Added css_slimmer filter.

docs/builtin_filters.rst

@@ -78,6 +78,12 @@ CSS compressors
 .. autoclass:: webassets.filter.cleancss.CleanCSSFilter
 
 
+``slimmer_css``
+~~~~~~~~~~~~~~~
+
+.. autoclass:: webassets.filter.slimmer.CSSSlimmer
+
+
 .. _filters-css-compilers:
 
 CSS Compilers

requirements-dev.pip

@@ -14,6 +14,7 @@ cssmin
 yuicompressor
 closure
 pyScss
+slimmer
 
 # Default rsmin package is not installable via pip
 http://michael.elsdoerfer.name/rjsmin/rjsmin-1.0.1-webassets.tar.gz

src/webassets/filter/slimmer.py

@@ -0,0 +1,26 @@
+from __future__ import absolute_import
+
+from webassets.filter import Filter
+
+
+__all__ = ('CSSSlimmer',)
+
+
+class Slimmer(Filter):
+
+    def setup(self):
+        super(Slimmer, self).setup()
+        import slimmer
+        self.slimmer = slimmer
+
+
+class CSSSlimmer(Slimmer):
+    """Minifies CSS by removing whitespace, comments etc., using the Python
+    `slimmer <http://pypi.python.org/pypi/slimmer/>`_ library.
+    """
+
+    name = 'css_slimmer'
+
+    def output(self, _in, out, **kw):
+        out.write(self.slimmer.css_slimmer(_in.read()))
+

tests/test_filters.py

@@ -358,6 +358,14 @@ def test_cleancss(self):
         self.mkbundle('foo.css', filters='cleancss', output='out.css').build()
         assert self.get('out.css') == 'h1{font-family:"Verdana";color:#FFF}'
 
+    def test_cssslimmer(self):
+        try:
+            import slimmer
+        except ImportError:
+            raise SkipTest()
+        self.mkbundle('foo.css', filters='css_slimmer', output='out.css').build()
+        assert self.get('out.css') == 'h1{font-family:"Verdana";color:#FFF}'
+
 
 class TestCoffeeScript(TempEnvironmentHelper):