PHP

Problem:

You are writing a wordpress plugin in which you need the path to the wp-content directory on the filesystem.

Solution:

Use the WP_CONTENT_DIR constant.

$path_to_wp_content = WP_CONTENT_DIR; // e.g. "/var/sites/techoverflow.net/wp-content"

Note that WP_CONTENT_DIR has no trailing slash.

Use WP_CONTENT_DIR . "/" like this

$path_to_wp_content = WP_CONTENT_DIR . "/"; // e.g. "/var/sites/techoverflow.net/wp-content/"

to get the path to wp_content including a trailing slash.

Problem:

In your custom WordPress plugin or theme you have code like

$query = new WP_Query( );
while ( $query->have_posts() ) {
        $query->the_post();
        // ... your code to process the post ...
}

But $query->have_posts() is always false and the loop is never executed.

Solution:

WP_Query works only if you use an appropriate query. Using no query at all is not equivalent to list all posts!

This is likely what you want to do:

$query = new WP_Query(array('post_type' => 'post'));

There are well-documented solutions to recover the wordpress admin access if you have MySQL, phpMyAdmin or shell access.

This solution shows you how to create a new admin user if you don’t know the admin username or password and you don’t have any form of MySQL or shell access (only FTP access is required).

Step 1: Identify your currently active theme

This can be done by looking at the source code of your homepage (go to your domain, then Ctrl+U to show the source) and then Ctrl+F-search for wp-content/themes. It will show hits like https://mydomain.de/wp-content/themes/twentyfifteen/style.css. This means the currently active theme is twentyfifteen.

Step 2: Create a new admin user using functions.php

Now open your FTP software (I recommend FileZilla) and find your wp-content folder. Inside wp-content, go to themes and then open the folder of your currently active theme.

If the currently active theme is not listed in your wp-content/themes folder, you might have the wrong wp-content folder. Check if there are any other folders around.

When you have found your theme folder, edit functions.php and, just after the first <?php, add this block of code:

function wpb_admin_account(){
    $user = 'newadmin';
    $pass = 'saiquae9shahZus6eeri3feNae8gie';
    $email = 'admin-email@example.org';
    if ( !username_exists( $user )  && !email_exists( $email ) ) {
        $user_id = wp_create_user( $user, $pass, $email );
        $user = new WP_User( $user_id );
        $user->set_role( 'administrator' );
    }
}
add_action('init','wpb_admin_account');

Be sure to replace the username, password and email! I recommend to use a new random password and a non-generic username! The username you enter here must.

Save the file and upload it to the server.

After that, goto your homepage and reload once (this will create the new user).

Then, try to login using your newly created user (go to e.g. https://my-domain.com/wp-admin to do so!). If it doesn’t work, check if you edited the functions.php for the correct theme and try to use a different username!

Step 3: Delete the code we just created

If you just leave in the code, this will create a potential security risk. So I recommend deleting it right away!

Also, be sure to delete any admin users you don’t need afterwards.