1Email::Sender::Manual::UQsueirckCSotnatrrti(b3u)ted PerlEmDaoiclu:m:eSnetnadteiro:n:Manual::QuickStart(3)
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6 Email::Sender::Manual::QuickStart - how to start using Email::Sender
7 right now
8
10 version 2.500
11
13 This library should run on perls released even a long time ago. It
14 should work on any version of perl released in the last five years.
15 Although it may work on older versions of perl, no guarantee is made
17 that the minimum required version will not be increased. The version
18 may be increased for any reason, and there is no promise that patches
19 will be accepted to lower the minimum required perl.
20
22 Let's Send Some Mail!
23 No messing around, let's just send some mail.
24 use strict;
26 use Email::Sender::Simple qw(sendmail);
27 use Email::MIME;
28 # You can make an email object in lots of ways. Pick one you like!
30 my $email = Email::MIME->create(...);
31 sendmail($email);
33 That's it. Your message goes out into the internet and tries to get
35 delivered to "x.ample@example.com".
36 In the example above, $email could be an Email::MIME object, a
38 MIME::Entity, a string containing an email message, or one of several
39 other types of input. If "Email::Abstract" can understand a value, it
40 can be passed to Email::Sender::Simple. Email::Sender::Simple tries to
41 make a good guess about how to send the message. It will usually try
42 to use the sendmail program on unix-like systems and to use SMTP on
43 Windows. You can specify a transport, if you need to, but normally
44 that shouldn't be an issue. (See "Picking a Transport", though, for
45 more information.)
46 Also note that we imported and used a "sendmail" routine in the example
48 above. This is exactly the same as saying:
49 Email::Sender::Simple->send($email);
51 ...but it's a lot easier to type. You can use either one.
53 envelope information
55 We didn't have to tell Email::Sender::Simple where to send the message.
57 If you don't specify recipients, it will use all the email addresses it
58 can find in the To and Cc headers by default. It will use
59 Email::Address to parse those fields. Similarly, if no sender is
60 specified, it will use the first address found in the From header.
61 In most email transmission systems, though, the headers are not by
63 necessity tied to the addresses used as the sender and recipients. For
64 example, your message header might say "From: mailing-list@example.com"
65 while your SMTP client says "MAIL FROM:<verp-1234@lists.example.com>".
66 This is a powerful feature, and is necessary for many email
67 application. Being able to set those distinctly is important, and
68 Email::Sender::Simple lets you do this:
69 sendmail($email, { to => [ $to_1, $to_2 ], from => $sender });
71 in case of error
73 When the message is sent successfully (at least on to its next hop),
75 "sendmail" will return a true value -- specifically, an
76 Email::Sender::Success object. This object only rarely has much use.
77 What's more useful is what happens if the message can't be sent.
78 If there is an error sending the message, an exception will be thrown.
80 It will be an object belonging to the class Email::Sender::Failure.
81 This object will have a "message" attribute describing the nature of
82 the failure. There are several specialized forms of failure, like
83 Email::Sender::Failure::Multi, which is thrown when more than one error
84 is encountered when trying to send. You don't need to know about these
85 to use Email::Sender::Simple, though. All you need to know is that
86 "sendmail" returns true on success and dies on failure.
87 If you'd rather not have to catch exceptions for failure to send mail,
89 you can use the "try_to_send" method, which can be imported as
90 "try_to_sendmail". This method will return just false on failure to
91 send mail.
92 For example:
94 Email::Sender::Simple->try_to_send($email, { ... });
96 use Email::Sender::Simple qw(try_to_sendmail);
98 try_to_sendmail($email, { ... });
99 Some Email::Sender transports can signal success if some, but not all,
101 recipients could be reached. Email::Sender::Simple does its best to
102 ensure that this never happens. When you are using
103 Email::Sender::Simple, mail should either be sent or not. Partial
104 success should never occur.
105 Picking a Transport
107 passing in your own transport
108 If Email::Sender::Simple doesn't pick the transport you want, or if you
110 have more specific needs, you can specify a transport in several ways.
111 The simplest is to build a transport object and pass it in. You can
112 read more about transports elsewhere. For now, we'll just assume that
113 you need to send mail via SMTP on an unusual port. You can send mail
114 like this:
115 my $transport = Email::Sender::Transport::SMTP->new({
117 host => 'smtp.example.com',
118 port => 2525,
119 });
120 sendmail($email, { transport => $transport });
122 Now, instead of guessing at what transport to use,
124 Email::Sender::Simple will use the one you provided. This transport
125 will have to be specified for each call to "sendmail", so you might
126 want to look at other options, which follow.
127 specifying transport in the environment
129 If you have a program that makes several calls to
131 Email::Sender::Simple, and you need to run this program using a
132 different mailserver, you can set environment variables to change the
133 default. For example:
134 $ export EMAIL_SENDER_TRANSPORT=SMTP
136 $ export EMAIL_SENDER_TRANSPORT_host=smtp.example.com
137 $ export EMAIL_SENDER_TRANSPORT_port=2525
138 $ perl your-program
140 It is important to note that if you have set the default transport by
142 using the environment, no subsequent "transport" args to "sendmail"
143 will be respected. If you set the default transport via the
144 environment, that's it. Everything will use that transport. (Also,
145 note that while we gave the host and port arguments above in lower
146 case, the casing of arguments in the environment is flattened to
147 support systems where environment variables are of a fixed case. So,
148 "EMAIL_SENDER_TRANSPORT_PORT" would also work.
149 This is extremely valuable behavior, as it allows you to audit every
151 message that would be sent by a program by running something like this:
152 $ export EMAIL_SENDER_TRANSPORT=Maildir
154 $ perl your-program
155 In that example, any message sent via Email::Sender::Simple would be
157 delivered to a maildir in the current directory.
158 subclassing to change the default transport
160 If you want to use a library that will behave like
162 Email::Sender::Simple but with a different default transport, you can
163 subclass Email::Sender::Simple and replace the
164 "build_default_transport" method.
165 Testing
167 Email::Sender::Simple makes it very, very easy to test code that sends
168 email. The simplest way is to do something like this:
169 use Test::More;
171 BEGIN { $ENV{EMAIL_SENDER_TRANSPORT} = 'Test' }
172 use YourCode;
173 YourCode->run;
175 my @deliveries = Email::Sender::Simple->default_transport->deliveries;
177 Now you've got an array containing every delivery performed through
179 Email::Sender::Simple, in order. Because you set the transport via the
180 environment, no other code will be able to force a different transport.
181 When testing code that forks, Email::Sender::Transport::SQLite can be
183 used to allow every child process to deliver to a single, easy to
184 inspect destination database.
185 Hey, where's my Bcc support?
187 A common question is "Why doesn't Email::Sender::Simple automatically
188 respect my Bcc header?" This is often combined with, "Here is a patch
189 to 'fix' it." This is not a bug or oversight. Bcc is being ignored
190 intentionally for now because simply adding the Bcc addresses to the
191 message recipients would not produce the usually-desired behavior.
192 For example, here is a set of headers:
194 From: sender@example.com
196 To: to_rcpt@example.com
197 Cc: cc_rcpt@example.com
198 Bcc: the_boss@example.com
199 In this case, we'd expect the message to be delivered to three people:
201 to_rcpt, cc_rcpt, and the_boss. This is why it's often suggested that
202 the Bcc header should be a source for envelope recipients. In fact,
203 though, a message with a Bcc header should probably be delivered only
204 to the Bcc recipients. The "B" in Bcc means "blind." The other
205 recipients should not see who has been Bcc'd. This means you want to
206 send two messages: one to to_rcpt and cc_rcpt, with no Bcc header
207 present; and another to the_boss only, with the Bcc header. If you
208 just pick up Bcc addresses as recipients, everyone will see who was
209 Bcc'd.
210 Email::Sender::Simple promises to send messages atomically. That is:
212 it won't deliver to only some of the recipients, and not to others.
213 That means it can't automatically detect the Bcc header and make two
214 deliveries. There would be a possibility for the second to fail after
215 the first succeeded, which would break the promise of a pure failure or
216 success.
217 The other strategy for dealing with Bcc is to remove the Bcc header
219 from the message and then inject the message with an envelope including
220 the Bcc addresses. The envelope information will not be visible to the
221 final recipients, so this is safe. Unfortunately, this requires
222 modifying the message, and Email::Sender::Simple should not be altering
223 the mutable email object passed to it. There is no "clone" method on
224 Email::Abstract, so it cannot just build a clone and modify that,
225 either. When such a method exists, Bcc handling may be possible.
226 Example Bcc Handling
228 If you want to support the Bcc header now, it is up to you to deal with
230 how you want to munge the mail and inject the (possibly) munged copies
231 into your outbound mailflow. It is not reasonable to suggest that
232 Email::Sender::Simple do this job.
233 Example 1: Explicitly set the envelope recipients for Bcc recipients
235 Create the email without a Bcc header, send it to the Bcc users
237 explicitly and then send it to the To/Cc users implicitly.
238 my $message = create_email_mime_msg; # <- whatever you do to get the message
240 $message->header_set('bcc'); # delete the Bcc header before sending
242 sendmail($message, { to => $rcpt }); # send to explicit Bcc address
243 sendmail($message); # and then send as normal
244 Example 2: Explicitly set the envelope recipients for all recipients
246 You can make a single call to "sendmail" by pulling all the recipient
248 addresses from the headers yourself and specifying all the envelope
249 recipients once. Again, delete the Bcc header before the message is
250 sent.
251
253 This is awesome! Where can I learn more?
254 Have a look at Email::Sender::Manual, where all the manual's documents
255 are listed. You can also look at the documentation for
256 Email::Sender::Simple and the various Email::Sender::Transport classes.
257
259 Ricardo Signes <rjbs@semiotic.systems>
260
262 This software is copyright (c) 2021 by Ricardo Signes.
263 This is free software; you can redistribute it and/or modify it under
265 the same terms as the Perl 5 programming language system itself.
266perl v5.36.0 2022-07-2E2mail::Sender::Manual::QuickStart(3)