124 lines
4.6 KiB
Python
124 lines
4.6 KiB
Python
from django.db import NotSupportedError
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from django.db.models.expressions import Func, Value
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from django.db.models.fields import TextField
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from django.db.models.fields.json import JSONField
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from django.db.models.functions import Cast
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class JSONArray(Func):
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function = "JSON_ARRAY"
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output_field = JSONField()
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def as_sql(self, compiler, connection, **extra_context):
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if not connection.features.supports_json_field:
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raise NotSupportedError(
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"JSONFields are not supported on this database backend."
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)
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return super().as_sql(compiler, connection, **extra_context)
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def as_native(self, compiler, connection, *, returning, **extra_context):
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# PostgreSQL 16+ and Oracle remove SQL NULL values from the array by
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# default. Adds the NULL ON NULL clause to keep NULL values in the
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# array, mapping them to JSON null values, which matches the behavior
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# of SQLite.
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null_on_null = "NULL ON NULL" if len(self.get_source_expressions()) > 0 else ""
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return self.as_sql(
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compiler,
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connection,
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template=(
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f"%(function)s(%(expressions)s {null_on_null} RETURNING {returning})"
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),
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**extra_context,
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)
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def as_postgresql(self, compiler, connection, **extra_context):
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# Casting source expressions is only required using JSONB_BUILD_ARRAY
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# or when using JSON_ARRAY on PostgreSQL 16+ with server-side bindings.
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# This is done in all cases for consistency.
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casted_obj = self.copy()
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casted_obj.set_source_expressions(
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[
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(
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# Conditional Cast to avoid unnecessary wrapping.
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expression
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if isinstance(expression, Cast)
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else Cast(expression, expression.output_field)
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)
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for expression in casted_obj.get_source_expressions()
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]
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)
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if connection.features.is_postgresql_16:
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return casted_obj.as_native(
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compiler, connection, returning="JSONB", **extra_context
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)
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return casted_obj.as_sql(
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compiler,
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connection,
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function="JSONB_BUILD_ARRAY",
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**extra_context,
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)
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def as_oracle(self, compiler, connection, **extra_context):
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return self.as_native(compiler, connection, returning="CLOB", **extra_context)
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class JSONObject(Func):
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function = "JSON_OBJECT"
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output_field = JSONField()
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def __init__(self, **fields):
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expressions = []
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for key, value in fields.items():
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expressions.extend((Value(key), value))
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super().__init__(*expressions)
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def as_sql(self, compiler, connection, **extra_context):
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if not connection.features.has_json_object_function:
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raise NotSupportedError(
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"JSONObject() is not supported on this database backend."
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)
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return super().as_sql(compiler, connection, **extra_context)
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def join(self, args):
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pairs = zip(args[::2], args[1::2], strict=True)
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# Wrap 'key' in parentheses in case of postgres cast :: syntax.
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return ", ".join([f"({key}) VALUE {value}" for key, value in pairs])
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def as_native(self, compiler, connection, *, returning, **extra_context):
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return self.as_sql(
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compiler,
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connection,
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arg_joiner=self,
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template=f"%(function)s(%(expressions)s RETURNING {returning})",
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**extra_context,
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)
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def as_postgresql(self, compiler, connection, **extra_context):
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# Casting keys to text is only required when using JSONB_BUILD_OBJECT
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# or when using JSON_OBJECT on PostgreSQL 16+ with server-side bindings.
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# This is done in all cases for consistency.
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copy = self.copy()
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copy.set_source_expressions(
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[
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Cast(expression, TextField()) if index % 2 == 0 else expression
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for index, expression in enumerate(copy.get_source_expressions())
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]
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)
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if connection.features.is_postgresql_16:
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return copy.as_native(
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compiler, connection, returning="JSONB", **extra_context
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)
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return super(JSONObject, copy).as_sql(
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compiler,
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connection,
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function="JSONB_BUILD_OBJECT",
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**extra_context,
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)
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def as_oracle(self, compiler, connection, **extra_context):
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return self.as_native(compiler, connection, returning="CLOB", **extra_context)
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