def login():
if 'user_id' in session:
return redirect('/wall')
elif request.method == 'GET':
return render_template('login.html', form=LoginForm())
else:
form = LoginForm.from_request(request)
if form.is_valid():
session['user_id'] = form.user_id
return redirect('/wall')
else:
return render_template('login.html', form=form)
