demo.py

#!/usr/bin/env python3
"""
Example usage of the Python JSON Diff library.
This demonstrates functionality similar to the Go json-diff repository.
"""

import json
from pprint import pprint
from jsondiff import JSONDiff, JSONReconstructor


def main():
    # Example JSON objects
    json1 = {
        "name": "John",
        "age": 30,
        "city": "New York",
        "hobbies": [["reading", "swimming"]],
        "address": {
            "street": "123 Main St",
            "zip": "10001"
        }
    }
    
    json2 = {
        "name": "John",
        "age": 31,  # Modified
        "city": "Boston",  # Modified
        "hobbies": [["reading", "swimming", "cycling"]],  # Array modified
        "address": {
            "street": "456 Oak Ave",  # Modified
            "zip": "10001",
            "country": "USA"  # Added
        },
        "email": "john@example.com",  # Added
        "obj":{ # object added
            "a":1
        }
    }
    
    print("=== JSON Diff Example ===")
    print("\nOriginal JSON:")
    print(json.dumps(json1, indent=2))
    
    print("\nModified JSON:")
    print(json.dumps(json2, indent=2))
    
    # Create diff
    differ = JSONDiff()
    diffs = differ.compare(json1, json2)
    
    print("\n=== Differences Found ===")

    for i, diff in enumerate(diffs, 1):
        print(f"\nDiff {i}:")
        print(f"  Field: {diff['field_name']}")
        print(f"  Change Type: {diff['change_type']}")
        print(f"  From: {diff['from_value']}")
        print(f"  To: {diff['to_value']}")
        print(f"  Full Path: {diff['full_path']}")
        print(f"  Value Type: {diff['value_type']}")
    
    print(f"\nTotal diffs: {len(diffs)}")
    print("Diff paths:", [d['full_path'] for d in diffs])
    
    # Test reconstruction
    print("\n=== JSON Reconstruction Example ===")
    reconstructor = JSONReconstructor()
    original_reconstructed = reconstructor.reverse_diff(json2, diffs)
    
    print("\nReconstructed Original JSON:")
    print(json.dumps(original_reconstructed, indent=2))
    
    print("\nReconstruction Test:")
    if original_reconstructed == json1:
        print("✅ SUCCESS: Reconstructed JSON matches original!")
    else:
        print("❌ FAILED: Reconstructed JSON does not match original")
        print("Expected:")
        print(json.dumps(json1, indent=2))
        print("Got:")
        print(json.dumps(original_reconstructed, indent=2))
    
    # Test with JSON strings
    print("\n=== Testing with JSON Strings ===")
    json1_str = json.dumps(json1)
    json2_str = json.dumps(json2)
    
    diffs_from_strings = differ.compare(json1_str, json2_str)
    print(f"Found {len(diffs_from_strings)} differences when comparing JSON strings")
    
    # Array modification example
    print("\n=== Array Modification Example ===")
    array1 = {"fruits": ["apple", "banana", "orange"]}
    array2 = {"fruits": ["apple", "orange", "grape"]}  # banana removed, grape added
    
    array_diffs = differ.compare(array1, array2)
    
    print("Array 1:", json.dumps(array1))
    print("Array 2:", json.dumps(array2))
    print("\nArray Differences:")
    for diff in array_diffs:
        print(f"  {diff['field_name']}: {diff['change_type']}")
        print(f"    From: {diff['from_value']}")
        print(f"    To: {diff['to_value']}")


if __name__ == "__main__":
    main()