Stripe : New customer created even when customer_id is not empty? - php

Question

I'm trying to retrieve my user's existing cards from Stripe with the below code. That said, when I use the below backend, even though I'm telling Stripe to ONLY create a new customer if $customer_id is NOT present, a new customer ID is created anyway even when customer_id is NOT null? I feel like I'm missing something obvious here...
.php
$email = $_POST['email'];
$customer_id = $_POST['customer_id']; //get this id from somewhere a database table, post parameter, etc.
$customer = \Stripe\Customer::create(array(
'email' => $email,
));
$customer_id = $_POST['customer_id']; //get this id from somewhere a database table, post parameter, etc.
// if the customer id doesn't exist create the customer
if ($customer_id !== null) {
$key = \Stripe\EphemeralKey::create(
["customer" => $customer->id],
["stripe_version" => $_POST['api_version']]
);
header('Content-Type: application/json');
exit(json_encode($key));
} else {
// \Stripe\Customer::retrieve($customer_id);
$cards = \Stripe\Customer::retrieve($customer_id)->sources->all();
// return the cards
header('Content-Type: application/json');
exit(json_encode($key));
}

Answer 1

Your IF condition should we switched around. Currently you create a customer if the customer_id is present. Based on the description you'd like to see the opposite, right?
In this case all you'd need to do is to switch around the if / else bodies:
if ($customer_id !== null) {
$cards = \Stripe\Customer::retrieve($customer_id)->sources->all();
// return the cards
header('Content-Type: application/json');
exit(json_encode($cards)); // you might want to return the cards here?
} else {
$key = \Stripe\EphemeralKey::create(
["customer" => $customer->id],
["stripe_version" => $_POST['api_version']]
);
header('Content-Type: application/json');
exit(json_encode($key));
}
AND remove the create block at the top. That will create a customer object as well, which you don't need.