Archive for the PHP Tag

like_escape() is Deprecated in WordPress 4.0

miqrogroove
2014-06-18T00:33:31+00:00

Plugin authors and website developers who work with WordPress database queries should notice an important change coming in WordPress 4.0.

The function like_escape() is no longer used in WordPress core code.  It is still available as a deprecated function, so it still works in any existing plugins that rely on it.  However, a new and different function is available that should be used in all new code.

Deprecated means that anyone using code that calls like_escape() with WP_DEBUG enabled will see an error message.  If WP_DEBUG_LOG is also enabled, the error message will appear in the /wp-content/debug.log file.

Let’s look at an example of core code where I removed like_escape() and implemented the new function $wpdb->esc_like().

3.9 Old Style

$search_orderby_s = like_escape( esc_sql( $q['s'] ) );
$search_orderby .= "WHEN $wpdb->posts.post_title LIKE '%{$search_orderby_s}%' THEN 1 ";

What did this do?  It was an old snippet from /wp-includes/query.php that set up a search for post titles.  The input $q[‘s’] was escaped using two functions before it was added to the post_title LIKE expression.  Now let’s see how I replaced that snippet in the next version.

4.0 New Style

$like = '%' . $wpdb->esc_like( $q['s'] ) . '%';
$search_orderby .= $wpdb->prepare( "WHEN $wpdb->posts.post_title LIKE %s THEN 1 ", $like );

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18 Jun 2014

Category:
Systems Engineering

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PHP Array Assignment and References

miqrogroove
2017-08-15T08:39:01+00:00

This is a quick explanation of some more referencing quirks in PHP.

Let’s say you need to store an array in a specific variable so that another variable can be freed up and overwritten with different information.  [To clarify, this array may be very large and copying it would be detrimental to performance in this particular application. For small arrays, copying and not referencing may be preferable.]

The operation for referencing the array with a new variable is quite simple:

$array_goes_here =& $need_to_free_up_this_var;

The code above will reference the array to prevent PHP from making an unnecessary copy of the whole thing.

Now here’s what you have to avoid:

$need_to_free_up_this_var = array(); /* wrong! */

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15 Feb 2013

Category:
Systems Engineering

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