dexcom_dumper: cache http remote record

This avoids polling the http server every 10 seconds while the dexcom
receiver is disconnected.

1 files changed, 21 insertions, 5 deletions

diff --git a/dexcom_reader/dexcom_dumper.py b/dexcom_reader/dexcom_dumper.py
index 3ac21c0..10317e1 100644
--- a/dexcom_reader/dexcom_dumper.py
+++ b/dexcom_reader/dexcom_dumper.py
@@ -183,6 +183,7 @@ def poll():
                         if (str(sys.exc_info()[0]) == "<class 'requests.exceptions.ConnectionError'>"):
                                 print_verbose('Error: could not connect to remote host.')
                         else:
+                                print_verbose('Exception: %s' % str(sys.exc_info()[0]))
                                 traceback.print_exc()
                                 dexcom_reconnect()
                         sleep_verbose(10)
@@ -247,22 +248,37 @@ def parsetime(s):
 # server restarts, etc.; it should send back the value it got in the
 # query to the server, so that the server can verify that the updates
 # are consecutive.
-def remote_update(rectype):
+REMOTE_HAS = {}
+def check_remote_has(rectype):
+        global REMOTE_HAS
+
+        if REMOTE_HAS.get(rectype, None) is not None:
+                return REMOTE_HAS[rectype]
+
         requests = import_requests()
-        url_path = '/' + rectype
 
-        resp = requests.get(HOST + url_path + '/1')
+        resp = requests.get(HOST + '/' + rectype + '/1')
         resp.raise_for_status()
+
         when = None
         if len(resp.json()):
                 when = parsetime(resp.json()[0]['system_time'])
-                #print_verbose("Latest record on server: %s" % when.isoformat())
+                print_verbose("Latest %s record on server: %s" % (rectype, when.isoformat()))
+
+        REMOTE_HAS[rectype] = when
+        return when
+
+def remote_update(rectype):
+        global REMOTE_HAS
+        when = check_remote_has(rectype)
 
         (rs, r) = since_and_first(when, rectype)
+
         connected(True)
         if len(rs):
+                REMOTE_HAS[rectype] = None
                 print_verbose("Sending %d %s record%s... " % (len(rs), rectype, '' if len(rs) == 1 else 's'), newline=False)
-                result = POST(url_path, toJSON(rs))
+                result = POST('/' + rectype, toJSON(rs))
                 print_verbose("done.  (Result: %s)" % result)
                 return (len(rs) if result else None, r)
         else: