Enhancing Your To-Do API with Pagination

Introduction

Welcome to the final lesson of our course on enhancing your To-Do API. Today, we will focus on implementing pagination . You have already learned how to filter and sort your To-Do items, which are essential for making your API more user-friendly and efficient. Imagine your app grows and some users have thousands of tasks. Loading all of them to the web-page can be inefficient. Pagination allows you to break down large data sets into smaller, manageable chunks. This not only improves performance but also enhances the user experience by preventing information overload. By the end of this lesson, you'll be able to implement and customize pagination for your To-Do API using Django Rest Framework’s PageNumberPagination . Let's get started!

Implementing Pagination

To enhance our To-Do API with pagination, we'll use Django Rest Framework’s PageNumberPagination . This allows us to manage large datasets by serving data in smaller, more manageable pages. First, create a pagination.py file in your app directory. Here’s a simple custom pagination class: Python # pagination.py from rest_framework.pagination import PageNumberPagination class TodoPagination(PageNumberPagination): page_size = 2 page_size_query_param = 'page_size' max_page_size = 10 # pagination.py from rest_framework.pagination import PageNumberPagination class TodoPagination(PageNumberPagination): page_size = 2 page_size_query_param = 'page_size' max_page_size = 10 Pagination is the process of dividing a large set of data into sequential pages. In Django Rest Framework, the PageNumberPagination class is a built-in utility to handle this. Here's how it works: page_size : This attribute sets the default number of records to be displayed per page. In our case, it is set to 2. page_size_query_param : This attribute allows the client to define the number of records per page by passing a query parameter (e.g., ?page_size=5). max_page_size : This attribute sets an upper limit on the number of records per page that the client can request. This is useful for preventing misuse where a client might request an excessively large page size. By using these settings, you can efficiently manage the dataset and provide a better user experience.

Applying Pagination

Next, we need to apply this pagination class to our views. Update the views.py file as follows: Python # views.py from rest_framework.filters import OrderingFilter from .pagination import TodoPagination # Importing the custom pagination class class TodoListCreate(generics.ListCreateAPIView): queryset = Todo.objects.all() serializer_class = TodoSerializer filter_backends = [OrderingFilter] ordering_fields = ['priority', 'task'] pagination_class = TodoPagination # Setting custom pagination class # Keep other views unchanged class TodoDetail(generics.RetrieveAPIView): queryset = Todo.objects.all() serializer_class = TodoSerializer class TodoUpdate(generics.UpdateAPIView): queryset = Todo.objects.all() serializer_class = TodoSerializer class TodoDelete(generics.DestroyAPIView): queryset = Todo.objects.all() serializer_class = TodoSerializer # views.py from rest_framework.filters import OrderingFilter from .pagination import TodoPagination # Importing the custom pagination class class TodoListCreate(generics.ListCreateAPIView): queryset = Todo.objects.all() serializer_class = TodoSerializer filter_backends = [OrderingFilter] ordering_fields = ['priority', 'task'] pagination_class = TodoPagination # Setting custom pagination class # Keep other views unchanged class TodoDetail(generics.RetrieveAPIView): queryset = Todo.objects.all() serializer_class = TodoSerializer class TodoUpdate(generics.UpdateAPIView): queryset = Todo.objects.all() serializer_class = TodoSerializer class TodoDelete(generics.DestroyAPIView): queryset = Todo.objects.all() serializer_class = TodoSerializer We import the custom TodoPagination class and set it in the TodoListCreate view using the pagination_class attribute. Now, our To-Do API is capable of paginating the results, making it easier to handle large datasets.

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Python

# pagination.py
from rest_framework.pagination import PageNumberPagination

class TodoPagination(PageNumberPagination):
    page_size = 2
    page_size_query_param = 'page_size'
    max_page_size = 10

Python

# views.py
from rest_framework.filters import OrderingFilter
from .pagination import TodoPagination  # Importing the custom pagination class

class TodoListCreate(generics.ListCreateAPIView):
    queryset = Todo.objects.all()
    serializer_class = TodoSerializer
    filter_backends = [OrderingFilter]
    ordering_fields = ['priority', 'task']
    pagination_class = TodoPagination  # Setting custom pagination class

# Keep other views unchanged
class TodoDetail(generics.RetrieveAPIView):
    queryset = Todo.objects.all()
    serializer_class = TodoSerializer

class TodoUpdate(generics.UpdateAPIView):
    queryset = Todo.objects.all()
    serializer_class = TodoSerializer

class TodoDelete(generics.DestroyAPIView):
    queryset = Todo.objects.all()
    serializer_class = TodoSerializer

Python

import requests
import json

base_url = 'http://0.0.0.0:3000/api/todos/'

# Function to print response items
def print_response_items(response):
    for item in response.json():
        print(json.dumps(item, indent=2))

# Create TODO items
todos = [
    {"task": "Buy groceries", "completed": False, "priority": 1},
    {"task": "Prepare presentation", "completed": True, "priority": 2},
    {"task": "Go to gym", "completed": False, "priority": 3},
    {"task": "Finish homework", "completed": True, "priority": 1},
    {"task": "Organize books", "completed": False, "priority": 2},
    {"task": "Clean the house", "completed": True, "priority": 3},
]

# Create TODO items
for todo in todos:
    response = requests.post(base_url, json=todo)
    print(f'Created TODO: {response.json()}')

# Pagination examples

# Get first page of TODOs
response = requests.get(base_url, params={'page': 1})
print('TODOs page 1:')
print_response_items(response)

# Get second page of TODOs
response = requests.get(base_url, params={'page': 2})
print('TODOs page 2:')
print_response_items(response)

import requests
import json

base_url = 'http://0.0.0.0:3000/api/todos/'

# Function to print response items
def print_response_items(response):
    for item in response.json():
        print(json.dumps(item, indent=2))

# Create TODO items
todos = [
    {"task": "Buy groceries", "completed": False, "priority": 1},
    {"task": "Prepare presentation", "completed": True, "priority": 2},
    {"task": "Go to gym", "completed": False, "priority": 3},
    {"task": "Finish homework", "completed": True, "priority": 1},
    {"task": "Organize books", "completed": False, "priority": 2},
    {"task": "Clean the house", "completed": True, "priority": 3},
]

# Create TODO items
for todo in todos:
    response = requests.post(base_url, json=todo)
    print(f'Created TODO: {response.json()}')

# Pagination examples

# Get first page of TODOs
response = requests.get(base_url, params={'page': 1})
print('TODOs page 1:')
print_response_items(response)

# Get second page of TODOs
response = requests.get(base_url, params={'page': 2})
print('TODOs page 2:')
print_response_items(response)

Python

import requests
import json

base_url = 'http://0.0.0.0:3000/api/todos/'

# Function to print response items
def print_response_items(response):
    for item in response.json():
        print(json.dumps(item, indent=2))

# Pagination examples with custom page size

# Get first page with a custom page size of 3
response = requests.get(base_url, params={'page': 1, 'page_size': 3})
print('TODOs page 1 with page size 3:')
print_response_items(response)

# Get second page with a custom page size of 3
response = requests.get(base_url, params={'page': 2, 'page_size': 3})
print('TODOs page 2 with page size 3:')
print_response_items(response)

import requests
import json

base_url = 'http://0.0.0.0:3000/api/todos/'

# Function to print response items
def print_response_items(response):
    for item in response.json():
        print(json.dumps(item, indent=2))

# Pagination examples with custom page size

# Get first page with a custom page size of 3
response = requests.get(base_url, params={'page': 1, 'page_size': 3})
print('TODOs page 1 with page size 3:')
print_response_items(response)

# Get second page with a custom page size of 3
response = requests.get(base_url, params={'page': 2, 'page_size': 3})
print('TODOs page 2 with page size 3:')
print_response_items(response)

Python

import requests
import json

base_url = 'http://0.0.0.0:3000/api/todos/'

# Function to print response items
def print_response_items(response):
    for item in response.json()['results']:
        print(json.dumps(item, indent=2))

# Function to get all TODO items
def get_all_todos():
    page = 1
    while True:
        response = requests.get(base_url, params={'page': page})
        if response.status_code != 200 or not response.json()['results']:
            break
        print(f'TODOs page {page}:')
        print_response_items(response)
        page += 1

# Fetch and print all TODO items
get_all_todos()

import requests
import json

base_url = 'http://0.0.0.0:3000/api/todos/'

# Function to print response items
def print_response_items(response):
    for item in response.json()['results']:
        print(json.dumps(item, indent=2))

# Function to get all TODO items
def get_all_todos():
    page = 1
    while True:
        response = requests.get(base_url, params={'page': page})
        if response.status_code != 200 or not response.json()['results']:
            break
        print(f'TODOs page {page}:')
        print_response_items(response)
        page += 1

# Fetch and print all TODO items
get_all_todos()

Python

import requests
import json

base_url = 'http://0.0.0.0:3000/api/todos/'

# Function to print response items
def print_response_items(response):
    for item in response.json():
        print(json.dumps(item, indent=2))

# Create TODO items
todos = [
    {"task": "Buy groceries", "completed": False, "priority": 1},
    {"task": "Prepare presentation", "completed": True, "priority": 2},
    {"task": "Go to gym", "completed": False, "priority": 3},
    {"task": "Finish homework", "completed": True, "priority": 1},
    {"task": "Organize books", "completed": False, "priority": 2},
    {"task": "Clean the house", "completed": True, "priority": 3},
]

# Create TODO items
for todo in todos:
    response = requests.post(base_url, json=todo)
    print(f'Created TODO: {response.json()}')

# Pagination examples

# Get first page of TODOs
response = requests.get(base_url, params={'page': 1})
print('TODOs page 1:')
print_response_items(response)

# Get second page of TODOs
response = requests.get(base_url, params={'page': 2})
print('TODOs page 2:')
print_response_items(response)

Python

import requests
import json

base_url = 'http://0.0.0.0:3000/api/todos/'

# Function to print response items
def print_response_items(response):
    for item in response.json():
        print(json.dumps(item, indent=2))

# Pagination examples with custom page size

# Get first page with a custom page size of 3
response = requests.get(base_url, params={'page': 1, 'page_size': 3})
print('TODOs page 1 with page size 3:')
print_response_items(response)

# Get second page with a custom page size of 3
response = requests.get(base_url, params={'page': 2, 'page_size': 3})
print('TODOs page 2 with page size 3:')
print_response_items(response)

Python

import requests
import json

base_url = 'http://0.0.0.0:3000/api/todos/'

# Function to print response items
def print_response_items(response):
    for item in response.json()['results']:
        print(json.dumps(item, indent=2))

# Function to get all TODO items
def get_all_todos():
    page = 1
    while True:
        response = requests.get(base_url, params={'page': page})
        if response.status_code != 200 or not response.json()['results']:
            break
        print(f'TODOs page {page}:')
        print_response_items(response)
        page += 1

# Fetch and print all TODO items
get_all_todos()

Introduction

Implementing Pagination

Applying Pagination

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Use Cases for Pagination in Real Practice

Testing Pagination Without Custom Page Size

Testing Pagination With Custom Page Size

Iterating Through All Pages

Summary And Preparation For Practice