How to get an email to trigger an HTTP request (or otherwise execute some function in PHP)

[eluser]sophistry[/eluser]
if i am reading this discussion properly, the only thing that is at issue is which piece of software is doing the "polling".

if you use a special configuration of sendmail to pass emails to a script you are using sendmail to "poll" for emails.

if you use a POP3 or IMAP library with cron (more portable because it is more widely supported IMO) then cron is doing the "polling" for emails.

what is the practical difference other than the "feeling" that you are over-polling the mailserver?

how often does your email client poll the mailserver? mine is set at 5 minute intervals. is that a waste of resources?

oh, and check out my imap_pop library (the POP3 lib on PHPscripts is pretty rudimentary) in the wiki. (link in sig).

cheers.