path: root/IkiWiki/Plugin/graphviz.pm

#!/usr/bin/perl
# graphviz plugin for ikiwiki: render graphviz source as an image.
# Josh Triplett
package IkiWiki::Plugin::graphviz;

use warnings;
use strict;
use IkiWiki 3.00;
use IPC::Open2;

sub import {
    hook(type => "getsetup", id => "graphviz", call => \&getsetup);
    hook(type => "preprocess", id => "graph", call => \&graph);
}

sub getsetup () {
    return
        plugin => {
            safe => 1,
            rebuild => undef,
            section => "widget",
        },
}

my %graphviz_programs = (
    "dot" => 1, "neato" => 1, "fdp" => 1, "twopi" => 1, "circo" => 1
);

sub render_graph (\%) {
    my %params = %{(shift)};

    my $src = "$params{type} g {\n";
    $src .= "charset=\"utf-8\";\n";
    $src .= "ratio=compress;\nsize=\"".($params{width}+0).", ".($params{height}+0)."\";\n"
        if defined $params{width} and defined $params{height};
    $src .= $params{src};
    $src .= "}\n";

    # Use the sha1 of the graphviz code as part of its filename.
    eval q{use Digest::SHA1};
    error($@) if $@;
    my $dest=$params{page}."/graph-".
        IkiWiki::possibly_foolish_untaint(Digest::SHA1::sha1_hex($src)).
        ".png";
    will_render($params{page}, $dest);

    if (! -e "$config{destdir}/$dest") {
        my $pid;
        my $sigpipe=0;
        $SIG{PIPE}=sub { $sigpipe=1 };
        $pid=open2(*IN, *OUT, "$params{prog} -Tpng");

        # open2 doesn't respect "use open ':utf8'"
        binmode (OUT, ':utf8');

        print OUT $src;
        close OUT;

        my $png;
        {
            local $/ = undef;
            $png = <IN>;
        }
        close IN;

        waitpid $pid, 0;
        $SIG{PIPE}="DEFAULT";
        error gettext("failed to run graphviz") if $sigpipe;

        if (! $params{preview}) {
            writefile($dest, $config{destdir}, $png, 1);
        }
        else {
            # can't write the file, so embed it in a data uri
            eval q{use MIME::Base64};
            error($@) if $@;
            return "<img src=\"data:image/png;base64,".
                encode_base64($png)."\" />";
        }
    }

    return "<img src=\"".urlto($dest, $params{destpage})."\" />\n";
}

sub graph (@) {
    my %params=@_;
    $params{src} = "" unless defined $params{src};
    $params{type} = "digraph" unless defined $params{type};
    $params{prog} = "dot" unless defined $params{prog};
    error gettext("prog not a valid graphviz program") unless $graphviz_programs{$params{prog}};

    return render_graph(%params);
}

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