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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<!-- saved from url=(0034)http://localhost:8000/ch18s11.html -->
<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>18.10. Extracting Attachments from Mail</title><link rel="stylesheet" href="./recipe_18_10_files/core.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.74.0"></head><body><div class="sect1" title="18.10. Extracting Attachments from Mail"><div class="titlepage"><div><div><h1 class="title"><a id="perlckbk2-CHP-18-SECT-10">18.10. Extracting Attachments from Mail</a></h1></div></div></div><div class="sect2" title="Problem"><div class="titlepage"><div><div><h2 class="title"><a id="perlckbk2-CHP-18-SECT-10.1">Problem</a></h2></div></div></div><p><a id="perlckbk2-CHP-18-ITERM-5799" class="indexterm">You have one or more mail messages with MIME
attachments, and you want to process these messages with a Perl
program to extract files or otherwise manipulate attachments.</a></p></div><div class="sect2" title="Solution"><div class="titlepage"><div><div><h2 class="title"><a id="perlckbk2-CHP-18-SECT-10.2">Solution</a></h2></div></div></div><p><a id="perlckbk2-CHP-18-SECT-10.2">Use the MIME-Tools bundle from CPAN:</a><a id="perlckbk2-CHP-18-ITERM-5800" class="indexterm"></a></p><a id="I_18_tt1862"><pre class="programlisting">use MIME::Parser;
$parser = MIME::Parser->new( );
$parser->output_to_core(1); # don't write attachments to disk
$message = $parser->parse_data($MESSAGE); # die( )s if can't parse
# OR
$message = $parser->parse($FILEHANDLE); # die( )s if can't parse
$head = $message->head( ); # object--see docs
$preamble = $message->preamble; # ref to array of lines
$epilogue = $message->epilogue; # ref to array of lines
$num_parts = $message->parts;
for (my $i=0; $i < $num_parts; $i++) {
my $part = $message->parts($i);
my $content_type = $part->mime_type;
my $body = $part->as_string;
}</pre></a></div><div class="sect2" title="Discussion"><div class="titlepage"><div><div><h2 class="title"><a id="perlckbk2-CHP-18-SECT-10.3">Discussion</a></h2></div></div></div><p><a id="perlckbk2-CHP-18-ITERM-5801" class="indexterm">Formally, a MIME message has only two parts: the head
(containing headers such as <code class="literal">From</code>
and <code class="literal">Subject</code>) and the body
(containing the message, rather than its metadata). The body, however,
has three parts: the preamble (text before the first attachment), a
series of parts (the attachments), and the epilogue (text after the
last attachment). This is shown in </a><a class="link" href="http://localhost:8000/ch18s11.html#perlckbk2-CHP-18-FIG-1" title="Figure 18-1. Composition of a MIME message">Figure 18-1</a>.</p><div class="figure"><a id="perlckbk2-CHP-18-FIG-1"></a><div class="figure-contents"><a id="perlckbk2-CHP-18-FIG-1"></a><div class="mediaobject"><a id="perlckbk2-CHP-18-FIG-1"></a><a id="I_18_tt1863"><img src="./recipe_18_10_files/httpatomoreillycomsourceoreillyimages146665.png" width="156" alt="Composition of a MIME message"></a></div></div><p class="title"><a id="I_18_tt1863">Figure 18-1. Composition of a MIME message</a></p></div><p><a id="I_18_tt1863">In the Solution, we disable the default behavior of MIME::Parser
that writes the attachments to disk. Doing so increases memory
consumption because now the decoded attachments must be stored in
memory, but prevents the need to clean up temporary files and
directories once the attachments are no longer needed.</a></p><p><a id="I_18_tt1863">To write attachments to a file, replace the call to <code class="literal">output_to_core</code> with calls to methods that
specify the directory in which to store the attachments and what to
name the files. The <code class="literal">output_under</code>
method specifies a directory under which each message will get its own
subdirectory; those subdirectories will contain the decoded
attachments:</a></p><a id="I_18_tt1864"><pre class="programlisting">$parser->output_under("/tmp");
# parsing creates files like /tmp/msg-1048509652-16134-0/foo.png</pre><p>Alternatively, <code class="literal">output_dir</code>
specifies a directory into which all attachment files go:</p></a><a id="I_18_tt1865"><pre class="programlisting">$parser->output_dir("/tmp");
# parsing creates files like /tmp/foo.png</pre><p>To clean up temporary files once parsing is done, say:</p></a><a id="I_18_tt1866"><pre class="programlisting">$parser->filer->purge;</pre><p>Because parsing can trigger exceptions, catch the exceptions if
you want to clean up:</p></a><a id="I_18_tt1867"><pre class="programlisting">eval { $message = $parser->parse($FILEHANDLE) };
# ...
$parser->filer->purge;</pre><p>Whether you create files on disk, you can still treat the
attachments as files by using the <code class="literal">open</code> method on an individual part:</p></a><a id="I_18_tt1868"><pre class="programlisting">for (my $i=0; $i < $num_parts; $i++) {
my $part = $message->parts($i);
my $fh = $part->open("r") or die "Can't open for reading: $!\n";
while (<$fh>) {
# reading lines from the current attachment
}
}</pre><p>There are actually six different classes that form part of the
MIME-Tools distribution, and each is well-documented. Start with the
MIME::Tools manpage and explore from there.</p></a></div><div class="sect2" title="See Also"><div class="titlepage"><div><div><h2 class="title"><a id="perlckbk2-CHP-18-SECT-10.4">See Also</a></h2></div></div></div><p><a id="perlckbk2-CHP-18-SECT-10.4">The MIME::Tools manpage and other documentation for the
MIME-Tools distribution</a></p></div></div><a id="perlckbk2-CHP-18-SECT-10.4">
</a></body></html>