Separate the storage layer into individual classes

README.md

@@ -44,9 +44,18 @@ to put or retrieve data from it. Table definitions should be specified in
 `_run_migrations`. There's currently no defined method for how migrations
 should work though.
 
-The `sync_token` table and `get_sync_token`, `save_sync_tokens` should be left
-in tact so that the bot can save its progress when syncing events from the
-homeserver.
+The `sync_token` table should be left in tact so that the bot can save its
+progress when syncing events from the homeserver.
+
+### `sync_token.py`
+
+A simple class that can load and save a sync token to/from the database.
+
+A `SyncToken` is an instance of a sync token, which is simply a string
+retrieved from a matrix homeserver when querying the `/sync` endpoint (which
+clients use to retrieve new events). It is given to the next call of the
+`/sync` endpoint in order to specify the starting point in the event timeline
+you would like to receive messages from.
 
 ### `callbacks.py`
 

main.py

@@ -12,6 +12,7 @@ from nio import (
 from callbacks import Callbacks
 from config import Config
 from storage import Storage
+from sync_token import SyncToken
 
 logger = logging.getLogger(__name__)
 
@@ -45,22 +46,23 @@ async def main():
     client.add_event_callback(callbacks.message, (RoomMessageText,))
     client.add_event_callback(callbacks.invite, (InviteEvent,))
 
-    # Retrieve the last sync token if it exists
-    token = store.get_sync_token()
+    # Create a new sync token, attempting to load one from the database if it has one already
+    sync_token = SyncToken(store)
 
     # Sync loop
     while True:
         # Sync with the server
-        sync_response = await client.sync(timeout=30000, full_state=True, since=token)
+        sync_response = await client.sync(timeout=30000, full_state=True,
+                                          since=sync_token.token)
 
         # Check if the sync had an error
         if type(sync_response) == SyncError:
             logger.warning("Error in client sync: %s", sync_response.message)
             continue
 
-        # Save the latest sync token
+        # Save the latest sync token to the database
         token = sync_response.next_batch
         if token:
-            store.save_sync_token(token)
+            sync_token.update(token)
 
 asyncio.get_event_loop().run_until_complete(main())

storage.py

@@ -6,6 +6,7 @@ latest_db_version = 0
 
 logger = logging.getLogger(__name__)
 
+
 class Storage(object):
     def __init__(self, db_path):
         """Setup the database
@@ -44,32 +45,3 @@ class Storage(object):
         # Initialize a connection to the database
         conn = sqlite3.connect(self.db_path)
         self.cursor = conn.cursor()
-
-        pass
-
-    def get_sync_token(self):
-        """Retrieve the next_batch token from the last sync response.
-
-        Used to sync without retrieving messages we've processed in the past
-
-        Returns:
-            A str containing the last sync token or None if one does not exist
-        """
-        self.cursor.execute("SELECT token FROM sync_token")
-        rows = self.cursor.fetchone()
-
-        if not rows:
-            return None
-
-        return rows[0]
-
-    def save_sync_token(self, token):
-        """Save a token from a sync response.
-
-        Can be retrieved later to sync from where we left off
-
-        Args:
-            token (str): A next_batch token as part of a sync response
-        """
-        self.cursor.execute("INSERT OR REPLACE INTO sync_token"
-                            " (token) VALUES (?)", (token,))

sync_token.py

@@ -0,0 +1,32 @@
+class SyncToken(object):
+    """A SyncToken is an instance of a sync token, which is a token retrieved from a matrix
+    homeserver. It is given to the /sync endpoint in order to specify at which point in the
+    event timeline you would like to receive messages after
+    """
+
+    def __init__(self, store):
+        """
+        Args:
+            store (Storage): An object to access the storage layer
+        """
+        self.store = store
+
+        # Attempt to load a token from the provided storage layer
+        self._load()
+
+    def _load(self):
+        """Load the latest sync token from the database"""
+        self.store.cursor.execute("SELECT token FROM sync_token")
+        rows = self.store.cursor.fetchone()
+
+        if rows:
+            self.token = rows[0]
+
+    def update(self, token):
+        """Update the sync token in the database
+
+        Args:
+            token (str): A sync token from a sync response sent by a matrix homeserver
+        """
+        self.store.cursor.execute("INSERT OR REPLACE INTO sync_token "
+                                  "(token) VALUES (?)", (token,))