Django REST Framework: URLs without PK - django

I'm using Django REST Framework with the HyperlinkedModelSerializer
serializer.py:
class ReportTypesViewSet(viewsets.ModelViewSet):
queryset = ReportType.objects.all()
serializer_class = ReportTypesSerializer
api.py:
class ReportTypesSerializer(serializers.HyperlinkedModelSerializer):
class Meta:
model = ReportType
fields = ('name', 'uuid', 'active', )
Now the API works, but the hyperlinks have the pk within their URLs, such as: http://localhost:8000/api/reporttypes/1/
I would like to map the objects via the UUID field (which the model provides) rather than the internal PK. I know I could change the primary key to the UUID field, but I've read that would cause other issues, such as decreased performance.
Is there a way I can reference the objects via the UUID, but still internally use the default pk (id)?

This is what you should do:
class ReportTypesViewSet(viewsets.ModelViewSet):
queryset = ReportType.objects.all()
serializer_class = ReportTypesSerializer
lookup_field = 'uuid'
This tells DRF that you are using the uuid field for lookups and not the pk which is the default

For your url config use slug instead pk:
path(_('api')+'/<slug:slug>/', app.api_view, name='api'),
For your model/serializer make sure it contains both uuid and id

Related

Edit update all schedules except primary key in Django Rest Framework

I wanna change all fields of a json object except 'pk' in DRF. I just need to keep one json data. When adding a new data ,this one should override existing data. Is there a way to do it with django ?
my models.py
class ClientUser2(models.Model):
phone_number = models.CharField(max_length=20,unique=True)
name = models.CharField(max_length=100,blank=True)
status = models.IntegerField(default=1)
class ClientNameSerializer(serializers.HyperlinkedModelSerializer):
class Meta:
model = ClientUser2
fields = ('url','phone_number','name','status','pk')
my views.py
class ClientViewSet(viewsets.ModelViewSet):
"""
API endpoint that allows messages to be viewed or edited.
"""
queryset = ClientUser2.objects.all()
serializer_class = ClientNameSerializer
and it's my api root
api_root
If you want to be able to only retrieve and update models you can use RetrieveUpdateApiView
Reference : https://www.django-rest-framework.org/api-guide/generic-views/#retrieveupdateapiview

django rest framework access item by lookup field instead of pk 3.4 DRF

I need to have lookup field in order my frontend sends email which should be deleted but I get item not found. I've researched a lot about this problem but I can't figure out which DRF version what supports.
class EmailReminderSerializer(serializers.ModelSerializer):
city = serializers.CharField(max_length=255)
url = serializers.HyperlinkedIdentityField(
view_name='web:email_reminder-detail',
)
class Meta:
model = EmailReminder
fields = '__all__'
extra_kwargs = {
'url': {'lookup_field': 'email'}
}
Now I have url but it points to instance pk, not by my desired lookup field.
Any suggestions of how it works in 3.4 version or do you have any other solutions to some lower version >=3.0?
Oh okay, I got it. For serialized models you only need lookup_field in your view but for hyperlinked serialized models you need extra_kwargs in serializers plus lookup field in views. Hope it helps someone
You should modify the lookup field in your view instead. As shown in DRF docs, you can do the following.
in views.py
from rest_framework import viewsets
class EmailReminderViewSet(viewsets.ModelViewSet):
serializer_class = TagSerializer
lookup_field = 'email'

Django Rest Framework – Custom Hyperlink field in serializer

How can I add a custom hyperlink field in a serializer? I would like to have a hyperlink field in my serializer that has query params in it. Since there is no way to pass query params from HyperlinkedRelatedField or HyperlinkedIdentityField as far as I know, I've tried using a SerializerMethodField. However, this only serializes to a string, and is not a clickable URL when I visit the API through my browser. My code looks something like this:
class MySerializer(serializers.HyperlinkedModelSerializer):
custom_field = serializers.SerializerMethodField()
class Meta:
model = MyModel
fields = ('url', 'custom_field')
def get_custom_field(self, obj):
result = '{}?{}'.format(
reverse('my-view'),
urllib.urlencode({'param': 'foo'})
)
return result
Also, I am having trouble understanding the difference between a HyperlinkedRelatedField and a HyperlinkedIdentityField, so a brief explanation would be appreciated.
This should do the trick:
from rest_framework.reverse import reverse
class MySerializer(serializers.HyperlinkedModelSerializer):
custom_field = serializers.SerializerMethodField()
class Meta:
model = MyModel
fields = ('url', 'custom_field')
def get_custom_field(self, obj):
result = '{}?{}'.format(
reverse('my-view', args=[obj.id], request=self.context['request']),
'param=foo'
)
return result
The reverse function in rest_framework takes a view name (whatever view you'd like to link to), either an args list (the object id, in this case) or kwargs, and a request object (which can be accessed inside the serializer at self.context['request']). It can additionally take a format parameter and any extra parameters (as a dictionary) that you want to pass to it.
The reverse function then builds a nice, fully-formed URL for you. You can add query params to it by simply adding as many ?{}&{}&{} to your result variable and then filling in the series of query params beneath the 'param=foo' inside your format function with whatever other params you want.
The HyperlinkedIdentityField is used on the object itself that is being serialized. So a HyperlinkedIdentifyField is being used in place of your primary key field on MyModel because you are using a HyperlinkedModelSerializer which creates a HyperlinkedIdentityField for the pk of the object itself being serialized.
The HyperlinkedRelatedField is used to define hyperlinked relationships to RELATED objects. So if there were a MySecondModel with a foreign key relationship to MyModel and you wanted to have a hyperlink on your MyModel serializer to all the related MySecondModel objects you would use a HyperlinkedRelatedField like so (remember to add the new field to your fields attribute in Meta):
class MySerializer(serializers.HyperlinkedModelSerializer):
custom_field = serializers.SerializerMethodField()
mysecondmodels = serializers.HyperlinkedRelatedField(
many=True
read_only=True,
view_name='mysecondmodel-detail'
)
class Meta:
model = MyModel
fields = ('url', 'custom_field', 'mysecondmodels')
def get_custom_field(self, obj):
result = '{}?{}'.format(
reverse('my-view', args=[obj.id], request=self.context['request']),
'param=foo'
)
return result
If it were a OneToOneField rather than ForeignKey field on MySecondModel then you would set many=False.
Hope this helps!

Django ORM access User table through multiple models

views.py
I'm creating a queryset that I want to serialize and return as JSON. The queryset looks like this:
all_objects = Program.objects.all()
test_data = serializers.serialize("json", all_objects, use_natural_keys=True)
This pulls back everything except for the 'User' model (which is linked across two models).
models.py
from django.db import models
from django.contrib.auth.models import User
class Time(models.Model):
user = models.ForeignKey(User)
...
class CostCode(models.Model):
program_name = models.TextField()
...
class Program(models.Model):
time = models.ForeignKey(Time)
program_select = models.ForeignKey(CostCode)
...
Question
My returned data has Time, Program, and CostCode information, but I'm unable to query back the 'User' table. How can I get back say the 'username' (from User Table) in the same queryset?
Note: I've changed my queryset to all_objects = Time.objects.all() and this gets User info, but then it doesn't pull in 'CostCode'. My models also have ModelManagers that return the get_by_natural_key so the relevant fields appear in my JSON.
Ultimately, I want data from all four models to appear in my serialized JSON fields, I'm just missing 'username'.
Here's a picture of how the JSON object currently appears in Firebug:
Thanks for any help!
It seems a bit heavyweight at first glance but you could look at using Django REST Framework:
http://www.django-rest-framework.org/api-guide/serializers#modelserializer
You can define and use the serializer classes without having to do anything else with the framework. The serializer returns a python dict which can then be easily dumped to JSON.
To get all fields from each related model as nested dicts you could do:
class ProgramSerializer(serializers.ModelSerializer):
class Meta:
model = Program
depth = 2
all_objects = Program.objects.all()
serializer = ProgramSerializer(all_objects, many=True)
json_str = json.dumps(serializer.data)
To customise which fields are included for each model you will need to define a ModelSerializer class for each of your models, for example to output only the username for the time.user:
class UserSerializer(serializers.ModelSerializer):
class Meta:
model = User
fields = ('username', )
class TimeSerializer(serializers.ModelSerializer):
"""
specifying the field here rather than relying on `depth` to automatically
render nested relations allows us to specify a custom serializer class
"""
user = UserSerializer()
class Meta:
model = Time
class ProgramSerializer(serializers.ModelSerializer):
time = TimeSerializer()
class Meta:
model = Program
depth = 1 # render nested CostCode with default output
all_objects = Program.objects.all()
serializer = ProgramSerializer(all_objects, many=True)
json_str = json.dumps(serializer.data)
What you really want is a "deep" serialization of objects which Django does not natively support. This is a common problem, and it is discussed in detail here: Serializing Foreign Key objects in Django. See that question for some alternatives.
Normally Django expects you to serialize the Time, CostCode, Program, and User objects separately (i.e. a separate JSON array for each) and to refer to them by IDs. The IDs can either be the numeric primary keys (PKs) or a "natural" key defined with natural_key.
You could use natural_key to return any fields you want, including user.username. Alternatively, you could define a custom serializer output whatever you want there. Either of these approaches will probably make it impossible to load the data back into a Django database, which may not be a problem for you.

django rest framework change primary key to use a unqiue field

I have a model which is called GameProfile, which is a one to one relation with User model. I used HyperlinkedModelSerializer across all my design.
For the GameProfile, the user field is suppose to be the primary key for querying, it is unique but I did not set it up as a primary key. Is there a way to change the default behavior of django serializer to point to user__id as the primary key and always use it for retreiving the profile in the detail view?
class GameProfileSerializer(serializers.HyperlinkedModelSerializer):
"""
"""
user_pk = serializers.Field(source='user.id')
class Meta:
model = GameProfile
class GameProfileViewSet(viewsets.ModelViewSet):
"""
"""
queryset = GameProfile.objects.all()
serializer_class = GameProfileSerializer
def get_queryset(self):
""" get_queryset
"""
queryset = super(GameProfileViewSet, self).get_queryset()
if not queryset.exists():
raise Http404
if self.request.user.is_authenticated() and not self.request.user.is_superuser:
return queryset.filter(user=self.request.user)
return queryset
please advise, thanks in advance:)
Assuming your GameProfile model looks like:
class GameProfile(models.Model)
user = models.OneToOneField('User')
The serializer will be:
class GameProfileSerializer(serializers.HyperlinkedModelSerializer):
user_id = serializers.Field(source='user.id')
class Meta:
model = GameProfile
Set the .lookup_field attribute on the view correctly:
lookup_field = 'user_id'
Url will be:
/gameprofile/<user_id>
In order to get the URLs to work, you might need to add lookup_field on the ViewSet, not just on the serializer. So you would have:
class GameProfileViewSet(viewsets.ModelViewSet):
queryset = GameProfile.objects.all()
serializer_class = GameProfileSerializer
lookup_field = 'user__id'
In this case the lookup_field uses the double-underscore notation rather than the dot notation (dots won't work in the regular expressions in the URL patterns). I was unable to get the solution proposed by #almalki and #patsweet to work; according to the documentation on serializers, "The value of this option [lookup_field] should correspond both with a kwarg in the URL conf, and with a field on the model", so it's possible that it doesn't work with RelatedFields.
If I'm understanding your question correctly, you want a url structure like so:
/api/<GameProfile-resource>/<user-pk>
If that is the case, you should checkout the lookup_field option. Link
You're Serializer class would look something like:
class GameProfileSerializer(serializers.HyperlinkedModelSerializer):
"""
"""
user_pk = serializers.Field(source='user.id')
class Meta:
model = GameProfile
lookup_field = 'user_pk' # Might have to use 'user__id'