postal is a library for constructing and sending RFC822-compliant Internet email messages. It wraps the Jakarta Mail package for message and SMTP support. It supports sendmail natively. Supports STARTTLS & SSL.
- Anything that can run Java should work
- sendmail support likely requires *nix, but
msmtp, et al., are worthy substitutes - Untested on Windows
- Jakarta Mail (in
lib/after build) - Java 8+
Served by Clojars. In your Leiningen project.clj:
Likewise substitute any tag name from git.
At a bare minimum, provide a map with :from and :to (and you'll
probably also be wanting :subject and :body, though they're
technically optional). Any other keys you supply will show up as
ancillary headers. This example will locally inject the message into
whatever sendmail-compatible interface your system provides.
user> (in-ns 'postal.core)
#<Namespace postal.core>
postal.core> (send-message {:from "[email protected]"
:to ["[email protected]" "[email protected]"]
:cc "[email protected]"
:subject "Hi!"
:body "Test."
:X-Tra "Something else"})
{:code 0, :error :SUCCESS, :message "message sent"}
postal.core>
To use SMTP, add an argument map before the message with at least
:host key.
postal.core> (send-message {:host "mail.isp.net"}
{:from "[email protected]"
:to "[email protected]"
:subject "Hi!"
:body "Test."})
{:code 0, :error :SUCCESS, :message "message sent"}
postal.core>
For legacy compatibility, you can also supply these connection
parameters as metadata on the message. (send-message ^{:host ...} {:from ...})
Authenticate to SMTP server with :user and :pass.
postal.core> (send-message {:host "mail.isp.net"
:user "jsmith"
:pass "sekrat!!1"}
{:from "[email protected]"
:to "[email protected]"
:subject "Hi!"
:body "Test."})
{:code 0, :error :SUCCESS, :message "message sent"}
postal.core>
You probably do not want to do this in the clear, so add :ssl to get
an encrypted connection. This will default to port 465 if you don't
specify one.
If your destination supports TLS instead, you can use :tls. This
will default to port 25, however, so if you need a different one
make sure you supply :port. (It's common for ISPs to block outgoing
port 25 to relays that aren't theirs.)
postal.core> (send-message {:host "smtp.gmail.com"
:user "[email protected]"
:pass "sekrat!!1"
:port 587
:tls true}
{:from "[email protected]"
:to "[email protected]"
:subject "Hi!"
:body "Test."})
{:code 0, :error :SUCCESS, :message "message sent"}
postal.core>
(Despite the documentation
mentioning SSL, your Google account is most likely restricted to TLS on port 587 and
furthermore you may have to configure your account to
"allow less secure apps" in order to send emails.)
Since Amazon SES uses authenticated SMTP, postal can use it. Just make sure you use a verified address and your SMTP credentials (visit the AWS Console to set those up). Also, if you're just sandboxing, you can only send to a verified address as well. Example:
postal.core> (send-message {:user "AKIAIDTP........" :pass "AikCFhx1P......."
:host "email-smtp.us-east-1.amazonaws.com"
:port 587}
{:from "[email protected]" :to "[email protected]"
:subject "Test from Amazon SES" :body "Test!!!11"})
{:error :SUCCESS, :code 0, :message "messages sent"}
postal.core>
Attachments and multipart messages can be added as sequences of maps:
postal.core> (send-message {:host "mail.isp.net"}
{:from "[email protected]"
:to "[email protected]"
:subject "Hi!"
:body [{:type "text/html"
:content "<b>Test!</b>"}
;;;; supports both dispositions:
{:type :attachment
:content (java.io.File. "/tmp/foo.txt")}
{:type :inline
:content (java.io.File. "/tmp/a.pdf")
:content-type "application/pdf"}]})
{:code 0, :error :SUCCESS, :message "message sent"}
postal.core>
If your attachment has a content-type that is not recognized by
Jakarta Mail, e.g., .pdf or .doc, you can set :content-type. You
can also set :file-name and :description if you don't like the
filename that :content uses.
If you want another multipart type than "mixed", you can specify it as a keyword as the first value in the map sequence. That way you can for example create an HTML-Email that displays a text message as fallback in email clients that do not support (or suppress) HTML-mails:
postal.core> (send-message {:host "localhost"
:port 2500
:user "user@localhost"
:pass "somePassword"}
{:from "[email protected]"
:to "[email protected]"
:subject "multipart/alternative test"
:body [:alternative
{:type "text/plain"
:content "This is a test."}
{:type "text/html"
:content "<html><head> </head><body>
<h1>Heading 1</h1><p>This is a test.</p>
</body></html>"}
]}))
Postal uses Jakarta Mail underneath, which defaults to charset
us-ascii. To set the charset, set the :type, like "text/html; charset=utf-8".
Postal will supply a message ID by default that looks like
[random]@postal.[host]. You can customize this by supplying a
:message-id header with a function that takes no args. The included
postal.support/message-id can be used if you'd like to make use of
its randomness and only customize the hostname.
{:from "[email protected]"
:to "[email protected]"
:subject "Message IDs!"
:body "Regards."
:message-id #(postal.support/message-id "foo.bar.dom")}
You can customize the default User-Agent header (by default
postal/VERSION).
{:from "[email protected]"
:to "[email protected]"
:subject "Message IDs!"
:body "Regards."
:user-agent "MyMailer 1.0"}
You can stress-test a server by:
postal.core> (stress ^{:host "localhost"
:num 1000
:delay 250 ;; msecs
:threads 5 ;; concurrent connections}
{:from "[email protected]"
:to "[email protected]"})
sent 1000 msgs to localhost:25
nil
postal.core>
% lein deps && lein jar
Alexander Kouznetsov
Allen Rohner
Andre Branco
Andres Cuervo
Andy Fingerhut
Camille Troillard
Christoph Henkelmann
Colin Jones
Dante Briones
Dimas Guardado
Gerrit Hentschel
J. David Lowe
Jeff Palmucci
Joe Gallo
Kevin DeJong
Kyle Kingsbury
Paul Biggar
Paul Stadig
Phil Hagelberg
Peter Onneby
Roman Flammer
Sam Ritchie
Stephen Nelson
Postal is (c) 2009-2019 Andrew A. Raines and released under the MIT license.