Python MySQL转义特殊字符

Question

我正在使用python将一个字符串插入带有特殊字符的MySQL中。

要插入的字符串如下所示：

macaddress_eth0;00:1E:68:C6:09:A0;macaddress_eth1;00:1E:68:C6:09:A1

这是SQL：

UPGRADE inventory_server 
set server_mac = macaddress\_eth0\;00\:1E\:68\:C6\:09\:A0\;macaddress\_eth1\;00\:1E\:68\:C6\:09\:A1' 
where server_name = 'myhost.fqdn.com

当我执行更新时，我收到此错误：

ERROR 1064 (42000): 
You have an error in your SQL syntax; check the manual that corresponds to your 
MySQL server version for the right syntax to use near 'UPGRADE inventory_server 
set server_mac = 'macaddress\_eth0\;00\:1E\:68\:C6\:09\' at line 1

python代码：

sql = 'UPGRADE inventory_server set server_mac = \'%s\' where server_name = \'%s\'' % (str(mydb.escape_string(macs)),host)
print sql

try:
    con = mydb.connect(DBHOST,DBUSER,DBPASS,DB);
    with con:
       cur = con.cursor(mydb.cursors.DictCursor)
       cur.execute(sql)
   con.commit()
except:
return False

如何将此文本原始插入？

Answer 1

这是您应该使用parameter binding而不是在Python中格式化参数的原因之一。

这样做：

sql = 'UPGRADE inventory_server set server_mac = %s where server_name = %s'

然后：

cur.execute(sql, macs, host)

这样，您可以将字符串作为字符串处理，让MySQL库找出如何引用并为您转义它。

最重要的是，您通常会获得更好的性能（因为MySQL可以编译和缓存一个查询并将其重用于不同的参数值）并避免使用SQL injection attacks（一种最常见的攻击方式）。

Answer 2

Python示例如何插入原始文本：

在MySQL中创建一个表：

create table penguins(id int primary key auto_increment, msg VARCHAR(4000))

Python代码：

#!/usr/bin/env python
import sqlalchemy
from sqlalchemy import text

engine = sqlalchemy.create_engine(
    "mysql+mysqlconnector://yourusername:yourpassword@yourhostname.com/your_database")
db = engine.connect()

weird_string = "~!@#$%^&*()_+`1234567890-={}|[]\;':\""

sql = text('INSERT INTO penguins (msg) VALUES (:msg)')
insert = db.execute(sql, msg=weird_string)

db.close()

运行它，检查输出：

select * from penguins

1      ~!@#$%^&*()_+`1234567890-={}|[]\;\':"

在插入时没有解释这些字符。

Answer 3

欢迎来到字符串编码格式的世界！

tl; dr-在MySQL列中存储数据时处理引号和转义字符的首选方法是使用参数化查询，并由MySQLDatabase驱动程序处理。另外，您可以通过在插入之前将引号和斜杠加倍来对其进行转义。

链接底部的完整示例

标准SQL更新

# as_json must have escape slashes and quotes doubled
query = """\
        UPDATE json_sandbox
        SET data = '{}'
        WHERE id = 1;
    """.format(as_json)

with DBConn(*client.conn_args) as c:
    c.cursor.execute(query)
    c.connection.commit()

参数化的SQL更新

# SQL Driver will do the escaping for you
query = """\
        UPDATE json_sandbox
        SET data = %s
        WHERE id = %s;
    """

with DBConn(*client.conn_args) as c:
    c.cursor.execute(query, (as_json, 1))
    c.connection.commit()

无效的JSON SQL

{
  "abc": 123,
  "quotes": "ain't it great",
  "multiLine1": "hello\nworld",
  "multiLine3": "hello\r\nuniverse\r\n"
}

有效的JSON SQL

{
  "abc": 123,
  "quotes": "ain''t it great",
  "multiLine1": "hello\\nworld",
  "multiLine3": "hello\\r\\nuniverse\\r\\n"
}

Python转换：

# must escape the escape characters, so each slash is doubled
# Some MySQL Python libraries also have an escape() or escape_string() method.
as_json = json.dumps(payload) \
    .replace("'", "''") \
    .replace('\\', '\\\\')

完整示例

import json
import yaml

from DataAccessLayer.mysql_va import get_sql_client, DBConn

client = get_sql_client()

def encode_and_store(payload):
    as_json = json.dumps(payload) \
        .replace("'", "''") \
        .replace('\\', '\\\\')

    query = """\
            UPDATE json_sandbox
            SET data = '{}'
            WHERE id = 1;
        """.format(as_json)

    with DBConn(*client.conn_args) as c:
        c.cursor.execute(query)
        c.connection.commit()

    return

def encode_and_store_2(payload):
    as_json = json.dumps(payload)

    query = """\
            UPDATE json_sandbox
            SET data = %s
            WHERE id = %s;
        """

    with DBConn(*client.conn_args) as c:
        c.cursor.execute(query, (as_json, 1))
        c.connection.commit()

    return


def retrieve_and_decode():
    query = """
        SELECT * FROM json_sandbox
        WHERE id = 1
    """

    with DBConn(*client.conn_args) as cnx:
        cursor = cnx.dict_cursor
        cursor.execute(query)

        rows = cursor.fetchall()


    as_json = rows[0].get('data')

    payload = yaml.safe_load(as_json)
    return payload



if __name__ == '__main__':

    payload = {
        "abc": 123,
        "quotes": "ain't it great",
        "multiLine1": "hello\nworld",
        "multiLine2": """
            hello
            world
        """,
        "multiLine3": "hello\r\nuniverse\r\n"
    }


    encode_and_store(payload)
    output_a = retrieve_and_decode()

    encode_and_store_2(payload)
    output_b = retrieve_and_decode()

    print("original: {}".format(payload))
    print("method_a: {}".format(output_a))
    print("method_b: {}".format(output_b))

    print('')
    print(output_a['multiLine1'])

    print('')
    print(output_b['multiLine2'])

    print('\nAll Equal?: {}'.format(payload == output_a == output_b))

Answer 4

虽然我也认为应该使用参数绑定，但也有：

>>> import MySQLdb
>>> example = r"""I don't like "special" chars ¯\_(ツ)_/¯"""
>>> example
'I don\'t like "special" chars \xc2\xaf\\_(\xe3\x83\x84)_/\xc2\xaf'
>>> MySQLdb.escape_string(example)
'I don\\\'t like \\"special\\" chars \xc2\xaf\\\\_(\xe3\x83\x84)_/\xc2\xaf'