Merge pull request #26 from Naz-iv/finetune-payments

Finetune payments and implemented optional logic

.env.sample

@@ -5,3 +5,4 @@ POSTGRES_DB=POSTGRES_DB
 POSTGRES_USER=POSTGRES_USER
 POSTGRES_PASSWORD=POSTGRES_PASSWORD
 RABBIT_URL=RABBIT_URL
+DOMAIN=http://localhost:8080

books_fixture.json

@@ -299,14 +299,6 @@
       "model": "session"
     }
   },
-  {
-    "model": "contenttypes.contenttype",
-    "pk": 7,
-    "fields": {
-      "app_label": "book_service",
-      "model": "book"
-    }
-  },
   {
     "model": "book_service.book",
     "pk": 1,

borrowing_service/serializers.py

@@ -1,8 +1,10 @@
 from django.db import transaction
+from django.db.models import Q
 from rest_framework import serializers
 from rest_framework.exceptions import ValidationError
 
 from borrowing_service.models import Borrowing
+from payment_service.models import Payment
 from payment_service.serializers import (
     PaymentSerializer,
     PaymentListSerializer
@@ -33,10 +35,20 @@ class Meta:
     def create(self, validated_data):
         user = validated_data.get("user")
         borrowed_book = validated_data.get("book")
+
         if borrowed_book.inventory == 0:
             raise ValidationError("Sorry no books available!")
-        if user.borrowings.filter(is_active=True).count():
-            raise ValidationError("You must return your active borrowing!")
+
+        pending_payments = Payment.objects.filter(
+            Q(borrowing__user_id=user.id)
+            & Q(status=Payment.PaymentStatus.PENDING)
+        ).count()
+        if pending_payments:
+            raise ValidationError(
+                "You must complete your pending payments "
+                "before borrowing new book!"
+            )
+
         borrowed_book.inventory -= 1
         borrowed_book.save()
         borrowing = Borrowing.objects.create(

core/celery.py

@@ -26,12 +26,16 @@
 app.config_from_object(settings, namespace="CELERY")
 
 # Celery Beat Settings
-# app.conf.beat_schedule = {
-#     "check-overdue-task": {
-#         "task": "borrowing_service.tasks.check_overdue_task",
-#         "schedule": crontab(minute="*/1"),
-#     }
-# }
+app.conf.beat_schedule = {
+    "check-overdue-task": {
+        "task": "borrowing_service.tasks.check_overdue_task",
+        "schedule": crontab(minute="*/1"),
+    },
+    "check-payment-session-expiry": {
+        "task": "payment_service.tasks.verify_session_status",
+        "schedule": crontab(minute="*/1"),
+    },
+}
 
 # Load task modules from all registered Django apps.
 app.autodiscover_tasks()

core/settings.py

@@ -150,10 +150,12 @@
     "ROTATE_REFRESH_TOKENS": False,
 }
 
-CELERY_BROKER_URL=os.environ["RABBIT_URL"]
+CELERY_BROKER_URL = os.environ["RABBIT_URL"]
 
 #CELERY BEAT
 CELERY_BEAT_SCHEDULER = "django_celery_beat.schedulers:DatabaseScheduler"
 
 STRIPE_SECRET_KEY = os.environ.get("STRIPE_SECRET_KEY")
 STRIPE_PUBLISHABLE_KEY = os.environ.get("STRIPE_PUBLISHABLE_KEY")
+
+DOMAIN = os.environ["DOMAIN"]

payment_service/migrations/0001_initial.py

@@ -1,4 +1,4 @@
-# Generated by Django 4.2.8 on 2023-12-15 14:54
+# Generated by Django 4.2.8 on 2023-12-15 22:44
 
 from django.db import migrations, models
 import django.db.models.deletion
@@ -8,7 +8,7 @@ class Migration(migrations.Migration):
     initial = True
 
     dependencies = [
-        ("borrowing_service", "0001_initial"),
+        ("borrowing_service", "0002_initial"),
     ]
 
     operations = [
@@ -40,11 +40,13 @@ class Migration(migrations.Migration):
                         max_length=40,
                     ),
                 ),
-                ("session_url", models.URLField()),
-                ("session_id", models.CharField(max_length=255)),
+                ("session_url", models.URLField(blank=True, null=True)),
+                ("session_id", models.CharField(blank=True, max_length=255, null=True)),
                 (
                     "money_to_be_paid",
-                    models.DecimalField(decimal_places=2, max_digits=10000),
+                    models.DecimalField(
+                        blank=True, decimal_places=2, max_digits=15, null=True
+                    ),
                 ),
                 (
                     "borrowing",

payment_service/migrations/0002_alter_payment_session_url.py

@@ -0,0 +1,18 @@
+# Generated by Django 4.0.4 on 2023-12-16 01:20
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('payment_service', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='payment',
+            name='session_url',
+            field=models.TextField(blank=True, null=True),
+        ),
+    ]

payment_service/models.py

@@ -7,6 +7,7 @@ class Payment(models.Model):
     class PaymentStatus(models.TextChoices):
         PENDING = "PENDING", _("pending")
         PAID = "PAID", _("paid")
+        EXPIRED = "EXPIRED", _("expired")
 
     class PaymentTypes(models.TextChoices):
         PAYMENT = "PAYMENT", _("payment")
@@ -25,8 +26,8 @@ class PaymentTypes(models.TextChoices):
     borrowing = models.ForeignKey(
         Borrowing, on_delete=models.CASCADE, related_name="payments"
     )
-    session_url = models.URLField(null=True, blank=True)
+    session_url = models.TextField(null=True, blank=True)
     session_id = models.CharField(max_length=255, null=True, blank=True)
     money_to_be_paid = models.DecimalField(
-        max_digits=10000, decimal_places=2, null=True, blank=True
+        max_digits=15, decimal_places=2, null=True, blank=True
     )

payment_service/serializers.py

@@ -1,5 +1,4 @@
 from rest_framework import serializers
-from rest_framework.serializers import ModelSerializer
 
 from payment_service.models import Payment
 

payment_service/services.py

@@ -1,11 +1,8 @@
 from __future__ import annotations
 
-from datetime import datetime
-
 import stripe
-from decimal import Decimal
 
-from django.urls import reverse_lazy, reverse
+from django.urls import reverse
 from stripe.checkout import Session
 
 from borrowing_service.models import Borrowing
@@ -39,8 +36,15 @@ def get_checkout_session(borrowing: Borrowing, payment_id: int) -> Session:
     else:
         payment_amount = calculate_payment_amount(borrowing)
 
-    success_url = reverse("payment_service:success", args=[payment_id])
-    cancel_url = reverse("payment_service:cancel", args=[payment_id])
+    success_url = reverse(
+        "payment_service:payments-payment-successful",
+        args=[payment_id]
+    )
+    cancel_url = reverse(
+        "payment_service:payments-payment-canceled",
+        args=[payment_id]
+    )
+    stripe.api_key = settings.STRIPE_SECRET_KEY
     return Session.create(
         payment_method_types=["card"],
         line_items=[
@@ -54,8 +58,8 @@ def get_checkout_session(borrowing: Borrowing, payment_id: int) -> Session:
             },
         ],
         mode="payment",
-        success_url=success_url,
-        cancel_url=cancel_url,
+        success_url=settings.DOMAIN + success_url,
+        cancel_url=settings.DOMAIN + cancel_url,
     )
 
 

payment_service/tasks.py

@@ -0,0 +1,26 @@
+import stripe
+from celery import shared_task
+
+from payment_service.models import Payment
+
+
+def check_if_session_expired(session_id: str) -> bool:
+    """Check is session status is expired"""
+    session = stripe.checkout.Session.retrieve(session_id)
+    status = session.get("payment_intent", {}).get("status")
+    if status == "expired":
+        return True
+    return False
+
+
+@shared_task
+def verify_session_status() -> None:
+    """Verify if pending sessions did not expire"""
+    print("checking for expired checkouts")
+
+    payments = Payment.objects.filter(status=Payment.PaymentStatus.PENDING)
+
+    for payment in payments:
+        if check_if_session_expired(payment.session_id):
+            payment.status = Payment.PaymentStatus.EXPIRED
+            payment.save()

payment_service/views.py

@@ -3,14 +3,14 @@
 from rest_framework.permissions import IsAuthenticated
 from rest_framework.response import Response
 from rest_framework.decorators import action
-from django.shortcuts import get_object_or_404
 from rest_framework import viewsets
 from payment_service.serializers import (
     PaymentListSerializer,
     PaymentSerializer
 )
 
 from payment_service.models import Payment
+from payment_service.services import get_checkout_session
 
 stripe.api_key = settings.STRIPE_SECRET_KEY
 
@@ -33,6 +33,15 @@ def get_serializer_class(self):
     @action(methods=["GET"], url_path="success", detail=True)
     def payment_successful(self, request, pk: None):
         payment = self.get_object()
+        session = stripe.checkout.Session.retrieve(payment.session_id)
+        status = session.get("payment_intent", {}).get("status")
+        if status != "succeeded":
+            return Response(
+                {"status": "fail",
+                 "message": "Payment failed, please complete payment "
+                            "within 24 hours from book borrowing time!"},
+                status=400,
+            )
         payment.status = "paid"
         payment.save()
         return Response(
@@ -46,6 +55,19 @@ def payment_successful(self, request, pk: None):
     @action(methods=["GET"], url_path="cancel", detail=True)
     def payment_canceled(self, request, pk: None):
         return Response(
-            {"status": "fail", "message": "Payment was canceled"},
+            {"status": "fail",
+             "message": "Payment was canceled. Please complete payment "
+                        "within 24 hours from book borrowing time!"},
             status=400,
         )
+
+    @action(methods=["POST"], url_path="renew-session", detail=True)
+    def renew_checkout(self, request, pk: None):
+        payment = self.get_object()
+        new_session = get_checkout_session(payment.borrowing, payment.id)
+
+        if new_session.status != "open":
+            raise stripe.error.StripeError
+
+        payment.session_id = new_session.id
+        payment.url = new_session.url