forked from s442783/HighNeed_projekt_inz
322 lines
9.5 KiB
Python
322 lines
9.5 KiB
Python
import datetime
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import json
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from psycopg2.extras import DateRange, DateTimeTZRange, NumericRange, Range
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from django.contrib.postgres import forms, lookups
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from django.db import models
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from django.db.models.lookups import PostgresOperatorLookup
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from .utils import AttributeSetter
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__all__ = [
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'RangeField', 'IntegerRangeField', 'BigIntegerRangeField',
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'DecimalRangeField', 'DateTimeRangeField', 'DateRangeField',
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'RangeBoundary', 'RangeOperators',
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]
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class RangeBoundary(models.Expression):
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"""A class that represents range boundaries."""
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def __init__(self, inclusive_lower=True, inclusive_upper=False):
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self.lower = '[' if inclusive_lower else '('
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self.upper = ']' if inclusive_upper else ')'
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def as_sql(self, compiler, connection):
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return "'%s%s'" % (self.lower, self.upper), []
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class RangeOperators:
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# https://www.postgresql.org/docs/current/functions-range.html#RANGE-OPERATORS-TABLE
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EQUAL = '='
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NOT_EQUAL = '<>'
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CONTAINS = '@>'
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CONTAINED_BY = '<@'
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OVERLAPS = '&&'
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FULLY_LT = '<<'
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FULLY_GT = '>>'
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NOT_LT = '&>'
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NOT_GT = '&<'
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ADJACENT_TO = '-|-'
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class RangeField(models.Field):
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empty_strings_allowed = False
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def __init__(self, *args, **kwargs):
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# Initializing base_field here ensures that its model matches the model for self.
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if hasattr(self, 'base_field'):
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self.base_field = self.base_field()
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super().__init__(*args, **kwargs)
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@property
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def model(self):
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try:
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return self.__dict__['model']
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except KeyError:
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raise AttributeError("'%s' object has no attribute 'model'" % self.__class__.__name__)
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@model.setter
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def model(self, model):
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self.__dict__['model'] = model
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self.base_field.model = model
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@classmethod
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def _choices_is_value(cls, value):
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return isinstance(value, (list, tuple)) or super()._choices_is_value(value)
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def get_prep_value(self, value):
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if value is None:
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return None
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elif isinstance(value, Range):
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return value
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elif isinstance(value, (list, tuple)):
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return self.range_type(value[0], value[1])
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return value
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def to_python(self, value):
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if isinstance(value, str):
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# Assume we're deserializing
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vals = json.loads(value)
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for end in ('lower', 'upper'):
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if end in vals:
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vals[end] = self.base_field.to_python(vals[end])
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value = self.range_type(**vals)
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elif isinstance(value, (list, tuple)):
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value = self.range_type(value[0], value[1])
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return value
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def set_attributes_from_name(self, name):
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super().set_attributes_from_name(name)
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self.base_field.set_attributes_from_name(name)
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def value_to_string(self, obj):
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value = self.value_from_object(obj)
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if value is None:
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return None
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if value.isempty:
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return json.dumps({"empty": True})
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base_field = self.base_field
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result = {"bounds": value._bounds}
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for end in ('lower', 'upper'):
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val = getattr(value, end)
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if val is None:
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result[end] = None
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else:
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obj = AttributeSetter(base_field.attname, val)
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result[end] = base_field.value_to_string(obj)
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return json.dumps(result)
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def formfield(self, **kwargs):
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kwargs.setdefault('form_class', self.form_field)
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return super().formfield(**kwargs)
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class IntegerRangeField(RangeField):
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base_field = models.IntegerField
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range_type = NumericRange
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form_field = forms.IntegerRangeField
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def db_type(self, connection):
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return 'int4range'
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class BigIntegerRangeField(RangeField):
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base_field = models.BigIntegerField
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range_type = NumericRange
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form_field = forms.IntegerRangeField
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def db_type(self, connection):
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return 'int8range'
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class DecimalRangeField(RangeField):
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base_field = models.DecimalField
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range_type = NumericRange
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form_field = forms.DecimalRangeField
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def db_type(self, connection):
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return 'numrange'
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class DateTimeRangeField(RangeField):
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base_field = models.DateTimeField
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range_type = DateTimeTZRange
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form_field = forms.DateTimeRangeField
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def db_type(self, connection):
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return 'tstzrange'
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class DateRangeField(RangeField):
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base_field = models.DateField
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range_type = DateRange
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form_field = forms.DateRangeField
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def db_type(self, connection):
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return 'daterange'
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RangeField.register_lookup(lookups.DataContains)
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RangeField.register_lookup(lookups.ContainedBy)
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RangeField.register_lookup(lookups.Overlap)
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class DateTimeRangeContains(PostgresOperatorLookup):
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"""
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Lookup for Date/DateTimeRange containment to cast the rhs to the correct
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type.
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"""
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lookup_name = 'contains'
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postgres_operator = RangeOperators.CONTAINS
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def process_rhs(self, compiler, connection):
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# Transform rhs value for db lookup.
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if isinstance(self.rhs, datetime.date):
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output_field = models.DateTimeField() if isinstance(self.rhs, datetime.datetime) else models.DateField()
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value = models.Value(self.rhs, output_field=output_field)
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self.rhs = value.resolve_expression(compiler.query)
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return super().process_rhs(compiler, connection)
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def as_postgresql(self, compiler, connection):
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sql, params = super().as_postgresql(compiler, connection)
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# Cast the rhs if needed.
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cast_sql = ''
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if (
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isinstance(self.rhs, models.Expression) and
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self.rhs._output_field_or_none and
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# Skip cast if rhs has a matching range type.
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not isinstance(self.rhs._output_field_or_none, self.lhs.output_field.__class__)
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):
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cast_internal_type = self.lhs.output_field.base_field.get_internal_type()
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cast_sql = '::{}'.format(connection.data_types.get(cast_internal_type))
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return '%s%s' % (sql, cast_sql), params
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DateRangeField.register_lookup(DateTimeRangeContains)
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DateTimeRangeField.register_lookup(DateTimeRangeContains)
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class RangeContainedBy(PostgresOperatorLookup):
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lookup_name = 'contained_by'
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type_mapping = {
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'smallint': 'int4range',
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'integer': 'int4range',
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'bigint': 'int8range',
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'double precision': 'numrange',
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'numeric': 'numrange',
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'date': 'daterange',
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'timestamp with time zone': 'tstzrange',
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}
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postgres_operator = RangeOperators.CONTAINED_BY
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def process_rhs(self, compiler, connection):
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rhs, rhs_params = super().process_rhs(compiler, connection)
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# Ignore precision for DecimalFields.
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db_type = self.lhs.output_field.cast_db_type(connection).split('(')[0]
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cast_type = self.type_mapping[db_type]
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return '%s::%s' % (rhs, cast_type), rhs_params
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def process_lhs(self, compiler, connection):
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lhs, lhs_params = super().process_lhs(compiler, connection)
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if isinstance(self.lhs.output_field, models.FloatField):
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lhs = '%s::numeric' % lhs
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elif isinstance(self.lhs.output_field, models.SmallIntegerField):
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lhs = '%s::integer' % lhs
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return lhs, lhs_params
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def get_prep_lookup(self):
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return RangeField().get_prep_value(self.rhs)
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models.DateField.register_lookup(RangeContainedBy)
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models.DateTimeField.register_lookup(RangeContainedBy)
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models.IntegerField.register_lookup(RangeContainedBy)
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models.FloatField.register_lookup(RangeContainedBy)
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models.DecimalField.register_lookup(RangeContainedBy)
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@RangeField.register_lookup
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class FullyLessThan(PostgresOperatorLookup):
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lookup_name = 'fully_lt'
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postgres_operator = RangeOperators.FULLY_LT
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@RangeField.register_lookup
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class FullGreaterThan(PostgresOperatorLookup):
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lookup_name = 'fully_gt'
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postgres_operator = RangeOperators.FULLY_GT
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@RangeField.register_lookup
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class NotLessThan(PostgresOperatorLookup):
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lookup_name = 'not_lt'
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postgres_operator = RangeOperators.NOT_LT
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@RangeField.register_lookup
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class NotGreaterThan(PostgresOperatorLookup):
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lookup_name = 'not_gt'
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postgres_operator = RangeOperators.NOT_GT
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@RangeField.register_lookup
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class AdjacentToLookup(PostgresOperatorLookup):
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lookup_name = 'adjacent_to'
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postgres_operator = RangeOperators.ADJACENT_TO
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@RangeField.register_lookup
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class RangeStartsWith(models.Transform):
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lookup_name = 'startswith'
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function = 'lower'
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@property
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def output_field(self):
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return self.lhs.output_field.base_field
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@RangeField.register_lookup
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class RangeEndsWith(models.Transform):
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lookup_name = 'endswith'
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function = 'upper'
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@property
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def output_field(self):
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return self.lhs.output_field.base_field
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@RangeField.register_lookup
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class IsEmpty(models.Transform):
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lookup_name = 'isempty'
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function = 'isempty'
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output_field = models.BooleanField()
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@RangeField.register_lookup
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class LowerInclusive(models.Transform):
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lookup_name = 'lower_inc'
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function = 'LOWER_INC'
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output_field = models.BooleanField()
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@RangeField.register_lookup
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class LowerInfinite(models.Transform):
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lookup_name = 'lower_inf'
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function = 'LOWER_INF'
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output_field = models.BooleanField()
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@RangeField.register_lookup
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class UpperInclusive(models.Transform):
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lookup_name = 'upper_inc'
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function = 'UPPER_INC'
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output_field = models.BooleanField()
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@RangeField.register_lookup
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class UpperInfinite(models.Transform):
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lookup_name = 'upper_inf'
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function = 'UPPER_INF'
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output_field = models.BooleanField()
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