src/custom_tools/downloads.py

import requests
from typing import Annotated

from langchain_core.tools import tool
from langgraph.prebuilt import InjectedState

from src.state import State

DEFAULT_API_URL = "https://agents-course-unit4-scoring.hf.space"

@tool
def download_file(
     task_id: str,
     state: Annotated[State, InjectedState]
     ) -> str:
        """Download a file specified by using the task id."""
        file_name = state.file_name
        task_id = state.task_id

        if not file_name:
            return "No file name in input, unable to download."
        if not task_id:
            return "No task id in input, unable to download."
        
        base_url = DEFAULT_API_URL + "/files"
        url = f"{base_url}/{task_id}" if task_id else None
        if not url:
            return "No URL provided."
        
        try:
            response = requests.get(url, stream=True)
            response.raise_for_status()  # Raise an error for bad responses
            
            local_file_path = f"downloads/{file_name}"
            with open(local_file_path, "wb") as f:
                for chunk in response.iter_content(chunk_size=8192):
                    f.write(chunk)
            
            return f"File downloaded successfully: {local_file_path}"
        except requests.exceptions.RequestException as e:
            return f"Error downloading file: {e}"