A Log of Coding Solutions
by Webhead
Everything works fine on your Mac OS setup, but for some reason, on your Linux server you get the error below. All file names look correct, case sensitive and all.
Class "Some/Namespace/App.php" not found.When you rename a file on Mac and it’s just changing the case, git won’t pick it up. So while you think it’s renamed on the server, it may not be! When renaming a file and it’s just changing the case, use:
git mv app.php App.phpby Webhead
$orderby = 'something';
$column_names = array( 0, 1, 2, 3, 'acolumn' );
if ( in_array( $orderby, $column_names ) ) {
$orderby = 'got here';
}
else {
$orderby = '';
}
// shows 'got here'
echo $orderby;To my surprise an any array with value of 0 will cause the in_array function to be true. This is because PHP converts the string being compared to a number. ‘something’ == 0 is true because ‘something’ gets converted to 0 as a number.
The same case is true for the opposite case, which is asked and answered on stack overflow (you’ll find a more detailed explanation there).
$orderby = 0;
$column_names = array( 1, 2, 3, 'acolumn' );
if ( in_array( $orderby, $column_names ) ) {
$orderby = 'got here';
}
else {
$orderby = '';
}
// shows 'got here'
echo $orderby;The solution is really to almost always set the third parameter to TRUE. This puts in_array into strict mode which compares the type of the needle.
$orderby = 'something';
$column_names = array( 0, 1, 2, 3, 'acolumn' );
if ( in_array( $orderby, $column_names, true ) ) {
$orderby = 'will not get here';
}
else {
$orderby = '';
}
// shows ''
echo $orderby;by Webhead
Recently I jumped on a project that uses the shorthand to declare an array by using the brackets []. I wondered why I have been using “array()” this whole time besides it being common in WordPress. Only to realize after deploying a plugin to a very old and out of date site that “[]” is not valid syntax in PHP 5.3.
by Webhead
My site was running fine and dandy for a few years. I made the necessary adjustments to make it compatible with PHP 7.2 and upgraded the server. A few days later I started receiving random 502 errors.
The problem apparently was a simple else if statement within a WordPress filter. Here is the important parts of the code:
function php72_killer() {
for($hour = 8; $hour < 17; $hour++) :
$display_hour = $hour;
$ampm = 'am';
if ( $hour == 0 ) {
$display_hour = 12;
}
else if ( $hour > 12 ) {
$display_hour = $hour - 12;
$ampm = 'pm';
}
else if ($hour==12) {
$ampm = 'pm';
}
endfor;
}
add_meta_box( 'some_id', 'Section Title', 'php72_killer', 'post_type', 'normal' );That last else if turned out to be the problem? Why? I don’t fully understand, but I found PHP 7.2 introduced optimized else ifs: https://derickrethans.nl/php7.2-switch.html
It’s important to note that this for loop with if-statements outside of the WordPress callback doesn’t cause random 502 errors.
So what fixed my 502 errors? not having a 2nd else if:
function php72_killer() {
for($hour = 8; $hour < 17; $hour++) :
$display_hour = $hour;
$ampm = 'am';
if ( $hour == 0 ) {
$display_hour = 12;
}
else if ( $hour > 12 ) {
$display_hour = $hour - 12;
$ampm = 'pm';
}
if ($hour==12) {
$ampm = 'pm';
}
endfor;
}
add_meta_box( 'some_id', 'Section Title', 'php72_killer', 'post_type', 'normal' );Go figure.
by Webhead
After creating a user with a certain role I need to do a custom sql query where it only selected users of a specific role. This failed to find anything:
select u.ID, u.display_name, u.user_login
from $wpdb->users as u
inner join $wpdb->usermeta as umr
on ( umr.user_id = u.ID )
and ( umr.meta_key = 'wp_capabilities' )
$user = get_userinfo( $user_id );
var_dump( $user->roles );
get_userinfo got the right role, so saving was correct.
$caps = get_user_meta( $user_id, 'wp_capabilities' );
var_dump( $caps );
$caps was null. weird.
You learn something new everyday. After looking through the WordPress core code I found that the meta key is actually composed of the table prefix and ‘capabilities’. So the correct query would be:
select u.ID, u.display_name, u.user_login
from $wpdb->users as u
inner join $wpdb->usermeta as umr
on ( umr.user_id = u.ID )
and ( umr.meta_key = '" . $wpdb->prefix . "capabilities' )
by Webhead
Non-hierarchical post types are like regular posts which normally do not have a menu_order attribute. Hierarchical post type are like pages which allows a parent/child and is normally ordered by the menu_order attribute. What if you have a custom post type that shouldn’t have a parent/child, but you still want to order it by something other than the post date? This code does the trick on the admin side.