fix

alkatorapi/views.py

@@ -8,6 +8,7 @@ from django.contrib.auth.models import User as DjangoUser
 from django.contrib.auth import authenticate
 from django.contrib.auth import login as auth_login, logout as auth_logout
 from django.core.mail import send_mail, mail_admins, EmailMessage
+from django.db.utils import IntegrityError
 from django.utils.datastructures import MultiValueDictKeyError
 from datetime import date, datetime, timedelta
 from weasyprint import HTML
@@ -354,12 +355,16 @@ def cart_add(request):
         cart.save()
     else:
         cart = user.cart
+    try:
         cart_product = CartProduct(
             product=Product.objects.get(id=_id),
             cart=cart,
             quantity=1,
         )
         cart_product.save()
+    except IntegrityError as e:
+            return HttpResponse('{"status":"failed", "reason":"Předmět už v košíku je!"}', content_type='application/json')
+    return HttpResponse('{"status":"success", "reason":"Úspěšně přidáno do košíku."}', status=200)
 
 
 def results(request):

frontend/src/scripts/index.js

@@ -81,14 +81,14 @@ class Main extends Component {
     }
     addToCart = (id) =>{
         fetch(addr_prefix + "/api/cart/add?id=" + id).then(resp => resp.json()).then(json=>{
-            if(json.reason){
+            if(json.status == "failed"){
                 this.setState({
-                    status_text: data.reason,
+                    status_text: json.reason,
                     status: "failed",
                 })
             }else{
                 this.setState({
-                    status_text: data.success,
+                    status_text: json.reason,
                     status: "success",
                     cart: [...this.state.cart, id],
                 });