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135 lines
3.9 KiB
135 lines
3.9 KiB
""" Utility functions for package."""
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from abc import ABCMeta, abstractmethod
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import datetime
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import decimal
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import inspect
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import json
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import sys
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from . import six
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class JSONSerializable(six.with_metaclass(ABCMeta, object)):
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""" Common functionality for json serializable objects."""
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serialize = staticmethod(json.dumps)
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deserialize = staticmethod(json.loads)
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@abstractmethod
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def json(self):
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raise NotImplementedError()
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@classmethod
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def from_json(cls, json_str):
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data = cls.deserialize(json_str)
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if not isinstance(data, dict):
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raise ValueError("data should be dict")
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return cls(**data)
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class DatetimeDecimalEncoder(json.JSONEncoder):
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""" Encoder for datetime and decimal serialization.
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Usage: json.dumps(object, cls=DatetimeDecimalEncoder)
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NOTE: _iterencode does not work
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"""
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def default(self, o):
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""" Encode JSON.
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:return str: A JSON encoded string
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"""
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if isinstance(o, decimal.Decimal):
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return float(o)
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if isinstance(o, (datetime.datetime, datetime.date)):
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return o.isoformat()
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return json.JSONEncoder.default(self, o)
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def is_invalid_params_py2(func, *args, **kwargs):
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""" Check, whether function 'func' accepts parameters 'args', 'kwargs'.
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NOTE: Method is called after funct(*args, **kwargs) generated TypeError,
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it is aimed to destinguish TypeError because of invalid parameters from
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TypeError from inside the function.
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.. versionadded: 1.9.0
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"""
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funcargs, varargs, varkwargs, defaults = inspect.getargspec(func)
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unexpected = set(kwargs.keys()) - set(funcargs)
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if len(unexpected) > 0:
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return True
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params = [funcarg for funcarg in funcargs if funcarg not in kwargs]
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funcargs_required = funcargs[:-len(defaults)] \
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if defaults is not None \
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else funcargs
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params_required = [
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funcarg for funcarg in funcargs_required
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if funcarg not in kwargs
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]
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return not (len(params_required) <= len(args) <= len(params))
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def is_invalid_params_py3(func, *args, **kwargs):
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"""
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Use inspect.signature instead of inspect.getargspec or
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inspect.getfullargspec (based on inspect.signature itself) as it provides
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more information about function parameters.
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.. versionadded: 1.11.2
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"""
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signature = inspect.signature(func)
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parameters = signature.parameters
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unexpected = set(kwargs.keys()) - set(parameters.keys())
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if len(unexpected) > 0:
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return True
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params = [
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parameter for name, parameter in parameters.items()
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if name not in kwargs
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]
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params_required = [
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param for param in params
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if param.default is param.empty
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]
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return not (len(params_required) <= len(args) <= len(params))
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def is_invalid_params(func, *args, **kwargs):
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"""
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Method:
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Validate pre-defined criteria, if any is True - function is invalid
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0. func should be callable
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1. kwargs should not have unexpected keywords
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2. remove kwargs.keys from func.parameters
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3. number of args should be <= remaining func.parameters
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4. number of args should be >= remaining func.parameters less default
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"""
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# For builtin functions inspect.getargspec(funct) return error. If builtin
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# function generates TypeError, it is because of wrong parameters.
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if not inspect.isfunction(func):
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return True
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if sys.version_info >= (3, 3):
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return is_invalid_params_py3(func, *args, **kwargs)
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else:
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# NOTE: use Python2 method for Python 3.2 as well. Starting from Python
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# 3.3 it is recommended to use inspect.signature instead.
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# In Python 3.0 - 3.2 inspect.getfullargspec is preferred but these
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# versions are almost not supported. Users should consider upgrading.
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return is_invalid_params_py2(func, *args, **kwargs)
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