views.py

from rest_framework_mongoengine import generics
from rest_framework.response import Response
from .serializers import LoginSerializer
from configuration.models import User
#from captive_portal.models import SessionHistory, Voucher
from .models import SessionHistory
from rest_framework import serializers

from rest_framework import status


class LoginView(generics.GenericAPIView):
    serializer_class = LoginSerializer
    authentication_classes = ()
    permission_classes = ()

    def post(self, request):
        serializer = self.get_serializer(data=request.data)

        # validate username, password, session_start and end date
        serializer.is_valid(raise_exception=True)

        # validate voucher data limit
        serializer.validate_voucher_data_limit()

        # create new session history
        serializer.create_session_history()
        user = User.objects.get(username=serializer.data.get('username'))
        serializer = self.get_serializer(user)
        return Response(serializer.data)



serializer.py


from rest_framework.exceptions import AuthenticationFailed
from rest_framework import serializers
from django.contrib.auth import authenticate
from .models import Token, SessionHistory
from configuration.models import User, UserRole, RolePermission
from rest_framework_mongoengine.serializers import DocumentSerializer
from django.utils import timezone
from captive_portal.models import Voucher

import datetime
from rest_framework.exceptions import ValidationError

class LoginSerializer(serializers.Serializer):

    username = serializers.CharField()
    password = serializers.CharField(write_only=True)
    first_name = serializers.CharField(read_only=True)
    last_name = serializers.CharField(read_only=True)
    email = serializers.EmailField(read_only=True)
    phone = serializers.CharField(read_only=True)
    token = serializers.CharField(read_only=True)
    is_superuser = serializers.BooleanField(read_only=True)
    roles = serializers.SerializerMethodField(read_only=True)
    address = serializers.CharField(read_only=True)
    state = serializers.CharField(read_only=True)
    city = serializers.CharField(read_only=True)
    country = serializers.CharField(read_only=True)

    start_datetime = serializers.DateTimeField()
    end_datetime = serializers.DateTimeField()
    voucher_id = serializers.CharField()

    class Meta:
        fields = '__all__'

    def __init__(self, *args, **kwargs):
        try:
            self.user = args[0]
        except:
            self.user = None

        super().__init__(*args, **kwargs)

    def validate(self, data):
        super().validate(data)
        username = data.get('username')
        password = data.get('password')

        if data['start_datetime'] >= data['end_datetime']:
             raise ValidationError('session history start date must be behind end date')

        if username and password:
            user = authenticate(self.context['request'], username=username, password=password)
            if not user:
                raise AuthenticationFailed(detail='invalid username or password')

            if not user.token:
                user.token = Token()
                user.save()

            self.user = User.objects.get(username=username)

        return data

    # check data usage....
    def validate_voucher_data_limit(self):
        data = self.validated_data
        voucher = Voucher.objects.get(id=data['voucher_id'])
        user_sessions = SessionHistory.objects.filter(user=self.user, voucher=voucher)
        data_usage = 0
        for session in user_sessions:
            data_usage = data_usage + session['data_usage']
            if data_usage >= voucher.data_limit:
                raise ValidationError('voucher data limit expired.')

    def create_session_history(self):
      data = self.validated_data
      voucher = Voucher.objects.get(id=data['voucher_id'])
      # pata ni ... sessionHistory k liye device kahan se ayega... baqi fields tu mil rahe
      SessionHistory.objects.create(user=self.user, voucher=voucher, start_datetime=data['start_datetime'], end_datetime=data['end_datetime'])

    @staticmethod
    def get_permissions(role):
        return [perm.get_perm_dict() for perm in RolePermission.objects.filter(role=role.to_dbref())]

    def get_role_dict(self, role):
        return {
                "name": role.name,
                "permissions": self.get_permissions(role)
            }

    def get_roles(self, obj):
        return [self.get_role_dict(userRole.role) for userRole in UserRole.objects().filter(user=self.user.to_dbref())]