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import os
import uuid
import logging
import time
from datetime import datetime, timedelta
from typing import Dict, Optional, Tuple, List
from fastapi import UploadFile
from pathlib import Path
from app.config import settings
logger = logging.getLogger(__name__)
class Session:
"""Object representing a user session"""
def __init__(self, session_id: str, image_path: str):
self.session_id = session_id
self.image_path = image_path
self.created_at = datetime.now()
self.last_accessed = datetime.now()
self.questions = [] # History of questions for this session
def is_expired(self) -> bool:
"""Check if the session has expired"""
expiry_time = self.last_accessed + timedelta(seconds=settings.MAX_SESSION_AGE)
return datetime.now() > expiry_time
def update_access_time(self):
"""Update the last accessed time"""
self.last_accessed = datetime.now()
def add_question(self, question: str, answer: Dict):
"""Add a question and its answer to the session history"""
self.questions.append({
"question": question,
"answer": answer,
"timestamp": datetime.now().isoformat()
})
self.update_access_time()
class SessionService:
"""Service for managing user sessions"""
def __init__(self):
"""Initialize the session service"""
self.sessions: Dict[str, Session] = {}
self.ensure_upload_dir()
# Start a background cleanup task
self._cleanup_sessions()
def ensure_upload_dir(self):
"""Ensure the upload directory exists"""
os.makedirs(settings.UPLOAD_DIR, exist_ok=True)
def create_session(self, file: UploadFile) -> str:
"""
Create a new session for the user
Args:
file (UploadFile): The uploaded image file
Returns:
str: The session ID
"""
# Generate a unique session ID
session_id = str(uuid.uuid4())
# Create a unique filename
timestamp = int(time.time())
file_extension = Path(file.filename).suffix
filename = f"{timestamp}_{session_id}{file_extension}"
# Save the uploaded file
file_path = os.path.join(settings.UPLOAD_DIR, filename)
with open(file_path, "wb") as f:
f.write(file.file.read())
# Create and store the session
self.sessions[session_id] = Session(session_id, file_path)
logger.info(f"Created new session {session_id} with image {file_path}")
return session_id
def get_session(self, session_id: str) -> Optional[Session]:
"""
Get a session by ID
Args:
session_id (str): The session ID
Returns:
Optional[Session]: The session, or None if not found or expired
"""
session = self.sessions.get(session_id)
if session is None:
return None
if session.is_expired():
self._remove_session(session_id)
return None
session.update_access_time()
return session
def complete_session(self, session_id: str) -> bool:
"""
Mark a session as complete and remove its resources
Args:
session_id (str): The session ID
Returns:
bool: True if successful, False otherwise
"""
session = self.sessions.get(session_id)
if not session:
logger.warning(f"Cannot complete nonexistent session: {session_id}")
return False
logger.info(f"Completing session {session_id}")
try:
# Remove the image file but keep session data temporarily for any final operations
if session.image_path and os.path.exists(session.image_path):
os.remove(session.image_path)
logger.info(f"Removed image file for completed session {session.image_path}")
# Set the image path to None to indicate it's been removed
session.image_path = None
return True
return True # No image to remove or already removed
except Exception as e:
logger.error(f"Error removing image file during session completion: {e}")
return False
def _remove_session(self, session_id: str):
"""
Remove a session and its associated file
Args:
session_id (str): The session ID
"""
session = self.sessions.pop(session_id, None)
if session:
try:
# Remove the image file
if session.image_path and os.path.exists(session.image_path):
os.remove(session.image_path)
logger.info(f"Removed session file {session.image_path}")
except Exception as e:
logger.error(f"Error removing session file: {e}")
def _cleanup_sessions(self):
"""Clean up expired sessions"""
expired_sessions = [
session_id for session_id, session in self.sessions.items()
if session.is_expired()
]
for session_id in expired_sessions:
self._remove_session(session_id)
if expired_sessions:
logger.info(f"Cleaned up {len(expired_sessions)} expired sessions") |