Email::MessageID(3) User Contributed Perl Documentation Email::MessageID(3)

Email::MessageID - Generate world unique message-ids.

version 1.408

use Email::MessageID;
my $mid = Email::MessageID->new->in_brackets;
print "Message-ID: $mid\x0D\x0A";

Message-ids are optional, but highly recommended, headers that identify a message uniquely. This software generates a unique message-id.

This library should run on perls released even a long time ago. It should work on any version of perl released in the last five years.

Although it may work on older versions of perl, no guarantee is made that the minimum required version will not be increased. The version may be increased for any reason, and there is no promise that patches will be accepted to lower the minimum required perl.

my $mid = Email::MessageID->new;
my $new_mid = Email::MessageID->new( host => $myhost );

This class method constructs an Email::MessageID object containing a unique message-id. You may specify custom "host" and "user" parameters.

By default, the "host" is generated from "Sys::Hostname::hostname".

By default, the "user" is generated using "Time::HiRes"'s "gettimeofday" and the process ID.

Using these values we have the ability to ensure world uniqueness down to a specific process running on a specific host, and the exact time down to six digits of microsecond precision.

my $domain_part = Email::MessageID->create_host;

This method returns the domain part of the message-id.

my $local_part = Email::MessageID->create_user;

This method returns a unique local part for the message-id. It includes some random data and some predictable data.

When using Email::MessageID directly to populate the "Message-ID" field, be sure to use "in_brackets" to get the string inside angle brackets:

header => [
  'Message-Id' => Email::MessageID->new->in_brackets,

Don't make this common mistake:

header => [
  'Message-Id' => Email::MessageID->new->as_string, # WRONG!

  • Casey West <>
  • Ricardo SIGNES <>

  • Aaron Crane <>
  • Pali <>
  • Ricardo Signes <>

This software is copyright (c) 2004 by Casey West.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

2023-07-25 perl v5.38.0