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