[wp-trac] Re: [WordPress Trac] #3723: Tagging

[WordPress Trac]

#3723: Tagging
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 Reporter:  ryan         |        Owner:  ryan
     Type:  enhancement  |       Status:  new 
 Priority:  normal       |    Milestone:  2.2 
Component:  General      |      Version:  2.1 
 Severity:  normal       |   Resolution:      
 Keywords:  tags         |  
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Comment (by ryan):

 I'm not particularly sold on the notion of a centralized taxonomy table,
 but here's a possible design.

 === Tagging a post ===

  * Comma separated tags are entered into a text box in the write post
 page.

  * write_post() parses $POST['tags'] and sends an array of tags (tag
 names, not ids) to wp_insert_post().

  * wp_insert_post() passes tags to wp_create_tags() along with a post id.

  * wp_create_tags() passes the list of tags to  wp_create_categories().

  * wp_create_categories() creates the tags in the categories table if they
 do not already exist and returns an array of IDs.

  * wp_create_tags() then calls wp_set_post_tags() with the array of tag
 IDs and the post ID.

  * wp_set_post_tags() creates relationships between the post and the tags
 in the post2tag table.

  * wp_set_post_tags() increments the tagged_count field for each tag.

 === Displaying tags for a post ===

  * Templates can use the_tags() and get_the_tags().

  * get_the_tags() gets all tags with a relationship to the post in the
 post2tag table.

 === Listing all tags ===

  * Templates can use wp_list_tags() and get_tags().

  * get_tags() retrieves all objects from the categories table with a
 tagged_count > 0.

 === Managing categories ===

  * The manage category list must filter out categories that are being used
 exclusively as a tag.  (link_count != 0 or count != 0) should be included.

  * If a category that already exists as a tag is added via Manage
 Categories, it must be brought into the list somehow even though it does
 not yet have a count or link_count.  A special count of -1 is used to
 signify unclaimed categories that should be listed.

  * When adding a new category or a category that has a tagged_count but no
 count or link_count, set count and link_count to -1.

  * Once the category is claimed by a post, set count to 1 and link_count
 to 0.  Vice versa when the category is claimed by a link.

  * If an unclaimed category is claimed by a tag, set count and link_count
 to 0.

  * A category cannot be deleted if tagged_count is > 0.  Instead, when
 deleting the category the count and link_count are set to zero so that the
 category is excluded from the category lists.

  * If the category is later re-added via Manage Categories, count and
 link_count are set to -1.

  * Currently, categories can have the same name and nicename if they have
 different parents.  With multiple categories having the same name, a tag
 needs to somehow consistently associate with one category even if that
 category should be reassigned to a different parent.  This association
 needs to be maintained so that the same tagged_count is always
 incremented.

 === Listing categories ===

  * get_categories() needs to be able to exclude categories with counts of
 -1 or 0 when fetching categories for the front page.  It needs to exclude
 only categories with counts of 0 when fetching categories for the lists in
 Manage Categories and the edit post and edit link pages.

-- 
Ticket URL: <http://trac.wordpress.org/ticket/3723#comment:42>
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