Help with Custom Mail Header

Hi -

I'm stuck on something 'simple' - custom mail header. Seems this should work but can't get it to come out correctly. Any help appreciated:

In your call to #mail:

    mail(:to => '',
         :from => email,          :subject => "Message from the site",          :headers['X-SMTPAPI'] => "{\"category\" : \"Drip Email\"}"     )

you're passing a hash of headers to the #mail method, and one of your keys is :headers['X-SMTPAPI']. Ruby tries to execute this as calling the # method on the symbol :headers, which returns nil (under ActiveSupport).

This all happens before the #mail method gets a chance to see it; in other words, your method call looks like this:

    mail(:to => '',
         :from => email,          :subject => "Message from the site",          nil => "{\"category\" : \"Drip Email\"}"     )

That's why you're seeing the {"category" : "Drip Email"} value appear in your email, but with an empty name for the header.

To set a header value, you can either specify it directly in the hash you pass to #mail:

    mail(:to => '',
         :from => email,          :subject => "Message from the site",          'X-SMTPAPI' => "{\"category\" : \"Drip Email\"}"     )

or you can use the #headers method separately:

    headers['X-SMTPAPI'] = "{\"category\" : \"Drip Email\"}"     mail(:to => '',
         :from => email,          :subject => "Message from the site"     )