Mysql CLI在localhost上连接正常，但mysqli_connect将localhost解析为机器名

Question

I have a seemingly straightforward call using mysqli_connect() that is failing due to host substitution of the name 'localhost'.

Example:

$username = 'foo';
$host = 'localhost';
$passwd = 'secret';

$link = mysqli_connect($host,$username, $passwd)...

Calling mysqli_connect with either 'localhost' or '127.0.0.1' as the host returns something like this:

(HY000/1045): Access denied for user 'foo'@'servername.mydomain.com'

I can connect using the same account with the locally-installed MySQL client just fine, so the user's permissions are valid:

SHOW GRANTS FOR 'foo'@'localhost';
GRANT USAGE ON *.* TO 'foo'@'localhost'

Evidently mysqli_connect is trying to connect using the DNS name of the local machine instead of localhost.

I know I could opt to issue a grant for the user with the host explicitly defined as the machine name, or allow from all hosts, but neither of those options is acceptable in this instance. I need it to get it to work using localhost.

Related: /etc/hosts defines localhost as follows:

127.0.0.1       localhost 

Answer 1

Passing the path to the socket as the last argument to mysqli_connect() was probably working all along. A subsequent call to a remote database was also failing with an identical error, and I didn't notice until now that the error was occurring at a later line number.