1. import json
  2. from typing import Dict, Any
  4. def deserialize_api_request(request_data: str, expected_schema: Dict[str, str]) -> Dict[str, Any]:
  5. """
  6. Deserializes API request data from a string, validating against an expected schema.
  8. Args:
  9. request_data: The JSON string containing the API request data.
  10. expected_schema: A dictionary defining the expected schema for the request.
  11. Keys are field names, and values are data types (e.g., "string", "integer", "boolean", "array", "object").
  13. Returns:
  14. A dictionary representing the deserialized request data, or None if deserialization fails or validation errors occur.
  16. Raises:
  17. ValueError: If the input is not a valid JSON string.
  18. """
  19. try:
  20. data = json.loads(request_data) # Parse the JSON string
  21. except json.JSONDecodeError as e:
  22. raise ValueError(f"Invalid JSON format: {e}")
  24. validated_data = {}
  25. for field, expected_type in expected_schema.items():
  26. if field not in data:
  27. print(f"Warning: Field '{field}' missing from request data.")
  28. continue # Skip missing fields
  30. value = data[field]
  32. if expected_type == "string":
  33. if not isinstance(value, str):
  34. print(f"Error: Field '{field}' should be a string, but is {type(value)}")
  35. return None
  36. validated_data[field] = value
  37. elif expected_type == "integer":
  38. if not isinstance(value, int):
  39. try:
  40. validated_data[field] = int(value)
  41. except (ValueError, TypeError):
  42. print(f"Error: Field '{field}' should be an integer, but is {type(value)}")
  43. return None
  44. else:
  45. validated_data[field] = value
  46. elif expected_type == "boolean":
  47. if not isinstance(value, bool):
  48. if isinstance(value, str):
  49. value = value.lower()
  50. if value in ['true', '1', 't']:
  51. validated_data[field] = True
  52. elif value in ['false', '0', 'f']:
  53. validated_data[field] = False
  54. else:
  55. print(f"Error: Field '{field}' should be a boolean, but is {type(value)}")
  56. return None
  57. else:
  58. print(f"Error: Field '{field}' should be a boolean, but is {type(value)}")
  59. return None
  60. else:
  61. validated_data[field] = value
  62. elif expected_type == "array":
  63. if not isinstance(value, list):
  64. print(f"Error: Field '{field}' should be an array, but is {type(value)}")
  65. return None
  66. validated_data[field] = value
  67. elif expected_type == "object":
  68. if not isinstance(value, dict):
  69. print(f"Error: Field '{field}' should be an object, but is {type(value)}")
  70. return None
  71. validated_data[field] = value
  72. else:
  73. print(f"Warning: Unknown type '{expected_type}' for field '{field}'.")
  74. continue # Skip unknown types
  76. return validated_data

Add your comment