[wp-trac] [WordPress Trac] #13318: Bug caching get_terms

[WordPress Trac]

#13318: Bug caching get_terms
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 Reporter:  djudorange                   |       Owner:
     Type:  defect (bug)                 |      Status:  reopened
 Priority:  normal                       |   Milestone:
Component:  Taxonomy                     |     Version:
 Severity:  normal                       |  Resolution:
 Keywords:  has-patch reporter-feedback  |
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Changes (by mfields):

 * cc: michael@… (added)
 * status:  closed => reopened
 * resolution:  wontfix =>


Comment:

 Hello,

 I would like to reopen this ticket give a valid use case and hopefully
 provide an acceptable solution. I ran into this caching issue while adding
 functionality to my [taxonomy list
 shortcode]http://wordpress.org/extend/plugins/taxonomy-list-shortcode/
 plugin. I thought that it would be a great idea to enable users to create
 a "glossary" of terms. I have one of these set up on my site:
 http://wordpress.mfields.org/glossary/

 For this to work correctly I needed to hook into the 'terms_clauses'
 filter to append custom SQL that would only query for terms that have
 descriptions. I passed a custom argument to get_terms() and coded the
 'terms_clauses' callback function to recognize this value.

 This worked really well in cases where this was the only call to
 get_terms() in the script. If get_terms() was called elsewhere in the
 script with the same core-supported arguments defined but without my
 custom parameter, the custom query would be used because it is stored in
 the object cache.

 I was able to piece together a hack to enable this to work that resets the
 cache key if my parameter was send:


 {{{
 function taxonomy_list_shortcode_reset_cache_key( $args ) {
         if ( isset( $args['taxonomy_list_has_description'] ) ) {
                 wp_cache_set( 'last_changed', time() . '-description-
 only', 'terms' );
         }
         else {
                 wp_cache_set( 'last_changed', time(), 'terms' );
         }

         return $args;
 }
 add_filter( 'get_terms_args', 'taxonomy_list_shortcode_reset_cache_key' );
 }}}

 While this is not a great solution, it was the only way that I could get
 the caching to work correctly.

 The solution that I would like to offer would be to add a new default
 value to those recognized by get_terms(). This argument would have the key
 "custom" and it's value would be set to a string which could be used to
 construct a unique cache key for custom queries.

-- 
Ticket URL: <http://core.trac.wordpress.org/ticket/13318#comment:6>
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