86 lines
2.9 KiB
Python
86 lines
2.9 KiB
Python
__all__ = ('QueryFieldList',)
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class QueryFieldList(object):
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"""Object that handles combinations of .only() and .exclude() calls"""
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ONLY = 1
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EXCLUDE = 0
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def __init__(self, fields=None, value=ONLY, always_include=None, _only_called=False):
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"""The QueryFieldList builder
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:param fields: A list of fields used in `.only()` or `.exclude()`
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:param value: How to handle the fields; either `ONLY` or `EXCLUDE`
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:param always_include: Any fields to always_include eg `_cls`
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:param _only_called: Has `.only()` been called? If so its a set of fields
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otherwise it performs a union.
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"""
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self.value = value
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self.fields = set(fields or [])
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self.always_include = set(always_include or [])
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self._id = None
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self._only_called = _only_called
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self.slice = {}
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def __add__(self, f):
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if isinstance(f.value, dict):
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for field in f.fields:
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self.slice[field] = f.value
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if not self.fields:
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self.fields = f.fields
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elif not self.fields:
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self.fields = f.fields
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self.value = f.value
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self.slice = {}
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elif self.value is self.ONLY and f.value is self.ONLY:
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self._clean_slice()
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if self._only_called:
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self.fields = self.fields.union(f.fields)
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else:
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self.fields = f.fields
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elif self.value is self.EXCLUDE and f.value is self.EXCLUDE:
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self.fields = self.fields.union(f.fields)
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self._clean_slice()
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elif self.value is self.ONLY and f.value is self.EXCLUDE:
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self.fields -= f.fields
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self._clean_slice()
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elif self.value is self.EXCLUDE and f.value is self.ONLY:
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self.value = self.ONLY
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self.fields = f.fields - self.fields
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self._clean_slice()
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if '_id' in f.fields:
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self._id = f.value
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if self.always_include:
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if self.value is self.ONLY and self.fields:
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if sorted(self.slice.keys()) != sorted(self.fields):
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self.fields = self.fields.union(self.always_include)
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else:
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self.fields -= self.always_include
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if getattr(f, '_only_called', False):
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self._only_called = True
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return self
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def __nonzero__(self):
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return bool(self.fields)
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def as_dict(self):
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field_list = {field: self.value for field in self.fields}
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if self.slice:
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field_list.update(self.slice)
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if self._id is not None:
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field_list['_id'] = self._id
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return field_list
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def reset(self):
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self.fields = set([])
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self.slice = {}
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self.value = self.ONLY
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def _clean_slice(self):
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if self.slice:
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for field in set(self.slice.keys()) - self.fields:
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del self.slice[field]
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