Reduce the time consumed by api in Django Rest Framework - django

Question

These are the models that I created i.e. Video, Tag, Category, Exercise and Package_Exercise respectively. and i want to fetch data based on the object in package exercise and fetch all the data from the Exercise i.e. video url, tag and category of each exercise. I wrote the code but its taking too much time how do I reduce the time taken by the code? What should be the best approach to handle these kind of situations? What would be the best approach based on the time complexity.
class Video(models.Model):
video = models.FileField(upload_to='videos_uploaded',null=False,validators=[FileExtensionValidator(allowed_extensions=['MOV','avi','mp4','webm','mkv'])])
name = models.CharField(max_length=100)
thumbnail = models.ImageField(upload_to="video_thumbnails",null=False)
description = models.TextField(max_length=200)
created_by = models.ForeignKey('accounts.User', on_delete=models.CASCADE, related_name='videos_created_by')
updated_by = models.ForeignKey('accounts.User', on_delete=models.CASCADE, related_name='videos_updated_by')
def __str__(self):
return self.name
class Tag(models.Model):
name=models.CharField(max_length=100)
def __str__(self):
return self.name
class Category(models.Model):
title=models.CharField(max_length=200)
created_by = models.ForeignKey('accounts.User', on_delete=models.CASCADE,
related_name='catagoery_created_by')
updated_by = models.ForeignKey('accounts.User', on_delete=models.CASCADE,
related_name='catagoery_exercise_updated_by')
def __str__(self):
return self.title
class Exercise(models.Model):
name=models.CharField(max_length=100,null=False)
description=models.TextField(max_length=300,null=False)
video=models.ForeignKey(Video,on_delete=models.CASCADE,null=False)
category=models.ForeignKey(Category,on_delete=models.CASCADE,null=False)
tag=models.ManyToManyField(Tag,null=False)
created_by = models.ForeignKey('accounts.User', on_delete=models.CASCADE,
related_name='exercise_created_by', null=False)
updated_by = models.ForeignKey('accounts.User', on_delete=models.CASCADE,
related_name='exercise_updated_by', null=False)
def __str__(self):
return self.name
class Package_Exercise(models.Model):
package = models.ForeignKey(Package,on_delete=models.CASCADE,related_name='package')
exercise = models.ForeignKey(Exercise,on_delete=models.CASCADE)
repetition = models.IntegerField()
number_of_sets = models.IntegerField()
rest_time = models.IntegerField()
created_by = models.ForeignKey('accounts.User', on_delete=models.CASCADE,
related_name='packages_exercise_created_by')
updated_by = models.ForeignKey('accounts.User', on_delete=models.CASCADE,
related_name='packages_exercise_updated_by')
Here is the serializer takes 2.3s for ~30 objects of data in the models.
class PackageSerializer(serializers.ModelSerializer):
exercises = serializers.SerializerMethodField()
class Meta:
model=Package
fields= ['id','package_name','description','amount','is_public','public_doctor','thumbnail','exercises']
def get_exercises(self, obj):
pkg_exercies = Package_Exercise.objects.filter(package = obj.id)
sam = []
for each in pkg_exercies:
sam.append(
{
"name":each.exercise.name,
"url":each.exercise.video.video.url,
"description":each.exercise.description,
"category":each.exercise.category.title,
"tag":each.exercise.tag.name
}
)
return sam
What are the ways to tackle these kind of situations in both POST and GET APIs

Answer 1

Make a new serializer for the package_excercise model and use it in PackageSerializer's method like this:
def get_exercises(self, obj):
pkg_exercies = Package_Exercise.objects.filter(package = obj.id)
serializer = ExcerciseSerializer(data=pkg_exercies, many=True)
serializer.is_valid()
return serializer.data
In this way, you will be using the best way possible for fetching desired data moreover you will not have to repeat the same code in the future.