bridgy-fed/webfinger.py

"""Handles requests for WebFinger endpoints.

https://webfinger.net/
https://tools.ietf.org/html/rfc7033

Largely based on webfinger-unofficial/user.py.

TODO: test:
* /.well-known/webfinger
* acct: URI handling
* user URL that redirects
"""
import json
import logging
import urlparse

import appengine_config

from granary import microformats2
import mf2py
import mf2util
from oauth_dropins.webutil import handlers, util
import webapp2

import common
import models


class UserHandler(handlers.XrdOrJrdHandler):
    """Fetches a site's home page, converts its mf2 to WebFinger, and serves."""
    JRD_TEMPLATE = False

    def template_prefix(self):
        return 'templates/webfinger_user'

    def template_vars(self, username, domain):
        url = 'http://%s/' % domain

        # TODO: unify with activitypub
        resp = common.requests_get(url)
        mf2 = mf2py.parse(resp.text, url=resp.url)
        # logging.debug('Parsed mf2 for %s: %s', resp.url, json.dumps(mf2, indent=2))

        hcard = mf2util.representative_hcard(mf2, resp.url)
        logging.info('Representative h-card: %s', json.dumps(hcard, indent=2))
        if not hcard:
            common.error(self, """\
Couldn't find a <a href="http://microformats.org/wiki/representative-hcard-parsing">\
representative h-card</a> on %s""" % resp.url)

        acct = '%s@%s' % (username, domain)
        key = models.MagicKey.get_or_create(acct)
        props = hcard.get('properties', {})
        urls = util.dedupe_urls(props.get('url', []) + [resp.url])
        canonical_url = urls[0]

        data = util.trim_nulls({
            'subject': 'acct:' + acct,
            'aliases': urls,
            'magic_keys': [{'value': key.href()}],
            'links': sum(([{
                'rel': 'http://webfinger.net/rel/profile-page',
                'type': 'text/html',
                'href': url,
            }] for url in urls), []) + [{
                'rel': 'http://webfinger.net/rel/avatar',
                'href': url,
            } for url in props.get('photo', [])] + [{
                'rel': 'canonical_uri',
                'type': 'text/html',
                'href': canonical_url,
            }, {
                'rel': 'http://schemas.google.com/g/2010#updates-from',
                'type': common.ATOM_CONTENT_TYPE,
                # TODO: feed discovery, fall back to granary
                # TODO: hub
                'href': 'https://granary-demo.appspot.com/url?input=html&output=atom&url=%s&hub=%s' % (resp.url, resp.url),
            }, {
                'rel': 'magic-public-key',
                'href': key.href(),
            }, {
                'rel': 'salmon',
                'href': '%s/%s/salmon' % (self.request.host_url, acct),
            }]
        })
        logging.info('Returning WebFinger data: %s', json.dumps(data, indent=2))
        return data


class WebfingerHandler(UserHandler):

    def is_jrd(self):
        return True

    def template_vars(self):
        acct = util.get_required_param(self, 'resource')
        try:
            username, domain = util.parse_acct_uri(acct)
            url = 'http://%s/' % domain
        except ValueError:
            # common.error(self, 'Invalid acct: URI %s' % acct)
            username = 'ryan'
            domain = 'snarfed.org'
        if not username:
            common.error(self, 'No username found in acct: URI %s' % acct)

        return super(WebfingerHandler, self).template_vars(username, domain)


app = webapp2.WSGIApplication([
    (r'/%s/?' % common.ACCT_RE, UserHandler),
    ('/.well-known/webfinger', WebfingerHandler),
] + handlers.HOST_META_ROUTES, debug=appengine_config.DEBUG)