Hello, one of the ipn variables, sent by paypal to my ipn listener, is called 'verify_sign'. I would like to know if this variable stays the same during a whole transaction, or if it changes for every ipn message sent by paypal, even if the transaction id is the same.
The reason I am asking is because I am trying to keep the work load of the ipn listener as small as possible, as is suggested by paypal. When the ipn listener receives a message:
1. it checks that the message came from paypal, status = 'verified'
2. saves the message in a file named with the value of 'verify_sign'.
3. sends an email to auto_sales_at_mydomain.com, with the value of
'verify_sign' in the body
4. The ipn listener is now free to send it's response back to paypal.
The email to auto_sales_at_mydomain.com is forwaded to a php file 'ipn_process.php'. Which:
1. reads the value of 'verify_sign' in the body of the email
2. opens the file with that name and makes a copy of the ipn data
3. deletes the file
4. processes the ipn data (to do...).
However, there could be a problem if paypal sends (too soon) another message with the same value of 'verify_sign'.
It's all a bit complicated, but I can't think of another way to process the ipn data asynchronously, without looking into php threads.
