1# mysql/pymysql.py
2# Copyright (C) 2005-2021 the SQLAlchemy authors and contributors
3# <see AUTHORS file>
4#
5# This module is part of SQLAlchemy and is released under
6# the MIT License: http://www.opensource.org/licenses/mit-license.php
7
8r"""
9
10.. dialect:: mysql+pymysql
11    :name: PyMySQL
12    :dbapi: pymysql
13    :connectstring: mysql+pymysql://<username>:<password>@<host>/<dbname>[?<options>]
14    :url: https://pymysql.readthedocs.io/
15
16Unicode
17-------
18
19Please see :ref:`mysql_unicode` for current recommendations on unicode
20handling.
21
22MySQL-Python Compatibility
23--------------------------
24
25The pymysql DBAPI is a pure Python port of the MySQL-python (MySQLdb) driver,
26and targets 100% compatibility.   Most behavioral notes for MySQL-python apply
27to the pymysql driver as well.
28
29"""  # noqa
30
31from .mysqldb import MySQLDialect_mysqldb
32from ...util import langhelpers
33from ...util import py3k
34
35
36class MySQLDialect_pymysql(MySQLDialect_mysqldb):
37    driver = "pymysql"
38
39    description_encoding = None
40
41    # generally, these two values should be both True
42    # or both False.   PyMySQL unicode tests pass all the way back
43    # to 0.4 either way.  See [ticket:3337]
44    supports_unicode_statements = True
45    supports_unicode_binds = True
46
47    def __init__(self, server_side_cursors=False, **kwargs):
48        super(MySQLDialect_pymysql, self).__init__(**kwargs)
49        self.server_side_cursors = server_side_cursors
50
51    @langhelpers.memoized_property
52    def supports_server_side_cursors(self):
53        try:
54            cursors = __import__("pymysql.cursors").cursors
55            self._sscursor = cursors.SSCursor
56            return True
57        except (ImportError, AttributeError):
58            return False
59
60    @classmethod
61    def dbapi(cls):
62        return __import__("pymysql")
63
64    def create_connect_args(self, url, _translate_args=None):
65        if _translate_args is None:
66            _translate_args = dict(username="user")
67        return super(MySQLDialect_pymysql, self).create_connect_args(
68            url, _translate_args=_translate_args
69        )
70
71    def is_disconnect(self, e, connection, cursor):
72        if super(MySQLDialect_pymysql, self).is_disconnect(
73            e, connection, cursor
74        ):
75            return True
76        elif isinstance(e, self.dbapi.Error):
77            str_e = str(e).lower()
78            return (
79                "already closed" in str_e or "connection was killed" in str_e
80            )
81        else:
82            return False
83
84    if py3k:
85
86        def _extract_error_code(self, exception):
87            if isinstance(exception.args[0], Exception):
88                exception = exception.args[0]
89            return exception.args[0]
90
91
92dialect = MySQLDialect_pymysql
93