(in continuation to webperl: fetching data over the web)
Webperl requires at the moment to statically bundle all needed modules.
The following Proof of Concept shows how to dynamically use non-bundled modules.
The modules need to be pure Perl and have to be present inside the $WEBLIB directory on your server (respecting the same domain policy avoids much trouble)
I just copied the desired libs from my installation and listed allowed modules to %INC_FETCH (to limit unnecessary traffic) .
The following page demonstrate how to use Data::Dump from weblib.
Data::Dump is currently not bundled with Web-Perl.
(Data::Dumper is since it's core)
The mechanism of adding a call-back to @INC to dynamically fetch modules from various sources is described in require
<!doctype html>
<html lang="en-us">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>WebPerl <script> Demos</title>
<script type="text/javascript">
function xfetch(url) {
var req = new XMLHttpRequest();
req.open('GET', url , false);
req.send(null);
if(req.status == 200) {
return req.responseText;
} else {
return "";
}
}
// alert(xfetch('http://localhost:5000/lib/Data/Dump.pm'));
// alert(xfetch('http://localhost:5000/webperl.js'));
</script>
<script src="webperl.js"></script>
<!-- Please see the documentation at http://webperl.zero-g.net/using.h
+tml -->
<script type="text/perl">
use warnings;
use strict;
use Data::Dumper;
use WebPerl qw/js/;
BEGIN {
my $WEBLIB = 'localhost:5000/lib';
# gather source of module
my $fetch = sub {
my ($module_path) = @_;
return js("window.xfetch('http://$WEBLIB/$module_path')");
};
# allowed modules in weblib
my %INC_FETCH =
(
'Data/Dump.pm' => 1,
);
# loader hook for @INC
my $loader = sub {
my ($sub,$filename) = @_;
if ( $INC_FETCH{$filename}) {
my $source = $fetch->($filename);
unless ($source) {
warn "Fetching $filename from $WEBLIB failed";
return;
}
open my $fh_source, "<", \$source;
my $pre = '';
#$pre = qq{warn '*** Loading $filename ***';};
return (\$pre, $fh_source);
}
return;
};
push @INC, $loader;
}
use Data::Dump qw/pp/;
my $HoA = { map { $_ => [reverse 1..5] } "a".."d" };
warn pp $HoA;
#use Data::Dumper;
#warn Dumper $HoA;
</script>
<!-- Optional STDOUT/STDERR text area (if you don't use this, output g
+oes to Javascript console) -->
<script>
window.addEventListener("load", function () {
document.getElementById('output')
.appendChild( Perl.makeOutputTextarea() );
});
</script>
</head>
<body>
<p>This is a demo of <a href="http://webperl.zero-g.net" target="_blan
+k">WebPerl</a>!</p>
<div id="output"></div>
<div id="buttons">
<button id="my_button">Testing!</button>
</div>
</body>
</html>
OUTPUT:
{
a => [5, 4, 3, 2, 1],
b => [5, 4, 3, 2, 1],
c => [5, 4, 3, 2, 1],
d => [5, 4, 3, 2, 1],
} at /tmp/scripts.pl line 56.
DISCLAIMER: This code is beta and follows the release often paradigm.
Successfully tested with Chrome AND Firefox. FF showed new "Content Security Policy" problems, I didn't have the time to dig into and install the necessary PLACK CORS modules. °
The principle is universal, as soon as webperl can run in a browser and has the capacity to dynamically fetch code, using unbundled (pure) Perl modules becomes trivial.
°) works like a charm in FF , forgot to disable "noscript" filtering for localhost! ;)
