I am creating an API to save class teachers. Now all the fields in the ClassTeacher model are foreign fields so I am using a SlugRelatedField in the serializer. It looks like SlugRelatedField does not support attribute lookup like this "user__username" and raises attribute error HOWEVER the object is still being saved.
models.py
class ClassTeacher(models.Model):
teacher = models.ForeignKey(Teacher, on_delete=models.CASCADE)
class_name = models.ForeignKey(Classes, on_delete=models.CASCADE)
school_id = models.ForeignKey(School, on_delete=models.CASCADE)
serializers.py
class ClassTeacherSerializer(ModelSerializer):
teacher = SlugRelatedField(slug_field='user__username', queryset=Teacher.objects.all()) <---- this is causing the error
class_name = SlugRelatedField(slug_field='class_name', queryset=Classes.objects.all())
school_id = SlugRelatedField(slug_field='school_id__username', queryset=School.objects.all()) <---- and I am assuming that this will too
class Meta:
model = ClassTeacher
fields = '__all__'
I tried adding a #property in the Teacher model to retrieve the username and use the property in the slug_field but that did not work too.
How can I save the object without getting the error?
EDIT 1:
teachers/models.py
class Teacher(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
name = models.CharField(max_length=30)
photo = models.URLField()
teacher/serializers.py
class TeacherSerializer(ModelSerializer):
class Meta:
model = Teacher
fields = '__all__'
school/models.py
class School(models.Model):
school_id = models.OneToOneField(User, on_delete=models.CASCADE)
principal = models.CharField(max_length=50)
name = models.CharField(max_length=50)
photo = models.URLField()
school/serializers.py
class SchoolSerializer(ModelSerializer):
class Meta:
model = School
fields = '__all__'
EDIT 2:
Here's how I used the #property by referring from here:
teacher/models.py
class Teacher(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
name = models.CharField(max_length=30)
photo = models.URLField()
#Here's the extra property part
#property
def username(self):
return self.user.username
classteacher/serializers.py
class ClassTeacherSerializer(ModelSerializer):
#Here I changed user__username to just username as mentioned in the above link
teacher = SlugRelatedField(slug_field='username', queryset=Teacher.objects.all())
class_name = SlugRelatedField(slug_field='class_name', queryset=Classes.objects.all())
school_id = SlugRelatedField(slug_field='school_id__username', queryset=School.objects.all())
class Meta:
model = ClassTeacher
fields = '__all__'
try renaming serializer field from teacher to user and using slug_field='username'
You can use #property for example
class User(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
name = models.CharField(max_length=30)
photo = models.URLField()
#property
def get_username(self):
return Teacher.objects.filter(user_id=self.id)
and than inside your ClassTeacherSerializer use slug_field='username'
let me know if it works.
Related
i want to count comments for every single Post
in models.py:
class Post(models.Model):
body = models.TextField(max_length=10000)
date = models.DateTimeField(auto_now_add=True, blank=True)
user = models.ForeignKey(User, on_delete=models.CASCADE)
liked_by = models.ManyToManyField(User, blank=True, related_name='liked_by')
class Meta:
ordering = ['-date']
class Comment(models.Model):
body = models.TextField(max_length=1000)
date = models.DateTimeField(auto_now_add=True, blank=True)
user = models.ForeignKey(User, on_delete=models.CASCADE)
post = models.ForeignKey(Post, on_delete=models.CASCADE)
class Meta:
ordering = ['-date']
in serializers.py:
class CommentSerializer(serializers.ModelSerializer):
class Meta:
model = Comment
fields = '__all__'
class PostSerializer(serializers.ModelSerializer):
#comments = CommentSerializer()
user = UserSerializers()
total_likes = serializers.SerializerMethodField()
liked_by = SimpleUserSerializer(many=True, read_only=True)
total_comments = serializers.SerializerMethodField()
class Meta:
model = Post
fields = ('body','date','user', 'total_likes', 'liked_by','total_comments')
def get_total_likes(self, instance):
return instance.liked_by.count()
def get_total_comments(self, instance):
return instance.comments.count()
when i run this code, it shows, AttributeError: 'Post' object has no attribute 'comments'.
how do i count comments of a post?
Since you haven't configured the related_name, Django uses the default related_name and hence you should access the reveres FK using comment_set instead of comments
Thus, the get_total_comments(...) method should look like
def get_total_comments(self, instance):
return instance.comment_set.count()
Reference
What is related_name used for in Django?
I'm trying to add a data using "Array Model Field"(djongo) as shown Djongo Documentation(Array Model Field) or
from djongo import models
class Blog(models.Model):
name = models.CharField(max_length=100)
tagline = models.TextField()
class Meta:
abstract = True
class MetaData(models.Model):
pub_date = models.DateField()
mod_date = models.DateField()
n_pingbacks = models.IntegerField()
rating = models.IntegerField()
class Meta:
abstract = True
class Author(models.Model):
name = models.CharField(max_length=200)
email = models.EmailField()
class Meta:
abstract = True
def __str__(self):
return self.name
class Entry(models.Model):
blog = models.EmbeddedModelField(
model_container=Blog,
)
meta_data = models.EmbeddedModelField(
model_container=MetaData,
)
headline = models.CharField(max_length=255)
body_text = models.TextField()
authors = models.ArrayModelField(
model_container=Author,
)
n_comments = models.IntegerField()
def __str__(self):
return self.headline
Into admin.py I added for registration of model in admin panel
from django.contrib import admin
from .models import Entry
admin.site.register(Entry)
And when I try to add a data via http://localhost:8000/admin/ I have a MigrationError...
Where is my mistake? And what am I not understanding?
You should use models.ObjectIdField() on all models to avoid calling django migrations.
Example:
class Author(models.Model):
_id = models.ObjectIdField()
name = models.CharField(max_length=200)
email = models.EmailField()
class Meta:
abstract = True
def __str__(self):
return self.name
See more in Djongo Docs
I'm a stupid. Sry. I didn't 'makemigration' after update a model.
And so here's what I did to make it work:
1. After update a model I did 'python manage.py makemigrations' and that power on.
I want to get all customer data and responses and also remarks.
This is model.py
class Customer(models.Model):
name = models.CharField(max_length=200)
email_address = models.CharField(max_length=200)
phone_number = models.CharField(max_length=20)
age = models.SmallIntegerField(default=14)
remarks = models.ManyToManyField(Remark,null=True,blank=True)
created_at = models.DateTimeField(auto_now_add=True)
def __str__(self):
return str(self.id)
class Response(models.Model):
question = models.ForeignKey(Question)
customer = models.ForeignKey(Customer)
response_text = models.CharField(max_length=100, null=True, blank=True)
created_at = models.DateTimeField(auto_now_add=True)
uuid = models.UUIDField()
def __str__(self):
return str(self.id)
This is serializers.py
class ResponseSerializer(ModelSerializer):
class Meta:
model = Response
fields = '__all__'
class RemarksSerializer(ModelSerializer):
class Meta:
model = Remark
fields = '__all__'
class CustomerInformationSerializer(ModelSerializer):
remarks = RemarksSerializer(many=True)
responses = serializers.SerializerMethodField()
def get_responses(self, obj):
responses = Response.objects.filter(customer=obj)
return ResponseSerializer(responses, many=True)
class Meta:
model = Customer
fields = ('name', 'email_address', 'phone_number', 'age', 'remarks', 'responses')
This is services.py
def customer_information(company_id=1):
cus = Customer.objects.filter(remarks__company_id=company_id)
return CustomerInformationSerializer(cus, many=True).data
This is views.py
class CustomerInformationView(APIView):
def get(self, request):
company_id = request.GET.get('company_id', 1)
resp = {'data': customer_information(company_id)}
return Response(data=resp, status=status.HTTP_200_OK)
This is url.py
url(r'^customer/$', CustomerInformationView.as_view()),
I'm having this problem. How can I solve this. Kindly guide me.
get function in your view should return responses.data, insted of responsed.
SIDE NOTE
First, let me point you to a resource that I think is GREAT for anything dealing with Django REST Framework:
Classy Django REST Framework. It is a fantastic resource because you can easily dig right into the source code to see how you may or may not need to override default operations.
MY ANSWER
What I suggest is that instead of using the APIView, you use ListAPIView.
It would look something like this:
from rest_framework.generics import ListAPIView
class Customer(models.Model):
name = models.CharField(max_length=200)
email_address = models.CharField(max_length=200)
phone_number = models.CharField(max_length=20)
age = models.SmallIntegerField(default=14)
remarks = models.ManyToManyField(Remark,null=True,blank=True)
created_at = models.DateTimeField(auto_now_add=True)
def __str__(self):
return str(self.id)
class Response(models.Model):
question = models.ForeignKey(Question)
customer = models.ForeignKey(Customer, related_name='responses')
response_text = models.CharField(max_length=100, null=True, blank=True)
created_at = models.DateTimeField(auto_now_add=True)
uuid = models.UUIDField()
def __str__(self):
return str(self.id)
class ResponseSerializer(ModelSerializer):
class Meta:
model = Response
fields = '__all__'
class RemarksSerializer(ModelSerializer):
class Meta:
model = Remark
fields = '__all__'
class CustomerInformationSerializer(ModelSerializer):
remarks = RemarksSerializer(many=True)
responses = ResponseSerializer(many=True)
class Meta:
model = Customer
fields = ('name', 'email_address', 'phone_number', 'age', 'remarks', 'responses')
class CustomerInformationView(ListAPIView):
queryset = Customer.objects.all()
serializer_class = CustomerInformationSerializer
lookup_field = 'remarks__company'
Note the change that I made by adding related_name to the customer field on your Response model. See Django documentation for more information on related_name. In short, it adds responses as a field name on your Customer model so that you can travel backwards through that relationship.
This is not tested, but this should be a better strategy to do what you want without having to have a get_responses method, or a services.py.
Some there might be error because of missing "/" at the end of path like "event-api"=incorrect and "event-api/" correct. That worked for me. Hope you also have same problem.
Incorrect: path('event-api',views.event_view,name="event-view")
Correct: path('event-api/',views.event_view,name="event-view")
I have just started learning Django Rest Framework and trying to make a simple API using Django rest Framework.
This is my models.py
from __future__ import unicode_literals
from django.db import models
class Student(models.Model):
created = models.DateTimeField(auto_now_add=True)
name = models.CharField(max_length=150, blank=False)
student_id = models.CharField(max_length=20, primary_key=True)
father_name = models.CharField(max_length=150)
mother_name = models.CharField(max_length=150)
class Meta:
ordering = ('student_id',)
class Subject(models.Model):
created = models.DateTimeField(auto_now_add=True)
subject_id = models.CharField(max_length=20, primary_key=True)
name = models.CharField(max_length=150)
class Meta:
ordering = ('subject_id',)
class Result(models.Model):
created = models.DateTimeField(auto_now_add=True)
grade = models.DecimalField(max_digits=5, decimal_places=3, blank=False)
student_id = models.ForeignKey(Student, on_delete=models.CASCADE)
subject_id = models.ForeignKey(Subject, on_delete=models.CASCADE)
class Meta:
ordering = ('created',)
And this is my serializers.py
from rest_framework import serializers
from models import *
class StudentSerializer(serializers.HyperlinkedModelSerializer):
class Meta:
model = Student
fields = ('student_id', 'name', 'father_name', 'mother_name')
class SubjectSerializer(serializers.HyperlinkedModelSerializer):
class Meta:
model = Subject
fields = ('subject_id', 'name')
class ResultSerializer(serializers.HyperlinkedModelSerializer):
class Meta:
model = Result
fields = ('grade', 'student_id', 'subject_id')
In my "Result" model, I have two foreign keys; student_id and subject_id. This is how it looks like:
My questions is, how can I show the "name" field in the drop down menu in stead of showing "Student Object" and "Subject Object"?
I have tried with
STUDENT_CHOICES = [(each.student_id, each.name) for each in Student.objects.all()]
SUBJECT_CHOICES = [(each.subject_id, each.name) for each in Subject.objects.all()]
in the model's "choices=" field but it didn't work out.
Thanks in advance.
I think you're looking for this part of the DRF documentation.
Basically, your Django model's own representation is used. So for example, in your Student model you can add __str__ method:
# this is for Python 3, use __unicode__ on Python 2
def __str__(self):
return self.name
Meta options documentation for Django is here, look for model methods.
These are my models and serializers. I want a representation of Question Model along with a list of people the question was asked to.
I am trying this:
#api_view(['GET', 'PATCH'])
def questions_by_id(request,user,pk):
question = Question.objects.get(pk=pk)
if request.method == 'GET':
serializer = QuestionSerializer(question)
return Response(serializer.data)
But I get an empty dictionary ({}). However when I remove the asked field from QuestionSerializer I get a complete representation of Question along with Places serialized nicely. What am I missing ?
class AskedToSerializer(serializers.ModelSerializer):
class Meta:
model = AskedTo
fields = ('to_user', 'answered')
class QuestionSerializer(serializers.ModelSerializer):
class Meta:
model = Question
places = PlaceSerializer(many=True, required=False)
asked = AskedToSerializer(source='askedto_set', many=True)
fields = ('id', 'created_on', 'title', 'places', 'answered','asked')
extra_kwargs = {'created_by': {'read_only': True}}
class Question(BaseModel):
title = models.CharField(max_length=200, null=False)
places = models.ManyToManyField(Place, blank=True)
answered = models.BooleanField(default=False)
class AskedTo(BaseModel):
ques = models.ForeignKey(Question, on_delete=models.CASCADE)
to_user = models.ForeignKey(settings.AUTH_USER_MODEL)
replied = models.BooleanField(default=False)
class Place(models.Model):
g_place_id = models.CharField(max_length=20,primary_key=True)
json = models.TextField(null=True)
name = models.CharField(max_length=40)
I figured it out. There were two errors.
Changed this:
class AskedToSerializer(serializers.ModelSerializer):
class Meta:
model = AskedTo
fields = ('to_user', 'answered')
to this (notice the change in fields, fields on model and serializer didn't match)
class AskedToSerializer(serializers.ModelSerializer):
class Meta:
model = AskedTo
fields = ('to_user', 'replied')
Secondly, I needed to define any extra fields outside class Meta
class QuestionSerializer(serializers.ModelSerializer):
places = PlaceSerializer(many=True, required=False)
asked = AskedToSerializer(source='askedto_set', many=True)
class Meta:
model = Question
fields = ('id', 'created_on', 'title', 'places', 'answered','asked')
extra_kwargs = {'created_by': {'read_only': True}}
Notice the change in definition of places and asked.
In my case, I have this models.py:
class Section(models.Model):
title = models.CharField(max_length=500)
description = models.TextField(blank=True)
user = models.ForeignKey(Profile, related_name="sections", on_delete=models.CASCADE)
class Feed(models.Model):
title = models.CharField(max_length=500)
link_rss = models.URLField(max_length=500)
link_web = models.URLField(max_length=500)
description = models.TextField(blank=True)
language = models.CharField(max_length=50, blank=True)
logo = models.URLField(blank=True)
sections = models.ManyToManyField(Section, related_name="feeds")
And I completed the serializers.py this:
class FeedSerializer(serializers.ModelSerializer):
sections = serializers.PrimaryKeyRelatedField(many=True, read_only=True)
class Meta:
model = Feed
fields = '__all__'
class SectionSerializer(serializers.ModelSerializer):
feeds = FeedSerializer(many=True, read_only=True)
class Meta:
model = Section
exclude = ('user',)