lesscss.py

import os
import tempfile
from compress.filter_base import FilterBase

class LessCSSFilter(FilterBase):
    """
    A filter for django-compress that adds LessCSS support.
    Based off of "compress.filters.csstidy.CSSTidyFilter".
    
    Supported settings:
    * LESSCSS_BINARY: The path to the LessCSS binary. Defaults to 'lessc'.
    * LESSCSS_ARGUMENTS: Any additional arguments to pass to the LessCSS 
        command line. Defaults to None.
    """
    def filter_css(self, css):
        """
        Compresses a string of CSS files using the LessCSS preprocessor.
        """
        from django.conf import settings
        BINARY = getattr(settings, 'LESSCSS_BINARY', 'lessc')
        ARGUMENTS = getattr(settings, 'LESSCSS_ARGUMENTS', None)
        
        tmp_file = tempfile.NamedTemporaryFile(mode='w+b')
        tmp_file.write(css)
        tmp_file.flush()
        
        output_file = tempfile.NamedTemporaryFile(mode='w+b')
        
        command = '%s %s %s' % (BINARY, tmp_file.name, output_file.name)
        
        if ARGUMENTS:
            command = '%s %s' % (command, ARGUMENTS)
        
        command_output = os.popen(command).read()
        
        filtered_css = output_file.read()
        output_file.close()
        tmp_file.close()
        
        if self.verbose:
            print command_output
        
        return filtered_css