How can I re-acquire a Shopify OAuth access token for a store that has previously installed my application?

I requested authorization for a public application to be able to access store data via the Shopify API.

The store successfully authorized my application via an authorization request URL such as

https://some-store.myshopify.com/admin/oauth/authorize?client_id=123abc&scope=read_inventory%2Cread_products&redirect_uri=http%3A%2F%mysite.com%2Fauth.php&state=123456

and the response was passed back to my application. This response (containing the code that can be exchanged for a permanent access token) was mishandled by my application (an error on the page meant that the access token was not stored).

Everything I read regarding requesting these tokens involves authorization by the store – but given the store has already authorized my application, passed back the code and that code has already successfully been exchanged for a token: is there a way my application can request that same token or a fresh one using my API keys given that the application is already authorized?

The only method I currently can find for requesting a token requires starting back at the beginning and fetching a code for exchange etc.

I working in PHP and using Luke Towers’ php shopify wrapper

This stage was completed successfully:

    function check_authorization_attempt()
{
    $data = $_GET;

    $api = new Shopify($data['shop'], [
        'api_key' => '123',
        'secret'  => '456',
    ]);

    $storedAttempt = null;
    $attempts = json_decode(file_get_contents('authattempts.json'));
    foreach ($attempts as $attempt) {
        if ($attempt->shop === $data['shop']) {
            $storedAttempt = $attempt;  
            break;
        }
    }

    return $api->authorizeApplication($storedAttempt->nonce, $data);
}

$response = check_authorization_attempt();

and I would have been able to read the access token from :

 $access_token = $response->access_token;

But this was the stage at which my application hit an error in accessing a database in which to write said token.

I cannot repeat it without repeating the auth request because the data in $_GET that’s passed to this function comes from Shopify’s response to the shop owner authorizing the access, and includes amoung other things the code for exchange.