Fixed django-compressor#28 -- Improved CssMinFilter by including cssmin (which prevents local imports).

Author: jezdez

compressor/filters/cssmin.py renamed to compressor/filters/cssmin/__init__.py

@@ -1,15 +1,10 @@
 from compressor.filters import FilterBase, FilterError
+from compressor.filters.cssmin.cssmin import cssmin
 
 class CSSMinFilter(FilterBase):
     """
     A filter that utilizes Zachary Voase's Python port of
     the YUI CSS compression algorithm: http://pypi.python.org/pypi/cssmin/
     """
     def output(self, **kwargs):
-        try:
-            import cssmin
-        except ImportError, e:
-            if self.verbose:
-                raise FilterError('Failed to import cssmin: %s' % e)
-            return self.content
-        return cssmin.cssmin(self.content)
+        return cssmin(self.content)

compressor/filters/cssmin/cssmin.py

@@ -0,0 +1,248 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+#
+# `cssmin.py` - A Python port of the YUI CSS compressor.
+# 
+# Copyright (c) 2010 Zachary Voase
+# 
+# Permission is hereby granted, free of charge, to any person
+# obtaining a copy of this software and associated documentation
+# files (the "Software"), to deal in the Software without
+# restriction, including without limitation the rights to use,
+# copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the
+# Software is furnished to do so, subject to the following
+# conditions:
+# 
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+# 
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+# OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+# OTHER DEALINGS IN THE SOFTWARE.
+# 
+"""`cssmin` - A Python port of the YUI CSS compressor."""
+
+
+from StringIO import StringIO # The pure-Python StringIO supports unicode.
+import re
+
+
+__version__ = '0.1.4'
+
+
+def remove_comments(css):
+    """Remove all CSS comment blocks."""
+    
+    iemac = False
+    preserve = False
+    comment_start = css.find("/*")
+    while comment_start >= 0:
+        # Preserve comments that look like `/*!...*/`.
+        # Slicing is used to make sure we don"t get an IndexError.
+        preserve = css[comment_start + 2:comment_start + 3] == "!"
+        
+        comment_end = css.find("*/", comment_start + 2)
+        if comment_end < 0:
+            if not preserve:
+                css = css[:comment_start]
+                break
+        elif comment_end >= (comment_start + 2):
+            if css[comment_end - 1] == "\\":
+                # This is an IE Mac-specific comment; leave this one and the
+                # following one alone.
+                comment_start = comment_end + 2
+                iemac = True
+            elif iemac:
+                comment_start = comment_end + 2
+                iemac = False
+            elif not preserve:
+                css = css[:comment_start] + css[comment_end + 2:]
+            else:
+                comment_start = comment_end + 2
+        comment_start = css.find("/*", comment_start)
+    
+    return css
+
+
+def remove_unnecessary_whitespace(css):
+    """Remove unnecessary whitespace characters."""
+    
+    def pseudoclasscolon(css):
+        
+        """
+        Prevents 'p :link' from becoming 'p:link'.
+        
+        Translates 'p :link' into 'p ___PSEUDOCLASSCOLON___link'; this is
+        translated back again later.
+        """
+        
+        regex = re.compile(r"(^|\})(([^\{\:])+\:)+([^\{]*\{)")
+        match = regex.search(css)
+        while match:
+            css = ''.join([
+                css[:match.start()],
+                match.group().replace(":", "___PSEUDOCLASSCOLON___"),
+                css[match.end():]])
+            match = regex.search(css)
+        return css
+    
+    css = pseudoclasscolon(css)
+    # Remove spaces from before things.
+    css = re.sub(r"\s+([!{};:>+\(\)\],])", r"\1", css)
+    
+    # If there is a `@charset`, then only allow one, and move to the beginning.
+    css = re.sub(r"^(.*)(@charset \"[^\"]*\";)", r"\2\1", css)
+    css = re.sub(r"^(\s*@charset [^;]+;\s*)+", r"\1", css)
+    
+    # Put the space back in for a few cases, such as `@media screen` and
+    # `(-webkit-min-device-pixel-ratio:0)`.
+    css = re.sub(r"\band\(", "and (", css)
+    
+    # Put the colons back.
+    css = css.replace('___PSEUDOCLASSCOLON___', ':')
+    
+    # Remove spaces from after things.
+    css = re.sub(r"([!{}:;>+\(\[,])\s+", r"\1", css)
+    
+    return css
+
+
+def remove_unnecessary_semicolons(css):
+    """Remove unnecessary semicolons."""
+    
+    return re.sub(r";+\}", "}", css)
+
+
+def remove_empty_rules(css):
+    """Remove empty rules."""
+    
+    return re.sub(r"[^\}\{]+\{\}", "", css)
+
+
+def normalize_rgb_colors_to_hex(css):
+    """Convert `rgb(51,102,153)` to `#336699`."""
+    
+    regex = re.compile(r"rgb\s*\(\s*([0-9,\s]+)\s*\)")
+    match = regex.search(css)
+    while match:
+        colors = map(lambda s: s.strip(), match.group(1).split(","))
+        hexcolor = '#%.2x%.2x%.2x' % tuple(map(int, colors))
+        css = css.replace(match.group(), hexcolor)
+        match = regex.search(css)
+    return css
+
+
+def condense_zero_units(css):
+    """Replace `0(px, em, %, etc)` with `0`."""
+    
+    return re.sub(r"([\s:])(0)(px|em|%|in|cm|mm|pc|pt|ex)", r"\1\2", css)
+
+
+def condense_multidimensional_zeros(css):
+    """Replace `:0 0 0 0;`, `:0 0 0;` etc. with `:0;`."""
+    
+    css = css.replace(":0 0 0 0;", ":0;")
+    css = css.replace(":0 0 0;", ":0;")
+    css = css.replace(":0 0;", ":0;")
+    
+    # Revert `background-position:0;` to the valid `background-position:0 0;`.
+    css = css.replace("background-position:0;", "background-position:0 0;")
+    
+    return css
+
+
+def condense_floating_points(css):
+    """Replace `0.6` with `.6` where possible."""
+    
+    return re.sub(r"(:|\s)0+\.(\d+)", r"\1.\2", css)
+
+
+def condense_hex_colors(css):
+    """Shorten colors from #AABBCC to #ABC where possible."""
+    
+    regex = re.compile(r"([^\"'=\s])(\s*)#([0-9a-fA-F])([0-9a-fA-F])([0-9a-fA-F])([0-9a-fA-F])([0-9a-fA-F])([0-9a-fA-F])")
+    match = regex.search(css)
+    while match:
+        first = match.group(3) + match.group(5) + match.group(7)
+        second = match.group(4) + match.group(6) + match.group(8)
+        if first.lower() == second.lower():
+            css = css.replace(match.group(), match.group(1) + match.group(2) + '#' + first)
+            match = regex.search(css, match.end() - 3)
+        else:
+            match = regex.search(css, match.end())
+    return css
+
+
+def condense_whitespace(css):
+    """Condense multiple adjacent whitespace characters into one."""
+    
+    return re.sub(r"\s+", " ", css)
+
+
+def condense_semicolons(css):
+    """Condense multiple adjacent semicolon characters into one."""
+    
+    return re.sub(r";;+", ";", css)
+
+
+def wrap_css_lines(css, line_length):
+    """Wrap the lines of the given CSS to an approximate length."""
+    
+    lines = []
+    line_start = 0
+    for i, char in enumerate(css):
+        # It's safe to break after `}` characters.
+        if char == '}' and (i - line_start >= line_length):
+            lines.append(css[line_start:i + 1])
+            line_start = i + 1
+    
+    if line_start < len(css):
+        lines.append(css[line_start:])
+    return '\n'.join(lines)
+
+
+def cssmin(css, wrap=None):
+    css = remove_comments(css)
+    css = condense_whitespace(css)
+    # A pseudo class for the Box Model Hack
+    # (see http://tantek.com/CSS/Examples/boxmodelhack.html)
+    css = css.replace('"\\"}\\""', "___PSEUDOCLASSBMH___")
+    css = remove_unnecessary_whitespace(css)
+    css = remove_unnecessary_semicolons(css)
+    css = condense_zero_units(css)
+    css = condense_multidimensional_zeros(css)
+    css = condense_floating_points(css)
+    css = normalize_rgb_colors_to_hex(css)
+    css = condense_hex_colors(css)
+    if wrap is not None:
+        css = wrap_css_lines(css, wrap)
+    css = css.replace("___PSEUDOCLASSBMH___", '"\\"}\\""')
+    css = condense_semicolons(css)
+    return css.strip()
+
+
+def main():
+    import optparse
+    import sys
+    
+    p = optparse.OptionParser(
+        prog="cssmin", version=__version__,
+        usage="%prog [--wrap N]",
+        description="""Reads raw CSS from stdin, and writes compressed CSS to stdout.""")
+    
+    p.add_option(
+        '-w', '--wrap', type='int', default=None, metavar='N',
+        help="Wrap output to approximately N chars per line.")
+    
+    options, args = p.parse_args()
+    sys.stdout.write(cssmin(sys.stdin.read(), wrap=options.wrap))
+
+
+if __name__ == '__main__':
+    main()

tests/core/tests.py

@@ -200,6 +200,20 @@ def test_avoid_reordering_css(self):
         self.assertEqual(media, [l.get('media', None) for l in links])
 
 
+class CssMinTestCase(TestCase):
+    def test_cssmin_filter(self):
+        from compressor.filters.cssmin import CSSMinFilter
+        content = """p {
+
+
+        background: rgb(51,102,153) url(http://github.com/'../../images/image.gif');
+
+
+        }
+"""
+        output =  "p{background:#369 url(http://github.com/'../../images/image.gif')}"
+        self.assertEqual(output, CSSMinFilter(content).output())
+
 def render(template_string, context_dict=None):
     """A shortcut for testing template output."""
     if context_dict is None: