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# -*- test-case-name: openid.test.test_yadis_discover -*-
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__all__ = ['discover', 'DiscoveryResult', 'DiscoveryFailure']
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from cStringIO import StringIO
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from openid import fetchers
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from openid.yadis.constants import \
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YADIS_HEADER_NAME, YADIS_CONTENT_TYPE, YADIS_ACCEPT_HEADER
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from openid.yadis.parsehtml import MetaNotFound, findHTMLMeta
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class DiscoveryFailure(Exception):
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"""Raised when a YADIS protocol error occurs in the discovery process"""
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def __init__(self, message, http_response):
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Exception.__init__(self, message)
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self.http_response = http_response
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class DiscoveryResult(object):
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"""Contains the result of performing Yadis discovery on a URI"""
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# The URI that was passed to the fetcher
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# The result of following redirects from the request_uri
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# The URI from which the response text was returned (set to
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# None if there was no XRDS document found)
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# The content-type returned with the response_text
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# The document returned from the xrds_uri
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def __init__(self, request_uri):
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"""Initialize the state of the object
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sets all attributes to None except the request_uri
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self.request_uri = request_uri
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def usedYadisLocation(self):
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"""Was the Yadis protocol's indirection used?"""
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return self.normalized_uri != self.xrds_uri
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"""Is the response text supposed to be an XRDS document?"""
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return (self.usedYadisLocation() or
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self.content_type == YADIS_CONTENT_TYPE)
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"""Discover services for a given URI.
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@param uri: The identity URI as a well-formed http or https
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URI. The well-formedness and the protocol are not checked, but
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the results of this function are undefined if those properties
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@return: DiscoveryResult object
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@raises Exception: Any exception that can be raised by fetching a URL with
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result = DiscoveryResult(uri)
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resp = fetchers.fetch(uri, headers={'Accept': YADIS_ACCEPT_HEADER})
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if resp.status != 200:
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raise DiscoveryFailure(
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'HTTP Response status from identity URL host is not 200. '
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'Got status %r' % (resp.status,), resp)
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# Note the URL after following redirects
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result.normalized_uri = resp.final_url
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# Attempt to find out where to go to discover the document
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# or if we already have it
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result.content_type = resp.headers.get('content-type')
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result.xrds_uri = whereIsYadis(resp)
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if result.xrds_uri and result.usedYadisLocation():
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resp = fetchers.fetch(result.xrds_uri)
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if resp.status != 200:
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exc = DiscoveryFailure(
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'HTTP Response status from Yadis host is not 200. '
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'Got status %r' % (resp.status,), resp)
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exc.identity_url = result.normalized_uri
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result.content_type = resp.headers.get('content-type')
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result.response_text = resp.body
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def whereIsYadis(resp):
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"""Given a HTTPResponse, return the location of the Yadis document.
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May be the URL just retrieved, another URL, or None, if I can't
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@returns: str or None
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# Attempt to find out where to go to discover the document
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# or if we already have it
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content_type = resp.headers.get('content-type')
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# According to the spec, the content-type header must be an exact
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# match, or else we have to look for an indirection.
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content_type.split(';', 1)[0].lower() == YADIS_CONTENT_TYPE):
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return resp.final_url
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yadis_loc = resp.headers.get(YADIS_HEADER_NAME.lower())
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# Parse as HTML if the header is missing.
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# XXX: do we want to do something with content-type, like
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# have a whitelist or a blacklist (for detecting that it's
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yadis_loc = findHTMLMeta(StringIO(resp.body))
added
removed
openid/yadis/discover.py
