how to restrict other user from updating an db object in Flask? - python-3.x

Question

I am new to flask and building an ticket assigner application. Generator end point will assign always the oldest ticket(status=q) from the system to the person logged in. Then either he will resolve(post method = s) the ticket or can update its status to pending (post method = p).
#main.route('/ticket/generator', methods=['GET', 'POST'])
#login_required
def generate_ticket():
ticket = Ticket.query.filter_by(status='q').order_by(Ticket.create_date).first()
form = GenerateTicketForm(obj=ticket)
if form.validate_on_submit():
ticket.ticket_id = form.ticket_id.data
ticket.status = form.status.data
db.session.add(ticket)
db.session.commit()
flash('Ticket Status Update Successfully.')
return redirect(url_for('main.generate_ticket'))
return render_template('generate_ticket.html', form=form)
I want to change the status when the ticket already assigned to someone, so that other do not get the same ticket. So I have created a class method to change the status when getting the oldest ticket:
#classmethod
def activate_tkt_flag(cls, ticket_id_, create_date_):
ticket_db_obj = cls(ticket_id=ticket_id_, create_date=create_date_)
ticket_in_memory = Ticket.query.get(ticket_db_obj.ticket_id)
ticket_in_memory.status = 'a'
db.session.commit()
return ticket_in_memory
If call that after the ticket object in the first query it rewrite the loop some how and assign a new ticket and forget about the previous one the it can not rewrite the the ticket any more and I am getting that error: Key (ticket_id)=(T5) already exists UPDATE ticket SET ticket_id=%(ticket_id)s, status=%(status)s WHERE ticket.ticket_id = %(ticket_ticket_id)s'] [parameters: {'ticket_id': 'T5', 'status': 's', 'ticket_ticket_id': 'T1'}]. If some one has better idea how to do it will be grateful, I am kind of stuck here. Here is the form looks like.

Answer 1

Finally I was able to solve it. I just create one end point which execute first and update the ticket status and pass the ticket id to the next end point. So the last end point show the ticket with updated status to render template html.
#main.route('/ticket/generator/<ticket_id>', methods=['GET', 'POST'])
#login_required
def generate_ticket(ticket_id):
ticket = Ticket.query.get(ticket_id)
form = GenerateTicketForm(obj=ticket)
if form.validate_on_submit():
ticket.ticket_id = form.ticket_id.data
ticket.status = form.status.data
db.session.add(ticket)
db.session.commit()
# flash('Ticket Status Update Successfully.')
return redirect(url_for('main.display_status', ticket_id=ticket.ticket_id))
return render_template('generate_ticket.html', form=form)
#main.route('/ticket/assign')
def assign_ticket():
ticket = Ticket.query.filter_by(status='q').order_by(Ticket.create_date).first_or_404()
ticket.status = 'a'
db.session.commit()
return redirect(url_for('main.generate_ticket', ticket_id=ticket.ticket_id))
The assign end point execute first then the ticket id handed over to generator end point.