Question

I am making a custom shortcode which basically is just meant to return my custom post type, here’s my code:

function shortcode_slider($atts, $content=null){  
    extract(shortcode_atts( array('id' => ''), $atts));  
    $return = $content;
    $return .= query_posts( array( 'post_status' => 'publish' , 'post_type' => 'slider'  ) );
    return $return;  
}  
add_shortcode('slider', 'shortcode_slider');

The shortcode works ok apart from one thing – when it returns all of the posts it also returns “array” at the top of the list – any idea why this would happen?

Also, I want to be able to use the “id” input to be able to specify a category, e.g.

 $return .= query_posts( array( 'post_status' => 'publish' , 'post_type' => 'slider', 'category' => $id  ) );

but I am unsure of the correct syntax for this.

Any help is much appreciated.

Answer 1

First of all, don’t use query_posts.
Please, check:

• When should you use WP_Query vs query_posts() vs get_posts()?
• When to use WP_query(), query_posts() and pre_get_posts

In a shortcode case, I’d go with get_posts. It will return what you need and won’t mess with the loop.

It is worth noting that you don’t really need to extract the attributes, using $atts['id'] does the work.

Follows a working shortcode, see comments:

add_shortcode( 'slider', 'shortcode_slider' );

function shortcode_slider( $atts, $content=null )
{  
    // Initialize variable and check for shortcode content
    $return = '';
    if( $content ) {
        $return = $content;
    }

    // Shortcode attribute: title="Lorem Ipsum"
    if( isset( $atts['title'] ) ) 
    {
        $return .= '<br><h2>' . $atts['title'] . '</h2>';
    }

    // Get our custom posts
    // 'category' is the category ID or a comma separated list of ID numbers
    $sliders = get_posts( array( 
        'post_status' => 'publish', 
        'post_type' => 'slider',
        'numberposts' => 10, 
        'order'=> 'ASC', 
        'orderby' => 'title',
        'category' => $atts['id']  
    ) );


    // Auxiliary variable, don't print <br> in the first element
    $first = '';

    // Iterate through the resulting array
    // and build the final output
    // Use $slide->post_author, ->post_excerpt, as usual
    //   $slide->ID can be used to call auxiliary functions 
    //   such as get_children or get_permalink
    foreach( $sliders as $slide ) 
    {
        $link = get_permalink( $slide->ID );
        $return .= 
            $first
            . '<a href="' . $link . '">'
            . $slide->post_title 
            . '</a>
        ';
        $first = '<br>';
    }

    return $return;  
}  

Shortcode applied in a default post type:

Custom post types:

Result:

Useful links:

• WordPress Shortcodes: A Complete Guide
• How to Add Shortcodes to Your WordPress Plugin