ikiwiki/IkiWiki/Plugin/external.pm

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Perl
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#!/usr/bin/perl
# Support for external plugins written in other languages.
# Communication via XML RPC to a pipe.
# See externaldemo for an example of a plugin that uses this.
package IkiWiki::Plugin::external;
use warnings;
use strict;
use IkiWiki 2.00;
use RPC::XML;
use RPC::XML::Parser;
use IPC::Open2;
use IO::Handle;
my %plugins;
sub import {
my $self=shift;
my $plugin=shift;
return unless defined $plugin;
my ($plugin_read, $plugin_write);
my $pid = open2($plugin_read, $plugin_write,
IkiWiki::possibly_foolish_untaint($plugin));
# open2 doesn't respect "use open ':utf8'"
binmode($plugin_read, ':utf8');
binmode($plugin_write, ':utf8');
$plugins{$plugin}={in => $plugin_read, out => $plugin_write, pid => $pid,
accum => ""};
$RPC::XML::ENCODING="utf-8";
rpc_call($plugins{$plugin}, "import");
}
sub rpc_write ($$) {
my $fh=shift;
my $string=shift;
$fh->print($string."\n");
$fh->flush;
}
sub rpc_call ($$;@) {
my $plugin=shift;
my $command=shift;
# send the command
my $req=RPC::XML::request->new($command, @_);
rpc_write($plugin->{out}, $req->as_string);
# process incoming rpc until a result is available
while ($_ = $plugin->{in}->getline) {
$plugin->{accum}.=$_;
while ($plugin->{accum} =~ /^\s*(<\?xml\s.*?<\/(?:methodCall|methodResponse)>)\n(.*)/s) {
$plugin->{accum}=$2;
my $r = RPC::XML::Parser->new->parse($1);
error("XML RPC parser failure: $r") unless ref $r;
if ($r->isa('RPC::XML::response')) {
my $value=$r->value;
if ($r->is_fault($value)) {
# throw the error as best we can
print STDERR $value->string."\n";
return "";
}
elsif ($value->isa('RPC::XML::array')) {
return @{$value->value};
}
elsif ($value->isa('RPC::XML::struct')) {
my %hash=%{$value->value};
# XML-RPC v1 does not allow for
# nil/null/None/undef values to be
# transmitted, so until
# XML::RPC::Parser honours v2
# (<nil/>), external plugins send
# a hash with one key "null" pointing
# to an empty string.
if (exists $hash{null} &&
$hash{null} eq "" &&
int(keys(%hash)) == 1) {
return undef;
}
return %hash;
}
else {
return $value->value;
}
}
my $name=$r->name;
my @args=map { $_->value } @{$r->args};
# When dispatching a function, first look in
# IkiWiki::RPC::XML. This allows overriding
# IkiWiki functions with RPC friendly versions.
my $ret;
if (exists $IkiWiki::RPC::XML::{$name}) {
$ret=$IkiWiki::RPC::XML::{$name}($plugin, @args);
}
elsif (exists $IkiWiki::{$name}) {
$ret=$IkiWiki::{$name}(@args);
}
else {
error("XML RPC call error, unknown function: $name");
}
# XML-RPC v1 does not allow for nil/null/None/undef
# values to be transmitted, so until XML::RPC::Parser
# honours v2 (<nil/>), send a hash with one key "null"
# pointing to an empty string.
if (! defined $ret) {
$ret={"null" => ""};
}
my $string=eval { RPC::XML::response->new($ret)->as_string };
if ($@ && ref $ret) {
# One common reason for serialisation to
# fail is a complex return type that cannot
# be represented as an XML RPC response.
# Handle this case by just returning 1.
$string=eval { RPC::XML::response->new(1)->as_string };
}
if ($@) {
error("XML response serialisation failed: $@");
}
rpc_write($plugin->{out}, $string);
}
}
return undef;
}
package IkiWiki::RPC::XML;
use Memoize;
sub getvar ($$$) {
my $plugin=shift;
my $varname="IkiWiki::".shift;
my $key=shift;
no strict 'refs';
my $ret=$varname->{$key};
use strict 'refs';
return $ret;
}
sub setvar ($$$;@) {
my $plugin=shift;
my $varname="IkiWiki::".shift;
my $key=shift;
my $value=shift;
no strict 'refs';
my $ret=$varname->{$key}=$value;
use strict 'refs';
return $ret;
}
sub getstate ($$$$) {
my $plugin=shift;
my $page=shift;
my $id=shift;
my $key=shift;
return $IkiWiki::pagestate{$page}{$id}{$key};
}
sub setstate ($$$$;@) {
my $plugin=shift;
my $page=shift;
my $id=shift;
my $key=shift;
my $value=shift;
return $IkiWiki::pagestate{$page}{$id}{$key}=$value;
}
sub getargv ($) {
my $plugin=shift;
return \@ARGV;
}
sub setargv ($@) {
my $plugin=shift;
my $array=shift;
@ARGV=@$array;
}
sub inject ($@) {
# Bind a given perl function name to a particular RPC request.
my $plugin=shift;
my %params=@_;
if (! exists $params{name} || ! exists $params{call}) {
die "inject needs name and call parameters";
}
my $sub = sub {
IkiWiki::Plugin::external::rpc_call($plugin, $params{call}, @_)
};
$sub=memoize($sub) if $params{memoize};
# This will add it to the symbol table even if not present.
no warnings;
eval qq{*$params{name}=\$sub};
use warnings;
# This will ensure that everywhere it was exported to sees
# the injected version.
IkiWiki::inject(name => $params{name}, call => $sub);
return 1;
}
sub hook ($@) {
# the call parameter is a function name to call, since XML RPC
# cannot pass a function reference
my $plugin=shift;
my %params=@_;
my $callback=$params{call};
delete $params{call};
IkiWiki::hook(%params, call => sub {
IkiWiki::Plugin::external::rpc_call($plugin, $callback, @_);
});
}
sub pagespec_match ($@) {
# convert pagespec_match's return object into a XML RPC boolean
my $plugin=shift;
return RPC::XML::boolean->new(0 + IkiWiki::pagespec_march(@_));
}
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