Core documentation for WordPress post/content management system.

Source Files

• /wp-includes/post.php – Core post API (CRUD, meta, statuses)
• /wp-includes/post-template.php – Template tags (the_title, the_content, etc.)
• /wp-includes/post-thumbnail-template.php – Featured image functions
• /wp-includes/post-formats.php – Post format functions
• /wp-includes/revision.php – Revision/autosave system

Post Object (WP_Post)

Every post in WordPress is a WP_Post object with these properties:

Post Statuses

Built-in Statuses

Status Properties

register_post_status( 'custom-status', array(
    'label'                     => 'Custom Status',
    'public'                    => false,      // Shown on frontend
    'internal'                  => false,      // Internal use only
    'protected'                 => false,      // Requires login
    'private'                   => false,      // Private to user
    'publicly_queryable'        => false,      // Can query on frontend
    'exclude_from_search'       => true,       // Exclude from search
    'show_in_admin_all_list'    => true,       // Show in admin list
    'show_in_admin_status_list' => true,       // Show in status dropdown
    'date_floating'             => false,      // Date not fixed
    'label_count'               => _n_noop(...),
) );

Status Functions

// Get status object
$status = get_post_status_object( 'publish' );

// Get all statuses
$statuses = get_post_stati( array( 'public' => true ), 'objects' );

// Check viewability
is_post_status_viewable( 'publish' );  // true
is_post_status_viewable( 'draft' );    // false

Post Formats

Post formats are a theme feature that allows different presentation styles for posts.

Available Formats

Theme Support

// In theme's functions.php
add_theme_support( 'post-formats', array(
    'aside',
    'gallery',
    'quote',
    'image',
    'video',
) );

Format Functions

// Get post format
$format = get_post_format( $post_id );  // Returns 'gallery', 'quote', etc. or false

// Check format
if ( has_post_format( 'video' ) ) { ... }
if ( has_post_format( array( 'video', 'audio' ) ) ) { ... }

// Set format
set_post_format( $post_id, 'gallery' );

// Get format display name
$name = get_post_format_string( 'gallery' );  // 'Gallery'

// Get all format strings
$formats = get_post_format_strings();

// Get format archive link
$url = get_post_format_link( 'video' );

CRUD Operations

Create

$post_id = wp_insert_post( array(
    'post_title'    => 'My Post Title',
    'post_content'  => 'Post content here...',
    'post_status'   => 'publish',
    'post_author'   => get_current_user_id(),
    'post_type'     => 'post',
    'post_category' => array( 1, 2 ),
    'tags_input'    => array( 'tag1', 'tag2' ),
    'meta_input'    => array(
        'custom_field' => 'value',
    ),
) );

Read

// Single post
$post = get_post( $post_id );
$post = get_post( $post_id, ARRAY_A );  // As array

// Multiple posts
$posts = get_posts( array(
    'numberposts' => 10,
    'post_type'   => 'post',
    'post_status' => 'publish',
) );

// Via WP_Query
$query = new WP_Query( array( 'p' => $post_id ) );

Update

$post_id = wp_update_post( array(
    'ID'           => $post_id,
    'post_title'   => 'Updated Title',
    'post_content' => 'Updated content',
) );

Delete

// Move to trash (default)
wp_trash_post( $post_id );

// Restore from trash
wp_untrash_post( $post_id );

// Permanent delete
wp_delete_post( $post_id, true );  // true = force delete

Post Meta

Post meta stores custom data associated with posts.

// Add
add_post_meta( $post_id, 'key', 'value' );
add_post_meta( $post_id, 'key', 'value', true );  // Unique

// Get
$value = get_post_meta( $post_id, 'key', true );   // Single value
$values = get_post_meta( $post_id, 'key', false ); // All values
$all = get_post_meta( $post_id );                  // All meta

// Update
update_post_meta( $post_id, 'key', 'new_value' );
update_post_meta( $post_id, 'key', 'new', 'old' ); // With prev check

// Delete
delete_post_meta( $post_id, 'key' );
delete_post_meta( $post_id, 'key', 'specific_value' );

// Register (for REST API, etc.)
register_post_meta( 'post', 'my_meta_key', array(
    'show_in_rest' => true,
    'single'       => true,
    'type'         => 'string',
) );

Revisions

Revisions track changes to posts over time.

Configuration

// In wp-config.php
define( 'WP_POST_REVISIONS', true );   // Unlimited (default)
define( 'WP_POST_REVISIONS', 5 );      // Keep 5 revisions
define( 'WP_POST_REVISIONS', false );  // Disable revisions

Revision Functions

// Get all revisions
$revisions = wp_get_post_revisions( $post_id );

// Get latest revision info
$info = wp_get_latest_revision_id_and_total_count( $post_id );
// Returns: array( 'latest_id' => 123, 'count' => 5 )

// Save a revision manually
$revision_id = wp_save_post_revision( $post_id );

// Restore a revision
wp_restore_post_revision( $revision_id );

// Delete a revision
wp_delete_post_revision( $revision_id );

// Check if post is a revision
$parent_id = wp_is_post_revision( $post );  // Returns parent ID or false

// Get autosave
$autosave = wp_get_post_autosave( $post_id, $user_id );

// Check revisions enabled
if ( wp_revisions_enabled( $post ) ) { ... }

// Get revision limit
$limit = wp_revisions_to_keep( $post );

Revisioned Fields

By default, these fields are tracked:

• post_title
• post_content
• post_excerpt

Custom meta can also be revisioned:

register_post_meta( 'post', 'my_meta', array(
    'revisions_enabled' => true,
) );

Featured Images (Post Thumbnails)

Theme Support

// Enable for all post types
add_theme_support( 'post-thumbnails' );

// Enable for specific types
add_theme_support( 'post-thumbnails', array( 'post', 'page', 'movie' ) );

// Set custom size
set_post_thumbnail_size( 150, 150, true );  // 150x150, cropped

Thumbnail Functions

// Check if has thumbnail
if ( has_post_thumbnail( $post_id ) ) { ... }

// Get thumbnail ID
$thumb_id = get_post_thumbnail_id( $post_id );

// Display thumbnail
the_post_thumbnail();
the_post_thumbnail( 'large' );
the_post_thumbnail( array( 300, 200 ) );

// Get HTML
$html = get_the_post_thumbnail( $post_id, 'medium', array( 'class' => 'my-class' ) );

// Get URL
$url = get_the_post_thumbnail_url( $post_id, 'full' );

// Get caption
$caption = get_the_post_thumbnail_caption( $post_id );

// Set thumbnail
set_post_thumbnail( $post_id, $attachment_id );

// Remove thumbnail
delete_post_thumbnail( $post_id );

Sticky Posts

Sticky posts appear at the top of archive listings.

// Make sticky
stick_post( $post_id );

// Remove sticky
unstick_post( $post_id );

// Check if sticky
if ( is_sticky( $post_id ) ) { ... }

// Get all sticky post IDs
$stickies = get_option( 'sticky_posts' );

Post Counting

// Count by status
$counts = wp_count_posts( 'post' );
// Returns: stdClass { publish: 50, draft: 10, pending: 3, ... }

// Count attachments by MIME
$counts = wp_count_attachments( 'image' );

Post Visibility

// Check if post type is viewable
is_post_type_viewable( 'post' );

// Check if status is viewable
is_post_status_viewable( 'publish' );

// Check if specific post is publicly viewable
is_post_publicly_viewable( $post_id );

// Check if embeddable
is_post_embeddable( $post_id );

Post Hierarchies

For hierarchical post types (pages):

// Get ancestors
$ancestors = get_post_ancestors( $post_id );

// Get page children
$children = get_children( array( 'post_parent' => $page_id ) );

// Get page URI (path)
$uri = get_page_uri( $page_id );  // 'parent-page/child-page'

Database Table

Posts are stored in {prefix}_posts table: