How do I read values (PHP defined constants) from wp-config.php? - php

Question

I need to get username, password etc from the wp-config file to connect to a custom PDO database.
Currently I have another file where I have this info, but I would like to only use the wp-config.
So how can I read the different properties of wp-config?

Answer 1

I have even defined my own constants in in wp-config.php and managed to retrieve them in theme without any includes.
wp-config.php
define('DEFAULT_ACCESS', 'employee');
functions.php
echo "DEFAULT_ACCESS :".DEFAULT_ACCESS;
outputs DEFAULT_ACCESS :employee

Answer 2

Here's some same code.
// ...Call the database connection settings
require( path to /wp-config.php );
// ...Connect to WP database
$dbc = mysql_connect(DB_HOST, DB_USER, DB_PASSWORD);
if ( !$dbc ) {
die( 'Not Connected: ' . mysql_error());
}
// Select the database
$db = mysql_select_db(DB_NAME);
if (!$db) {
echo "There is no database: " . $db;
}
// ...Formulate the query
$query = "
SELECT *
FROM `wp_posts`
WHERE `post_status` = 'publish'
AND `post_password` = ''
AND `post_type` = 'post'
";
// ...Perform the query
$result = mysql_query( $query );
// ...Check results of the query and terminate the script if invalid results
if ( !$result ) {
$message = '<p>Invalid query.</p>' . "\n";
$message .= '<p>Whole query: ' . $query ."</p> \n";
die ( $message );
}
// Init a variable for the number of rows of results
$num_rows = mysql_num_rows( $result );
// Print the number of posts
echo "$num_rows Posts";
// Free the resources associated with the result set
if ( $result ) {
mysql_free_result( $result );
mysql_close();
}

Answer 3

I would just include the file then I would have access to the variable in it varibales.
<?php
require_once('wp-config.php');
echo DB_NAME;
?>
This is assuming you're on the same server and you can access wp-config.php through the file system.
If you're doing this for a plugin, these values are already available. You won't need to include the file again.

Answer 4

You can get all the global constants from wp-config.php simply echo the const like that:
<?php
echo DB_HOST;
echo DB_NAME;
echo DB_USER;
echo DB_PASSWORD;

Answer 5

Here is a function to read all WP DB defines:
function get_wordpress_data() {
$content = #file_get_contents( '../wp-config.php' );
if( ! $content ) {
return false;
}
$params = [
'db_name' => "/define.+?'DB_NAME'.+?'(.*?)'.+/",
'db_user' => "/define.+?'DB_USER'.+?'(.*?)'.+/",
'db_password' => "/define.+?'DB_PASSWORD'.+?'(.*?)'.+/",
'db_host' => "/define.+?'DB_HOST'.+?'(.*?)'.+/",
'table_prefix' => "/\\\$table_prefix.+?'(.+?)'.+/",
];
$return = [];
foreach( $params as $key => $value ) {
$found = preg_match_all( $value, $content, $result );
if( $found ) {
$return[ $key ] = $result[ 1 ][ 0 ];
} else {
$return[ $key ] = false;
}
}
return $return;
}
this returns an array like this:
array (size=5)
'db_name' => string '.........'
'db_user' => string '.........'
'db_password' => string '.........'
'db_host' => string 'localhost'
'table_prefix' => string 'wp_'

Answer 6

If you want to connect to DB, for current versions of PHP, using mysqli extention is recommended (mysql extention is going to deprecate):
require_once ("../wp-config.php"); // path to wp-config depends on your file locatoin
$mysqli = new mysqli(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}

Answer 7

Just add required wp-load.php file.
you can use all wordpress functionality like
get_recent_posts() and many more...