How to get posts by custom taxonomy in WordPress?

Question

In WordPress, I am trying to get posts from a custom post type 'color', custom taxonomy 'color-name', using the following:

Notes: I have a custom post type, Color, with custom posts that are titled things like, 'Coral', 'Peony'. I also have a custom taxonomy, color-name. Through a hook on saving a color post, categories in that custom taxonomy get created. Then, the custom post type Color, can be tagged with other related colors.

$slug = str_replace(" ", "_", $page_title);
$slug = strtolower($slug);

//Slug is - 'coral', 'peony', etc.

$args = array( 'post_type' => 'color',
               'posts_per_page' => -1,
               'tax_query' => array( array (
                       'taxonomy' => 'color-name',
                       'field' => 'slug',
                       'terms' => $slug
                                   ) )
);
$myposts = query_posts( $args );

I've tried many variations of this after Googling, and nothing is working - I either get all posts, or no posts. Here's another version of args I've tried: (results in no posts):

  $args = array('color-name' => $page_title,
                'post_type' => 'color',
                'post_status' => 'publish',
                'posts_per_page' => -1,
                'caller_get_posts'=> 1
               );

I've wrestled with this before and gave up and just made a custom sql call. Does anyone know definitively how to get this working through WordPress functions?

How are you getting your terms. It seems that is your problem. Also, NEVER use query_posts, it breaks the main query and in most cases outright fails in pagination. Also, caller_get_posts is longtime depreciated, was replaced with ignore_sticky_posts — Pieter Goosen
You mean this piece? 'terms' => $slug? $slug is a string, like "peony". — heykatieben
Yes, I meant that. I believe $slug is your problem. Are you sure the result from $slug is a string and not an array. Please edit your question and add your code for $slug. I want to have a look at that — Pieter Goosen
Here's what I'm trying to do, in words: List all posts tagged 'blue' under a custom taxonomy called color-name, that are also in a custom post type 'color' — heykatieben
OK, that make a bit of sense. The part that doesn't, blue, is that a post tag or a term inside color-name — Pieter Goosen

henrywright henrywright · Accepted Answer · 2014-07-28T21:35:57

I would use WP_Query instead of query_posts(). For example:

$args = array(
    'post_type' => 'color',
    'tax_query' => array(
        array(
            'taxonomy' => 'color-name',
            'field' => 'slug',
            'terms' => $slug
        )
    )
);
$query = new WP_Query( $args );

if ( $query->have_posts() ) {
    while ( $query->have_posts() ) {
        $query->the_post();
        // Do something.
    }
} else {
    // No posts found.
}
wp_reset_postdata();

Ref: http://codex.wordpress.org/Class_Reference/WP_Query

How to get posts by custom taxonomy in WordPress?

1 Answers