Issue connecting to MySQL with mysqli in PHP [duplicate] - php

Question

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Warning: mysqli_connect(): (HY000/1045): Access denied for user 'username'#'localhost' (using password: YES)
(25 answers)
Closed 6 years ago.
Been going through tons of answers but none have exactly matched my issue.
I have a MySQL database running and am attempting to connect in PHP with mysqli. The connection code is as follows:
<?php
if(!isset($_COOKIE["uid"])) {
$servername = "localhost";
$username = "study";
$password = "somepassword";
$dbname = "user_study";
$conn = new mysqli($servername, $username, $password, $dbname);
if($conn->connect_error){
die("aww");
}
}
However every time I get the error
mysqli::mysqli(): (28000/1045): Access denied for user
'study'#'localhost' (using password: YES)
I know that the user 'study'#'localhost' has permissions to access this database, because I am able to access it through the MySQL command line just fine. I have tried other accounts such as roots with the same result.
Is there anything else I should be checking?
New information (2/23)
It seems that even when I shut the database down I'm getting an access denied result, meaning it seems to be trying to connect to some other database on the server. How would I ensure it is connecting to the correct one?

Answer 1

I think the error message indicates that PHP was able to contact the MySQL Server using the socket file. (It would have been a different error otherwise.)
There's a couple of reasons you could get this error. If we can successfully connect to MySQL Server with a the mysql command line client like this:
> mysql --no-defaults -h localhost -u study -psomepassword user_study
That's going to rule out a lot of the possible reasons for the failure.
The most reasonable explanation for the error message from PHP is that the password being provided in the connection attempt from PHP does not match the password MySQL is expecting.
Some ideas we should be able to rule out. Privileges on the user_study database have been granted to 'study'#'localhost', e.g.
GRANT SELECT ON user_study.* TO 'user'#'localhost'
On a totally different tack, given the assignment statement:
$password = "somepassword";
And assuming that you wouldn't be supplying the actual password in the question... we're left wondering if the actual password contains characters that are subject to PHP string interpretation, such as backslash character, or a dollar sign.
For debugging, I suggest doing an echo $password; following the assignment, and verify that the string emitted is what is expected.
Another possibility is that there isn't an exact match in the mysql.user table, and the user 'study' is actually matching to a different mysql.user... an entry with an empty user ''#'localhost'.
I'd be taking a look at all of the entries in the mysql.user table where user='study' and user=''.
I also want to rule out the possibility that the mysql command line client using a .mylogin.cnf file.
I'm also tempted to suggest that changes were applied to the mysql.user table and a FLUSH PRIVILEGES statement wasn't executed... but that doesn't jive with the behavior (successful connection) observed in the mysql command line client.
We're assuming obviously that the MySQL Server is running local, on the same machine that PHP is executing on. And we're expecting to connect via the local socket file.
As a test, I'd suggest connecting via TCP. Specifying host as 127.0.0.1. That would require a different entry in the mysql.user table. We'd test connection from the mysql command line client:
> mysql --no-defaults -h 127.0.0.1 -u study -psomepassword user_study
But this gets into a whole host of other configuration issues with the MySQL Server, networking enabled, bind address, DNS name resolution, listening port, iptables, firewall, et al.
--
If the problem was an unsupported authentication protocol, I'd expect a different error. If the problem was the inability to connect to the socket file, I'd also expect a different error.
All of the usual causes for this error seem to be ruled out by a successful connection from the command line client, running on the local machine, connecting to using the same credentials.