Unable to retrieve a session's variable values in a Stripe webhook

问题

I am setting up a Stripe subscription webhook in my website. I followed through the documentation and the webhook is now set in my website.

Now I am looking to update a record on my website's database where a column on the record is set to another value after one of my users subscribes to my membership plan. I tried to retrieve a session value in the session PHPSESSID where it contains an email address.

Using the SQL 'WHERE' clause, I tried the following:

$sql = "UPDATE xxxxxx SET Plan = 'Professional' WHERE EmailAddress = '$email'";

 if ($conn->query($sql) === TRUE) 
 {
     echo "You have subscribed to the professional plan";
 } 
 else 
 {
     echo "Error: " . $sql . "<br>" . $conn->error;
 }

            $conn->close();

Please note that:

• the SQL syntax works perfectly on my phpmyadmin site.
• The mysqli is connected to my website's database.
• The webhook also works with no problem at all.

The only problem is I cannot run the SQL query on the webhook after the payment is processed. After a little bit of debugging, I found out that the email variable in the PHPSESSID session isn't passed to the "UPDATE xxxxxx SET Plan = 'Professional'" line.

<?php    
session_name("PHPSESSID");   
session_start();    
$email = $_SESSION["email_address"];

require_once('stripe-php/init.php');

\Stripe\Stripe::setApiKey('xxxxxx');

$endpoint_secret = 'xxxxxx';

$payload = @file_get_contents('php://input');
$sig_header = $_SERVER['HTTP_STRIPE_SIGNATURE'];
$event = null; 

 try {
  $event = \Stripe\Webhook::constructEvent(
    $payload, $sig_header, $endpoint_secret
  );
 } catch(\UnexpectedValueException $e) {
  http_response_code(400);
  exit();
} catch(\Stripe\Error\SignatureVerification $e) {
  http_response_code(400);
  exit();
} 

// Handle the checkout.session.completed event
if ($event->type == 'checkout.session.completed') 
{
    $servername = "localhost";
    $username = "xxxxxx";
    $password = "xxxxxxx";
    $dbname = "xxxxxxx";

    // Create connection
    $conn = new mysqli($servername, $username, $password, $dbname);

    // Check connection
    if ($conn->connect_error) 
    {
        die("Connection failed: " . $conn->connect_error);
    } 

    $amount = $event['data']['object']['display_items'][0]['amount'];


    switch ($amount)
    {
        case 499:
        {       
            $sql = "UPDATE xxxxxx SET Plan = 'Professional' WHERE EmailAddress = '$email'";

            if ($conn->query($sql) === TRUE) 
            {
                echo "You have subscribed to the professional plan";
            } 
            else 
            {
                echo "Error: " . $sql . "<br>" . $conn->error;
            }

            $conn->close();
        }
        break;

        case 899:
        {

            $sql = "UPDATE xxxxxx SET Plan = 'Premium' WHERE EmailAddress = 'xxxxxx'";

            if ($conn->query($sql) === TRUE) 
            {
                echo "You have subscribed to the Premium plan";
            } 
            else 
            {
                echo "Error: " . $sql . "<br>" . $conn->error;
            }

            $conn->close();
        }
        break;   

        default:
        {

            $sql = "UPDATE xxxxxx SET Plan = 'Premium' WHERE EmailAddress = '$email'";

            if ($conn->query($sql) === TRUE) 
            {
                echo "You have subscribed to the Premium plan on free trial.";
            } 
            else 
            {
                echo "Error: " . $sql . "<br>" . $conn->error;
            }

            $conn->close();
        }
    }
}

http_response_code(200);
?>

Any suggestions on how to pass the value on the variable? Or am I doing the whole webhook thing wrong here?

回答1:

Solved it!

I realized that on the webhook JSON log, there is a customer ID after a user has completed the payment. So, I can use the ID to fetch the email address.

Here's the code:

$amount = $event['data']['object']['display_items'][0]['amount'];
// Retrieve the customer ID
$customerToken = $event['data']['object']['customer'];
switch ($amount)
{
    case 499:
    {
        // Fetch the email address      
        $customerInfo = \Stripe\Customer::retrieve($customerToken);
        $email = $customerInfo->email;

        // Use the email variable on the SQL query           
        $sql = "UPDATE JobDesktop.UserDatabase SET Plan = 'Professional' WHERE EmailAddress = '$email'";

        if ($conn->query($sql) === TRUE) 
        {
            echo "You have subscribed to the professional plan";
        } 
        else 
        {
            echo "Error: " . $sql . "<br>" . $conn->error;
        }

        $conn->close();
    }
// The rest of the code down below

来源：https://stackoverflow.com/questions/56864252/unable-to-retrieve-a-sessions-variable-values-in-a-stripe-webhook