File Coverage

blib/lib/Dancer2/Plugin.pm

Criterion	Covered	Total	%
statement	224	229	97.8
branch	61	80	76.2
condition	15	23	65.2
subroutine	49	54	90.7
pod	6	24	25.0
total	355	410	86.5

package Dancer2::Plugin;
# ABSTRACT: base class for Dancer2 plugins
$Dancer2::Plugin::VERSION = '2.0.1';
use strict;
use warnings;

use Moo;
use Carp;
use List::Util qw/ reduce /;
use Module::Runtime 'require_module';
use Attribute::Handlers;
use Scalar::Util;
use Ref::Util qw;

our $CUR_PLUGIN;

extends 'Exporter::Tiny';

with 'Dancer2::Core::Role::Hookable';

has app => (
    is       => 'ro',
    weak_ref => 1,
    required => 1,
);

has config => (
    is => 'ro',
    lazy => 1,
    default => sub {
        my $self = shift;
        my $config = $self->app->config;
        my $package = ref $self; # TODO
        $package =~ s/Dancer2::Plugin:://;
        $config->{plugins}{$package} || {};
    },
);

my $_keywords = {};
sub keywords { $_keywords }

my $REF_ADDR_REGEX = qr{
    [A-Za-z0-9\:\_]+
    =HASH
    \(
        ([0-9a-fx]+)
    \)
}x;
my %instances;

# backwards compatibility
our $_keywords_by_plugin = {};

has '+hooks' => (
    default => sub {
        my $plugin = shift;
        my $name = 'plugin.' . lc ref $plugin;
        $name =~ s/Dancer2::Plugin:://i;
        $name =~ s/::/_/g;

        +{
            map { join( '.', $name, $_ ) => [] }
                @{ $plugin->ClassHooks }
        };
    },
);

sub add_hooks {
    my $class = shift;
    push @{ $class->ClassHooks }, @_;
}

sub execute_plugin_hook {
    my ( $self, $name, @args ) = @_;
    my $plugin_class = ref $self;

    $self->isa('Dancer2::Plugin')
        or croak "Cannot call plugin hook ($name) from outside plugin";
    $plugin_class =~ s/^Dancer2::Plugin:://; # short names

    my $full_name = 'plugin.' . lc($plugin_class) . ".$name";
    $full_name =~ s/::/_/g;

    $self->app->execute_hook( $full_name, @args );
}

sub find_plugin {
    my ( $self, $name ) = @_;
    return $self->app->find_plugin($name);
}

# both functions are there for D2::Core::Role::Hookable
# back-compatibility. Aren't used
sub supported_hooks { [] }
sub hook_aliases    { $_[0]->{'hook_aliases'} ||= {} }

### has() STUFF  ########################################

# our wrapping around Moo::has, done to be able to intercept
# both 'from_config' and 'plugin_keyword'
sub _p2_has {
    my $class = shift;
    $class->_p2_has_from_config( $class->_p2_has_keyword( @_ ) );
};

sub _p2_has_from_config {
    my( $class, $name, %args ) = @_;

    my $config_name = delete $args{'from_config'}
        or return ( $name, %args );

    $args{lazy} = 1;

    if ( is_coderef($config_name) ) {
        $args{default} ||= $config_name;
        $config_name = 1;
    }

    $config_name = $name if $config_name eq '1';
    my $orig_default = $args{default} || sub{};
    $args{default} = sub {
        my $plugin = shift;
        my $value = reduce { eval { $a->{$b} } } $plugin->config, split /\./, $config_name;
        return defined $value ? $value: $orig_default->($plugin);
    };

    return $name => %args;
}

sub _p2_has_keyword {
    my( $class, $name, %args ) = @_;

    if( my $keyword = delete $args{plugin_keyword} ) {

        $keyword = $name if $keyword eq '1';

        $class->keywords->{$_} = sub { (shift)->$name(@_) }
            for ref $keyword ? @$keyword : $keyword;
    }

    return $name => %args;
}

### ATTRIBUTE HANDLER STUFF ########################################

# :PluginKeyword shenanigans

sub PluginKeyword :ATTR(CODE,BEGIN) {
    my( $class, $sym_ref, $code, undef, $args ) = @_;

    # importing at BEGIN stage doesn't work with 5.10 :-(
    return unless ref $sym_ref;

    my $func_name = *{$sym_ref}{NAME};

    $args = join '', @$args if is_arrayref($args);

    for my $name ( split ' ', $args || $func_name ) {
        $class->keywords->{$name} = $code;
    }

}

## EXPORT STUFF ##############################################################

# this @EXPORT will only be taken
# into account when we do a 'use Dancer2::Plugin'
# I.e., it'll only do its magic for the
# plugins themselves, not when they are
# called
our @EXPORT = qw/ :plugin /;

# compatibility - it will be removed soon!
my $no_dsl = {};
my $exported_app = {};
sub _exporter_expand_tag {
    my( $class, $name, $args, $global ) = @_;

    my $caller = $global->{into};

    $name eq 'no_dsl' and $no_dsl->{$caller} = 1;
    # no_dsl check here is for compatibility only
    # it will be removed soon!
    return _exporter_plugin($caller)
        if $name eq 'plugin' or $name eq 'no_dsl';

    return _exporter_app($class,$caller,$global)
        if $name eq 'app' and $caller->can('app') and !$no_dsl->{$class};

    return;

}

# plugin has been called within a D2 app. Modify
# the app and export keywords
sub _exporter_app {
    my( $class, $caller, $global ) = @_;

    $exported_app->{$caller} = 1;

    # The check for ->dsl->app is to handle plugins as well.
    # Otherwise you can only import from a plugin to an app,
    # but with this, you can import to anything
    # that has a DSL with an app, which translates to "also plugins"
    my $app = eval("${caller}::app()") || eval { $caller->dsl->app } ## no critic qw(BuiltinFunctions::ProhibitStringyEval)
        or return; ## no critic

    return unless $app->can('with_plugin');

    my $plugin = $app->with_plugin( '+' . $class );
    $global->{'plugin'} = $plugin;

    return unless $class->can('keywords');

    # Add our hooks to the app, so they're recognized
    # this is for compatibility so you can call execute_hook()
    # without the fully qualified plugin name.
    # The reason we need to do this here instead of when adding a
    # hook is because we need to register in the app, and only now it
    # exists.
    # This adds a caveat that two plugins cannot register
    # the same hook name, but that will be deprecated anyway.
    {;
        foreach my $hook ( @{ $plugin->ClassHooks } ) {
            my $full_name = 'plugin.' . lc($class) . ".$hook";
            $full_name =~ s/Dancer2::Plugin:://i;
            $full_name =~ s/::/_/g;

            # this adds it to the plugin
            $plugin->hook_aliases->{$hook} = $full_name;

            # this adds it to the app
            $plugin->app->hook_aliases->{$hook} = $full_name;

            # copy the hooks from the plugin to the app
            # this is in case they were created at import time
            # rather than after
            @{ $plugin->app->hooks }{ keys %{ $plugin->hooks } } =
                values %{ $plugin->hooks };
        }
    }

    {
        # get the reference
        my ($plugin_addr) = "$plugin" =~ $REF_ADDR_REGEX;

        $instances{$plugin_addr}{'config'} = sub { $plugin->config };
        $instances{$plugin_addr}{'app'}    = $plugin->app;

        Scalar::Util::weaken( $instances{$plugin_addr}{'app'} );

        ## no critic
        no strict 'refs';

        # we used a forward declaration
        # so the compiled form "plugin_setting;" can be overridden
        # with this implementation,
        # which works on runtime ("plugin_setting()")
        # we can't use can() here because the forward declaration will
        # create a CODE stub
        no warnings 'redefine';
        *{"${class}::plugin_setting"} = sub {
            my ($plugin_addr) = "$CUR_PLUGIN" =~ $REF_ADDR_REGEX;

            $plugin_addr
                or Carp::croak('Can\'t find originating plugin');

            # we need to do this because plugins might call "set"
            # in order to change plugin configuration but it doesn't
            # change the plugin object, it changes the app object
            # so we merge them.
            my $name = ref $CUR_PLUGIN;
            $name =~ s/^Dancer2::Plugin:://g;

            my $plugin_inst       = $instances{$plugin_addr};
            my $plugin_config     = $plugin_inst->{'config'}->();
            my $app_plugin_config = $plugin_inst->{'app'}->config->{'plugins'}{$name};

            return { %{ $plugin_config || {} }, %{ $app_plugin_config || {} } };
        };

        # FIXME:
        # why doesn't this work? it's like it's already defined somewhere
        # but i'm not sure where. seems like AUTOLOAD runs it.
        #$class->can('execute_hook') or
            *{"${class}::execute_hook"}   = sub {
                # this can also be called by App.pm itself
                # if the plugin is a
                # "candidate" for a hook
                # See: App.pm "execute_hook" method, "around" modifier
                if ( $_[0]->isa('Dancer2::Plugin') ) {
                    # this means it's probably our hook, we need to verify it
                    my ( $plugin_self, $hook_name, @args ) = @_;

                    my $plugin_class = lc $class;
                    $plugin_class =~ s/^dancer2::plugin:://;
                    $plugin_class =~ s{::}{_}g;

                    # you're either calling it with the full qualifier or not
                    # if not, use the execute_plugin_hook instead
                    if ( $plugin->hooks->{"plugin.$plugin_class.$hook_name"} ) {
                        Carp::carp("Please use fully qualified hook name or "
                                 . "the method execute_plugin_hook");
                        $hook_name = "plugin.$plugin_class.$hook_name";
                    }

                    $hook_name =~ /^plugin\.$plugin_class/
                        or Carp::croak('Unknown plugin called through other plugin');

                    # now we can't really use the app to execute it because
                    # the "around" modifier is the one calling us to begin
                    # with, so we need to call it directly ourselves
                    # this is okay because the modifier is there only to
                    # call candidates, like us (this is in fact how and
                    # why we were called)
                    $_->( $plugin_self, @args )
                        for @{ $plugin->hooks->{$hook_name} };

                    return;
                }

                return $plugin->app->execute_hook(@_);
        };
    }

    local $CUR_PLUGIN = $plugin;
    $_->($plugin) for @{ $plugin->_DANCER2_IMPORT_TIME_SUBS() };

    map { [ $_ =>  {plugin => $plugin}  ] } keys %{ $plugin->keywords };
}

# turns the caller namespace into
# a D2P2 class, with exported keywords
sub _exporter_plugin {
    my $caller = shift;
    require_module('Dancer2::Core::DSL');
    my $keywords_list = join ' ', keys %{ Dancer2::Core::DSL->dsl_keywords };

    eval <<"END"; ## no critic
        {
            package $caller;
            use Moo;
            use Carp ();
            use Attribute::Handlers;

            extends 'Dancer2::Plugin';

            our \@EXPORT = ( ':app' );

            around has => sub {
                my( \$orig, \$name, \%args ) = \@_;

                if (ref \$name eq 'ARRAY'
                        && exists \$args{'plugin_keyword'}
                        && ref \$args{'plugin_keyword'} eq 'ARRAY') {

                    Carp::croak('Setting "plugin_keyword" to an array is disallowed'
                        . ' when defining multiple attributes simultaneously');
                }

                \$orig->( ${caller}->_p2_has( \$_, \%args) )
                    for ref \$name ? @\$name : \$name;
            };

            sub PluginKeyword :ATTR(CODE,BEGIN) {
                goto &Dancer2::Plugin::PluginKeyword;
            }

            sub execute_plugin_hook {
                goto &Dancer2::Plugin::execute_plugin_hook;
            }

            my \$_keywords = {};
            sub keywords { \$_keywords }

            my \$_ClassHooks = [];
            sub ClassHooks { \$_ClassHooks }

            # this is important as it'll do the keywords mapping between the
            # plugin and the app
            sub register_plugin { Dancer2::Plugin::register_plugin(\@_) }

            sub register {
                my ( \$keyword, \$sub ) = \@_;
                \$_keywords->{\$keyword} = \$sub;

                \$keyword =~ /^[a-zA-Z_]+[a-zA-Z0-9_]*\$/
                  or Carp::croak(
                    "You can't use '\$keyword', it is an invalid name"
                  . " (it should match ^[a-zA-Z_]+[a-zA-Z0-9_]*\\\$ )");


                grep +( \$keyword eq \$_ ), qw<$keywords_list>
                    and Carp::croak("You can't use '\$keyword', this is a reserved keyword");

                \$Dancer2::Plugin::_keywords_by_plugin->{\$keyword}
                    and Carp::croak("You can't use \$keyword, "
                      . "this is a keyword reserved by "
                      . \$Dancer2::Plugin::_keywords_by_plugin->{\$keyword});

                \$Dancer2::Plugin::_keywords_by_plugin->{\$keyword} = "$caller";

                # Exporter::Tiny doesn't seem to generate the subs
                # in the caller properly, so we have to do it manually
                {
                    no strict 'refs';
                    *{"${caller}::\$keyword"} = \$sub;
                }
            }

            my \@_DANCER2_IMPORT_TIME_SUBS;
            sub _DANCER2_IMPORT_TIME_SUBS {\\\@_DANCER2_IMPORT_TIME_SUBS}
            sub on_plugin_import (&) {
                push \@_DANCER2_IMPORT_TIME_SUBS, \$_[0];
            }

            sub register_hook { goto &plugin_hooks }

            sub plugin_setting { Carp::croak "DEPRECATED: Plugin DSL method 'plugin_setting'. "
                . "Please use '\\\$self->config' instead\n" };

            sub plugin_args {
                Carp::carp "Plugin DSL method 'plugin_args' is deprecated. "
                         . "Use '\\\@_' instead'.\n";

                \@_;
            }
        }
END

    $no_dsl->{$caller} or eval <<"END"; ## no critic
        {
            package $caller;

            # FIXME: AUTOLOAD might pick up on this
            sub dancer_app {
                Carp::croak "DEPRECATED: Plugin DSL method 'dancer_app'. "
                         . "Please use '\\\$self->app' instead'.\n";
            }

            # FIXME: AUTOLOAD might pick up on this
            sub request {
                Carp::croak "DEPRECATED: Plugin DSL method 'request'. "
                         . "Please use '\\\$self->app->request' instead'.\n";
            }

            # FIXME: AUTOLOAD might pick up on this
            sub var {
                Carp::croak "DEPRECATED: Plugin DSL method 'var'. "
                         . "Please use '\\\$self->app->request->var' instead'.\n";
            }

            # FIXME: AUTOLOAD might pick up on this
            sub hook {
                Carp::croak "DEPRECATED: Plugin DSL method 'hook'. "
                         . "Please use '\\\$self->app->add_hook' instead'.\n";
            }

        }
END

    die $@ if $@;

    my $app_dsl_cb = _find_consumer();

    if ( $app_dsl_cb ) {
        my $dsl = $app_dsl_cb->();

        {
            ## no critic qw(TestingAndDebugging::ProhibitNoWarnings)
            no strict 'refs';
            no warnings 'redefine';
            *{"${caller}::dsl"} = sub {$dsl};
        }
    }

    return map { [ $_ => { class => $caller } ] }
               qw/ plugin_keywords plugin_hooks /;
}

sub _find_consumer {
    my $class;

    ## no critic qw(ControlStructures::ProhibitCStyleForLoops)
    for ( my $i = 1; my $caller = caller($i); $i++ ) {
        $class = $caller->can('dsl')
            and last;
    }

    # If you use a Dancer2 plugin outside a Dancer App, this fails.
    # It also breaks a bunch of the tests. -- SX
    #$class
    #    or croak('Could not find Dancer2 app');

    return $class;
}

# This has to be called for now at the end of every plugin package, in order to
# map the keywords of the associated app to the plugin, so that these keywords
# can be called from within the plugin code. This function is deprecated, as
# it's tied to the old plugin system. It's kept here for backcompat reason, but
# should go away with the old plugin system.
sub register_plugin {

    my $plugin_module = caller(1);

    # if you ask yourself why we do the injection in the plugin
    # module namespace every time the plugin is used, and not only
    # once, it's because it can be used by different app that could
    # have a different DSL with a different list of keywords.

    my $_DANCER2_IMPORT_TIME_SUBS = $plugin_module->_DANCER2_IMPORT_TIME_SUBS;
    unshift(@$_DANCER2_IMPORT_TIME_SUBS, sub {
                my $app_dsl_cb = _find_consumer();

                # Here we want to verify that "register_plugin" compat keyword
                # was in fact only called from an app.
                $app_dsl_cb
                      or Carp::croak(
                        'I could not find a Dancer App for this plugin');

                my $dsl = $app_dsl_cb->();

                foreach my $keyword ( keys %{ $dsl->dsl_keywords} ) {
                    # if not yet defined, inject the keyword in the plugin
                    # namespace, but make sure the code will always get the
                    # coderef from the right associated app, because one plugin
                    # can be used by multiple apps. Note that we remove the
                    # first parameter (plugin instance) from what we pass to
                    # the keyword implementation of the App
                    no strict 'refs';
                    $plugin_module->can($keyword)
                      or *{"${plugin_module}::$keyword"} = sub {
                        $_[0]
                          ? do {
                            my $cb = shift()->app->name->can($keyword);
                            $cb->(@_);
                          }
                          : $app_dsl_cb->(@_);
                      };
                }
            });
}

sub _exporter_expand_sub {
    my( $plugin, $name, $args, $global ) = @_;
    my $class = $args->{class};

    return _exported_plugin_keywords($plugin,$class)
        if $name eq 'plugin_keywords';

    return _exported_plugin_hooks($class)
        if $name eq 'plugin_hooks';

    $exported_app->{ $global->{'into'} }
        or Carp::croak('Specific subroutines cannot be exported from plugin');

    # otherwise, we're exporting a keyword

    my $p = $args->{plugin};
    my $sub = $p->keywords->{$name};
    return $name => sub(@) {
        # localize the plugin so we can get it later
        local $CUR_PLUGIN = $p;
        $sub->($p,@_);
    }
}

# "There's a good reason for this, I swear!"
#    -- Sawyer X
# basically, if someone adds a hook to the app directly
# that needs to access a DSL that needs the current object
# (such as "plugin_setting"),
# that object needs to be available
# So:
# we override App's "add_hook" to provide a register a
# different hook callback, that closes over the plugin when
# it's available, relocalizes it when the callback runs and
# after localizing it, calls the original hook callback
{
    ## no critic;
    no strict 'refs';
    no warnings 'redefine';
    my $orig_cb = Dancer2::Core::App->can('add_hook');
    $orig_cb and *{'Dancer2::Core::App::add_hook'} = sub {
        my ( $app, $hook ) = @_;

        my $hook_code = Scalar::Util::blessed($hook) ? $hook->code : $hook->{code};
        my $plugin    = $CUR_PLUGIN;

        $hook->{'code'} = sub {
            local $CUR_PLUGIN = $plugin;
            $hook_code->(@_);
        };

        $orig_cb->(@_);
    };
}


# define the exported 'plugin_keywords'
sub _exported_plugin_keywords{
    my( $plugin, $class ) = @_;

    return plugin_keywords => sub(@) {
        while( my $name = shift @_ ) {
            ## no critic
            my $sub = is_coderef($_[0])
                ? shift @_
                : eval '\&'.$class."::" . ( ref $name ? $name->[0] : $name );
            $class->keywords->{$_} = $sub for ref $name ? @$name : $name;
        }
    }
}

sub _exported_plugin_hooks {
    my $class = shift;
    return plugin_hooks => sub (@) { $class->add_hooks(@_) }
}

1;

__END__