setup_postdata() WP 1.5.0
Set up the global post data. Useful for easy usage of Template Tags related to the design of the post: the_title(), the_permalink(), etc.
Fills global variables: $id, $authordata, $currentday, $currentmonth, $page, $pages, $multipage, $more, $numpages. This variables are needed for correct work of the Template Tags that should be used within the WordPress Loop.
The $post variable passed to the function must be global, i.e. the function expects the passed variable $post is already global. If the function is used within WordPress Loop, then the current $post object in the loop must be passed.
When this function is used, we always need to flush the post data with wp_reset_postdata() after The Loop.
No Hooks.
Return
true|false. True when finished.
Usage
setup_postdata( $post );
- $post(WP_Post|object|int) (required)
- WP_Post instance or Post ID/object.
Examples
#1 How to pass the $post argument correctly
Let's say we get the post data into the $post_object variable, then we need to create a variable called $post and pass that data into it. setup_postdata() works only with the global variable $post.
global $post; // Pass the received post data to the $post variable and not to any other. $post = $post_object; setup_postdata( $post ); // the_title(); // the_permalink();
A short record of the example above:
setup_postdata( $GLOBALS['post'] = & $post_object );
And here is a wrong variant:
global $post; setup_postdata( $post_object ); // bad
#2 An example with get_posts() loop
Get posts from category 1 and display them as links:
<ul>
<?php
global $post;
$myposts = get_posts( array( 'numberposts' => 5, 'offset'=> 1, 'category' => 1 ) );
foreach( $myposts as $post ){
setup_postdata($post);
?>
<li><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
<?php
}
wp_reset_postdata(); // important
?>
</ul>
#3 Get posts directly from the database
<ul>
<?php
global $wpdb, $post;
$result = $wpdb->get_results(
"SELECT * FROM $wpdb->posts WHERE post_type = 'post' AND post_status = 'publish'"
);
foreach( $result as $post ){
setup_postdata( $post );
?>
<li><a href="<?php the_permalink()?>"><?php the_title();?></a></li>
<?php
}
wp_reset_postdata(); // important
?>
</ul>
#4 If not $post variable passed to the function argument
Demonstration of what happens if you pass not the global variable $post as an argument, but any other - the function will not work as it expected.
Let's pass $pst, but not $post:
global $post;
$posts = get_posts( "posts_per_page=2" );
foreach( $posts as $pst ){
setup_postdata( $pst );
echo the_title();
echo '<br>';
}
echo '$post->post_title - '. $post->post_title . '<br>';
/*
Display:
current global post title
current global post title
$post->post_title - current global post title
*/
Now lets pass normal $post:
// repeat only with $post instead of $pst
$posts = get_posts("posts_per_page=2");
foreach( $posts as $post ){
setup_postdata( $post );
echo the_title();
echo '<br>';
}
echo '$post->post_title - '. $post->post_title . '<br>';
/*
Display:
Received first post title
Received second post title
$post->post_title - Received second post title
*/Notes
- Global. WP_Query. $wp_query WordPress Query object.
Changelog
| Since 1.5.0 | Introduced. |
| Since 4.4.0 | Added the ability to pass a post ID to $post. |
Code of setup_postdata() setup postdata WP 5.8
function setup_postdata( $post ) {
global $wp_query;
if ( ! empty( $wp_query ) && $wp_query instanceof WP_Query ) {
return $wp_query->setup_postdata( $post );
}
return false;
}
