Costco receipts converter from json to csv

convert_json_to_csv.py

#!/usr/bin/env python3

# Download receipts using https://gist.github.com/dlh3/7e18fec42cc7c43d51e93a6d2bcac6fb

"""
Convert Costco JSON to CSV format
Handles nested JSON structure with receipts and item arrays
"""

import json
import csv
import os
from typing import List, Dict, Any

def flatten_receipt_items(receipt: Dict[str, Any]) -> List[Dict[str, Any]]:
    """
    Flatten receipt data with items into separate rows for each item
    """
    base_receipt_data = {k: v for k, v in receipt.items() if k != 'itemArray'}
    
    if 'itemArray' not in receipt or not receipt['itemArray']:
        # If no items, return just the receipt data
        return [base_receipt_data]
    
    flattened_rows = []
    for item in receipt['itemArray']:
        row = base_receipt_data.copy()
        # Add item data with prefix to avoid conflicts
        for key, value in item.items():
            row[f'item_{key}'] = value
        flattened_rows.append(row)
    
    return flattened_rows

def convert_json_to_csv(input_file: str, output_file: str) -> None:
    """
    Convert JSON receipts to CSV format
    """
    with open(input_file, 'r', encoding='utf-8') as f:
        data = json.load(f)
    
    all_rows = []
    
    # Process each receipt
    for receipt in data['receipts']:
        flattened_items = flatten_receipt_items(receipt)
        all_rows.extend(flattened_items)
    
    if not all_rows:
        print("No data to convert")
        return
    
    # Get all unique fieldnames from all rows
    fieldnames = set()
    for row in all_rows:
        fieldnames.update(row.keys())
    
    fieldnames = sorted(list(fieldnames))
    
    # Write to CSV
    with open(output_file, 'w', newline='', encoding='utf-8') as f:
        writer = csv.DictWriter(f, fieldnames=fieldnames)
        writer.writeheader()
        writer.writerows(all_rows)
    
    print(f"Successfully converted {len(all_rows)} rows to {output_file}")
    print(f"CSV contains {len(fieldnames)} columns")

if __name__ == "__main__":
    input_file = "costco2025.json"
    output_file = "costco2025.csv"
    
    if os.path.exists(input_file):
        convert_json_to_csv(input_file, output_file)
    else:
        print(f"Input file not found: {input_file}")