PayPal Checkout Buttons - client/server communication - paypal

Question

I am integrating the smart checkout of Paypal. I do not understand what the javascript portion expects back from the server. This is what I have got in JS
...
...
createOrder: function(data, actions) {
return fetch('/paypal/sandbox/createOrder', {
method: 'post',
headers: {
'content-type': 'application/json'
}
}).then(function(res) {
return res.json();
}).then(function(data) {
return data.orderID;
});
},
...
...
And this is what the server side does when /paypal/sandbox/createOrder' is called …
$request = new OrdersCreateRequest();
$request->prefer('return=representation');
$request->body = $this->buildRequestBody();
$response = $this->PayPalClient->execute($request);
What I can not find anywhere: What am I supposed to do with the response? I tried to echo it plain, echo it as JSON, but I always get errors like "Expected order id"
What do I need to respond to the client request?

Answer 1

The structure of the communication between your createOrder frontend JS and your backend server route (which in turn calls the PayPal API) is something you define. It can be is simple or as complex as you need it to be. You can send as many parameters back and forth as you want. You can use JSON, XML, Morse code, RFC 1149, or whatever you want for this transmission between your client and server.
The only required bit of information is the Order ID, which your server-side code in turn gets from the PayPal API v2/checkout/orders call (as id in the response), and which your createOrder function must then propagate back to its caller once obtained, which in the sample code happens here:
...
return data.orderID;
One very simple implementation would be to echo the whole v2/checkout/orders API response , not just id, and change the above client-side code to be return data.id so it reads that key name