06/05 Optimize app

app/routes/reports.py

@@ -1,5 +1,5 @@
 from flask import (Blueprint, render_template, request, redirect, url_for,
-                   Response, flash, send_file)
+                   Response, flash, send_file, stream_with_context)
 from flask_login import login_required, current_user
 from app.models.transaction import Transaction
 from app.services.report_service import (
@@ -8,7 +8,7 @@ from app.services.report_service import (
     take_net_worth_snapshot, category_mom_comparison,
 )
 from app.services.export_service import (
-    transactions_to_csv, transactions_to_excel,
+    transactions_csv_stream, transactions_to_excel,
     report_to_pdf, build_report_html,
 )
 from datetime import date
@@ -141,14 +141,13 @@ def export_csv():
     )
     if txn_type != 'all':
         query = query.filter(Transaction.transaction_type == txn_type)
-    transactions = query.order_by(Transaction.date.desc()).all()
+    query = query.order_by(Transaction.date.desc())
 
-    csv_data = transactions_to_csv(transactions)
     label = f'{year}-{month:02d}' if month else str(year)
     filename = f'pfm_transactions_{label}.csv'
 
     return Response(
-        csv_data,
+        stream_with_context(transactions_csv_stream(query)),
         mimetype='text/csv',
         headers={'Content-Disposition': f'attachment; filename="{filename}"'}
     )
@@ -167,11 +166,11 @@ def export_excel():
                                   __import__('calendar').monthrange(year, month)[1]),
         Transaction.transaction_type.in_(['income', 'expense']),
     )
-    transactions = query.order_by(Transaction.date.desc()).all()
+    query = query.order_by(Transaction.date.desc())
 
     label = f'{year}-{month:02d}' if month else str(year)
     period_label = f'{year} Month {month}' if month else str(year)
-    excel_bytes = transactions_to_excel(transactions, period_label)
+    excel_bytes = transactions_to_excel(query, period_label)
     filename = f'pfm_transactions_{label}.xlsx'
 
     return send_file(