Update 2025-04-13_16:25:39

venv/lib/python3.11/site-packages/sqlalchemy/engine/mock.py

@@ -0,0 +1,133 @@
+# engine/mock.py
+# Copyright (C) 2005-2025 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+
+from __future__ import annotations
+
+from operator import attrgetter
+import typing
+from typing import Any
+from typing import Callable
+from typing import cast
+from typing import Optional
+from typing import Type
+from typing import Union
+
+from . import url as _url
+from .. import util
+
+
+if typing.TYPE_CHECKING:
+    from .base import Engine
+    from .interfaces import _CoreAnyExecuteParams
+    from .interfaces import CoreExecuteOptionsParameter
+    from .interfaces import Dialect
+    from .url import URL
+    from ..sql.base import Executable
+    from ..sql.ddl import SchemaDropper
+    from ..sql.ddl import SchemaGenerator
+    from ..sql.schema import HasSchemaAttr
+    from ..sql.schema import SchemaItem
+
+
+class MockConnection:
+    def __init__(self, dialect: Dialect, execute: Callable[..., Any]):
+        self._dialect = dialect
+        self._execute_impl = execute
+
+    engine: Engine = cast(Any, property(lambda s: s))
+    dialect: Dialect = cast(Any, property(attrgetter("_dialect")))
+    name: str = cast(Any, property(lambda s: s._dialect.name))
+
+    def connect(self, **kwargs: Any) -> MockConnection:
+        return self
+
+    def schema_for_object(self, obj: HasSchemaAttr) -> Optional[str]:
+        return obj.schema
+
+    def execution_options(self, **kw: Any) -> MockConnection:
+        return self
+
+    def _run_ddl_visitor(
+        self,
+        visitorcallable: Type[Union[SchemaGenerator, SchemaDropper]],
+        element: SchemaItem,
+        **kwargs: Any,
+    ) -> None:
+        kwargs["checkfirst"] = False
+        visitorcallable(self.dialect, self, **kwargs).traverse_single(element)
+
+    def execute(
+        self,
+        obj: Executable,
+        parameters: Optional[_CoreAnyExecuteParams] = None,
+        execution_options: Optional[CoreExecuteOptionsParameter] = None,
+    ) -> Any:
+        return self._execute_impl(obj, parameters)
+
+
+def create_mock_engine(
+    url: Union[str, URL], executor: Any, **kw: Any
+) -> MockConnection:
+    """Create a "mock" engine used for echoing DDL.
+
+    This is a utility function used for debugging or storing the output of DDL
+    sequences as generated by :meth:`_schema.MetaData.create_all`
+    and related methods.
+
+    The function accepts a URL which is used only to determine the kind of
+    dialect to be used, as well as an "executor" callable function which
+    will receive a SQL expression object and parameters, which can then be
+    echoed or otherwise printed.   The executor's return value is not handled,
+    nor does the engine allow regular string statements to be invoked, and
+    is therefore only useful for DDL that is sent to the database without
+    receiving any results.
+
+    E.g.::
+
+        from sqlalchemy import create_mock_engine
+
+
+        def dump(sql, *multiparams, **params):
+            print(sql.compile(dialect=engine.dialect))
+
+
+        engine = create_mock_engine("postgresql+psycopg2://", dump)
+        metadata.create_all(engine, checkfirst=False)
+
+    :param url: A string URL which typically needs to contain only the
+     database backend name.
+
+    :param executor: a callable which receives the arguments ``sql``,
+     ``*multiparams`` and ``**params``.  The ``sql`` parameter is typically
+     an instance of :class:`.ExecutableDDLElement`, which can then be compiled
+     into a string using :meth:`.ExecutableDDLElement.compile`.
+
+    .. versionadded:: 1.4 - the :func:`.create_mock_engine` function replaces
+       the previous "mock" engine strategy used with
+       :func:`_sa.create_engine`.
+
+    .. seealso::
+
+        :ref:`faq_ddl_as_string`
+
+    """
+
+    # create url.URL object
+    u = _url.make_url(url)
+
+    dialect_cls = u.get_dialect()
+
+    dialect_args = {}
+    # consume dialect arguments from kwargs
+    for k in util.get_cls_kwargs(dialect_cls):
+        if k in kw:
+            dialect_args[k] = kw.pop(k)
+
+    # create dialect
+    dialect = dialect_cls(**dialect_args)
+
+    return MockConnection(dialect, executor)