Django many 2 many through rest framework

Question

I am working on a small project but i cant get the serializers to work

I have tried these and i am not sure what i am doing wrong. My model is a many to many through

class User(AbstractUser):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)

    phone = models.CharField(max_length=50, unique=True)
    identity_number = models.CharField(max_length=50, unique=True)
    address = models.CharField(max_length=200)
    city = models.CharField(max_length=200)
    post_code = models.CharField(max_length=7, null=True)

    visited = models.ManyToManyField(
        Company,
        through="CompanyUser",
        through_fields=(
            "user",
            "company",
        ),
    )

    is_visitor = models.BooleanField("visitor status", default=False)
    is_company = models.BooleanField("company status", default=False)

class CompanyUser(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    company = models.ForeignKey(
       Company, on_delete=models.CASCADE, related_name="company_visitors"
    )
    user = models.ForeignKey(
       User, on_delete=models.CASCADE, related_name="company_visited"
    )

    checked_in = models.DateTimeField(auto_now_add=False)
    checked_out = models.DateTimeField(auto_now=False)

#serializers.py

class CompanyVisitedSerializer(serializers.HyperlinkedModelSerializer):
    
    company_id = serializers.ReadOnlyField(source="company.id")
    company_address = serializers.ReadOnlyField(source="company.business_address")
    company_name = serializers.ReadOnlyField(source="company.business_name")
    company_address = serializers.ReadOnlyField(source="company.business_address")
    checked_in = serializers.ReadOnlyField(source="user.checked_in")
    checked_out = serializers.ReadOnlyField(source="user.checked_out")
    
    class Meta:
        model = CompanyUser
        fields = (
            "checked_in",
            "checked_out",
            "company_name",
            "company_address",
            "company_id",
        )
    
    
class VisitorSerializer(serializers.ModelSerializer):
    
    # visited = CompanySerializer(many=True)
    visited = CompanyVisitedSerializer(
        many=True,
    )

but i get this back empty {}:

    {
  "address": "192 millie road",
  "city": "singapore",
  "phone": "2066980",
  ...
  "visited": [
    {}, //i want to populate this with { company: name_of_company, checkin, checkout}
    {}
  ]
}

I have read through these:

Let `CompanyVisitedSerializer` inherit from a `ModelSerializer`, not a `HyperlinkedModelSerializer`. — Willem Van Onsem, Jul 09 '21 at 19:37
Ah but the model of a `visited` is a `Company`, not a `CompanyUser`. — Willem Van Onsem, Jul 09 '21 at 19:46
If you want to make use of the `CompanyUser`, the relation is `company_visitors`, not `visited`. — Willem Van Onsem, Jul 09 '21 at 19:46

score 1 · Accepted Answer · answered Jul 09 '21 at 19:48

The model to which visited is pointing is a Company, not a CompanyUser. If you want to work with the CompanyUser, the relation is company_visited, so:

class VisitorSerializer(serializers.ModelSerializer):
    visited = CompanyVisitedSerializer(
        source='company_visited',
        many=True
    )

Django many 2 many through rest framework

1 Answers1