Initial python3 changes

Mostly just updating libraries, removing string encoding/decoding,
fixing some edge cases. No new functionality was added in this
commit.

lib/beetsplug/plexupdate.py

@@ -0,0 +1,110 @@
+"""Updates an Plex library whenever the beets library is changed.
+
+Plex Home users enter the Plex Token to enable updating.
+Put something like the following in your config.yaml to configure:
+    plex:
+        host: localhost
+        port: 32400
+        token: token
+"""
+
+import requests
+from xml.etree import ElementTree
+from urllib.parse import urljoin, urlencode
+from beets import config
+from beets.plugins import BeetsPlugin
+
+
+def get_music_section(host, port, token, library_name, secure,
+                      ignore_cert_errors):
+    """Getting the section key for the music library in Plex.
+    """
+    api_endpoint = append_token('library/sections', token)
+    url = urljoin('{}://{}:{}'.format(get_protocol(secure), host,
+                  port), api_endpoint)
+
+    # Sends request.
+    r = requests.get(url, verify=not ignore_cert_errors)
+
+    # Parse xml tree and extract music section key.
+    tree = ElementTree.fromstring(r.content)
+    for child in tree.findall('Directory'):
+        if child.get('title') == library_name:
+            return child.get('key')
+
+
+def update_plex(host, port, token, library_name, secure,
+                ignore_cert_errors):
+    """Ignore certificate errors if configured to.
+    """
+    if ignore_cert_errors:
+        import urllib3
+        urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)
+    """Sends request to the Plex api to start a library refresh.
+    """
+    # Getting section key and build url.
+    section_key = get_music_section(host, port, token, library_name,
+                                    secure, ignore_cert_errors)
+    api_endpoint = f'library/sections/{section_key}/refresh'
+    api_endpoint = append_token(api_endpoint, token)
+    url = urljoin('{}://{}:{}'.format(get_protocol(secure), host,
+                  port), api_endpoint)
+
+    # Sends request and returns requests object.
+    r = requests.get(url, verify=not ignore_cert_errors)
+    return r
+
+
+def append_token(url, token):
+    """Appends the Plex Home token to the api call if required.
+    """
+    if token:
+        url += '?' + urlencode({'X-Plex-Token': token})
+    return url
+
+
+def get_protocol(secure):
+    if secure:
+        return 'https'
+    else:
+        return 'http'
+
+
+class PlexUpdate(BeetsPlugin):
+    def __init__(self):
+        super().__init__()
+
+        # Adding defaults.
+        config['plex'].add({
+            'host': 'localhost',
+            'port': 32400,
+            'token': '',
+            'library_name': 'Music',
+            'secure': False,
+            'ignore_cert_errors': False})
+
+        config['plex']['token'].redact = True
+        self.register_listener('database_change', self.listen_for_db_change)
+
+    def listen_for_db_change(self, lib, model):
+        """Listens for beets db change and register the update for the end"""
+        self.register_listener('cli_exit', self.update)
+
+    def update(self, lib):
+        """When the client exists try to send refresh request to Plex server.
+        """
+        self._log.info('Updating Plex library...')
+
+        # Try to send update request.
+        try:
+            update_plex(
+                config['plex']['host'].get(),
+                config['plex']['port'].get(),
+                config['plex']['token'].get(),
+                config['plex']['library_name'].get(),
+                config['plex']['secure'].get(bool),
+                config['plex']['ignore_cert_errors'].get(bool))
+            self._log.info('... started.')
+
+        except requests.exceptions.RequestException:
+            self._log.warning('Update failed.')