Editing Contribute: Plugins/ExportPluginsZip (section)

== List Handling ==
=== Setting Up ===
Here we setup an in-memory file for the Zip, and create an Archive object.
<pre>
  my $archive = '';
  open (my $FH, '>', \$archive) or
    die("Could not create filehandle: $!");
  my $zip = Archive::Any::Create->new;
</pre>

=== Navigation ===
Here we begin to setup the HTML file that we'll add to our archive for navigation. First we setup a header.
<pre>
  my $index = <<END;
  <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
  <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
    <head>
      <meta http-equiv="Content-Type" content="text/html;charset=utf-8"/>
      <title>EPrints Search Results</title>
    </head>
  <body>
END
</pre>

Now we get the Session object, we'll be using it to manipulate [http://en.wikipedia.org/wiki/Document_Object_Model DOM] objects later.
<pre>
  my $session = $plugin->{session};
</pre>

=== Handling DataObjs ===
We loop over the DataObjs as we have done before.

This time we setup some [http://en.wikipedia.org/wiki/Document_Object_Model DOM] objects to be added to our index. Each eprint will have it's title printed out followed by a list of documents.
<pre>
    my $div = $session->make_element('div');
    my $heading = $session->make_element('h2');
    $heading->appendChild($session->make_text($dataobj->get_value('title')));
    $div->appendChild($heading);

    my $uldoc = $session->make_element('ul');
    $div->appendChild($uldoc);
</pre>

We create a directory for each eprint. Note it is not necessary to explicitly create a directory, we simply have to set the appropriate file path. However this means that if you do not add files to a certain directory it will not be created, rather than having an empty directory for a given eprint.

<pre>
    my $dirpath = 'eprints-search/'.$dataobj->get_id().'/';
</pre>

==== Dealing With Documents ====
We then loop over all the documents belonging to each DataObj. The get_all_documents method returns an array of Document objects.
<pre>
    my $i = 1;
    foreach my $doc ($dataobj->get_all_documents)
    {
      my $subdirpath = $dirpath."doc$i/";
</pre>

Here we create a list item for the document containing a link to the main file. 
<pre>
      my $lidoc = $session->make_element('li');
      $uldoc->appendChild($lidoc);

      my $adoc = $session->make_element('a', href=>$dataobj->get_id."/doc$i/".$doc->get_main);
      $lidoc->appendChild($adoc);
</pre>
If a description of the main file has been set we use that as the link text, otherwise we use the filename.
<pre>
      if ($doc->exists_and_set('formatdesc'))
      {
        $adoc->appendChild($session->make_text($doc->get_value('formatdesc')));
      }
      else
      {
        $adoc->appendChild($session->make_text($doc->get_main));
      }
</pre>

==== Dealing With Files ====
The files method of the Document object returns a hash whose keys are file names and values are file sizes.
<pre>
      my %files = $doc->files;
</pre>

We loop over each file belonging to the document, in most cases there will only be one file.
<pre>
      foreach my $filename (sort keys %files)
      {
        my $filepath = $subdirpath.$filename;
        my $file = $doc->local_path.'/'.$filename;
</pre>

We need to read the contents of the file and add it to a file in the zip. First we'll create another in-memory file to hold the contents.
<pre>
        my $data = '';
        open (my $datafh ,'>', \$data);
</pre>

We open our file and print it straight out to our in-memory file.
<pre>
        open (INFH, "<$file") or die ("Could not open file $file");
        while (<INFH>)
        {
          print {$datafh} $_;
        }
        close INFH;
</pre>

Then we add the file data to our file.
<pre>
        $zip->add_file($filepath, $data);
</pre>

Finally we add the [http://en.wikipedia.org/wiki/Document_Object_Model DOM] object for our eprint to the index.
<pre>
    $index .= EPrints::XML::to_string($div);
</pre>

=== Finishing Off ===
After finishing off our index file we add it to the zip file.
<pre>
  $index .= '</body></html>';
  $zip->add_file('eprints-search/index.htm',$index);
</pre>

If a file handle has been provided we write to it, otherwise we write to the scalar file handle created earlier. We then return in the usual fashion.
<pre>
  if (defined $opts{fh})
  {
    $zip->write_filehandle($opts{fh},'zip');
    return undef;
  }
  $zip->write_filehandle($FH,'zip');
  return $archive;
</pre>