Django tag for compressing in-page javascript

Django-compress is great, but it doesn't offer any tags for compressing in-page javascript.

Are there some solutions out there? Even removing newlines (and adding ";" w开发者_Python百科here needed) would be just great.

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Okay, i've done this myself, using JSCompressor by Michael Palmer (http://code.activestate.com/recipes/496882/)

Here's the code:

from django import template

def do_foldjs(parser, token):
    nodelist = parser.parse(('endfoldjs',))
    parser.delete_first_token()
    return FoldJSNode(nodelist)

class FoldJSNode(template.Node):
    def __init__(self, nodelist):
        self.nodelist = nodelist
    def render(self, context):
        output = self.nodelist.render(context)

        try:
            compressor = JSCompressor(compressionLevel=2)
            return compressor.compress(output)
        except:
            return output


import re



class JSCompressor(object):

    def __init__(self, compressionLevel=2, measureCompression=False):
        '''
        compressionLevel:
        0 - no compression, script returned unchanged. For debugging only -
            try if you suspect that compression compromises your script
        1 - Strip comments and empty lines, don't change line breaks and indentation (code remains readable)
        2 - Additionally strip insignificant whitespace (code will become quite unreadable)

        measureCompression: append a comment stating the extent of compression

            @author: Michael Palmer
            @see: http://code.activestate.com/recipes/496882/
            @see: http://webscripts.softpedia.com/developer/Michael-Palmer-8459.html
            @see: http://webscripts.softpedia.com/script/Development-Scripts-js/JavaScript-code-compression--18221.html
        '''
        self.compressionLevel = compressionLevel
        self.measureCompression = measureCompression

    # a bunch of regexes used in compression
    # first, exempt string and regex literals from compression by transient substitution

    findLiterals = re.compile(r'''
        (\'.*?(?<=[^\\])\')             |       # single-quoted strings
        (\".*?(?<=[^\\])\")             |       # double-quoted strings
        ((?<![\*\/])\/(?![\/\*]).*?(?<![\\])\/) # JS regexes, trying hard not to be tripped up by comments
        ''', re.VERBOSE)

    # literals are temporarily replaced by numbered placeholders

    literalMarker = '@_@%d@_@'                  # temporary replacement
    backSubst = re.compile('@_@(\d+)@_@')       # put the string literals back in

    mlc1 = re.compile(r'(\/\*.*?\*\/)')         # /* ... */ comments on single line
    mlc = re.compile(r'(\/\*.*?\*\/)', re.DOTALL)  # real multiline comments
    slc = re.compile('\/\/.*')                  # remove single line comments

    collapseWs = re.compile('(?<=\S)[ \t]+')    # collapse successive non-leading white space characters into one

    squeeze = re.compile('''
        \s+(?=[\}\]\)\:\&\|\=\;\,\.\+])   |     # remove whitespace preceding control characters
        (?<=[\{\[\(\:\&\|\=\;\,\.\+])\s+  |     # ... or following such
        [ \t]+(?=\W)                      |     # remove spaces or tabs preceding non-word characters
        (?<=\W)[ \t]+                           # ... or following such
        '''
        , re.VERBOSE | re.DOTALL)

    def compress(self, script):
        '''
        perform compression and return compressed script
        '''
        if self.compressionLevel == 0:
            return script

        lengthBefore = len(script)

        # first, substitute string literals by placeholders to prevent the regexes messing with them
        literals = []

        def insertMarker(mo):
            l = mo.group()
            literals.append(l)
            return self.literalMarker % (len(literals) - 1)

        script = self.findLiterals.sub(insertMarker, script)

        # now, to the literal-stripped carcass, apply some kludgy regexes for deflation...
        script = self.slc.sub('', script)       # strip single line comments
        script = self.mlc1.sub(' ', script)     # replace /* .. */ comments on single lines by space
        script = self.mlc.sub('\n', script)     # replace real multiline comments by newlines

        # remove empty lines and trailing whitespace
        script = '\n'.join([l.rstrip() for l in script.splitlines() if l.strip()])

        if self.compressionLevel == 2:              # squeeze out any dispensible whitespace
            script = self.squeeze.sub('', script)
        elif self.compressionLevel == 1:            # only collapse multiple whitespace characters
            script = self.collapseWs.sub(' ', script)

        # now back-substitute the string and regex literals
        def backsub(mo):
            return literals[int(mo.group(1))]

        script = self.backSubst.sub(backsub, script)

        if self.measureCompression:
            lengthAfter = float(len(script))
            squeezedBy = int(100*(1-lengthAfter/lengthBefore))
            script += '\n// squeezed out %s%%\n' % squeezedBy

        return script

Registration:

register = template.Library()
register.tag('foldjs', do_foldjs)

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Why do you even have in-page Javascript? You can (and should) always move Javascript to external files, so that they can be cached by the browser. That is unless, of course, you're loading variables into Javascript. In that case, there shouldn't be much to compress anyway.

If you're trying to achieve obfuscation however...that's a different story altogether.

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One very simple option is to move the minification out of Django. Google's mod_pagespeed Apache module does a very good job, especially if you have to deal with legacy projects.