密码验证失败，输入复杂密码 [英] Password authentication fails with complex password

问题描述

我编写了一个Python脚本，该脚本使用 psycopg2 2.6 和 Python 2.7.8 连接到本地PostgreSQL数据库.连接设置和命令如下:

I wrote a Python script which connects to the local PostgreSQL database using psycopg2 2.6 and Python 2.7.8. The connection settings and commands are the following:

HOST = '127.0.0.1'
DATABASE_NAME = 'myappdatabase'
DATABASE_PORT = '5432'
DATABASE_USER = 'myappuser'
DATABASE_PASSWORD = 'secret'
DATABASE_TABLE = 'myappdata'

def _database_connection():
    conn_string = "host='{0}' dbname='{1}' port='{2}' user='{3}' \
        password='{4}'".format(HOST, DATABASE_NAME, DATABASE_PORT, \
        DATABASE_USER, DATABASE_PASSWORD)
    return psycopg2.connect(conn_string)

该脚本可以在没有安装PostgreSQL 9.4的计算机上正常运行. sudo vi /etc/postgresql/9.4/main/pg_hba.conf中的配置未修改，看起来像这样，没有注释:

The script works without problems on machine one which has PostgreSQL 9.4 installed. The configuration in sudo vi /etc/postgresql/9.4/main/pg_hba.conf is not modified and looks like this, without comments:

local   all             postgres                                peer
local   all             all                                     peer
host    all             all             127.0.0.1/32            md5
host    all             all             ::1/128                 md5

我还可以使用 pgAdmin III 成功连接到相同的数据库.

I can also successfully connect to the same database using pgAdmin III.

在具有相同设置的第二台计算机上，我无法通过脚本连接.发生以下错误:

On a second machine with the same setup I cannot connect via the script. The following error occurs:

psycopg2.OperationalError:严重:用户"myappuser"的密码身份验证失败
致命:用户"myappuser"的密码身份验证失败

psycopg2.OperationalError: FATAL: password authentication failed for user "myappuser"
FATAL: password authentication failed for user "myappuser"

这两台机器之间唯一的差异是数据库密码.因此，我将其更改为简单的密码-繁荣起来，它可以正常工作.因此，我将其改回了一个复杂的...，它不再再次起作用.密码是这样的:

The only difference between these two machines is the database password. So I changed it to a simple password - and boom, it works. So I changed it back to a complicated ... and it does not work again. The password is something like this:

DATABASE_PASSWORD ='zyx @ 12AA \ w2'

DATABASE_PASSWORD = 'zyx@12AA\w2'

所以我想:这很愚蠢.一定是我的错误." 因此，我将第一台机器上的数据库密码设置为与第二台机器上的相同.而且，Python脚本也会失败.

So I thought: "This is stupid. It must be my mistake." So I set the database password on machine one to the same as on the second machine. And whoop the Python script also fails.

推荐答案

在这种情况下，密码中的反斜杠被解释为转义符. Python会将\w中的反斜杠视为文字\，即使未将其指定为原始字符串，因为\w不是有效的转义序列，但基础库也

The backslash in the password in this case is interpreted as escape character. Python would treat the backslash in \w as literal \ even if it's not specified as a raw string because \w is not a valid escape sequence, but the underlying library also parses escape sequences, therefore the backslash has to be escaped (doubled).

为避免这种情况，请指定连接参数作为关键字参数 :

To avoid this, specify the connection parameters as keyword arguments instead:

psycopg2.connect(host=HOST,
                 database=DATABASE_NAME,
                 port=DATABASE_PORT,
                 user=DATABASE_USER,
                 password=DATABASE_PASSWORD)

这可以避免密码中的特殊字符出现问题.另外，密码中的单引号字符会破坏连接字符串.

This avoids problems with special characters in passwords. Also a single quote chacacter in the password would break the connection string.

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