Code forHow to Minify CSS with Python Tutorial

minify_css_tutorial.py

import cssutilsimport reimport loggingimport osimport timecssutils.log.setLevel(logging.CRITICAL)startTime = time.time()os.system('cls')def getFilesByExtension(ext, root):    foundFiles = []    for root, directories, files in os.walk(root):        for f in files:            if f.endswith(ext):                # os.path.join(root, f) is the full path to the file                foundFiles.append(os.path.join(root, f))     return foundFilesdef flattenStyleSheet(sheet):    ruleList = []    for rule in sheet.cssRules:        if rule.typeString == 'MEDIA_RULE':            ruleList += rule.cssRules        elif rule.typeString == 'STYLE_RULE':            ruleList.append(rule)    return ruleListdef findAllCSSClasses():    usedClasses = {}    # Find all used classes    for htmlFile in htmlFiles:        with open(htmlFile, 'r') as f:            htmlContent = f.read()        regex = r'class="(.*?)"'        # re.DOTALL is needed to match newlines        matched = re.finditer(regex, htmlContent, re.MULTILINE | re.DOTALL)         # matched is a list of re.Match objects        for i in matched:            for className in i.groups()[0].split(' '): # i.groups()[0] is the first group in the regex                usedClasses[className] = ''    return list(usedClasses.keys())def translateUsedClasses(classList):    for i, usedClass in enumerate(classList):        for translation in translations:            # If the class is found in the translations list, replace it            regex = translation[0]            subst = translation[1]            if re.search(regex, usedClass):                # re.sub() replaces the regex with the subst                result = re.sub(regex, subst, usedClass, 1, re.MULTILINE) # 1 is the max number of replacements                # Replace the class in the list                classList[i] = result    return classListhtmlFiles = getFilesByExtension('.html', '.')cssFiles = getFilesByExtension('.css', 'style')# Use Translations if the class names in the Markup dont exactly # match the CSS Selector ( Except for the dot at the begining. )translations = [    [        '@',        '\\@'    ],    [        r"(.*?):(.*)",        r"\g<1>\\:\g<2>:\g<1>",    ],    [        r"child(.*)",        "child\\g<1> > *",    ],]usedClasses = findAllCSSClasses()usedClasses = translateUsedClasses(usedClasses)output = 'min.css'newCSS = ''for cssFile in cssFiles:    # Parse the CSS File    sheet = cssutils.parseFile(cssFile)    rules = flattenStyleSheet(sheet)    noClassSelectors = []    for rule in rules:        for usedClass in usedClasses:            if '.' + usedClass == rule.selectorText:                # If the class is used in the HTML, add it to the new CSS                usedClasses.remove(usedClass) # Remove the class from the list                if rule.parentRule:                    newCSS += str(rule.parentRule.cssText)                else:                    newCSS += str(rule.cssText)        if rule.selectorText[0] != '.' and not rule.selectorText in noClassSelectors:             # If the selector doesnt start with a dot and is not already in the list,            # add it            noClassSelectors.append(rule.selectorText)            if rule.parentRule:                newCSS += str(rule.parentRule.cssText)            else:                newCSS += str(rule.cssText)newCSS = newCSS.replace('\n', '')newCSS = newCSS.replace('  ', '')with open(output, 'w') as f:    f.write(newCSS)print('TIME: ', time.time() - startTime)

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