Update 2025-04-24_11:44:19

venv/lib/python3.11/site-packages/sqlalchemy/dialects/sqlite/pysqlcipher.py

@@ -0,0 +1,157 @@
+# dialects/sqlite/pysqlcipher.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
+# mypy: ignore-errors
+
+
+"""
+.. dialect:: sqlite+pysqlcipher
+    :name: pysqlcipher
+    :dbapi: sqlcipher 3 or pysqlcipher
+    :connectstring: sqlite+pysqlcipher://:passphrase@/file_path[?kdf_iter=<iter>]
+
+    Dialect for support of DBAPIs that make use of the
+    `SQLCipher <https://www.zetetic.net/sqlcipher>`_ backend.
+
+
+Driver
+------
+
+Current dialect selection logic is:
+
+* If the :paramref:`_sa.create_engine.module` parameter supplies a DBAPI module,
+  that module is used.
+* Otherwise for Python 3, choose https://pypi.org/project/sqlcipher3/
+* If not available, fall back to https://pypi.org/project/pysqlcipher3/
+* For Python 2, https://pypi.org/project/pysqlcipher/ is used.
+
+.. warning:: The ``pysqlcipher3`` and ``pysqlcipher`` DBAPI drivers are no
+   longer maintained; the ``sqlcipher3`` driver as of this writing appears
+   to be current.  For future compatibility, any pysqlcipher-compatible DBAPI
+   may be used as follows::
+
+        import sqlcipher_compatible_driver
+
+        from sqlalchemy import create_engine
+
+        e = create_engine(
+            "sqlite+pysqlcipher://:password@/dbname.db",
+            module=sqlcipher_compatible_driver,
+        )
+
+These drivers make use of the SQLCipher engine. This system essentially
+introduces new PRAGMA commands to SQLite which allows the setting of a
+passphrase and other encryption parameters, allowing the database file to be
+encrypted.
+
+
+Connect Strings
+---------------
+
+The format of the connect string is in every way the same as that
+of the :mod:`~sqlalchemy.dialects.sqlite.pysqlite` driver, except that the
+"password" field is now accepted, which should contain a passphrase::
+
+    e = create_engine("sqlite+pysqlcipher://:testing@/foo.db")
+
+For an absolute file path, two leading slashes should be used for the
+database name::
+
+    e = create_engine("sqlite+pysqlcipher://:testing@//path/to/foo.db")
+
+A selection of additional encryption-related pragmas supported by SQLCipher
+as documented at https://www.zetetic.net/sqlcipher/sqlcipher-api/ can be passed
+in the query string, and will result in that PRAGMA being called for each
+new connection.  Currently, ``cipher``, ``kdf_iter``
+``cipher_page_size`` and ``cipher_use_hmac`` are supported::
+
+    e = create_engine(
+        "sqlite+pysqlcipher://:testing@/foo.db?cipher=aes-256-cfb&kdf_iter=64000"
+    )
+
+.. warning:: Previous versions of sqlalchemy did not take into consideration
+   the encryption-related pragmas passed in the url string, that were silently
+   ignored. This may cause errors when opening files saved by a
+   previous sqlalchemy version if the encryption options do not match.
+
+
+Pooling Behavior
+----------------
+
+The driver makes a change to the default pool behavior of pysqlite
+as described in :ref:`pysqlite_threading_pooling`.   The pysqlcipher driver
+has been observed to be significantly slower on connection than the
+pysqlite driver, most likely due to the encryption overhead, so the
+dialect here defaults to using the :class:`.SingletonThreadPool`
+implementation,
+instead of the :class:`.NullPool` pool used by pysqlite.  As always, the pool
+implementation is entirely configurable using the
+:paramref:`_sa.create_engine.poolclass` parameter; the :class:`.
+StaticPool` may
+be more feasible for single-threaded use, or :class:`.NullPool` may be used
+to prevent unencrypted connections from being held open for long periods of
+time, at the expense of slower startup time for new connections.
+
+
+"""  # noqa
+
+from .pysqlite import SQLiteDialect_pysqlite
+from ... import pool
+
+
+class SQLiteDialect_pysqlcipher(SQLiteDialect_pysqlite):
+    driver = "pysqlcipher"
+    supports_statement_cache = True
+
+    pragmas = ("kdf_iter", "cipher", "cipher_page_size", "cipher_use_hmac")
+
+    @classmethod
+    def import_dbapi(cls):
+        try:
+            import sqlcipher3 as sqlcipher
+        except ImportError:
+            pass
+        else:
+            return sqlcipher
+
+        from pysqlcipher3 import dbapi2 as sqlcipher
+
+        return sqlcipher
+
+    @classmethod
+    def get_pool_class(cls, url):
+        return pool.SingletonThreadPool
+
+    def on_connect_url(self, url):
+        super_on_connect = super().on_connect_url(url)
+
+        # pull the info we need from the URL early.  Even though URL
+        # is immutable, we don't want any in-place changes to the URL
+        # to affect things
+        passphrase = url.password or ""
+        url_query = dict(url.query)
+
+        def on_connect(conn):
+            cursor = conn.cursor()
+            cursor.execute('pragma key="%s"' % passphrase)
+            for prag in self.pragmas:
+                value = url_query.get(prag, None)
+                if value is not None:
+                    cursor.execute('pragma %s="%s"' % (prag, value))
+            cursor.close()
+
+            if super_on_connect:
+                super_on_connect(conn)
+
+        return on_connect
+
+    def create_connect_args(self, url):
+        plain_url = url._replace(password=None)
+        plain_url = plain_url.difference_update_query(self.pragmas)
+        return super().create_connect_args(plain_url)
+
+
+dialect = SQLiteDialect_pysqlcipher