adds cleanup functionality for old devices

- device now last field 'last connection' which gets updated
  at every server connection from the respective device
- manual cleanup script in database deletes all devices which
  have never been updated, or have a timestamp older than 30 days

database/__init__.py

@@ -0,0 +1,14 @@
+from server import db
+import time
+from database.models import Device
+
+def cleanDevices():
+    allDevs = db.session.query(Device)
+    devices = allDevs.filter(Device.lastConnection <= int(round(time.time())) - 60*60*24*30).all()
+    devices += allDevs.filter(Device.lastConnection == None)
+    for device in devices:
+        print(device.deviceName)
+        db.session.delete(device)
+
+    db.session.commit()
+

database/migrations/versions/121eab3835ee_.py

@@ -0,0 +1,28 @@
+"""empty message
+
+Revision ID: 121eab3835ee
+Revises: e5ef5e4a807b
+Create Date: 2020-07-17 08:03:36.947158
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '121eab3835ee'
+down_revision = 'e5ef5e4a807b'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('device', sa.Column('lastConnection', sa.BigInteger(), nullable=True))
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('device', 'lastConnection')
+    # ### end Alembic commands ###

database/models.py

@@ -61,6 +61,7 @@ class Device(db.Model):
     user_id = db.Column(db.Integer, db.ForeignKey('user.id'))
     deviceName = db.Column(db.String(64), unique=True)
     connection = db.Column(db.Boolean)
+    lastConnection = db.Column(db.BigInteger)
 
 class Calendar(db.Model):
     id = db.Column(db.Integer, primary_key=True, autoincrement=True)

server/routes.py

@@ -1,6 +1,7 @@
 # Python standard libraries
 import json
 import os
+import time
 
 # Third-party libraries
 import flask
@@ -204,6 +205,7 @@ def downloader(device):
     if request_device.user_id == None: 
         return jsonify(kind="unregistered")
 
+    request_device.lastConnection=int(round(time.time()))
     request_device.connection=True
     db.session.commit()
     request_user = db.session.query(User).filter(User.id==request_device.user_id).first()