My Monkey Do

A Log of Coding Solutions

Coding

PHP – ‘anything’ in_array 0 is true

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$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;

Shorthand for array

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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 Only to realize after deploying a plugin to a very old and out of date site that “[]” is not valid syntax in PHP 5.3.

PHP 7.2 and the 502 error

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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.

SVG as Background

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When using an SVG as background with background-size: cover, the background would sometimes appear with a space on the left side.  Depending on the browser width it would be anywhere from 1px to 5px.   To solve this the SVG needs the preserveAspectRatio=”none” property.

Found the solution to a similar problem here: https://stackoverflow.com/questions/9185434/using-svg-as-background-image

Javascript Done Resize

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Normally code in the resize event is meant to just run once when the user is done resizing.  This code below, from css-tricks and seen elsewhere will do the trick:


var resizeTimer;
$(window).on('resize', function(e) {
clearTimeout(resizeTimer);
resizeTimer = setTimeout(function() {
// Run code here, resizing has "stopped"
}, 250);
});