes.types_map['.js'] = 'application/javascript; charset=utf-8'
 
         self.user_manager = UserManager()
+        self.internal_routes = InternalRoutes()
         self.supports = ["custom_nodes_from_web"]
         self.prompt_queue = None
         self.loop = loop
@@ -602,6 +605,7 @@ class PromptServer():
 
     def add_routes(self):
         self.user_manager.add_routes(self.routes)
+        self.app.add_subapp('/internal', self.internal_routes.get_app())
 
         # Prefix every route with /api for easier matching for delegation.
         # This is very useful for frontend dev server, which need to forward