glom.py

import shutils, hashlib, os
from pylons import config, request
from webhelpers.html.tags import javascript_link, stylesheet_link

sha1  = lambda x : hashlib.sha1(x).hexdigest()
mtime = lambda path: os.path.stat(path).st_mtime

# FIXME factor out pylons adapter
class Glommer(object):

    @property
    def key(self):
        return 'glom.' + self.type

    @property
    def files(self):
        return request.environ.get(self.key, [])

    def src_path(self, path):
        return os.path.join(config['static_files'], self.type, path)

    def dest_path(self, filename):
        dir_path = os.path.join(config['static_files'], config['glom.emit_dirname'], self.type)

        if not os.path.is_dir(dir_path):
            os.makedirs(dir_path)

        return os.path.join(dir_path, path)

    def link_path(self, filename):
        return '/' + config['glom.emit_dirname'] +'/' + self.type '/' + self.filename

    def add_file(self, path):
        key = self.key

        if key not in request.environ:
            request.environ[key] = []
        
        request.environ[key].append(path)

        return ''

    @property
    def is_debug(self):
        return config['debug']

    def build_tag(self, path):
        return self.builder(path)

    def include(self, path):
        return self.add_file(path) if not self.is_debug else self.build_tag(path)

    def emit(self, filename=None):
        files = self.files
        paths = [ self.src_path(f) for f in files ]

        if not paths:
            return ''
            
        if filename is None:
            filename = sha1(','.join(files)) + '.' + self.type
            
        dest_path  = self.dest_path(filename)
        dest_mtime = mtime(dest_path)
        src_mtime  = max(mtime(f) for f in paths)

        if not os.path.is_file(dest_path) or src_mtime > dest_mtime:
            dest = open(dest_path, 'wb')

            for f in paths:
                shutil.copyfile(open(f, 'wb'), dest)

            dest.close()

        return self.build_tag(self.link_path(filename))

class JSGlommer(Glommer):
    type    = 'js'
    builder = javascript_link

class CSSGlommer(Glommer):
    type    = 'css'
    builder = stylesheet_link

js  = JSGlommer()
css = CSSGlommer()