/src/pentest/plecost/xgoogle/sponsoredlinks.py

#!/usr/bin/python

#

# Peteris Krumins (peter@catonmat.net)

# http://www.catonmat.net  --  good coders code, great reuse

#

# http://www.catonmat.net/blog/python-library-for-google-sponsored-links-search/

#

# Code is licensed under MIT license.

#



import re

import urllib

import random

from htmlentitydefs import name2codepoint

from BeautifulSoup import BeautifulSoup



from browser import Browser, BrowserError



#

# TODO: join GoogleSearch and SponsoredLinks classes under a single base class

#



class SLError(Exception):

    """ Sponsored Links Error """

    pass



class SLParseError(Exception):

    """

    Parse error in Google results.

    self.msg attribute contains explanation why parsing failed

    self.tag attribute contains BeautifulSoup object with the most relevant tag that failed to parse

    Thrown only in debug mode

    """

     

    def __init__(self, msg, tag):

        self.msg = msg

        self.tag = tag



    def __str__(self):

        return self.msg



    def html(self):

        return self.tag.prettify()



GET_ALL_SLEEP_FUNCTION = object()



class SponsoredLink(object):

    """ a single sponsored link """

    def __init__(self, title, url, display_url, desc):

        self.title = title

        self.url = url

        self.display_url = display_url

        self.desc = desc



class SponsoredLinks(object):

    SEARCH_URL_0 = "http://www.google.com/sponsoredlinks?q=%(query)s&btnG=Search+Sponsored+Links&hl=en"

    NEXT_PAGE_0 = "http://www.google.com/sponsoredlinks?q=%(query)s&sa=N&start=%(start)d&hl=en"

    SEARCH_URL_1 = "http://www.google.com/sponsoredlinks?q=%(query)s&num=%(num)d&btnG=Search+Sponsored+Links&hl=en"

    NEXT_PAGE_1 = "http://www.google.com/sponsoredlinks?q=%(query)s&num=%(num)d&sa=N&start=%(start)d&hl=en"



    def __init__(self, query, random_agent=False, debug=False):

        self.query = query

        self.debug = debug

        self.browser = Browser(debug=debug)

        self._page = 0

        self.eor = False

        self.results_info = None

        self._results_per_page = 10



        if random_agent:

            self.browser.set_random_user_agent()



    @property

    def num_results(self):

        if not self.results_info:

            page = self._get_results_page()

            self.results_info = self._extract_info(page)

            if self.results_info['total'] == 0:

                self.eor = True

        return self.results_info['total']



    def _get_results_per_page(self):

        return self._results_per_page



    def _set_results_par_page(self, rpp):

        self._results_per_page = rpp



    results_per_page = property(_get_results_per_page, _set_results_par_page)



    def get_results(self):

        if self.eor:

            return []

        page = self._get_results_page()

        info = self._extract_info(page)

        if self.results_info is None:

            self.results_info = info

        if info['to'] == info['total']:

            self.eor = True

        results = self._extract_results(page)

        if not results:

            self.eor = True

            return []

        self._page += 1

        return results



    def _get_all_results_sleep_fn(self):

        return random.random()*5 + 1 # sleep from 1 - 6 seconds



    def get_all_results(self, sleep_function=None):

        if sleep_function is GET_ALL_SLEEP_FUNCTION:

            sleep_function = self._get_all_results_sleep_fn

        if sleep_function is None:

            sleep_function = lambda: None 

        ret_results = []

        while True:

            res = self.get_results()

            if not res:

                return ret_results

            ret_results.extend(res)

        return ret_results



    def _maybe_raise(self, cls, *arg):

        if self.debug:

            raise cls(*arg)



    def _extract_info(self, soup):

        empty_info = { 'from': 0, 'to': 0, 'total': 0 }

        stats_span = soup.find('span', id='stats')

        if not stats_span:

            return empty_info

        txt = ''.join(stats_span.findAll(text=True))

        txt = txt.replace(',', '').replace(" ", ' ')

        matches = re.search(r'Results (\d+) - (\d+) of (?:about )?(\d+)', txt)

        if not matches:

            return empty_info

        return {'from': int(matches.group(1)), 'to': int(matches.group(2)), 'total': int(matches.group(3))}



    def _get_results_page(self):

        if self._page == 0:

            if self._results_per_page == 10:

                url = SponsoredLinks.SEARCH_URL_0

            else:

                url = SponsoredLinks.SEARCH_URL_1

        else:

            if self._results_per_page == 10:

                url = SponsoredLinks.NEXT_PAGE_0

            else:

                url = SponsoredLinks.NEXT_PAGE_1



        safe_url = url % { 'query': urllib.quote_plus(self.query),

                           'start': self._page * self._results_per_page,

                           'num': self._results_per_page }



        try:

            page = self.browser.get_page(safe_url)

        except BrowserError, e:

            raise SLError, "Failed getting %s: %s" % (e.url, e.error)



        return BeautifulSoup(page)



    def _extract_results(self, soup):

        results = soup.findAll('div', {'class': 'g'})

        ret_res = []

        for result in results:

            eres = self._extract_result(result)

            if eres:

                ret_res.append(eres)

        return ret_res



    def _extract_result(self, result):

        title, url = self._extract_title_url(result)

        display_url = self._extract_display_url(result) # Warning: removes 'cite' from the result

        desc = self._extract_description(result)

        if not title or not url or not display_url or not desc:

            return None

        return SponsoredLink(title, url, display_url, desc)



    def _extract_title_url(self, result):

        title_a = result.find('a')

        if not title_a:

            self._maybe_raise(SLParseError, "Title tag in sponsored link was not found", result)

            return None, None

        title = ''.join(title_a.findAll(text=True))

        title = self._html_unescape(title)

        url = title_a['href']

        match = re.search(r'q=(http[^&]+)&', url)

        if not match:

            self._maybe_raise(SLParseError, "URL inside a sponsored link was not found", result)

            return None, None

        url = urllib.unquote(match.group(1))

        return title, url



    def _extract_display_url(self, result):

        cite = result.find('cite')

        if not cite:

            self._maybe_raise(SLParseError, "<cite> not found inside result", result)

            return None



        return ''.join(cite.findAll(text=True))



    def _extract_description(self, result):

        cite = result.find('cite')

        if not cite:

            return None

        cite.extract()



        desc_div = result.find('div', {'class': 'line23'})

        if not desc_div:

            self._maybe_raise(ParseError, "Description tag not found in sponsored link", result)

            return None



        desc_strs = desc_div.findAll(text=True)[0:-1]

        desc = ''.join(desc_strs)

        desc = desc.replace("\n", " ")

        desc = desc.replace("  ", " ")

        return self._html_unescape(desc)



    def _html_unescape(self, str):

        def entity_replacer(m):

            entity = m.group(1)

            if entity in name2codepoint:

                return unichr(name2codepoint[entity])

            else:

                return m.group(0)



        def ascii_replacer(m):

            cp = int(m.group(1))

            if cp <= 255:

                return unichr(cp)

            else:

                return m.group(0)



        s =    re.sub(r'&#(\d+);',  ascii_replacer, str, re.U)

        return re.sub(r'&([^;]+);', entity_replacer, s, re.U)