Email::Sender::Manual:UsercContributed PerEmail::Sender::Manual::QuickStart(3)NAMEEmail::Sender::Manual::QuickStart - how to start using Email::Sender
right now
VERSION
version 0.110005
QUICK START
Let's Send Some Mail!
No messing around, let's just send some mail.
use strict;
use Email::Sender::Simple qw(sendmail);
use Email::Simple;
use Email::Simple::Creator;
my $email = Email::Simple->create(
header => [
To => '"Xavier Q. Ample" <x.ample@example.com>',
From => '"Bob Fishman" <orz@example.mil>',
Subject => "don't forget to *enjoy the sauce*",
],
body => "This message is short, but at least it's cheap.\n",
);
sendmail($email);
That's it. Your message goes out into the internet and tries to get
delivered to "x.ample@example.com".
In the example above, $email could be an Email::Simple object, a
MIME::Entity, a string containing an email message, or one of several
other types of input. If "Email::Abstract" can understand a value, it
can be passed to Email::Sender::Simple. Email::Sender::Simple tries to
make a good guess about how to send the message. It will usually try
to use the sendmail program on unix-like systems and to use SMTP on
Windows. You can specify a transport, if you need to, but normally
that shouldn't be an issue. (See "Picking a Transport", though, for
more information.)
Also note that we imported and used a "sendmail" routine in the example
above. This is exactly the same as saying:
Email::Sender::Simple->send($email);
...but it's a lot easier to type. You can use either one.
envelope information
We didn't have to tell Email::Sender::Simple where to send the message.
If you don't specify recipients, it will use all the email addresses it
can find in the To and Cc headers by default. It will use
Email::Address to parse those fields. Similarly, if no sender is
specified, it will use the first address found in the From header.
In most email transmission systems, though, the headers are not by
necessity tied to the addresses used as the sender and recipients. For
example, your message header might say "From: mailing-list@example.com"
while your SMTP client says "MAIL FROM:<verp-1234@lists.example.com>".
This is a powerful feature, and is necessary for many email
application. Being able to set those distinctly is important, and
Email::Sender::Simple lets you do this:
sendmail($email, { to => [ $to_1, $to_2 ], from => $sender });
in case of error
When the message is sent successfully (at least on to its next hop),
"sendmail" will return a true value -- specifically, an
Email::Sender::Success object. This object only rarely has much use.
What's more useful is what happens if the message can't be sent.
If there is an error sending the message, an exception will be thrown.
It will be an object belonging to the class Email::Sender::Failure.
This object will have a "message" attribute describing the nature of
the failure. There are several specialized forms of failure, like
Email::Sender::Failure::Multi, which is thrown when more than one error
is encountered when trying to send. You don't need to know about these
to use Email::Sender::Simple, though. All you need to know is that
"sendmail" returns true on success and dies on failure.
If you'd rather not have to catch exceptions for failure to send mail,
you can use the "try_to_send" method, which can be imported as
"try_to_sendmail". This method will return just false on failure to
send mail.
For example:
Email::Sender::Simple->try_to_send($email, { ... });
use Email::Sender::Simple qw(try_to_sendmail);
try_to_sendmail($email, { ... });
Some Email::Sender transports can signal success if some, but not all,
recipients could be reached. Email::Sender::Simple does its best to
ensure that this never happens. When you are using
Email::Sender::Simple, mail should either be sent or not. Partial
success should never occur.
Picking a Transport
passing in your own transport
If Email::Sender::Simple doesn't pick the transport you want, or if you
have more specific needs, you can specify a transport in several ways.
The simplest is to build a transport object and pass it in. You can
read more about transports elsewhere. For now, we'll just assume that
you need to send mail via SMTP on an unusual port. You can send mail
like this:
my $transport = Email::Sender::Transport::SMTP->new({
host => 'smtp.example.com',
port => 2525,
});
sendmail($email, { transport => $transport });
Now, instead of guessing at what transport to use,
Email::Sender::Simple will use the one you provided. This transport
will have to be specified for each call to "sendmail", so you might
want to look at other options, which follow.
specifying transport in the environment
If you have a program that makes several calls to
Email::Sender::Simple, and you need to run this program using a
different mailserver, you can set environment variables to change the
default. For example:
$ export EMAIL_SENDER_TRANSPORT=SMTP
$ export EMAIL_SENDER_TRANSPORT_host=smtp.example.com
$ export EMAIL_SENDER_TRANSPORT_port=2525
$ perl your-program
It is important to note that if you have set the default transport by
using the environment, no subsequent "transport" args to "sendmail"
will be respected. If you set the default transport via the
environment, that's it. Everything will use that transport. (Also,
note that while we gave the host and port arguments above in lower
case, the casing of arguments in the environment is flattened to
support systems where environment variables are of a fixed case. So,
"EMAIL_SENDER_TRANSPORT_PORT" would also work.
This is extremely valuable behavior, as it allows you to audit every
message that would be sent by a program by running something like this:
$ export EMAIL_SENDER_TRANSPORT=Maildir
$ perl your-program
In that example, any message sent via Email::Sender::Simple would be
delivered to a maildir in the current directory.
subclassing to change the default transport
If you want to use a library that will behave like
Email::Sender::Simple but with a different default transport, you can
subclass Email::Sender::Simple and replace the
"build_default_transport" method.
Testing
Email::Sender::Simple makes it very, very easy to test code that sends
email. The simplest way is to do something like this:
use Test::More;
BEGIN { $ENV{EMAIL_SENDER_TRANSPORT} = 'Test' }
use YourCode;
YourCode->run;
my @deliveries = Email::Sender::Simple->default_transport->deliveries;
Now you've got an array containing every delivery performed through
Email::Sender::Simple, in order. Because you set the transport via the
environment, no other code will be able to force a different transport.
When testing code that forks, Email::Sender::Transport::SQLite can be
used to allow every child process to deliver to a single, easy to
inspect destination database.
Hey, where's my Bcc support?
A common question is "Why doesn't Email::Sender::Simple automatically
respect my Bcc header?" This is often combined with, "Here is a patch
to 'fix' it." This is not a bug or oversight. Bcc is being ignored
intentionally for now because simply adding the Bcc addresses to the
message recipients would not produce the usually-desired behavior.
For example, here is a set of headers:
From: sender@example.com
To: to_rcpt@example.com
Cc: cc_rcpt@example.com
Bcc: the_boss@example.com
In this case, we'd expect the message to be delivered to three people:
to_rcpt, cc_rcpt, and the_boss. This is why it's often suggested that
the Bcc header should be a source for envelope recipients. In fact,
though, a message with a Bcc header should probably be delivered only
to the Bcc recipients. The "B" in Bcc means "blind." The other
recipients should not see who has been Bcc'd. This means you want to
send two messages: one to to_rcpt and cc_rcpt, with no Bcc header
present; and another to the_boss only, with the Bcc header. If you
just pick up Bcc addresses as recipients, everyone will see who was
Bcc'd.
Email::Sender::Simple promises to send messages atomically. That is:
it won't deliver to only some of the recipients, and not to others.
That means it can't automatically detect the Bcc header and make two
deliveries. There would be a possibility for the second to fail after
the first succeeded, which would break the promise of a pure failure or
success.
The other strategy for dealing with Bcc is to remove the Bcc header
from the message and then inject the message with an envelope including
the Bcc addresses. The envelope information will not be visible to the
final recipients, so this is safe. Unfortunately, this requires
modifying the message, and Email::Sender::Simple should not be altering
the mutable email object passed to it. There is no "clone" method on
Email::Abstract, so it cannot just build a clone and modify that,
either. When such a method exists, Bcc handling may be possible.
Example Bcc Handling
If you want to support the Bcc header now, it is up to you to deal with
how you want to munge the mail and inject the (possibly) munged copies
into your outbound mailflow. It is not reasonable to suggest that
Email::Sender::Simple do this job.
Example 1: Explicitly set the envelope recipients for Bcc recipients
Create the email without a Bcc header, send it to the Bcc users
explicitly and then send it to the To/Cc users implicitly.
my $message = create_email_mime_msg; # <- whatever you do to get the message
$message->delete_header('bcc'); # delete the Bcc header before sending
sendmail($message, { to => $rcpt' }); # send to explicit Bcc address
sendmail($message); # and then send as normal
Example 2: Explicitly set the envelope recipients for all recipients
You can make a single call to "sendmail" by pulling all the recipient
addresses from the headers yourself and specifying all the envelope
recipients once. Again, delete the Bcc header before the message is
sent.
SEE ALSO
This is awesome! Where can I learn more?
Have a look at Email::Sender::Manual, where all the manual's documents
are listed. You can also look at the documentation for
Email::Sender::Simple and the various Email::Sender::Transport classes.
AUTHOR
Ricardo Signes <rjbs@cpan.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2012 by Ricardo Signes.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
perl v5.14.22012-03-Email::Sender::Manual::QuickStart(3)
