Package: cssutils
OverviewA Python package to parse and build CSS Cascading Style Sheets. DOM only, not any rendering facilities!Based upon and partly implementing the following specifications :CSS 2.1rev1General CSS rules and properties are defined hereCSS3 Module: SyntaxUsed in parts since cssutils 0.9.4. cssutils tries to use the features from CSS 2.1 and CSS 3 with preference to CSS3 but as this is not final yet some parts are from CSS 2.1CSS Fonts Module Level 3Added changes and additional stuff (since cssutils v0.9.6)MediaQueriesMediaQueries are part ofstylesheets.MediaListsince v0.9.4, used in @import and @media rules.NamespacesAdded in v0.9.1, updated to definition in CSSOM in v0.9.4, updated in 0.9.5 for dev versionCSS3 Module: Pages MediaMost properties of this spec are implemented including MarginRulesSelectorsThe selector syntax defined here (and not in CSS 2.1) should be parsable with cssutils (shouldmind though ;) )CSS Backgrounds and Borders Module Level 3,CSS3 Basic User Interface Module,CSS Text Level 3Some validation for properties included, mainlycursor,outline,resize,box-shadow,text-shadowVariables/CSS Custom PropertiesExperimental specification of CSS Variables which cssutils implements partly. The vars defined in the newer CSS Custom Properties spec should in main parts be at least parsable with cssutils.DOM Level 2 Style CSSDOM for package css. 0.9.8 removes support for CSSValue and related API, see PropertyValue and Value API for nowDOM Level 2 Style StylesheetsDOM for package stylesheetsCSSOMA few details (mainly the NamespaceRule DOM) are taken from here. Plan is to move implementation to the stuff defined here which is newer but still no REC so might change anytime…The cssutils tokenizer is a customized implementation ofCSS3 Module: Syntax (W3C Working Draft 13 August 2003)which itself is based on the CSS 2.1 tokenizer. It tries to be as compliant as possible but uses some (helpful) parts of the CSS 2.1 tokenizer.I guess cssutils is neither CSS 2.1 nor CSS 3 compliant but tries to at least be able to parse both grammars including some more real world cases (some CSS hacks are actually parsed and serialized). Both official grammars are not final nor bugfree but still feasible. cssutils aim is not to be fully compliant to any CSS specification (the specifications seem to be in a constant flow anyway) but cssutilsshouldbe able to read and write as many as possible CSS stylesheets “in the wild” while at the same time implement the official APIs which are well documented. Some minor extensions are provided as well.Compatibilitycssutils is developed on modern Python versions. Check the package metadata
for compatibilty.Beware, cssutils is known to be thread unsafe.Exampleimport cssutils

css = '''/* a comment with umlaut &auml; */
     @namespace html "http://www.w3.org/1999/xhtml";
     @variables { BG: #fff }
     html|a { color:red; background: var(BG) }'''
sheet = cssutils.parseString(css)

for rule in sheet:
    if rule.type == rule.STYLE_RULE:
        # find property
        for property in rule.style:
            if property.name == 'color':
                property.value = 'green'
                property.priority = 'IMPORTANT'
                break
        # or simply:
        rule.style['margin'] = '01.0eM' # or: ('1em', 'important')

sheet.encoding = 'ascii'
sheet.namespaces['xhtml'] = 'http://www.w3.org/1999/xhtml'
sheet.namespaces['atom'] = 'http://www.w3.org/2005/Atom'
sheet.add('atom|title {color: #000000 !important}')
sheet.add('@import "sheets/import.css";')

# cssutils.ser.prefs.resolveVariables == True since 0.9.7b2
print sheet.cssTextresults in:@charset "ascii";
@import "sheets/import.css";
/* a comment with umlaut \E4  */
@namespace xhtml "http://www.w3.org/1999/xhtml";
@namespace atom "http://www.w3.org/2005/Atom";
xhtml|a {
    color: green !important;
    background: #fff;
    margin: 1em
    }
atom|title {
    color: #000 !important
    }Kind Requestcssutils is far from being perfect or even complete. If you find any bugs (especially specification violations) or have problems or suggestions please put them in theIssue Tracker.ThanksSpecial thanks to Christof Höke for seminal creation of the library.Thanks to Simon Sapin, Jason R. Coombs, and Walter Doerwald for patches, help and discussion. Thanks to Kevin D. Smith for the value validating module. Thanks also to Cory Dodt, Tim Gerla, James Dobson and Amit Moscovich for helpful suggestions and code patches. Thanks to Fredrik Hedman for help on port of encutils to Python 3.For EnterpriseAvailable as part of the Tidelift Subscription.This project and the maintainers of thousands of other packages are working with Tidelift to deliver one enterprise subscription that covers all of the open source you use.Learn more.