4.34 Sending email with sendmail

The library (vicare posix sendmail) exports a simple API to send email through the external program sendmail. This library is a demonstration of the basic mechanism needed to execute an external program, write data to its standard input and read data from its standard output.

The source distribution of Vicare includes a simple demo program demo-sendmail.sps in the tests subdirectory of the source tree.

The executable file sendmail must be reachable in the current PATH; sendmail is executed with the options:

sendmail -t -i -v

the ASCII text displayed on the standard output is captured for diagnostic.

Function: sendmail message

Send an email message spawning a subprocess that launches sendmail. message must be a bytevector representing the message in ASCII encoding. When successful: return a string representing the output of sendmail; otherwise raise an exception.

The source and destination addresses are extracted from the message itself.

Example:

#!r6rs
(import (vicare)
  (vicare posix sendmail))

(define (send-it message)
  (define rv
    (sendmail (string->ascii message)))
  (display rv)
  (newline)
  (flush-output-port (current-output-port)))

(send-it "From: <marco@localhost>
To: <marco@localhost>
Subject: demo 01
MIME-Version: 1.0
Content-Type: text/plain

This is demo 01.
--\x20;
Marco Maggi
")