adding full project without the pi sign edits

calendar_grabber.py

@@ -1,8 +1,54 @@
+from datetime import datetime
+
+from google.oauth2 import service_account
+from googleapiclient.discovery import build
+from googleapiclient.errors import HttpError
+
+from event import Event
+from time import sleep
+
 
 class CalGrab(object):
 
-    def __init__(self):
-        print("Hello")
+    def __init__(self, auth_file, calendars=[], callbacks=[]):
+        self.calendars = calendars
+        self.callbacks = callbacks
+        self.creds = service_account.Credentials.from_service_account_file(
+            auth_file, scopes=['https://www.googleapis.com/auth/calendar.readonly'])
+        try:
+            self.service = build('calendar', 'v3', credentials=self.creds)
+        except HttpError as error:
+            raise error
 
+    def update_at_interval(self, frequency, time_to_update=-1):
+        """
 
+        :param frequency: Amount of time to wait between updates in seconds
+        :param time_to_update: normally set to -1 aka no limit.  Time in minutes to continually ping the api for.
+        :return: None
+        """
+        try:
+            start = None
+            while True:
+                now = datetime.utcnow() # 'Z' indicates UTC time
+                now_str = now.isoformat() + 'Z'
+                if start ==None:
+                    start = now
+                print('Getting the upcoming 10 events')
+                events_result = self.service.events().list(calendarId='loskorep@productiveedge.com', timeMin=now_str,
+                                                      maxResults=10, singleEvents=True,
+                                                      orderBy='startTime').execute()
+                events = events_result.get('items', [])
 
+                if not events:
+                    print('No upcoming events found.')
+                    return
+
+                events = [Event.get_from_gcal_api_json(json) for json in events]
+                for callback in self.callbacks:
+                    callback(events)
+                if (now-start).total_seconds() > time_to_update:
+                    return
+                sleep(frequency)
+        except HttpError as error:
+            print('An error occurred: %s' % error)