combine javascript files at deployment in python

Question

I'm trying to reduce the number of scripts included in our website and we use buildout to handle deployments. Has anybody successfully implemented a method of combining and compressing scripts with buildout?

Answer 1

Here's a Python script I made that I use with all my heavy JavaScript projects. I'm using YUICompressor, but you can change the code to use another compressor.

import os, os.path, shutil

YUI_COMPRESSOR = 'yuicompressor-2.4.2.jar'

def compress(in_files, out_file, in_type='js', verbose=False,
             temp_file='.temp'):
    temp = open(temp_file, 'w')
    for f in in_files:
        fh = open(f)
        data = fh.read() + '\n'
        fh.close()

        temp.write(data)

        print ' + %s' % f
    temp.close()

    options = ['-o "%s"' % out_file,
               '--type %s' % in_type]

    if verbose:
        options.append('-v')

    os.system('java -jar "%s" %s "%s"' % (YUI_COMPRESSOR,
                                          ' '.join(options),
                                          temp_file))

    org_size = os.path.getsize(temp_file)
    new_size = os.path.getsize(out_file)

    print '=> %s' % out_file
    print 'Original: %.2f kB' % (org_size / 1024.0)
    print 'Compressed: %.2f kB' % (new_size / 1024.0)
    print 'Reduction: %.1f%%' % (float(org_size - new_size) / org_size * 100)
    print ''

    #os.remove(temp_file)

I use it like this (the below is just a code snippet, and assumes that the compress function exists in the current namespace):

SCRIPTS = [
    'app/js/libs/EventSource.js',
    'app/js/libs/Hash.js',
    'app/js/libs/JSON.js',
    'app/js/libs/ServiceClient.js',
    'app/js/libs/jquery.hash.js',
    'app/js/libs/Application.js',
    'app/js/intro.js',
    'app/js/jquery-extras.js',
    'app/js/settings.js',
    'app/js/api.js',
    'app/js/game.js',
    'app/js/user.js',
    'app/js/pages.intro.js',
    'app/js/pages.home.js',
    'app/js/pages.log-in.js',
    'app/js/pages.log-out.js',
    'app/js/pages.new-command.js',
    'app/js/pages.new-frame.js',
    'app/js/pages.not-found.js',
    'app/js/pages.register.js',
    'app/js/pages.outro.js',
    'app/js/outro.js',
    ]
SCRIPTS_OUT_DEBUG = 'app/js/multifarce.js'
SCRIPTS_OUT = 'app/js/multifarce.min.js'

STYLESHEETS = [
    'app/media/style.css',
    ]
STYLESHEETS_OUT = 'app/media/style.min.css'

def main():
    print 'Compressing JavaScript...'
    compress(SCRIPTS, SCRIPTS_OUT, 'js', False, SCRIPTS_OUT_DEBUG)

    print 'Compressing CSS...'
    compress(STYLESHEETS, STYLESHEETS_OUT, 'css')

if __name__ == '__main__':
    main()