Insert a post.
If the $postarr parameter has ‘ID’ set to a value, then post will be updated.
Source code
function wp_insert_post($postarr, $wp_error = false) {
global $wpdb, $wp_rewrite, $user_ID;
$defaults = array('post_status' => 'draft', 'post_type' => 'post', 'post_author' => $user_ID,
'ping_status' => get_option('default_ping_status'), 'post_parent' => 0,
'menu_order' => 0, 'to_ping' => '', 'pinged' => '', 'post_password' => '',
'guid' => '', 'post_content_filtered' => '', 'post_excerpt' => '', 'import_id' => 0,
'post_content' => '', 'post_title' => '');
$postarr = wp_parse_args($postarr, $defaults);
unset( $postarr[ 'filter' ] );
$postarr = sanitize_post($postarr, 'db');
// export array as variables
extract($postarr, EXTR_SKIP);
// Are we updating or creating?
$update = false;
if ( !empty($ID) ) {
$update = true;
$previous_status = get_post_field('post_status', $ID);
} else {
$previous_status = 'new';
}
$maybe_empty = ! $post_content && ! $post_title && ! $post_excerpt && post_type_supports( $post_type, 'editor' )
&& post_type_supports( $post_type, 'title' ) && post_type_supports( $post_type, 'excerpt' );
if ( apply_filters( 'wp_insert_post_empty_content', $maybe_empty, $postarr ) ) {
if ( $wp_error )
return new WP_Error( 'empty_content', __( 'Content, title, and excerpt are empty.' ) );
else
return 0;
}
if ( empty($post_type) )
$post_type = 'post';
if ( empty($post_status) )
$post_status = 'draft';
if ( !empty($post_category) )
$post_category = array_filter($post_category); // Filter out empty terms
// Make sure we set a valid category.
if ( empty($post_category) || 0 == count($post_category) || !is_array($post_category) ) {
// 'post' requires at least one category.
if ( 'post' == $post_type && 'auto-draft' != $post_status )
$post_category = array( get_option('default_category') );
else
$post_category = array();
}
if ( empty($post_author) )
$post_author = $user_ID;
$post_ID = 0;
// Get the post ID and GUID
if ( $update ) {
$post_ID = (int) $ID;
$guid = get_post_field( 'guid', $post_ID );
$post_before = get_post($post_ID);
}
// Don't allow contributors to set the post slug for pending review posts
if ( 'pending' == $post_status && !current_user_can( 'publish_posts' ) )
$post_name = '';
// Create a valid post name. Drafts and pending posts are allowed to have an empty
// post name.
if ( empty($post_name) ) {
if ( !in_array( $post_status, array( 'draft', 'pending', 'auto-draft' ) ) )
$post_name = sanitize_title($post_title);
else
$post_name = '';
} else {
// On updates, we need to check to see if it's using the old, fixed sanitization context.
$check_name = sanitize_title( $post_name, '', 'old-save' );
if ( $update && strtolower( urlencode( $post_name ) ) == $check_name && get_post_field( 'post_name', $ID ) == $check_name )
$post_name = $check_name;
else // new post, or slug has changed.
$post_name = sanitize_title($post_name);
}
// If the post date is empty (due to having been new or a draft) and status is not 'draft' or 'pending', set date to now
if ( empty($post_date) || '0000-00-00 00:00:00' == $post_date )
$post_date = current_time('mysql');
if ( empty($post_date_gmt) || '0000-00-00 00:00:00' == $post_date_gmt ) {
if ( !in_array( $post_status, array( 'draft', 'pending', 'auto-draft' ) ) )
$post_date_gmt = get_gmt_from_date($post_date);
else
$post_date_gmt = '0000-00-00 00:00:00';
}
if ( $update || '0000-00-00 00:00:00' == $post_date ) {
$post_modified = current_time( 'mysql' );
$post_modified_gmt = current_time( 'mysql', 1 );
} else {
$post_modified = $post_date;
$post_modified_gmt = $post_date_gmt;
}
if ( 'publish' == $post_status ) {
$now = gmdate('Y-m-d H:i:59');
if ( mysql2date('U', $post_date_gmt, false) > mysql2date('U', $now, false) )
$post_status = 'future';
} elseif( 'future' == $post_status ) {
$now = gmdate('Y-m-d H:i:59');
if ( mysql2date('U', $post_date_gmt, false) <= mysql2date('U', $now, false) )
$post_status = 'publish';
}
if ( empty($comment_status) ) {
if ( $update )
$comment_status = 'closed';
else
$comment_status = get_option('default_comment_status');
}
if ( empty($ping_status) )
$ping_status = get_option('default_ping_status');
if ( isset($to_ping) )
$to_ping = preg_replace('|\s+|', "\n", $to_ping);
else
$to_ping = '';
if ( ! isset($pinged) )
$pinged = '';
if ( isset($post_parent) )
$post_parent = (int) $post_parent;
else
$post_parent = 0;
// Check the post_parent to see if it will cause a hierarchy loop
$post_parent = apply_filters( 'wp_insert_post_parent', $post_parent, $post_ID, compact( array_keys( $postarr ) ), $postarr );
if ( isset($menu_order) )
$menu_order = (int) $menu_order;
else
$menu_order = 0;
if ( !isset($post_password) || 'private' == $post_status )
$post_password = '';
$post_name = wp_unique_post_slug($post_name, $post_ID, $post_status, $post_type, $post_parent);
// expected_slashed (everything!)
$data = compact( array( 'post_author', 'post_date', 'post_date_gmt', 'post_content', 'post_content_filtered', 'post_title', 'post_excerpt', 'post_status', 'post_type', 'comment_status', 'ping_status', 'post_password', 'post_name', 'to_ping', 'pinged', 'post_modified', 'post_modified_gmt', 'post_parent', 'menu_order', 'guid' ) );
$data = apply_filters('wp_insert_post_data', $data, $postarr);
$data = stripslashes_deep( $data );
$where = array( 'ID' => $post_ID );
if ( $update ) {
do_action( 'pre_post_update', $post_ID );
if ( false === $wpdb->update( $wpdb->posts, $data, $where ) ) {
if ( $wp_error )
return new WP_Error('db_update_error', __('Could not update post in the database'), $wpdb->last_error);
else
return 0;
}
} else {
if ( isset($post_mime_type) )
$data['post_mime_type'] = stripslashes( $post_mime_type ); // This isn't in the update
// If there is a suggested ID, use it if not already present
if ( !empty($import_id) ) {
$import_id = (int) $import_id;
if ( ! $wpdb->get_var( $wpdb->prepare("SELECT ID FROM $wpdb->posts WHERE ID = %d", $import_id) ) ) {
$data['ID'] = $import_id;
}
}
if ( false === $wpdb->insert( $wpdb->posts, $data ) ) {
if ( $wp_error )
return new WP_Error('db_insert_error', __('Could not insert post into the database'), $wpdb->last_error);
else
return 0;
}
$post_ID = (int) $wpdb->insert_id;
// use the newly generated $post_ID
$where = array( 'ID' => $post_ID );
}
if ( empty($data['post_name']) && !in_array( $data['post_status'], array( 'draft', 'pending', 'auto-draft' ) ) ) {
$data['post_name'] = sanitize_title($data['post_title'], $post_ID);
$wpdb->update( $wpdb->posts, array( 'post_name' => $data['post_name'] ), $where );
}
if ( is_object_in_taxonomy($post_type, 'category') )
wp_set_post_categories( $post_ID, $post_category );
if ( isset( $tags_input ) && is_object_in_taxonomy($post_type, 'post_tag') )
wp_set_post_tags( $post_ID, $tags_input );
// new-style support for all custom taxonomies
if ( !empty($tax_input) ) {
foreach ( $tax_input as $taxonomy => $tags ) {
$taxonomy_obj = get_taxonomy($taxonomy);
if ( is_array($tags) ) // array = hierarchical, string = non-hierarchical.
$tags = array_filter($tags);
if ( current_user_can($taxonomy_obj->cap->assign_terms) )
wp_set_post_terms( $post_ID, $tags, $taxonomy );
}
}
$current_guid = get_post_field( 'guid', $post_ID );
if ( 'page' == $data['post_type'] )
clean_page_cache($post_ID);
else
clean_post_cache($post_ID);
// Set GUID
if ( !$update && '' == $current_guid )
$wpdb->update( $wpdb->posts, array( 'guid' => get_permalink( $post_ID ) ), $where );
$post = get_post($post_ID);
if ( !empty($page_template) && 'page' == $data['post_type'] ) {
$post->page_template = $page_template;
$page_templates = get_page_templates();
if ( 'default' != $page_template && !in_array($page_template, $page_templates) ) {
if ( $wp_error )
return new WP_Error('invalid_page_template', __('The page template is invalid.'));
else
return 0;
}
update_post_meta($post_ID, '_wp_page_template', $page_template);
}
wp_transition_post_status($data['post_status'], $previous_status, $post);
if ( $update ) {
do_action('edit_post', $post_ID, $post);
$post_after = get_post($post_ID);
do_action( 'post_updated', $post_ID, $post_after, $post_before);
}
do_action('save_post', $post_ID, $post);
do_action('wp_insert_post', $post_ID, $post);
return $post_ID;
}
February 12, 2011 
A HitchHackers guide through WordPress 