Google Cloud Storage cache management with PHP - php

Question

I have a PHP file to upload images to Google cloud storage, but everytime an user changes their profile image, it shows the previous one for a long time, so they think the image is not updated at all. I would like to know what cache and metadata configuration is required to avoid this issue.
I would prefer not to use "custom metadata" because this message on the Cloud documentation https://cloud.google.com/storage/docs/metadata -> "Note that using custom metadata incurs storage and network costs."
This is my code:
require 'vendor/autoload.php';
use Google\Cloud\Storage\StorageClient;
$storage = new StorageClient([
'keyFilePath' => $keypath
]);
$storage->registerStreamWrapper();
$bucket = $storage->bucket($url);
$filename = $_FILES['profile_picture']['name'];
$newFileName = $_POST['user_id'].'_profile.jpg';
$bucket->upload(
fopen($_FILES["profile_picture"]["tmp_name"], 'r'),
[
'name' => $dir.$newFileName,
'metadata' => [
'cacheControl' => 'Cache-Control: no-cache, max-age=0',
]
]
);
I dont know if CacheControl is enough (and if the sintax is correct) or I need to include Custom-Time and what is the sintax for it.
My try:
$bucket->upload(
fopen($_FILES["profile_picture"]["tmp_name"], 'r'),
[
'name' => $dir.$newFileName,
'metadata' => [
'cacheControl' => 'Cache-Control: no-cache, max-age=0',
'Custom-Time' => date('Y-m-d\TH:i:s.00\Z');
]
]
);
The documentation dont have anything abour PHP syntax: https://cloud.google.com/storage/docs/metadata
Please help

Answer 1

I believe you should use:
$bucket->upload(
fopen($_FILES["profile_picture"]["tmp_name"], 'r'),
[
'name' => $dir.$newFileName,
'metadata' => [
'cacheControl' => 'no-cache, max-age=0',
]
]
);
I have noticed that you repeating the cacheControl in your code. Also, remember that:
If you allow caching, downloads may continue to receive older versions
of an object, even after uploading a newer version. This is because
the older version remains "fresh" in the cache for a period of time
determined by max-age. Additionally, because objects can be cached at
various places on the Internet, there is no way to force a cached
object to expire globally. If you want to prevent serving cached
versions of publicly readable objects, set Cache-Control:no-cache,
max-age=0 on the object.
for further read, refer to this documentation

Answer 2

My solution with the correct metadata syntax:
$bucket->upload(
fopen($_FILES["profile_picture"]["tmp_name"], 'r'),
[
'name' => $_SESSION['idcompany'].'/uploads/'.$newFileName,
'metadata' => [
'cacheControl' => 'no-cache, max-age=0',
'customTime' => gmdate('Y-m-d\TH:i:s.00\Z')
]
]
);