hat-json 0.4.0.dev20210105

Hat JSON library

This library is part of Hat Open project - open-source framework of tools and libraries for developing applications used for remote monitoring, control and management of intelligent electronic devices such as IoT devices, PLCs, industrial automation or home automation systems.

Development of Hat Open and associated repositories is sponsored by Končar - Power Plant and Electric Traction Engineering Inc. (Končar KET - https://www.koncar-ket.hr).

For more information see:

• hat-json documentation - https://core.hat-open.com/docs/libraries/util.html

• Hat Core homepage - https://core.hat-open.com

• Hat Core git repository - https://github.com/hat-open/hat-core.git

Warning

This project is currently in state of active development. Features, functionality and API are unstable.

About

JSON data manipulation and validation functions.

• type definitions:

  Array: typing.Type = typing.List['Data']
  Object: typing.Type = typing.Dict[str, 'Data']
  Data: typing.Type = typing.Union[None, bool, int, float, str, Array, Object]
  """JSON data type identifier."""
  
  Format = enum.Enum('Format', ['JSON', 'YAML'])
  """Encoding format"""
  
  Path: typing.Type = typing.Union[int, str, typing.List['Path']]
  """Data path"""

• hat.json.equals and hat.json.flatten:

  def equals(a: Data,
             b: Data
             ) -> bool:
      """Equality comparison of json serializable data.
  
      Tests for equality of data according to JSON format. Notably, ``bool``
      values are not considered equal to numeric values in any case. This is
      different from default equality comparison, which considers `False`
      equal to `0` and `0.0`; and `True` equal to `1` and `1.0`.
  
      Example::
  
          assert equals(0, 0.0) is True
          assert equals({'a': 1, 'b': 2}, {'b': 2, 'a': 1}) is True
          assert equals(1, True) is False
  
      """
  
  def flatten(data: Data
              ) -> typing.Iterable[Data]:
      """Flatten JSON data
  
      If `data` is array, this generator recursively yields result of
      `flatten` call with each element of input list. For other `Data` types,
      input data is yielded.
  
      Example::
  
          data = [1, [], [2], {'a': [3]}]
          result = [1, 2, {'a': [3]}]
          assert list(flatten(data)) == result
  
      """

• hat.json.get and hat.json.set_:

  def get(data: Data,
          path: Path
          ) -> Data:
      """Get data element referenced by path
  
      Example::
  
          data = {'a': [1, 2, [3, 4]]}
          path = ['a', 2, 0]
          assert get(data, path) == 3
  
          data = [1, 2, 3]
          assert get(data, 0) == 1
          assert get(data, 5) is None
  
      """
  
  def set_(data: Data,
           path: Path,
           value: Data
           ) -> Data:
      """Create new data by setting data path element value
  
      Example::
  
          data = [1, {'a': 2, 'b': 3}, 4]
          path = [1, 'b']
          result = set_(data, path, 5)
          assert result == [1, {'a': 2, 'b': 5}, 4]
          assert result is not data
  
          data = [1, 2, 3]
          result = set_(data, 4, 4)
          assert result == [1, 2, 3, None, 4]
  
      """

• hat.json.diff and hat.json.patch:

  def diff(src: Data,
           dst: Data
           ) -> Data:
      """Generate JSON Patch diff.
  
      Example::
  
          src = [1, {'a': 2}, 3]
          dst = [1, {'a': 4}, 3]
          result = diff(src, dst)
          assert result == [{'op': 'replace', 'path': '/1/a', 'value': 4}]
  
      """
  
  def patch(data: Data,
            diff: Data
            ) -> Data:
      """Apply JSON Patch diff.
  
      Example::
  
          data = [1, {'a': 2}, 3]
          d = [{'op': 'replace', 'path': '/1/a', 'value': 4}]
          result = patch(data, d)
          assert result == [1, {'a': 4}, 3]
  
      """

• hat.json.encode and hat.json.decode:

  def encode(data: Data,
             format: Format = Format.JSON,
             indent: typing.Optional[int] = None
             ) -> str:
      """Encode JSON data.
  
      Args:
          data: JSON data
          format: encoding format
          indent: indentation size
  
      """
  
  def decode(data_str: str,
             format: Format = Format.JSON
             ) -> Data:
      """Decode JSON data.
  
      Args:
          data_str: encoded JSON data
          format: encoding format
  
      """

• hat.json.encode_file and hat.json.decode_file:

  def encode_file(data: Data,
                  path: pathlib.PurePath,
                  format: typing.Optional[Format] = None,
                  indent: typing.Optional[int] = 4):
      """Encode JSON data to file.
  
      If `format` is ``None``, encoding format is derived from path suffix.
  
      Args:
          data: JSON data
          path: file path
          format: encoding format
          indent: indentation size
  
      """
  
  def decode_file(path: pathlib.PurePath,
                  format: typing.Optional[Format] = None
                  ) -> Data:
      """Decode JSON data from file.
  
      If `format` is ``None``, encoding format is derived from path suffix.
  
      Args:
          path: file path
          format: encoding format
  
      """

• hat.json.SchemaRepository:

  class SchemaRepository:
      """JSON Schema repository.
  
      A repository that holds json schemas and enables validation against
      them.
  
      Repository can be initialized with multiple arguments, which can be
      instances of ``pathlib.PurePath``, ``Data`` or ``SchemaRepository``.
  
      If an argument is of type ``pathlib.PurePath``, and path points to file
      with a suffix '.json', '.yml' or '.yaml', json serializable data is
      decoded from the file. Otherwise, it is assumed that path points to a
      directory, which is recursively searched for json and yaml files. All
      decoded schemas are added to the repository. If a schema with the same
      `id` was previosly added, an exception is raised.
  
      If an argument is of type ``Data``, it should be a json serializable
      data representation of a JSON schema. If a schema with the same `id`
      was previosly added, an exception is raised.
  
      If an argument is of type ``SchemaRepository``, its schemas are added
      to the new repository. Previously added schemas with the same `id` are
      replaced.
  
      """
  
      def __init__(self, *args: typing.Union[pathlib.PurePath,
                                             Data,
                                             'SchemaRepository']): ...
  
      def validate(self,
                   schema_id: str,
                   data: Data):
          """Validate data against JSON schema.
  
          Args:
              schema_id: JSON schema identifier
              data: data to be validated
  
          Raises:
              jsonschema.ValidationError
  
          """
  
      def to_json(self) -> Data:
          """Export repository content as json serializable data.
  
          Entire repository content is exported as json serializable data.
          New repository can be created from the exported content by using
          :meth:`SchemaRepository.from_json`.
  
          """
  
      @staticmethod
      def from_json(data: typing.Union[pathlib.PurePath,
                                       Data]
                    ) -> 'SchemaRepository':
          """Create new repository from content exported as json serializable
          data.
  
          Creates a new repository from content of another repository that was
          exported by using :meth:`SchemaRepository.to_json`.
  
          Args:
              data: repository data
  
          """