Add model downloading endpoint. (#4248)

* Add model downloading endpoint.

* Move client session init to async function.

* Break up large function.

* Send "download_progress" as websocket event.

* Fixed

* Fixed.

* Use async mock.

* Move server set up to right before run call.

* Validate that model subdirectory cannot contain relative paths.

* Add download_model test checking for invalid paths.

* Remove DS_Store.

* Consolidate DownloadStatus and DownloadModelResult

* Add progress_interval as an optional parameter.

* Use tuple type from annotations.

* Use pydantic.

* Update comment.

* Revert "Use pydantic."

This reverts commit 7461e8eb00.

* Add new line.

* Add newline EOF.

* Validate model filename as well.

* Add comment to not reply on internal.

* Restrict downloading to safetensor files only.

server.py

@@ -12,7 +12,6 @@ import json
 import glob
 import struct
 import ssl
-import hashlib
 from PIL import Image, ImageOps
 from PIL.PngImagePlugin import PngInfo
 from io import BytesIO
@@ -28,7 +27,8 @@ import comfy.model_management
 import node_helpers
 from app.frontend_management import FrontendManager
 from app.user_manager import UserManager
-
+from model_filemanager import download_model, DownloadModelStatus
+from typing import Optional
 
 class BinaryEventTypes:
     PREVIEW_IMAGE = 1
@@ -76,6 +76,7 @@ class PromptServer():
         self.prompt_queue = None
         self.loop = loop
         self.messages = asyncio.Queue()
+        self.client_session:Optional[aiohttp.ClientSession] = None
         self.number = 0
 
         middlewares = [cache_control]
@@ -559,6 +560,36 @@ class PromptServer():
                     self.prompt_queue.delete_history_item(id_to_delete)
 
             return web.Response(status=200)
+        
+        # Internal route. Should not be depended upon and is subject to change at any time.
+        # TODO(robinhuang): Move to internal route table class once we refactor PromptServer to pass around Websocket.
+        @routes.post("/internal/models/download")
+        async def download_handler(request):
+            async def report_progress(filename: str, status: DownloadModelStatus):
+                await self.send_json("download_progress", status.to_dict())
+
+            data = await request.json()
+            url = data.get('url')
+            model_directory = data.get('model_directory')
+            model_filename = data.get('model_filename')
+            progress_interval = data.get('progress_interval', 1.0) # In seconds, how often to report download progress.
+
+            if not url or not model_directory or not model_filename:
+                return web.json_response({"status": "error", "message": "Missing URL or folder path or filename"}, status=400)
+
+            session = self.client_session
+            if session is None:
+                logging.error("Client session is not initialized")
+                return web.Response(status=500)
+            
+            task = asyncio.create_task(download_model(lambda url: session.get(url), model_filename, url, model_directory, report_progress, progress_interval))
+            await task
+
+            return web.json_response(task.result().to_dict())
+
+    async def setup(self):
+        timeout = aiohttp.ClientTimeout(total=None) # no timeout
+        self.client_session = aiohttp.ClientSession(timeout=timeout)
 
     def add_routes(self):
         self.user_manager.add_routes(self.routes)