pip install BeautifulSoup

habr_tm.py

#!/usr/bin/python

import SocketServer
import SimpleHTTPServer
import urllib
import re
from BeautifulSoup import BeautifulSoup, NavigableString, Tag, PageElement

TARGET = 'habrahabr.ru'
HOST = '127.0.0.1'
PORT = 8232
PROXY_URL = 'http://%s:%s' % (HOST, PORT)
URL_REGEX = re.compile('^https?://%s' % TARGET)

# fix ampersand bug
PageElement._sub_entity = lambda self, x: x.group(0)[0]


def find_text(tag):
    t_tag = type(tag)
    if t_tag == Tag:
        if tag.name in ['script', 'style']:
            return []
        # replace target url
        if tag.name == 'a' and tag.get('href'):
            tag['href'] = URL_REGEX.sub(PROXY_URL, tag['href'])

    # text
    if t_tag == NavigableString:
        return [tag]

    # deep
    data = []
    if hasattr(tag, 'contents'):
        for i in tag.contents:
            data.extend(find_text(i))
    return data


def tm_injection(data):
    ln = 0
    for c in data:
        if c.isalpha():
            ln += 1
        else:
            if ln == 6:
                c = '™' + c
            ln = 0
        yield c
    if ln == 6:
        yield '™'


class HabrWrapper(object):

    def __init__(self, f):
        self.file = f

    def read(self, size=None):
        # read all
        page = ''
        while 1:
            buf = self.file.read(16*1024)
            if not buf:
                break
            page += buf
        if not page:
            return
        soup = BeautifulSoup(page)
        soup.convertHTMLEntities = False

        text_tags = find_text(soup)
        for tag in text_tags:
            m_str = ''.join(tm_injection(tag.string))
            tag.replaceWith(m_str)
        return soup

    def __getattr__(self, attr):
        return getattr(self.file, attr)


class Proxy(SimpleHTTPServer.SimpleHTTPRequestHandler):

    def do_GET(self):
        print self.requestline
        f = urllib.urlopen('http://%s%s' % (TARGET, self.path))
        if f.headers['Content-Type'].startswith('text/html;'):
            f = HabrWrapper(f)
        self.copyfile(f, self.wfile)


if __name__ == '__main__':
    httpd = SocketServer.TCPServer((HOST, PORT), Proxy)
    print 'Starting proxy server at %s' % PROXY_URL
    httpd.serve_forever()