check for existing record before inserting

mastodon_email_bridge/mastodon_email_bridge.py

@@ -235,8 +235,16 @@ class MastodonEmailBridge:
         conn.quit()
         self._log.debug("Adding entry to database...")
         cur = self.sqlite.cursor()
-        cur.execute(f"INSERT INTO sent_items (id, date) VALUES ({data['id']}, {time.time()})")
-        self.sqlite.commit()
+        res = cur.execute("SELECT id FROM sent_items WHERE id =?", data['id'])
+        rows = res.fetchall()
+        if len(rows) == 0:
+            cur.execute(f"INSERT INTO sent_items (id, date) VALUES ({data['id']}, {time.time()})")
+            self.sqlite.commit()
+        else:
+            self._log.warning(
+                "There was at least one record already with the same id %s, check if another instance of this script is running.",
+                data['id']
+            )
         self.sent_items.append(data['id'])
         return True