ajax – Creating archive.php in wordpress using custom field

Question:

I'm trying to create a calendar page in WordPress where the user selects the month by a select :

<select>
     <option>Janeiro 2015</option>
     <option>Dezembro 2014</option>
     <option>Novembro 2014</option>
     <option>Outubro 2014</option>
     <option>Setembro 2014</option>
</select>

Posts are then loaded via Ajax. I created a POST form called agenda and a custom field called agenda_data .

I need help on two items, the rest I think I can unroll on my own.

1. In select the last 12 months appear, the WordPress function wp_get_archives does this. However it returns based on the published dates and I would like it to be based on the date of the custom field.

2. An archive.php that displays the posts also based on the custom field date and not the post publish date.

I haven't found anything on the internet that could help me.

Answer:

It seems that there is not much way, the filters available in the wp_get_archives function are not enough to do this filtering. The solution is to copy the function to a meu_get_archives($args) and adapt it to your needs: https://core.trac.wordpress.org/browser/tags/4.3.1/src/wp-includes/general-template.php #L1354

As for the archive.php page, instead of the traditional <?php if( have_posts() ) : ?> , you have to do a custom WP_Query , using the Order & Orderby parameter:

'order' => 'ASC',
'orderby' => 'meta_val_num'

Or you could use the pre_get_posts filter, which is recommended to filter the main query and leave the archive.php template as it is.

^{References:
– Order Custom Post Type Archive by multiple values ​​in functions.php
– Archive Listings Filtered by Date Values ​​in a Custom Field/Post Meta? (here Mike Schinkel's answer is a master class )}