Metabox multiple custom post select -> display selected items?

Question

I'm building a theme that needs some cross-information(?) between custom post types.

I have a metabox to select custom post types and display them inside the single page of another custom post type. So far things work 50%...

Right now I am using this code to display their thumbnail (but I will require their title and own meta):

$guests = get_post_meta($post->ID, 'cl_guest', true);
$guest_id = get_post_meta(get_the_ID(), 'cl_guest', true);
$guest_post = get_post( $guest_id[0] ); 
foreach($guest_id as $guest) { 
echo get_the_post_thumbnail($guest_post->ID, 'thumbnail', array( 
       'class' => "img-responsive img-circle", 
       'alt' => trim(strip_tags( $guest_post->post_title )),
       'title' => trim(strip_tags( $guest_post->post_title ))
       )); 
        }

It displays the correct number of posts, but it repeats the first item (ordered by ascending id).

Any help is appreciated! <3

Answer 1

Based on the code you've posted I assume cl_guest post meta contains an array of post IDs. Building upon this assumption, you could do something like this.

1) Add these helper functions to your theme's funtions.php file

// custom template tag to render guests
function render_guests( array $guests ) {
  if ( $guests ) {
    // you could use foreach loop instead of array_walk
    array_walk( $guests, 'render_guest' );
  }
}

// Helper function to get guest ids
function get_guest_ids( int $id ) {
  $meta = get_post_meta( $id, 'cl_guest', true);
  return ( $meta && is_array( $meta ) ) ? array_map( 'intval', $meta ) : array();
}

// helper function to render single guest
function render_guest( int $id ) {
  // get meta if needed
  $meta = get_guest_meta( $id );
  $title = get_the_title( $id );
  $thumbnail = get_guest_thumbnail( $id, $title, $title );
  // modify output as needed
  echo '<div class="guest">' . $thumbnail . $title . '</div>';
}

// helper function
function get_guest_meta( int $id ) {
  return get_post_meta( $id, 'some_meta_key', true );
}

// helper function
function get_guest_thumbnail( int $id, string $alt = '', string $title = '' ) {
  return get_the_post_thumbnail(
    $id, 
    'thumbnail', 
    array( 
     'class' => "img-responsive img-circle", 
     'alt'   => esc_attr( $alt ),
     'title' => esc_attr( $title )
    )
  );
}

2) add the custom tempalte tag to your post template where you want to display the guests

<?php render_guests( get_guest_ids( get_the_ID() ) ); ?>

P.S. You might wonder why I've split the code to multiple functions. The reason is that I'm just practicing a new coding style where each function is supposed to do one thing.

EDIT 1 Here's how you could render images and title+meta separately. First couple new helper functions.

function render_guest_images( array $ids ) {
  if ( $ids ) {
    array_walk( $ids, 'render_guest_image' );
  }
}

function render_guest_image( int $id ) {
  $title = get_the_title( $id );
  echo get_guest_thumbnail( $id, $title, $title );
}

function render_guest_infos( array $ids ) {
  if ( $ids ) {
    array_walk( $ids, 'render_guest_info' );
  }  
}

function render_guest_info( int $id ) {
  $title = get_the_title( $id );
  $meta = get_guest_meta( $id ); // this could either return data that you render here or ready-to-use html that you just concatenate to the echo below
  echo '<div class="guest-info">' . $title . '</div>';
}

// add this before you add the rendering functions on your post template
$guest_ids = get_guest_ids( get_the_ID() );

// somewhere on your post template
render_guest_images( $guest_ids );

// somewhere else on your post template
render_guest_infos( $guest_ids );

EDIT 2

without separate helper and render functions

// before any loops
$guest_ids = get_post_meta( get_the_id(), 'cl_guest', true);
$guest_ids = ( $guest_ids && is_array( $guest_ids ) ) ? array_map( 'intval', $guest_ids ) : array();

$guest_posts = array();
if ( $guest_ids ) {
  foreach ( $guest_ids as $guest_id ) {
    if ( $post = get_post( $guest_id ) ) {
      $guest_posts[] = $post;      
    }
  }
}

// titles only
if ( $guest_posts ) {
  foreach( $guest_posts as $guest_post ) {
    echo esc_html( $guest_post->post_title );
  }
}

// thumbnails
if ( $guest_posts ) {
  foreach( $guest_posts as $guest_post ) {
    echo get_the_post_thumbnail( 
      $guest_post->ID, 
      'thumbnail', 
      array( 
      'class' => "img-responsive img-circle", 
      'alt'   => esc_attr( $guest_post->post_title ),
      'title' => esc_attr( $guest_post->post_title )
      )
    );
  }
}

// meta only
if ( $guest_posts ) {
  foreach( $guest_posts as $guest_post ) {
    $meta = get_post_meta( $guest_post->ID, 'some_meta_key', true );
    // do something with meta
  }
}