Django : how to make rest api comment with Modelviewset - django

I tried to use Django's Modelviewset to implement the comment function, but there was a problem.
model :
class Comment(models.Model):
created = models.DateTimeField(auto_now_add= True)
content = models.CharField(max_length = 255, null = True)
author = models.ForeignKey(User, on_delete= models.CASCADE, null = True)
writer = models.CharField(max_length = 255, null = True)
class Meta:
abstract = True
ordering = ['-id']
class TalkComment(Comment):
title = "talk"
post = models.ForeignKey(Talk, on_delete= models.CASCADE, null = True)
serializers :
class TalkCommentSerializer(serializers.ModelSerializer):
class Meta:
model = models.TalkComment
fields = '__all__'
view :
class TalkCommentViewset(viewsets.ModelViewSet):
queryset = models.TalkComment.objects.all()
serializer_class = serializers.TalkCommentSerializer
url :
router.register(r'talk/(?P<id>\d+)/comment', postview.TalkCommentViewset)
/api/talk/2/comment/
All I wanted was to get the comments from that one post, but all the comments are coming.
How can I get a specific comment from a specific post?

You're getting all of the comments cause you initialized queryset to return all of the commnents. For getting comments of one specific post you must change the queryset. To do that you must override get_queryset method (cause you need to get post_id argument from request):
class TalkCommentViewset(viewsets.ModelViewSet):
serializer_class = serializers.TalkCommentSerializer
def get_queryset(self):
post_id = self.kwargs["id"]
queryset = TalkComment.objects.filter(post__id=post_id)
return queryset

Related

DRF Invalid pk object does not exist for foreign key on POST create

I have two classes related to each other.
One class I have made the primary key a char field so I can easily reference to it or create it to match the id of the actual object (all objects will have this unique name).
from django.db import models
class Ven(models.Model):
id = models.CharField(max_length=80, primary_key=True)
statusOn = models.BooleanField(default=True)
class Device(models.Model):
device_id = models.CharField(max_length=80)
ven_id = models.ForeignKey(VEN, related_name='devices', on_delete=models.SET_NULL, null=True)
class DeviceSerializer(serializers.ModelSerializer):
class Meta:
model = Device
fields = ['id', 'device_id', 'ven_id']
class VENSerializer(serializers.ModelSerializer):
class Meta:
model = VEN
fields = ['id', 'statusOn', 'devices']
class DeviceList(generics.ListCreateAPIView):
logger.info("DeviceList: view")
# permission_classes = [permissions.IsAuthenticated]
queryset = Device.objects.all()
serializer_class = DeviceSerializer
however when I try to run my test:
class DevicesTestCase(TestCase):
def setUp(self):
self.factory = Client()
def test_create_device(self):
device = {
"ven_id": "TEST_VEN_1",
"device_id": "TEST_DEVICE_1",
"statusOn": True,
}
response = self.factory.post('/devices/', data=device)
self.assertEqual(response.status_code, 201)
my response returns 400 and states:
b'{"ven_id":["Invalid pk \\"TEST_VEN_1\\" - object does not exist."]}'
I'm trying to write a custom create in my serializer to create the ven if it does not exist but it's not being called. Data is being validated else where. My breakpoint in my view set's perform_create also does not fire.
I don't want to write a bunch of workaround code for something that should be straightforward. I know I'm missing/messing something up somewhere.
I think you need to customize the create method in the DeviceSerializer.
class DeviceSerializer(serializers.ModelSerializer):
ven_id = serializers.CharField()
status_on = serializers.BooleanField(write_only = True)
class Meta:
model = Device
fields = ['id', 'device_id', 'ven_id']
def create(self, validated_data):
ven_id = validated_data.pop('ven_id')
status_on = validated_data.pop('status_on')
try:
ven = Ven.objects.get(id = ven_id)
except Ven.DoesNotExist:
ven = Ven.objects.create(id = ven_id, statusOn = status_on)
new_device = Device.objects.create(ven_id = ven, **validated_data)
return new_device

Getting field value with DjangoRestFramework serializer

I have two models:
class Restaurant(models.Model):
adress = models.CharField(max_length=240)
name = models.CharField(max_length=140)
class RestaurantReview(models.Model):
review_author = models.ForeignKey(settings.AUTH_USER_MODEL,
on_delete=models.CASCADE)
restaurant = models.ForeignKey(Restaurant, on_delete=models.CASCADE)
created_at = models.DateTimeField(auto_now_add=True)
I use DRF and front-end I need the values of the fields to use in Vue.je templates. Here is my serializer:
class RestaurantReviewSerializer(serializers.ModelSerializer):
restaurant_name = serializers.CharField(source='restaurant.name')
restaurant_adress = serializers.CharField(source='restaurant.adress')
created_at = serializers.SerializerMethodField()
review_author = serializers.StringRelatedField(read_only=True)
class Meta:
model = RestaurantReview
fields = ('id','restaurant_name','restaurant_adress','created_at','review_author')
def get_created_at(self, instance):
return instance.created_at.strftime("%d %B, %Y")
I get the right data I need but my problem is now I can't update/create new models. As suggested I added ('read_only'=True) but the result is the same.
Should I use to_representation to get the same CRUD posibilities than with:
class RestaurantReviewSerializer(serializers.ModelSerializer):
class Meta:
model = RestaurantReview
field = fields = '__all__'
But with the benefit to have for exemple 'restaurant' named after its name and not its ID so I can use it in my template?
Follow to comment above.
Use single viewset and override get_serializer_class. No other thing to change.
class RestaurantReviewViewSet(viewsets.ModelViewSet):
queryset = RestaurantReview.objects.all()
def get_serializer_class(self):
if self.request.method == 'GET':
return RestaurantReviewGETSerializer # your above serializer
else:
return RestaurantReviewSerializer # default serializer

django queryset annotate all field in childtable

models.py
class Userinfo(models.Model):
useruid = models.BigAutoField(db_column='UserUID', primary_key=True)
useremail = models.CharField(
db_column='UserEmail', unique=True, max_length=100)
userpassword = models.CharField(db_column='UserPassword', max_length=128)
passwordsalt = models.CharField(db_column='PasswordSalt', max_length=128)
class Meta:
managed = False
db_table = 'userinfo'
class Postinfo(models.Model):
postuid = models.BigAutoField(db_column='PostUID',primary_key=True)
useruid = models.ForeignKey(
'Userinfo', db_column='UserUID', on_delete=models.CASCADE)
content = models.TextField(db_column='Content')
class Meta:
managed = False
db_table = 'postinfo'
if i get userlist and user's last post
i think use annotate
models.Userinfo.objects.all().annotate(lastpost="??").order_by("-useruid")
what values in "??"
like this form
[{userinfo1,"lastpost":{postinfofields}},{userinfo2,"lastpost":{postinfofields}},{userinfo3,"lastpost":{postinfofields}}]
can i this query not use forloop?
Serializer.py
class PostSerializer(serializers.ModelSerializer):
class Meta:
model = Postinfo
fields = ('postuid','content')
class UserSerializer(serializers.ModelSerializer):
lastpost = PostSerializer()
class Meta:
model = Userinfo
fields = ['useruid', 'useremail', 'lastpost']
view.py
userinfos = models.Userinfo.objects.all().order_by("-useruid")
result = UserSerializer(userinfos,many=True)
print(result.data)
raise Exception
Got AttributeError when attempting to get a value for field `lastpost` on serializer `UserSerializer`.
The serializer field might be named incorrectly and not match any attribute or key on the `Userinfo` instance.
Original exception text was: 'Userinfo' object has no attribute 'lastpost'.
if i add read_only=True print this
[OrderedDict([('useuid', 1), ('useremail', 'test')]), OrderedDict([('useruid', 2), ('useremail', 'test2')])]
You can use model's property for this:
class Userinfo(models.Model):
useruid = models.BigAutoField(db_column='UserUID', primary_key=True)
useremail = models.CharField(
db_column='UserEmail', unique=True, max_length=100)
userpassword = models.CharField(db_column='UserPassword', max_length=128)
passwordsalt = models.CharField(db_column='PasswordSalt', max_length=128)
#property
def lastpost(self):
return self.postinfo_set.latest('postuid')
Now you dont need annotation, just use it for example in template like this:
{{ user.lastpost.content }}
UPD
To serialize property with ModelSerializer just add serializer's field 'lastpost':
class PostSerializer(serializers.ModelSerializer):
class Meta:
model = Postinfo
fields = ('postuid','content')
class UserSerializer(serializers.ModelSerializer):
lastpost = PostSerializer()
class Meta:
model = Userinfo
fields = ['useruid', 'useremail', 'lastpost']
UPD2
You can also implement logic directly on the serializer level, without model's property. Just use SerializerMethodField:
class UserSerializer(serializers.ModelSerializer):
lastpost = SerializerMethodField()
class Meta:
model = Userinfo
fields = ['useruid', 'useremail', 'lastpost']
def get_lastpos(self, obj):
last = obj.postinfo_set.latest('postuid')
serializer = PostSerializer(last)
return serializer.data

related objects queries django rest framework

I have the following models
class STUser(AbstractBaseUser):
email = models.EmailField(unique=True)
name = models.CharField(max_length=255)
companyname = models.CharField(max_length=200, blank=True, null=True)
...
class VenuePermissions(models.Model):
user = models.ForeignKey(STUser, on_delete=models.CASCADE)
venue = models.ForeignKey(Venue, on_delete=models.CASCADE)
signupvaildatestring = models.CharField(max_length=200, blank=True, null=True)
...
I want to grab all the STUser objects and grab all their permissions.
So what I would like is to grab all the VenuePermissions objects. And grab the user and venue object of each venuePermission
Two ways I can do this. use the VenuePermissions_set attribute on STUser but then how do I grab the venue when its just going to be a pk value?
Or focus on the VenuePermissions objects and grab the user and venue from the pk values but how?
I remember nested queries, and I kinda did one in my browse code.
here is an example:
rooms = Room.objects.filter(venue=OuterRef('pk'), sixtyroundseatingoption= True)
venuelist = venuelist.annotate(sixtyrounds=Exists(rooms))
venuelist = venuelist.filter(Q(sixtyrounds = True) | Q(fullbuyoutsixtyroundseatingoption = True))
I've done the set objects in a serializer before
Example serializer:
class RoomAndImageSerializer(serializers.ModelSerializer):
roomimage_set = RoomImageSerializer(many=True, read_only=True)
class Meta:
model = Room
fields = ('pk','name')
any help with this query would be appreciated!
So this is what I am currently trying, I will post an answer if this works:
class VenueUserList(ListAPIView):
serializer_class = VenueUserListSerializer
queryset = VenuePermissions.objects.select_related('user').select_related('venue').filter(signupvaildatestring=None)
class VenueUserListSerializer(serializers.ModelSerializer):
user = UserSerializer()
venue = VenueSerializer()
class Meta:
model = VenuePermissions
fields = ('user', 'venue', 'isvenueviewer', 'isvenueeventplanner', 'isvenueadministrator')
Here is the answer. However I still need to group venues by user. Working on that.
class VenueUserList(ListAPIView):
serializer_class = VenueUserListSerializer
queryset = VenuePermissions.objects.select_related('user').select_related('venue').filter(signupvaildatestring=None)
class VenueUserListSerializer(serializers.ModelSerializer):
user = UserSerializer()
venue = VenueSerializer()
class Meta:
model = VenuePermissions
fields = ('user', 'venue', 'isvenueviewer', 'isvenueeventplanner', 'isvenueadministrator')

Limit number of ForeignKey elements in list view

I have a resources like these:
models.py
class Place(models.Model):
id = models.CharField(max_length = 256, primary_key = True)
name = models.CharField(max_length = 1024)
class Review(models.Model):
id = models.CharField(max_length = 256, primary_key = True)
p_id = models.ForeignKey(Place, related_name = 'place_review')
text = models.TextField()
api.py
class ReviewResource(ModelResource):
class Meta:
queryset = Review.objects.all()
resource_name = 'place_review'
class PlaceResource(ModelResource):
place_review = fields.OneToManyField(ReviewResource,
'place_review',
full=True)
class Meta:
queryset = Place.objects.all()
resource_name = 'place'
Using above model and resource, I want to limit number of reviews in list view of Place to 3, in detail/show view I want to show more reviews (possible different style, e.g. if review contains image, show it in detail view, hide it in list view)
I have tried to put attribute=lambda bundle: Review.objects.all()[:3], but whenever I don't have any reviews for place it fails with The model '' has an empty attribute ' at 0x7f0a180d0de8>' and doesn't allow a null value. message.
What can you suggest for this case, are there any workarounds for this problem?