Pyhton中防止SQL注入的方法

代碼如下:

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字串與後面的tuple之間的分隔字元是逗號，平時拼字SQL用的是%。

如果按照以下寫法，是容易產生SQL注入的：

代碼如下:

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

這個和PHP裡的PDO是類似的，原理同MySQL Prepared Statements。

Python

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

# Do NOT do it this way.

代碼如下:

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

Instead, do this:

代碼如下:

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.

代碼如下:

'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:

代碼如下:

>>> 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 ?

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