How to add category to: ‘wp-admin/post-new.php’?

4 comments

1. Dave James Miller over at GitHub nailed this one for me. None of the work is from me, I’m just posting his code wrapped into a plguin since it works perfectly as advertised:

   <?php
   /**
    * Plugin Name: Set default category from url parameter
    * Plugin URI:  https://gist.github.com/davejamesmiller/1966543
    * Description: enables you to setup new post links with the post_title, category and tags in the url: <code><a href="<?= esc_attr(admin_url('post-new.php?post_title=Default+title&category=category1&tags=tag1,tag2')) ?>">New post</a></code>
    * Version:     0.0.1
    * Author:      davejamesmiller
    * Author URI:  https://gist.github.com/davejamesmiller
    */
   
   // I used this code to automatically set the default post title, category and
   // tags for a new WordPress post based on which link was clicked. It could also
   // be tweaked to hard-code the values instead of using request parameters.
   
   
   add_filter('wp_get_object_terms', function($terms, $object_ids, $taxonomies, $args)
   {
       if (!$terms && basename($_SERVER['PHP_SELF']) == 'post-new.php') {
   
           // Category - note: only 1 category is supported currently
           if ($taxonomies == "'category'" && isset($_REQUEST['category'])) {
               $id = get_cat_id($_REQUEST['category']);
               if ($id) {
                   return array($id);
               }
           }
   
           // Tags
           if ($taxonomies == "'post_tag'" && isset($_REQUEST['tags'])) {
               $tags = $_REQUEST['tags'];
               $tags = is_array($tags) ? $tags : explode( ',', trim($tags, " ntrx0B,") );
               $term_ids = array();
               foreach ($tags as $term) {
                   if ( !$term_info = term_exists($term, 'post_tag') ) {
                       // Skip if a non-existent term ID is passed.
                       if ( is_int($term) )
                           continue;
                       $term_info = wp_insert_term($term, 'post_tag');
                   }
                   $term_ids[] = $term_info['term_id'];
               }
               return $term_ids;
           }
       }
       return $terms;
   }, 10, 4);
   

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2. Hook into wp_insert_post, test the post status for auto-draft, and the URL for a GET parameter.

   But first we need a helper function to get and sanitize the GET parameter:

   /**
    * Set default category.
    *
    * @wp-hook pre_option_default_category
    * @return  string Category slug
    */
   function t5_get_default_cat_by_url()
   {
       if ( ! isset( $_GET['post_cat'] ) )
           return FALSE;
   
       return array_map( 'sanitize_title', explode( ',', $_GET['post_cat'] ) );
   }
   

   Now the auto-draft handler:

   add_action( 'wp_insert_post', 't5_draft_category', 10, 2 );
   
   /**
    * Add category by URL parameter to auto-drafts.
    *
    * @wp-hook wp_insert_post
    * @param   int $post_ID
    * @param   object $post
    * @return  WP_Error|array An error object or term ID array.
    */
   function t5_draft_category( $post_ID, $post )
   {
       if ( ! $cat = t5_get_default_cat_by_url()
           or 'auto-draft' !== $post->post_status )
           return;
   
       // return value will be used in unit tests only.
       return wp_set_object_terms( $post_ID, $cat, 'category' );
   }
   

   This works only if get_default_post_to_edit() was called with the second parameter $create_in_db set to TRUE. To catch the other case you have to filter the option default_category:

   add_filter( 'pre_option_default_category', 't5_get_default_cat_by_url' );
   

   Now you can use the parameter post_cat to pass a comma separated list of category slugs:

   

   See also:

   • Template plugin for blog posts?
   • Open WordPress ‘Add New Post’ admin page with parameters set via $_GET
   • Force category choice before creating new post?

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3. I think you can go about the default option default_category and filter option_default_category this, if the url have a param for the category, like this example source. Use it as plugin, test it. Was write from scratch and not tested.

   The url param is post_cat and you can set the category, like this url:
   /wp-admin/post-new.php?post_cat=categoryname

   <?php
   /**
    * Plugin Name: .my Test
    * Plugin URI:  http://bueltge.de/
    * Description: 
    * Version:     0.0.1
    * Author:      Frank B&uuml;ltge
    * Author URI:  http://bueltge.de/
    */
   class Set_Default_Cat_From_Url_Param {
   
       protected static $classobj = NULL;
   
       public static function init() {
   
           NULL === self::$classobj and self::$classobj = new self();
   
           return self::$classobj;
       }
   
       function __construct() {
   
           if ( isset( $_GET['post_cat'] ) )
               add_filter( 'option_default_category', array( $this, 'get_category' ) );
       }
   
       function get_category( $category ) {
   
           if ( isset( $_GET['post_cat'] ) )
               $category = get_cat_ID( esc_attr( $_GET['post_cat'] ) );
   
           return $category;
       }
   
   }
   add_action( 'load-post-new.php', array( 'Set_Default_Cat_From_Url_Param', 'init' ) );
   

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4. I realize this has already been answered, but I wanted to add my own take. I’ve added it to a gist here https://gist.github.com/malcalevak/ba05b4fbed0c6e33ac8c18c1451bd857

   To save you the hassle, though, here’s the code:

   function set_category () {
   
       global $post;
     //Check for a category parameter in our URL, and sanitize it as a string
       $category_slug = filter_input(INPUT_GET, 'category', FILTER_SANITIZE_STRING, array("options" => array("default" => 0)));
   
     //If we've got a category by that name, set the post terms for it
       if ( $category = get_category_by_slug($category_slug) ) {
           wp_set_post_terms( $post->ID, array($category->term_id), 'category' );
       }
   
   }
   
   //hook it into our post-new.php specific action hook
   add_action( 'admin_head-post-new.php', 'set_category', 10, 1 );
   

   Similar to all the others, you’d trigger it via /wp-admin/post-new.php?category=categoryname

   FYI, if you’re using Advanced Custom Fields, like @Aphire, this WILL work.

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