Add example for using user location.

Uses http://freegeoip.com to get an approximate location based
on the machine's IP address.

examples/user_location.py

@@ -0,0 +1,125 @@
+#!/usr/bin/env python
+
+import sys
+import logging
+import getpass
+from optparse import OptionParser
+
+try:
+    import json
+except ImportError:
+    import simplejson as json
+
+try:
+    import requests
+except ImportError:
+    print('This demo requires the requests package for using HTTP.')
+    sys.exit()
+
+from sleekxmpp import ClientXMPP
+
+
+class LocationBot(ClientXMPP):
+
+    def __init__(self, jid, password):
+        super(LocationBot, self).__init__(jid, password)
+
+        self.add_event_handler('session_start', self.start)
+        self.add_event_handler('user_location_publish', 
+                               self.user_location_publish)
+
+        self.register_plugin('xep_0004')
+        self.register_plugin('xep_0030')
+        self.register_plugin('xep_0060')
+        self.register_plugin('xep_0115')
+        self.register_plugin('xep_0128')
+        self.register_plugin('xep_0163')
+        self.register_plugin('xep_0080')
+
+        self.current_tune = None
+
+    def start(self, event):
+        self.send_presence()
+        self.get_roster()
+        self['xep_0115'].update_caps()
+
+        print("Using freegeoip.net to get geolocation.")
+        r = requests.get('http://freegeoip.net/json/')
+        try:
+            data = json.loads(r.text)
+        except:
+            print("Could not retrieve user location.")
+            self.disconnect()
+            return
+
+        self['xep_0080'].publish_location(
+                lat=data['latitude'],
+                lon=data['longitude'],
+                locality=data['city'],
+                region=data['region_name'],
+                country=data['country_name'],
+                countrycode=data['country_code'],
+                postalcode=data['zipcode'])
+
+    def user_location_publish(self, msg):
+        geo = msg['pubsub_event']['items']['item']['geoloc']
+        print("%s is at:" % msg['from'])
+        for key, val in geo.values.items():
+            if val:
+                print("  %s: %s" % (key, val))
+
+
+if __name__ == '__main__':
+    # Setup the command line arguments.
+    optp = OptionParser()
+
+    # Output verbosity options.
+    optp.add_option('-q', '--quiet', help='set logging to ERROR',
+                    action='store_const', dest='loglevel',
+                    const=logging.ERROR, default=logging.INFO)
+    optp.add_option('-d', '--debug', help='set logging to DEBUG',
+                    action='store_const', dest='loglevel',
+                    const=logging.DEBUG, default=logging.INFO)
+    optp.add_option('-v', '--verbose', help='set logging to COMM',
+                    action='store_const', dest='loglevel',
+                    const=5, default=logging.INFO)
+
+    # JID and password options.
+    optp.add_option("-j", "--jid", dest="jid",
+                    help="JID to use")
+    optp.add_option("-p", "--password", dest="password",
+                    help="password to use")
+
+    opts, args = optp.parse_args()
+
+    # Setup logging.
+    logging.basicConfig(level=opts.loglevel,
+                        format='%(levelname)-8s %(message)s')
+
+    if opts.jid is None:
+        opts.jid = raw_input("Username: ")
+    if opts.password is None:
+        opts.password = getpass.getpass("Password: ")
+
+    xmpp = LocationBot(opts.jid, opts.password)
+
+    # If you are working with an OpenFire server, you may need
+    # to adjust the SSL version used:
+    # xmpp.ssl_version = ssl.PROTOCOL_SSLv3
+
+    # If you want to verify the SSL certificates offered by a server:
+    # xmpp.ca_certs = "path/to/ca/cert"
+
+    # Connect to the XMPP server and start processing XMPP stanzas.
+    if xmpp.connect():
+        # If you do not have the dnspython library installed, you will need
+        # to manually specify the name of the server if it does not match
+        # the one in the JID. For example, to use Google Talk you would
+        # need to use:
+        #
+        # if xmpp.connect(('talk.google.com', 5222)):
+        #     ...
+        xmpp.process(block=True)
+        print("Done")
+    else:
+        print("Unable to connect.")