Source
File: wp-admin/includes/class-file-upload-upgrader.php
public function __construct( $form, $urlholder ) {
if ( empty( $_FILES[ $form ]['name'] ) && empty( $_GET[ $urlholder ] ) ) {
wp_die( __( 'Please select a file' ) );
}
// Handle a newly uploaded file. Else, assume it's already been uploaded.
if ( ! empty( $_FILES ) ) {
$overrides = array(
'test_form' => false,
'test_type' => false,
);
$file = wp_handle_upload( $_FILES[ $form ], $overrides );
if ( isset( $file['error'] ) ) {
wp_die( $file['error'] );
}
$this->filename = $_FILES[ $form ]['name'];
$this->package = $file['file'];
// Construct the object array.
$object = array(
'post_title' => $this->filename,
'post_content' => $file['url'],
'post_mime_type' => $file['type'],
'guid' => $file['url'],
'context' => 'upgrader',
'post_status' => 'private',
);
// Save the data.
$this->id = wp_insert_attachment( $object, $file['file'] );
// Schedule a cleanup for 2 hours from now in case of failed installation.
wp_schedule_single_event( time() + 2 * HOUR_IN_SECONDS, 'upgrader_scheduled_cleanup', array( $this->id ) );
} elseif ( is_numeric( $_GET[ $urlholder ] ) ) {
// Numeric Package = previously uploaded file, see above.
$this->id = (int) $_GET[ $urlholder ];
$attachment = get_post( $this->id );
if ( empty( $attachment ) ) {
wp_die( __( 'Please select a file' ) );
}
$this->filename = $attachment->post_title;
$this->package = get_attached_file( $attachment->ID );
} else {
// Else, It's set to something, Back compat for plugins using the old (pre-3.3) File_Uploader handler.
$uploads = wp_upload_dir();
if ( ! ( $uploads && false === $uploads['error'] ) ) {
wp_die( $uploads['error'] );
}
$this->filename = sanitize_file_name( $_GET[ $urlholder ] );
$this->package = $uploads['basedir'] . '/' . $this->filename;
if ( 0 !== strpos( realpath( $this->package ), realpath( $uploads['basedir'] ) ) ) {
wp_die( __( 'Please select a file' ) );
}
}
}