How to find out that a letter has come to the e-mail, using php?

Question

PHP

Question for experienced colleagues.
This is our task: letters come to e-mail, we need to quickly receive them via imap and process them. Receiving and processing implemented. How to do now to find out when the letter arrived? Use cron to constantly check the box, or does node.js have a way? Tell me which way to dig. Thanks in advance.

Answer 1

Use cron.

Answer 2

Kronom is the easiest way to go to imap.

Answer 3

1. In e-mail servers, there are usually commands to run immediately after receiving and before sending letters.
2. Open the socket in front of the e-mail server on and catch traffic.
For example: [port 25] -> [socket-sniffer-transport: PHP/node.js/other] -> [port 26 (E-Mail server)]
(from outside connect to 26 - close, resp.)