email_alerts_v2/FETCH_MODIFICATION_SUMMARY.md

Fetch Folder Emails Modification Summary

Changes Made

1. Database Module (database.py)

• Added get_latest_email_date() function to retrieve the most recent email date for a given account and folder
• Added import for datetime to support the new function

2. ZohoClient Module (zoho_client.py)

• Modified fetch_folder_emails() to accept two new optional parameters:
  • db_session: Database session for querying latest email dates
  • account_email: Account email to identify which emails to check for latest date
• Updated logic to:
  1. Check database for latest email date if db_session and account_email are provided
  2. Use latest date (minus 1 minute buffer) as start date for IMAP search
  3. Fall back to days_back parameter if no database date is available
• Updated fetch_emails() wrapper to support the new parameters
• Enhanced documentation with detailed parameter descriptions

3. App Module (app.py)

• Modified email fetching calls to pass database session and account email
• Reorganized code to create database session before fetching emails

How It Works

Before

• Always fetched emails starting from X days back
• No awareness of what emails were already in the database
• Could result in fetching duplicate emails or missing recent ones

After

• Intelligently determines start date based on database contents
• If emails exist in database: starts from the latest email date
• If no emails in database: falls back to days_back parameter
• Adds 1-minute buffer to avoid missing emails with same timestamp
• Reduces unnecessary email fetching and improves efficiency

Usage Examples

Basic Usage (Backwards Compatible)

client = ZohoClient()
emails = client.fetch_folder_emails(folder="INBOX", days_back=7)

With Database Integration (Recommended)

from database import SessionLocal

db = SessionLocal()
client = ZohoClient()
emails = client.fetch_folder_emails(
    folder="INBOX",
    days_back=30,  # Fallback only
    db_session=db,
    account_email="user@example.com"
)
db.close()

Benefits

1. Efficiency: Only fetches new emails since last sync
2. Reliability: Ensures no emails are missed between syncs
3. Backwards Compatibility: Still works without database parameters
4. Flexibility: Falls back gracefully when database is empty
5. Performance: Reduces IMAP server load and processing time

Testing

Use test_fetch_with_db.py to test the new functionality:

python test_fetch_with_db.py

The test script demonstrates:

• Checking latest email date in database
• Fetching emails with database integration
• Displaying results