🔧 refactor(__main__.py, main.py): move setup_static_files function to main.py and rename create_app to setup_app

✨ feat(__main__.py, main.py): add support for a custom static files directory to be passed as an argument to the app
The `setup_static_files` function has been moved from `__main__.py` to `main.py` to improve code organization. The function has also been renamed to `setup_app` to better reflect its purpose. The `create_app` function has been renamed to `setup_app` to follow the naming convention of the new function. The `setup_app` function now accepts an optional argument `static_files_dir` which allows the user to specify a custom directory for static files. This improves the flexibility of the app as it can now be run with a custom frontend.

src/backend/langflow/__main__.py

@@ -1,6 +1,5 @@
 import sys
 import time
-from fastapi import FastAPI
 import httpx
 from multiprocess import Process, cpu_count  # type: ignore
 import platform
@@ -11,9 +10,7 @@ from rich.panel import Panel
 from rich import box
 from rich import print as rprint
 import typer
-from fastapi.staticfiles import StaticFiles
+from langflow.main import setup_app
-from fastapi.responses import FileResponse
-from langflow.main import create_app
 from langflow.settings import settings
 from langflow.utils.logger import configure, logger
 import webbrowser
@@ -144,15 +141,9 @@ def serve(
         remove_api_keys=remove_api_keys,
         cache=cache,
     )
-    # get the directory of the current file
+    # create path object if path is provided
-    if not path:
+    path = Path(path) if path else path
-        frontend_path = Path(__file__).parent
+    app = setup_app(static_files_dir=path)
-        static_files_dir = frontend_path / "frontend"
-    else:
-        static_files_dir = Path(path)
-
-    app = create_app()
-    setup_static_files(app, static_files_dir)
     # check if port is being used
     if is_port_in_use(port, host):
         port = get_free_port(port)
@@ -200,29 +191,6 @@ def run_on_windows(host, port, log_level, options, app):
     run_langflow(host, port, log_level, options, app)
 
 
-def setup_static_files(app: FastAPI, static_files_dir: Path):
-    """
-    Setup the static files directory.
-
-    Args:
-        app (FastAPI): FastAPI app.
-        path (str): Path to the static files directory.
-    """
-    app.mount(
-        "/",
-        StaticFiles(directory=static_files_dir, html=True),
-        name="static",
-    )
-
-    @app.exception_handler(404)
-    async def custom_404_handler(request, __):
-        path = static_files_dir / "index.html"
-
-        if not path.exists():
-            raise RuntimeError(f"File at path {path} does not exist.")
-        return FileResponse(path)
-
-
 def is_port_in_use(port, host="localhost"):
     """
     Check if a port is in use.

src/backend/langflow/main.py

@@ -1,5 +1,9 @@
+from pathlib import Path
+from typing import Optional
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
+from fastapi.responses import FileResponse
+from fastapi.staticfiles import StaticFiles
 
 from langflow.api import router
 from langflow.database.base import create_db_and_tables
@@ -33,6 +37,42 @@ def create_app():
     return app
 
 
+def setup_static_files(app: FastAPI, static_files_dir: Path):
+    """
+    Setup the static files directory.
+    Args:
+        app (FastAPI): FastAPI app.
+        path (str): Path to the static files directory.
+    """
+    app.mount(
+        "/",
+        StaticFiles(directory=static_files_dir, html=True),
+        name="static",
+    )
+
+    @app.exception_handler(404)
+    async def custom_404_handler(request, __):
+        path = static_files_dir / "index.html"
+
+        if not path.exists():
+            raise RuntimeError(f"File at path {path} does not exist.")
+        return FileResponse(path)
+
+
+# app = create_app()
+# setup_static_files(app, static_files_dir)
+def setup_app(static_files_dir: Optional[Path]) -> FastAPI:
+    """Setup the FastAPI app."""
+    # get the directory of the current file
+    if not static_files_dir:
+        frontend_path = Path(__file__).parent
+        static_files_dir = frontend_path / "frontend"
+
+    app = create_app()
+    setup_static_files(app, static_files_dir)
+    return app
+
+
 app = create_app()