Setting the post thumbnail from code fails - php

Question

I had a non-finished version for setting a post thumbnail from a base64 encoded image (from an API) which i dind't use at the time but now i need it.
function attach_image ( $base64, $post_id, $filename ) {
if ( empty($base64) ) {
return false;
}
$upload_dir = wp_upload_dir();
$upload_path = str_replace( '/', DIRECTORY_SEPARATOR, $upload_dir['path'] ) . DIRECTORY_SEPARATOR;
$decoded = base64_decode($base64) ;
$hashed_filename = md5( $filename . microtime() ) . '_' . $filename;
$image_upload = file_put_contents( $upload_path . $hashed_filename, $decoded );
if( !function_exists( 'wp_handle_sideload' ) ) {
require_once( ABSPATH . 'wp-admin/includes/file.php' );
}
$wp_filetype = wp_check_filetype(basename($filename), null );
$attachment = array(
'post_mime_type' => $wp_filetype['type'],
'post_title' => preg_replace('/\.[^.]+$/', '', basename($filename)),
'post_content' => '',
'post_status' => 'inherit'
);
$attach_id = wp_insert_attachment( $attachment, $hashed_filename, $parent_id );
$attach_data = wp_generate_attachment_metadata( $attach_id, $hashed_filename );
wp_update_attachment_metadata( $attach_id, $attach_data );
add_post_meta($post_id, '_thumbnail_id', $attach_id, true);
}
This almost work,
The images gets copied to the current wp-content/year/month folder
The image has the hash prepended in the name ( 0acaa00c73c27baa3277ff22ba5acf05_xk35480.jpg )
The image is set as the post thumbnail (for the $post_id )
But the problem is that,
If the image saved is:
wp-content/uploads/2019/09/0acaa00c73c27baa3277ff22ba5acf05_xk35480.jpg
The post thumnail url is:
wp-content/uploads/xk35480.jpg
Note that the year, month and hash are lost. So obviously the thumbnail url returns 404
So the question is, can you spot the problem?

Answer 1

I was able to make it work by prepending wp_upload_dir()['path'].'/' to the wp_insert_attachment and to the wp_generate_attachment_metadata functions but I wonder if it can be done "better"
function attach_image ( $base64, $post_id, $filename ) {
if ( empty($base64) ) {
return false;
}
$upload_dir = wp_upload_dir();
$upload_path = str_replace( '/', DIRECTORY_SEPARATOR, $upload_dir['path'] ) . DIRECTORY_SEPARATOR;
$decoded = base64_decode($base64) ;
$hashed_filename = md5( $filename . microtime() ) . '_' . $filename;
$image_upload = file_put_contents( $upload_path . $hashed_filename, $decoded );
if( !function_exists( 'wp_handle_sideload' ) ) {
require_once( ABSPATH . 'wp-admin/includes/file.php' );
}
$wp_filetype = wp_check_filetype(basename($filename), null );
$attachment = array(
'post_mime_type' => $wp_filetype['type'],
'post_title' => preg_replace('/\.[^.]+$/', '', basename($filename)),
'post_content' => '',
'post_status' => 'inherit'
);
$attach_id = wp_insert_attachment( $attachment, wp_upload_dir()['path'].'/'.$hashed_filename, $post_id );
$attach_data = wp_generate_attachment_metadata( $attach_id, wp_upload_dir()['path'].'/'.$hashed_filename );
wp_update_attachment_metadata( $attach_id, $attach_data );
add_post_meta($post_id, '_thumbnail_id', $attach_id, true);
}