Python应用防止SQL注入的方法 Preventing SQL injection

c=db.cursor()
max_price=5
c.execute("""SELECT spam, eggs, sausage FROM breakfast
          WHERE price < %s""", (max_price,))

注意,上面的SQL字符串与后面的tuple之间的分隔符是逗号,平时拼写SQL用的是%。

如果按照以下写法,是容易产生SQL注入的:

c.execute("""SELECT spam, eggs, sausage FROM breakfast
          WHERE price < %s""" % (max_price,))

这个和PHP里的PDO是类似的,原理同MySQL Prepared Statements。

 

Python

Using the Python DB API, don’t do this:

# Do NOT do it this way. cmd = "update people set name='%s' where id='%s'" % (name, id) curs.execute(cmd) 

Instead, do this:

cmd = "update people set name=%s where id=%s" curs.execute(cmd, (name, id)) 

Note that the placeholder syntax depends on the database you are using.

'qmark' Question mark style, e.g. '...WHERE name=?' 'numeric' Numeric, positional style, e.g. '...WHERE name=:1' 'named' Named style, e.g. '...WHERE name=:name' 'format' ANSI C printf format codes, e.g. '...WHERE name=%s' 'pyformat' Python extended format codes, e.g. '...WHERE name=%(name)s' 

The values for the most common databases are:

>>> import MySQLdb; print MySQLdb.paramstyle format >>> import psycopg2; print psycopg2.paramstyle pyformat >>> import sqlite3; print sqlite3.paramstyle qmark 

So if you are using MySQL or PostgreSQL, use %s (even for numbers and other non-string values!) and if you are using SQLite use ?

About 智足者富

http://chenpeng.info

发表评论

电子邮件地址不会被公开。 必填项已用*标注

您可以使用这些HTML标签和属性:

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>