Programming tricks used on this site

[code]/**

* Default post thumbnail image.

*

*/



function mk_filter_thumbnail_id( $thumbnail_id, $post = null ) {

     if ( ! $thumbnail_id ) {

          $thumbnail_id = 289; //id of default featured image

     }

    return $thumbnail_id;

}



if (! is_admin() ) { //don't do this on admin pages, it sometimes overwrites thumbnails in the back-end view of the media library

add_filter( 'post_thumbnail_id', 'mk_filter_thumbnail_id', 20, 5 );

}[/code]

[code]/*

* Plugin Name: MK Custom Shortcodes

* Plugin URI:        https://michaelkupietz.com/plugins/the-basics/

* Description:       My custom shortcodes.

* Version:           1

* Requires at least: 5.2

* Requires PHP:      7.2

* Author:            Michael Kupietz

* Author URI:        https://michaelkupietz.com/

* License:           GPL v2 or later

* License URI:       https://www.gnu.org/licenses/gpl-2.0.html

* Update URI:        https://michaelkupietz.com/my-plugin/

* Text Domain:       mk-plugin

* Domain Path:       /languages

*/ 



// first, some useful functions

add_action( 'save_post', 'setLastUpdateTimestamp' );

add_action( 'create_category', 'setLastUpdateTimestamp' );

add_action( 'edited_category', 'setLastUpdateTimestamp' );

add_action( 'delete_category', 'setLastUpdateTimestamp' );

add_action( 'create_post_tag', 'setLastUpdateTimestamp', 10, 2 );

add_action( 'edited_terms', 'setLastUpdateTimestamp', 10, 2 );

add_action( 'delete_term', 'setLastUpdateTimestamp', 10, 3 );

add_action( 'trash_post', 'setLastUpdateTimestamp' );



function setLastUpdateTimestamp() {

     if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {

          return;

     }

     // If this is a revision, don't do anything.

     if ( wp_is_post_revision( $post_id ) ) {

          return;

     }



     set_transient( 'mkFuncTransient_LastUpdateCheck',microtime(true),2592000);

}



function latestPostUpdate() {

     $theDate = get_transient( 'mkFuncTransient_LastUpdate_all');

     if ( ! (isset($theDate) && $theDate > 0)) {

          $theDate=microtime(true);

          set_transient( 'mkFuncTransient_LastUpdate_all',$theDate,2592000); //dont expire for 1 month                    

          }

      }

     return $theDate;

}



function getFunctionTransient ($functionName,$arguments=[]) {

     //call with: $transientData = getFunctionTransient(__FUNCTION__,$arguments); 

     if ( $transientData != null) {return $transientData;}

     //the $arguments term in the call is optional. It's only for functions that return different values based on their arguments, so you can cache and retrieve the values of different calls with different arguments.

     $data = get_transient( 'mkFuncTransient'.$functionName . hash( 'sha512',json_encode( $arguments ) ) ); //per https://daext.com/blog/improve-the-shortcode-performance-with-the-wordpress-transients-api/

     $lastUpdate = get_transient( 'mkFuncTransient_LastUpdate' . $functionName . hash( 'sha512', json_encode( $arguments ) ) );

     $lastPostUpdate = latestPostUpdate();



     if ( $data !== false and $lastUpdate < $lastPostUpdate ) {

          return $data;

     } else {

          return null;

     }

}



function setFunctionTransient ($functionName, $value = null, $arguments=[]) {

     //call this right before returning value of function with as: setFunctionTransient(__FUNCTION__,$returnValue,$arguments);

     //you can leave out returnvalue, or set it to null, to delete the transient.

     //the $arguments term in the call is optional. It's only for functions that return different values based on their arguments, so you can cache and retrieve the values of different calls with different arguments.

     if ( $value === null) {

          delete_transient( 'mkFuncTransient'.$functionName . hash( 'sha512',json_encode( $arguments ) ) );

          delete_transient( 'mkFuncTransient_LastUpdate' . $functionName . hash( 'sha512', json_encode( $arguments ) ));

          return $value;

     } else {

          set_transient( 'mkFuncTransient'.$functionName . hash( 'sha512',json_encode( $arguments ) ) , $value , 2592000); //dont expire for 1 month

          set_transient( 'mkFuncTransient_LastUpdate' . $functionName . hash( 'sha512', json_encode( $arguments ) ), latestPostUpdate(), 2592000 );

          return $value;

     }

}



[ ... the rest of my shortcode routines follow here ... ][/code]

[code]function hierarchicalsitemap_shortcode_htmlmap($atts, $content = null) {

.... a bunch of fancy PHP to generate the menu HTML from the categories goes here ....

$out = [result of above code];

return $out;

}



add_shortcode("htmlmap", "hierarchicalsitemap_shortcode_htmlmap" );[/code]

[code]function hierarchicalsitemap_shortcode_htmlmap($atts, $content = null) {

     $origAtts=array($atts,$content);

     $data = getFunctionTransient(__FUNCTION__,	$origAtts); 

     if ( $data != null) {return $data;}

[.... a bunch of fancy PHP to generate the menu HTML from the categories goes here ....]

     setFunctionTransient(__FUNCTION__, $out, $origAtts);

     return $out;

}[/code]