#!/usr/bin/env python3
"""
JSON Schema Validator
Validates a JSON schema file to ensure it's well-formed and follows JSON Schema specifications.
"""
import json
import sys
from pathlib import Path
try:
from jsonschema import (
Draft4Validator,
Draft6Validator,
Draft7Validator,
Draft202012Validator,
ValidationError
)
from jsonschema.exceptions import SchemaError
except ImportError:
print("Error: jsonschema library not found.")
print("Install it with: pip install jsonschema")
sys.exit(1)
# Try to import colorama for Windows color support
try:
from colorama import init, Fore, Style
init(autoreset=True)
HAS_COLORAMA = True
except ImportError:
HAS_COLORAMA = False
# ANSI color codes
class Colors:
if HAS_COLORAMA:
GREEN = Fore.GREEN
RED = Fore.RED
ORANGE = Fore.YELLOW # Orange is represented as yellow/bright yellow in terminals
RESET = Style.RESET_ALL
else:
# Fallback to ANSI codes
GREEN = '\033[92m'
RED = '\033[91m'
ORANGE = '\033[93m' # Yellow/Orange
RESET = '\033[0m'
def get_validator_for_schema(schema):
"""
Determine the appropriate validator based on the $schema field.
Args:
schema: The JSON schema dictionary
Returns:
The appropriate validator class
"""
schema_uri = schema.get('$schema', '')
# Map schema URIs to validators
if 'draft/2020-12' in schema_uri:
return Draft202012Validator
elif 'draft-07' in schema_uri or 'draft/07' in schema_uri:
return Draft7Validator
elif 'draft-06' in schema_uri or 'draft/06' in schema_uri:
return Draft6Validator
elif 'draft-04' in schema_uri or 'draft/04' in schema_uri:
return Draft4Validator
else:
# Default to Draft 2020-12 (latest standard)
return Draft202012Validator
def show_schema_preview(schema, missing_schema_field=False):
"""Show a preview of how the schema should be structured."""
if missing_schema_field:
print(f"\n {Colors.ORANGE}Example - Your schema should start like this:{Colors.RESET}")
print(f" {Colors.GREEN}{{")
print(f' "$schema": "https://json-schema.org/draft/2020-12/schema",{Colors.RESET}')
# Show first few fields of their current schema
shown_fields = 0
for key in list(schema.keys())[:3]:
value = schema[key]
if isinstance(value, (dict, list)):
print(f' "{key}": ...,')
else:
value_str = json.dumps(value)
if len(value_str) > 40:
value_str = value_str[:40] + "..."
print(f' "{key}": {value_str},')
shown_fields += 1
if len(schema) > 3:
print(f" ...")
print(f" {Colors.GREEN}}}{Colors.RESET}\n")
def validate_schema_file(filename):
"""
Validate a JSON schema file.
Args:
filename: Path to the JSON schema file
Returns:
True if valid, False otherwise
"""
file_path = Path(filename)
# Check if file exists
if not file_path.exists():
print(f"{Colors.RED}Error: File '{filename}' not found.{Colors.RESET}")
return False
# Read and parse the JSON file
try:
with open(file_path, 'r', encoding='utf-8') as f:
schema = json.load(f)
except json.JSONDecodeError as e:
print(f"{Colors.RED}Error: Invalid JSON format in '{filename}'{Colors.RESET}")
print(f" {e}")
return False
except Exception as e:
print(f"{Colors.RED}Error reading file: {e}{Colors.RESET}")
return False
# Get the appropriate validator for the schema
validator_class = get_validator_for_schema(schema)
# Validate the schema
try:
validator_class.check_schema(schema)
print(f"{Colors.GREEN}✓ Schema in '{filename}' is valid!{Colors.RESET}")
# Check schema type and print with warning color if not specified
schema_type = schema.get('$schema', 'Not specified')
if schema_type == 'Not specified':
print(f"\n {Colors.ORANGE}⚠ Warning: $schema field is missing from the root of your JSON schema{Colors.RESET}")
print(f" {Colors.ORANGE}├─ Location: Root level of the JSON object (typically line 1-2 in {filename}){Colors.RESET}")
print(f" {Colors.ORANGE}├─ Issue: Without $schema, validators may interpret your schema differently{Colors.RESET}")
print(f" {Colors.ORANGE}└─ Defaulting to: Draft 2020-12 for this validation{Colors.RESET}")
# Show example of how to fix it
show_schema_preview(schema, missing_schema_field=True)
else:
print(f" Schema type: {schema_type}")
# Show which validator was used
validator_name = validator_class.__name__.replace('Validator', '')
print(f" Validated with: {validator_name}")
if 'title' in schema:
print(f" Title: {schema['title']}")
return True
except SchemaError as e:
print(f"{Colors.RED}✗ Invalid JSON Schema in '{filename}'{Colors.RESET}")
print(f" {e.message}")
return False
except Exception as e:
print(f"{Colors.RED}Error validating schema: {e}{Colors.RESET}")
return False
def main():
"""Main function to handle command line arguments and user input."""
filename = None
# Check if filename was provided as command line argument
if len(sys.argv) > 1:
filename = sys.argv[1]
else:
# Prompt user for filename
print("JSON Schema Validator")
print("-" * 40)
filename = input("Enter the JSON schema filename: ").strip()
if not filename:
print(f"{Colors.RED}Error: No filename provided.{Colors.RESET}")
sys.exit(1)
# Validate the schema
success = validate_schema_file(filename)
# Exit with appropriate status code
sys.exit(0 if success else 1)
if __name__ == "__main__":
main()
