Dancecard

It has been mentioned before that a web framework is nothing without its ecosystem. Let's face it, Dancer just wouldn't be half as nice without all its plugins and interfaces to template systems. Likewise, web development with Dancer (or any other framework) would be much more of a chore without all the nifty JavaScript libraries out there. This is why jQuery comes pre-packaged with Dancer: if the cast majority of projects will use it, it just makes sense to have it already there.

But that about all the other JavaScript librabries that you're using? Wouldn't be nice to keep a registry of them, and be able to quickly add them to any new project? Yes it would. So let's take a few moments, and see if we can record all those potential dance partners on a dance card...

Building the Registry

First, we want our little utility to store the different projects are where to get them. For this first iteration, let's assume that all those projects will be plucked from Git repositories.

use Path::Class;
use File::HomeDir;
use Config::INI::Reader;

my $config_file = file( File::HomeDir->my_home, '.dancecard' );

add_repo(@ARGV);

sub add_repo {
    my( $url, $name ) = @_;
        
    unless ( $name ) {
        $name = $1 if $url =~ m#([^/]+?)(?:\.git)?$#;
    }

    open my $config_fh, '>>', $config_file->stringify;

    print $config_fh <<"END_REMOTE";
[$name]
    url = $url

END_REMOTE

    say "library '$name' added"
}

Primitive, but for the moment it'll do.

Adding the Libraries to the Current Project

Now, let's add the possibility to add any of those libraries to the current project. Let's be fancy and let's do it through an interactive menu. Oh, and let's show in green libraries that we can add, and in blue libraries that are already present:

use Term::Prompt;
use Term::ANSIColor;

sub select_libs {
    $config_file->touch;
    my $config = Config::INI::Reader->read_file($config_file->stringify);

    die "no library added yet" unless %$config;

    die "no 'public/' directory found, are we in a Dancer project?\n"
        unless -d 'public';

    while ( 1 ) {
        my @menu_items = map {
            colored( $_, -d dir('public', $_ ) ? 'blue' : 'green' );
        } keys %$config;

        my @results = prompt( 'm', {
                prompt  => 'libraries to add',
                title   => "\ndev libaries",
                items   => \@menu_items,
                accept_empty_selection     => 1,
                accept_multiple_selections => 1,
            },
            'empty to exit',
            undef
        );

        last unless @results;

        for( (keys %$config)[@results] ) {
            copy_lib( $_ => $config->{$_} );
        }
    }
}

sub copy_lib {
    my( $name, $data ) = @_;

    require Git::Repository;

    say "\ncloning '$name'...";

    Git::Repository->run( clone => $data->{url}, "public/".$name );

    say 'done';
}

Putting the dancecard together

And now, we put it all together:

#!/usr/bin/env perl

use 5.10.0;

use strict;
use warnings;

use Path::Class;
use Term::Prompt;
use Term::ANSIColor;
use File::HomeDir;
use Config::INI::Reader;

my $config_file = file( File::HomeDir->my_home, '.dancecard' );

if ( @ARGV ) {
    add_repo(@ARGV);
}
else {
    select_libs();
}

sub add_repo {
    my( $url, $name ) = @_;
        
    unless ( $name ) {
        $name = $1 if $url =~ m#([^/]+?)(?:\.git)?$#;
    }

    open my $config_fh, '>>', $config_file->stringify;

    print $config_fh <<"END_REMOTE";
[$name]
    url = $url

END_REMOTE

    say "library '$name' added"
}

sub select_libs {
    $config_file->touch;
    my $config = Config::INI::Reader->read_file($config_file->stringify);

    die "no library added yet" unless %$config;

    die "no 'public/' directory found, are we in a Dancer project?\n"
        unless -d 'public';

    while ( 1 ) {
        my @menu_items = map {
            colored( $_, -d dir('public', $_ ) ? 'blue' : 'green' );
        } keys %$config;

        my @results = prompt( 'm', {
                prompt                 => 'libraries to add',
                title                  => "\ndev libaries",
                items                  => \@menu_items,
                accept_empty_selection => 1,
                accept_multiple_selections => 1,
            },
            'empty to exit',
            undef
        );

        last unless @results;

        for( (keys %$config)[@results] ) {
            copy_lib( $_ => $config->{$_} );
        }
    }
}

sub copy_lib {
    my( $name, $data ) = @_;

    require Git::Repository;

    say "\ncloning '$name'...";

    Git::Repository->run( clone => $data->{url}, "public/".$name );

    say 'done';
}

The result (without, alas, the full color display):

$ dancecard git://github.com/Seldaek/slippy.git
library 'slippy' added

$ dancecard git://github.com/twitter/bootstrap.git
library 'bootstrap' added

$ dancecard git://github.com/FortAwesome/Font-Awesome.git
library 'Font-Awesome' added

$ dancer -a myapp && cd myapp

$ dancecard 

dev libaries
-------------
1) Font-Awesome 2) bootstrap    3) slippy       

libraries to add (empty to exit) 1

cloning 'Font-Awesome'...
done

dev libaries
-------------
1) *Font-Awesome* 2) bootstrap    3) slippy       

libraries to add (empty to exit) 2

cloning 'bootstrap'...
done

dev libaries
-------------
1) *Font-Awesome* 2) *bootstrap*    3) slippy       

libraries to add (empty to exit)

Conclusion

This little dancecard script is already a handy little thing. But it only scratches the surface of what could be done: there could be an option to only download the latest version of a library instead of the whole Git history, direct http links instead of git urls, ways to group libraries together, a check that would update the current libraries to their latest versions, etc. This, however, is feature creep that will have to wait for another day...

Author

This article has been written by Yanick Champoux for the Perl Dancer Advent Calendar 2012.

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