How to check if an email was sent from or originated from a specific plugin?

Question

How to check if an email was sent from or originated from a specific plugin.

E.g. I have an SMTP plugin which sends all mail via SMTP however I would like to determine in the SMTP plugin. If an email originated from plugin x then the SMTP plugin would assign different "from" and "reply-to" headers as oppose to if it originated from plugin y

Answer 1

I don't think there is any way of knowing something x is orginated from some plugin x. If both plugins do not offer any administrative controls for setting from and reply to address, you might want to hack the plugin files code sending email. if it is using wp_mail function to send email, you can pass your headers as below before wp_mail,

$headers = 'From: My Name <myname@mydomain.com>' . "\r\n";
wp_mail('test@test.com', 'subject', 'message', $headers);

or you can have filter for from address

add_filter( 'wp_mail_from', 'my_mail_from' );
function my_mail_from( $email )
{
    return 'myemail@mydomain.com';
}
wp_mail('test@test.com', 'subject', 'message');
remove_filter( 'wp_mail_from', 'my_mail_from' );