wordpress函数wp_get_attachment_image

描述

通过id获取缩略图的图片信息，注意一点是这个获取的图片信息带img标签

用法

参数

$attachment_id

(integer) (必填) 附件ID

默认值: None

$size

(string/array) (可选) 图像大小。字符串关键字（缩略图、中、大或全）或以像素表示宽度和高度的两项数组，例如数组（32,32）。从2.5版起，此参数不影响媒体图标的大小，媒体图标始终以其原始大小显示。

默认值: ‘thumbnail’

不要使用需要检查所有图像大小的数组，应该考虑使用add_image_size注册大小，以便生成裁剪版本。它比找到最接近的图像更有效.

$icon

(boolean) (可选) 使用媒体图标表示附件。

默认值: ‘False’

1 (True)
0 (False) – 默认
$attr

(string/array) (可选) 查询字符串或属性数组。

默认值: None

示列

WordPress函数wp_delete_attachment()

WordPress函数wp_delete_attachment()代码实现通过id进行删除附件

用法：

<?php wp_delete_attachment( $attachmentid, $force_delete ); ?>

参数：

$attachmentid

(integer) (必填) 要删除的附件ID

默认值:None

$force_delete

(bool) (可选) 是否绕过回收站并强制删除

默认值: false

源文件：

/**
* Trash or delete an attachment.
*
* When an attachment is permanently deleted, the file will also be removed.
* Deletion removes all post meta fields, taxonomy, comments, etc. associated
* with the attachment (except the main post).
*
* The attachment is moved to the trash instead of permanently deleted unless trash
* for media is disabled, item is already in the trash, or $force_delete is true.
*
* @since 2.0.0
*
* @global wpdb $wpdb WordPress database abstraction object.
*
* @param int  $post_id      Attachment ID.
* @param bool $force_delete Optional. Whether to bypass trash and force deletion.
*                           Default false.
* @return mixed False on failure. Post data on success.
*/
function wp_delete_attachment( $post_id, $force_delete = false ) {
global $wpdb;
if ( !$post = $wpdb->get_row( $wpdb->prepare(\"SELECT * FROM $wpdb->posts WHERE ID = %d\", $post_id) ) )
return $post;
if ( \'attachment\' != $post->post_type )
return false;
if ( !$force_delete && EMPTY_TRASH_DAYS && MEDIA_TRASH && \'trash\' != $post->post_status )
return wp_trash_post( $post_id );
delete_post_meta($post_id, \'_wp_trash_meta_status\');
delete_post_meta($post_id, \'_wp_trash_meta_time\');
$meta = wp_get_attachment_metadata( $post_id );
$backup_sizes = get_post_meta( $post->ID, \'_wp_attachment_backup_sizes\', true );
$file = get_attached_file( $post_id );
if ( is_multisite() )
delete_transient( \'dirsize_cache\' );
/**
* Fires before an attachment is deleted, at the start of wp_delete_attachment().
*
* @since 2.0.0
*
* @param int $post_id Attachment ID.
*/
do_action( \'delete_attachment\', $post_id );
wp_delete_object_term_relationships($post_id, array(\'category\', \'post_tag\'));
wp_delete_object_term_relationships($post_id, get_object_taxonomies($post->post_type));
// Delete all for any posts.
delete_metadata( \'post\', null, \'_thumbnail_id\', $post_id, true );
$comment_ids = $wpdb->get_col( $wpdb->prepare( \"SELECT comment_ID FROM $wpdb->comments WHERE comment_post_ID = %d\", $post_id ));
foreach ( $comment_ids as $comment_id )
wp_delete_comment( $comment_id, true );
$post_meta_ids = $wpdb->get_col( $wpdb->prepare( \"SELECT meta_id FROM $wpdb->postmeta WHERE post_id = %d \", $post_id ));
foreach ( $post_meta_ids as $mid )
delete_metadata_by_mid( \'post\', $mid );
/** This action is documented in wp-includes/post.php */
do_action( \'delete_post\', $post_id );
$result = $wpdb->delete( $wpdb->posts, array( \'ID\' => $post_id ) );
if ( ! $result ) {
return false;
}
/** This action is documented in wp-includes/post.php */
do_action( \'deleted_post\', $post_id );
$uploadpath = wp_upload_dir();
if ( ! empty($meta[\'thumb\']) ) {
// Don\'t delete the thumb if another attachment uses it.
if (! $wpdb->get_row( $wpdb->prepare( \"SELECT meta_id FROM $wpdb->postmeta WHERE meta_key = \'_wp_attachment_metadata\' AND meta_value LIKE %s AND post_id <> %d\", \'%\' . $wpdb->esc_like( $meta[\'thumb\'] ) . \'%\', $post_id)) ) {
$thumbfile = str_replace(basename($file), $meta[\'thumb\'], $file);
/** This filter is documented in wp-includes/functions.php */
$thumbfile = apply_filters( \'wp_delete_file\', $thumbfile );
@ unlink( path_join($uploadpath[\'basedir\'], $thumbfile) );
}
}
// Remove intermediate and backup images if there are any.
if ( isset( $meta[\'sizes\'] ) && is_array( $meta[\'sizes\'] ) ) {
foreach ( $meta[\'sizes\'] as $size => $sizeinfo ) {
$intermediate_file = str_replace( basename( $file ), $sizeinfo[\'file\'], $file );
/** This filter is documented in wp-includes/functions.php */
$intermediate_file = apply_filters( \'wp_delete_file\', $intermediate_file );
@ unlink( path_join( $uploadpath[\'basedir\'], $intermediate_file ) );
}
}
if ( is_array($backup_sizes) ) {
foreach ( $backup_sizes as $size ) {
$del_file = path_join( dirname($meta[\'file\']), $size[\'file\'] );
/** This filter is documented in wp-includes/functions.php */
$del_file = apply_filters( \'wp_delete_file\', $del_file );
@ unlink( path_join($uploadpath[\'basedir\'], $del_file) );
}
}
wp_delete_file( $file );
clean_post_cache( $post );
return $post;
}