As a very rough benchmark, I created a ~20MB xml file (I took the doc in the OP, and copied the middle part over and over). I filtered the doc using XSLT (using XML::LibXSLT, and the XSLT in the node above), and XML::Twig (the solution elsewhere in this thread). The XSLT took about 3 seconds, the XML::Twig took about 20. Both used vast quantities of memory.
And though I'm not familiar with XML::Parser::Expat, I hacked together something which seems to work (though I am likely missing something for some types of XML content), and ran in about 3 seconds without using much memory at all.
Update: repeated XSLT with 40MB file, took just a few more seconds.
I wonder if Jenda is using XML::XSLT or XML::LibXSLT below. (and an 80MB file took ~25 secs w/XSLT and ~20 w/expat) (XML::LibXSLT 1.62, XML::LibXML 1.63).
Here is what I used:
xslt.pl:
#!/usr/bin/perl
use strict;
use warnings;
use XML::LibXML;
use XML::LibXSLT;
my $parser = XML::LibXML->new();
my $xslt = XML::LibXSLT->new();
my $source = $parser->parse_file('tmp.xml');
my $style_doc = $parser->parse_string(<<EOT);
<?xml version='1.0'?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" versi
+on="1.0">
<xsl:strip-space elements="*"/>
<xsl:output method="xml" indent="yes"/>
<xsl:template match="@* | node()">
<xsl:copy>
<xsl:apply-templates select="@* | node()" />
</xsl:copy>
</xsl:template>
<xsl:template match="comment()" />
</xsl:stylesheet>
EOT
my $stylesheet = $xslt->parse_stylesheet($style_doc);
my $results = $stylesheet->transform($source);
print $stylesheet->output_string($results);
----------------------------------------------
twig.pl:
#!/usr/bin/perl
use strict;
use warnings;
use XML::Twig;
my $twig = XML::Twig->new (comments => 'drop', pretty_print => 'indent
+ed');
$twig->parsefile("tmp.xml");
$twig->print();
----------------------------------
expat.pl:
#!/usr/bin/perl
use strict;
use warnings;
use XML::Parser::Expat;
my $parser = new XML::Parser::Expat;
$parser->setHandlers('Start' => \&sh,
'End' => \&eh,
'Char' => \&ch);
$parser->parsefile('tmp.xml');
sub sh {
my ($p, $e) = @_;
print $p->recognized_string();
}
sub eh {
my ($p, $e) = @_;
print $p->recognized_string();
}
sub ch {
my ($p, $s) = @_;
print $s;
}
