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- from __future__ import annotations
- import dataclasses
- import decimal
- import json
- import typing as t
- import uuid
- import weakref
- from datetime import date
- from werkzeug.http import http_date
- from ..globals import request
- if t.TYPE_CHECKING: # pragma: no cover
- from ..app import Flask
- from ..wrappers import Response
- class JSONProvider:
- """A standard set of JSON operations for an application. Subclasses
- of this can be used to customize JSON behavior or use different
- JSON libraries.
- To implement a provider for a specific library, subclass this base
- class and implement at least :meth:`dumps` and :meth:`loads`. All
- other methods have default implementations.
- To use a different provider, either subclass ``Flask`` and set
- :attr:`~flask.Flask.json_provider_class` to a provider class, or set
- :attr:`app.json <flask.Flask.json>` to an instance of the class.
- :param app: An application instance. This will be stored as a
- :class:`weakref.proxy` on the :attr:`_app` attribute.
- .. versionadded:: 2.2
- """
- def __init__(self, app: Flask) -> None:
- self._app = weakref.proxy(app)
- def dumps(self, obj: t.Any, **kwargs: t.Any) -> str:
- """Serialize data as JSON.
- :param obj: The data to serialize.
- :param kwargs: May be passed to the underlying JSON library.
- """
- raise NotImplementedError
- def dump(self, obj: t.Any, fp: t.IO[str], **kwargs: t.Any) -> None:
- """Serialize data as JSON and write to a file.
- :param obj: The data to serialize.
- :param fp: A file opened for writing text. Should use the UTF-8
- encoding to be valid JSON.
- :param kwargs: May be passed to the underlying JSON library.
- """
- fp.write(self.dumps(obj, **kwargs))
- def loads(self, s: str | bytes, **kwargs: t.Any) -> t.Any:
- """Deserialize data as JSON.
- :param s: Text or UTF-8 bytes.
- :param kwargs: May be passed to the underlying JSON library.
- """
- raise NotImplementedError
- def load(self, fp: t.IO[t.AnyStr], **kwargs: t.Any) -> t.Any:
- """Deserialize data as JSON read from a file.
- :param fp: A file opened for reading text or UTF-8 bytes.
- :param kwargs: May be passed to the underlying JSON library.
- """
- return self.loads(fp.read(), **kwargs)
- def _prepare_response_obj(
- self, args: t.Tuple[t.Any, ...], kwargs: t.Dict[str, t.Any]
- ) -> t.Any:
- if args and kwargs:
- raise TypeError("app.json.response() takes either args or kwargs, not both")
- if not args and not kwargs:
- return None
- if len(args) == 1:
- return args[0]
- return args or kwargs
- def response(self, *args: t.Any, **kwargs: t.Any) -> Response:
- """Serialize the given arguments as JSON, and return a
- :class:`~flask.Response` object with the ``application/json``
- mimetype.
- The :func:`~flask.json.jsonify` function calls this method for
- the current application.
- Either positional or keyword arguments can be given, not both.
- If no arguments are given, ``None`` is serialized.
- :param args: A single value to serialize, or multiple values to
- treat as a list to serialize.
- :param kwargs: Treat as a dict to serialize.
- """
- obj = self._prepare_response_obj(args, kwargs)
- return self._app.response_class(self.dumps(obj), mimetype="application/json")
- def _default(o: t.Any) -> t.Any:
- if isinstance(o, date):
- return http_date(o)
- if isinstance(o, (decimal.Decimal, uuid.UUID)):
- return str(o)
- if dataclasses and dataclasses.is_dataclass(o):
- return dataclasses.asdict(o)
- if hasattr(o, "__html__"):
- return str(o.__html__())
- raise TypeError(f"Object of type {type(o).__name__} is not JSON serializable")
- class DefaultJSONProvider(JSONProvider):
- """Provide JSON operations using Python's built-in :mod:`json`
- library. Serializes the following additional data types:
- - :class:`datetime.datetime` and :class:`datetime.date` are
- serialized to :rfc:`822` strings. This is the same as the HTTP
- date format.
- - :class:`uuid.UUID` is serialized to a string.
- - :class:`dataclasses.dataclass` is passed to
- :func:`dataclasses.asdict`.
- - :class:`~markupsafe.Markup` (or any object with a ``__html__``
- method) will call the ``__html__`` method to get a string.
- """
- default: t.Callable[[t.Any], t.Any] = staticmethod(
- _default
- ) # type: ignore[assignment]
- """Apply this function to any object that :meth:`json.dumps` does
- not know how to serialize. It should return a valid JSON type or
- raise a ``TypeError``.
- """
- ensure_ascii = True
- """Replace non-ASCII characters with escape sequences. This may be
- more compatible with some clients, but can be disabled for better
- performance and size.
- """
- sort_keys = True
- """Sort the keys in any serialized dicts. This may be useful for
- some caching situations, but can be disabled for better performance.
- When enabled, keys must all be strings, they are not converted
- before sorting.
- """
- compact: bool | None = None
- """If ``True``, or ``None`` out of debug mode, the :meth:`response`
- output will not add indentation, newlines, or spaces. If ``False``,
- or ``None`` in debug mode, it will use a non-compact representation.
- """
- mimetype = "application/json"
- """The mimetype set in :meth:`response`."""
- def dumps(self, obj: t.Any, **kwargs: t.Any) -> str:
- """Serialize data as JSON to a string.
- Keyword arguments are passed to :func:`json.dumps`. Sets some
- parameter defaults from the :attr:`default`,
- :attr:`ensure_ascii`, and :attr:`sort_keys` attributes.
- :param obj: The data to serialize.
- :param kwargs: Passed to :func:`json.dumps`.
- """
- cls = self._app._json_encoder
- bp = self._app.blueprints.get(request.blueprint) if request else None
- if bp is not None and bp._json_encoder is not None:
- cls = bp._json_encoder
- if cls is not None:
- import warnings
- warnings.warn(
- "Setting 'json_encoder' on the app or a blueprint is"
- " deprecated and will be removed in Flask 2.3."
- " Customize 'app.json' instead.",
- DeprecationWarning,
- )
- kwargs.setdefault("cls", cls)
- if "default" not in cls.__dict__:
- kwargs.setdefault("default", self.default)
- else:
- kwargs.setdefault("default", self.default)
- ensure_ascii = self._app.config["JSON_AS_ASCII"]
- sort_keys = self._app.config["JSON_SORT_KEYS"]
- if ensure_ascii is not None:
- import warnings
- warnings.warn(
- "The 'JSON_AS_ASCII' config key is deprecated and will"
- " be removed in Flask 2.3. Set 'app.json.ensure_ascii'"
- " instead.",
- DeprecationWarning,
- )
- else:
- ensure_ascii = self.ensure_ascii
- if sort_keys is not None:
- import warnings
- warnings.warn(
- "The 'JSON_SORT_KEYS' config key is deprecated and will"
- " be removed in Flask 2.3. Set 'app.json.sort_keys'"
- " instead.",
- DeprecationWarning,
- )
- else:
- sort_keys = self.sort_keys
- kwargs.setdefault("ensure_ascii", ensure_ascii)
- kwargs.setdefault("sort_keys", sort_keys)
- return json.dumps(obj, **kwargs)
- def loads(self, s: str | bytes, **kwargs: t.Any) -> t.Any:
- """Deserialize data as JSON from a string or bytes.
- :param s: Text or UTF-8 bytes.
- :param kwargs: Passed to :func:`json.loads`.
- """
- cls = self._app._json_decoder
- bp = self._app.blueprints.get(request.blueprint) if request else None
- if bp is not None and bp._json_decoder is not None:
- cls = bp._json_decoder
- if cls is not None:
- import warnings
- warnings.warn(
- "Setting 'json_decoder' on the app or a blueprint is"
- " deprecated and will be removed in Flask 2.3."
- " Customize 'app.json' instead.",
- DeprecationWarning,
- )
- kwargs.setdefault("cls", cls)
- return json.loads(s, **kwargs)
- def response(self, *args: t.Any, **kwargs: t.Any) -> Response:
- """Serialize the given arguments as JSON, and return a
- :class:`~flask.Response` object with it. The response mimetype
- will be "application/json" and can be changed with
- :attr:`mimetype`.
- If :attr:`compact` is ``False`` or debug mode is enabled, the
- output will be formatted to be easier to read.
- Either positional or keyword arguments can be given, not both.
- If no arguments are given, ``None`` is serialized.
- :param args: A single value to serialize, or multiple values to
- treat as a list to serialize.
- :param kwargs: Treat as a dict to serialize.
- """
- obj = self._prepare_response_obj(args, kwargs)
- dump_args: t.Dict[str, t.Any] = {}
- pretty = self._app.config["JSONIFY_PRETTYPRINT_REGULAR"]
- mimetype = self._app.config["JSONIFY_MIMETYPE"]
- if pretty is not None:
- import warnings
- warnings.warn(
- "The 'JSONIFY_PRETTYPRINT_REGULAR' config key is"
- " deprecated and will be removed in Flask 2.3. Set"
- " 'app.json.compact' instead.",
- DeprecationWarning,
- )
- compact: bool | None = not pretty
- else:
- compact = self.compact
- if (compact is None and self._app.debug) or compact is False:
- dump_args.setdefault("indent", 2)
- else:
- dump_args.setdefault("separators", (",", ":"))
- if mimetype is not None:
- import warnings
- warnings.warn(
- "The 'JSONIFY_MIMETYPE' config key is deprecated and"
- " will be removed in Flask 2.3. Set 'app.json.mimetype'"
- " instead.",
- DeprecationWarning,
- )
- else:
- mimetype = self.mimetype
- return self._app.response_class(
- f"{self.dumps(obj, **dump_args)}\n", mimetype=mimetype
- )
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