microidutils.py

#Djangoid - Django-based OpenID server/provider
#Copyright (C) 2006  Nicolas Trangez <ikke nicolast be>
#
#This program is free software; you can redistribute it and/or modify
#it under the terms of the GNU General Public License as published by
#the Free Software Foundation; either version 2 of the License.
#
#This program is distributed in the hope that it will be useful,
#but WITHOUT ANY WARRANTY; without even the implied warranty of
#MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#GNU General Public License for more details.
#
#You should have received a copy of the GNU General Public License
#along with this program; if not, write to the Free Software
#Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
#
#EOL
from urllib2 import urlopen, URLError
import sha
from HTMLParser import HTMLParser, HTMLParseError

def microid(c, p, newstyle = True, hash = "sha1"):
        """
        This function generates a MicroID digest based on claimer URI and property URI

        >>> microid("http://nicolast.be", "http://www.eikke.com", False)
        'a6a18b671b0239ed85a32543ec487f443582e926'
        >>> microid("http://nicolast.be", "http://blog.eikke.com")
        'http+http:sha1:207ec367c4f64dc9d37c47fb490ed9c2f686f875'
        >>> microid("mailto:spambox@nicolast.be", "http://nicolast.be")
        'mailto+http:sha1:6646f18368bc40c4095092d61807ae98de9ef19a'
        """
        hashfunc = None
        if hash == "sha1":
                hashfunc = sha.new
        else:
                raise Exception, "Only sha1 hashing is supported for now"

        digest = hashfunc(hashfunc(c).hexdigest() + hashfunc(p).hexdigest()).hexdigest()

        if newstyle:
                s1 = c.split(":")[0]
                s2 = p.split(":")[0]
                digest = "%(firsturi)s+%(seconduri)s:%(hash)s:%(microid)s" % {"firsturi": s1, "seconduri": s2, "hash": hash, "microid": digest}
        return digest

class MicroIDParser(HTMLParser):
        in_head = False
        microids = []

        def handle_starttag(self, tag, attrs):
                if tag.lower() == "head":
                        self.in_head = True
                if self.in_head and tag.lower() == "meta" and self.get_attr(attrs, "name") and self.get_attr(attrs, "name").lower() == "microid":
                        self.microids.append(self.get_attr(attrs, "content"))

        def handle_endtag(self, tag):
                if tag.lower() == "head":
                        self.in_head = False

        def get_microids(self):
                return self.microids

        def get_attr(self, attrs, name):
                for a in attrs:
                        if a[0] == name:
                                return a[1]
                return None

def find_microid(uri):
        ret = None
        p = MicroIDParser()
        buffsize = 4096
        try:
                handle = urlopen(uri)
                html = handle.read(buffsize)
                while html:
                        p.feed(html)
                        html = handle.read(buffsize)
                ret = p.get_microids()
        except URLError, ue:
                pass
        except HTMLParseError, he:
                pass
        except ValueError, ve:
                pass

        return ret