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Diffstat (limited to 'python/werkzeug/wrappers/json.py')
-rw-r--r-- | python/werkzeug/wrappers/json.py | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/python/werkzeug/wrappers/json.py b/python/werkzeug/wrappers/json.py new file mode 100644 index 0000000..6d5dc33 --- /dev/null +++ b/python/werkzeug/wrappers/json.py @@ -0,0 +1,145 @@ +from __future__ import absolute_import + +import datetime +import uuid + +from .._compat import text_type +from ..exceptions import BadRequest +from ..utils import detect_utf_encoding + +try: + import simplejson as _json +except ImportError: + import json as _json + + +class _JSONModule(object): + @staticmethod + def _default(o): + if isinstance(o, datetime.date): + return o.isoformat() + + if isinstance(o, uuid.UUID): + return str(o) + + if hasattr(o, "__html__"): + return text_type(o.__html__()) + + raise TypeError() + + @classmethod + def dumps(cls, obj, **kw): + kw.setdefault("separators", (",", ":")) + kw.setdefault("default", cls._default) + kw.setdefault("sort_keys", True) + return _json.dumps(obj, **kw) + + @staticmethod + def loads(s, **kw): + if isinstance(s, bytes): + # Needed for Python < 3.6 + encoding = detect_utf_encoding(s) + s = s.decode(encoding) + + return _json.loads(s, **kw) + + +class JSONMixin(object): + """Mixin to parse :attr:`data` as JSON. Can be mixed in for both + :class:`~werkzeug.wrappers.Request` and + :class:`~werkzeug.wrappers.Response` classes. + + If `simplejson`_ is installed it is preferred over Python's built-in + :mod:`json` module. + + .. _simplejson: https://simplejson.readthedocs.io/en/latest/ + """ + + #: A module or other object that has ``dumps`` and ``loads`` + #: functions that match the API of the built-in :mod:`json` module. + json_module = _JSONModule + + @property + def json(self): + """The parsed JSON data if :attr:`mimetype` indicates JSON + (:mimetype:`application/json`, see :meth:`is_json`). + + Calls :meth:`get_json` with default arguments. + """ + return self.get_json() + + @property + def is_json(self): + """Check if the mimetype indicates JSON data, either + :mimetype:`application/json` or :mimetype:`application/*+json`. + """ + mt = self.mimetype + return ( + mt == "application/json" + or mt.startswith("application/") + and mt.endswith("+json") + ) + + def _get_data_for_json(self, cache): + try: + return self.get_data(cache=cache) + except TypeError: + # Response doesn't have cache param. + return self.get_data() + + # Cached values for ``(silent=False, silent=True)``. Initialized + # with sentinel values. + _cached_json = (Ellipsis, Ellipsis) + + def get_json(self, force=False, silent=False, cache=True): + """Parse :attr:`data` as JSON. + + If the mimetype does not indicate JSON + (:mimetype:`application/json`, see :meth:`is_json`), this + returns ``None``. + + If parsing fails, :meth:`on_json_loading_failed` is called and + its return value is used as the return value. + + :param force: Ignore the mimetype and always try to parse JSON. + :param silent: Silence parsing errors and return ``None`` + instead. + :param cache: Store the parsed JSON to return for subsequent + calls. + """ + if cache and self._cached_json[silent] is not Ellipsis: + return self._cached_json[silent] + + if not (force or self.is_json): + return None + + data = self._get_data_for_json(cache=cache) + + try: + rv = self.json_module.loads(data) + except ValueError as e: + if silent: + rv = None + + if cache: + normal_rv, _ = self._cached_json + self._cached_json = (normal_rv, rv) + else: + rv = self.on_json_loading_failed(e) + + if cache: + _, silent_rv = self._cached_json + self._cached_json = (rv, silent_rv) + else: + if cache: + self._cached_json = (rv, rv) + + return rv + + def on_json_loading_failed(self, e): + """Called if :meth:`get_json` parsing fails and isn't silenced. + If this method returns a value, it is used as the return value + for :meth:`get_json`. The default implementation raises + :exc:`~werkzeug.exceptions.BadRequest`. + """ + raise BadRequest("Failed to decode JSON object: {0}".format(e)) |