Decrease discovery overhead

pychromecast/dial.py

@@ -2,11 +2,9 @@
 Implements the DIAL-protocol to communicate with the Chromecast
 """
 from collections import namedtuple
-import json
 import logging
 import socket
-import ssl
-import urllib.request
+import requests
 from uuid import UUID
 
 import zeroconf
@@ -58,7 +56,7 @@ def _get_host_from_zc_service_info(service_info: zeroconf.ServiceInfo):
     return (host, port)
 
 
-def _get_status(host, services, zconf, path, secure, timeout):
+def _get_status(host, services, zconf, path, secure, timeout, session=None):
     """
     :param host: Hostname or ip to fetch status from
     :type host: str
@@ -75,21 +73,30 @@ def _get_status(host, services, zconf, path, secure, timeout):
 
     headers = {"content-type": "application/json"}
 
-    context = None
     if secure:
         url = FORMAT_BASE_URL_HTTPS.format(host) + path
-        context = ssl.SSLContext()
-        context.verify_mode = ssl.CERT_NONE
     else:
         url = FORMAT_BASE_URL_HTTP.format(host) + path
 
-    req = urllib.request.Request(url, headers=headers)
-    with urllib.request.urlopen(req, timeout=timeout, context=context) as response:
-        data = response.read()
-    return json.loads(data.decode("utf-8"))
+    has_session = bool(session)
+    if not has_session:
+        session = get_requests_session()
+
+    try:
+        return session.get(url, headers=headers, timeout=timeout).json()
+    finally:
+        if not has_session:
+            session.close()
+
+
+def get_requests_session():
+    """Create a requests session."""
+    session = requests.Session()
+    session.verify = False
+    return session
 
 
-def get_device_status(host, services=None, zconf=None, timeout=10):
+def get_device_status(host, services=None, zconf=None, timeout=10, session=None):
     """
     :param host: Hostname or ip to fetch status from
     :type host: str
@@ -99,7 +106,7 @@ def get_device_status(host, services=None, zconf=None, timeout=10):
 
     try:
         status = _get_status(
-            host, services, zconf, "/setup/eureka_info?options=detail", True, timeout
+            host, services, zconf, "/setup/eureka_info?options=detail", True, timeout, session
         )
 
         friendly_name = status.get("name", "Unknown Chromecast")
@@ -119,7 +126,7 @@ def get_device_status(host, services=None, zconf=None, timeout=10):
 
         return DeviceStatus(friendly_name, model_name, manufacturer, uuid, cast_type)
 
-    except (urllib.error.HTTPError, urllib.error.URLError, OSError, ValueError):
+    except (requests.exceptions.Timeout, requests.exceptions.RequestException, OSError, ValueError):
         return None
 
 
@@ -144,7 +151,7 @@ def _get_group_info(host, group):
     return MultizoneInfo(name, uuid, leader_host, leader_port)
 
 
-def get_multizone_status(host, services=None, zconf=None, timeout=10):
+def get_multizone_status(host, services=None, zconf=None, timeout=10, session=None):
     """
     :param host: Hostname or ip to fetch status from
     :type host: str
@@ -154,7 +161,7 @@ def get_multizone_status(host, services=None, zconf=None, timeout=10):
 
     try:
         status = _get_status(
-            host, services, zconf, "/setup/eureka_info?params=multizone", True, timeout
+            host, services, zconf, "/setup/eureka_info?params=multizone", True, timeout, session
         )
 
         dynamic_groups = []
@@ -169,7 +176,7 @@ def get_multizone_status(host, services=None, zconf=None, timeout=10):
 
         return MultizoneStatus(dynamic_groups, groups)
 
-    except (urllib.error.HTTPError, urllib.error.URLError, OSError, ValueError):
+    except (requests.exceptions.Timeout, requests.exceptions.RequestException, OSError, ValueError):
         return None
 
 

pychromecast/discovery.py

@@ -11,7 +11,7 @@
 import zeroconf
 
 from .const import SERVICE_TYPE_HOST, SERVICE_TYPE_MDNS
-from .dial import get_device_status, get_multizone_status
+from .dial import get_device_status, get_multizone_status, get_requests_session
 
 DISCOVER_TIMEOUT = 5
 
@@ -234,6 +234,7 @@ def update_hosts(self, known_hosts):
     def run(self):
         """Start worker thread."""
         _LOGGER.debug("HostBrowser thread started")
+        self.session = get_requests_session()
         try:
             while not self.stop.is_set():
                 self._poll_hosts()
@@ -242,6 +243,7 @@ def run(self):
         except Exception:  # pylint: disable=broad-except
             _LOGGER.exception("Unhandled exception in worker thread")
             raise
+        self.session.close()
         _LOGGER.debug("HostBrowser thread done")
 
     def _poll_hosts(self):
@@ -252,7 +254,7 @@ def _poll_hosts(self):
             uuids = []
             if self.stop.is_set():
                 break
-            device_status = get_device_status(host, timeout=4)
+            device_status = get_device_status(host, timeout=4, session=self.session)
             try:
                 hoststatus = self._known_hosts[host]
             except KeyError:
@@ -280,7 +282,7 @@ def _poll_hosts(self):
             )
             uuids.append(device_status.uuid)
 
-            multizone_status = get_multizone_status(host)
+            multizone_status = get_multizone_status(host, session=self.session)
             if not multizone_status:
                 return