Build an API Pagination Handler

tutorials

Build an API Pagination Handler

This tutorial walks you through build an api pagination handler from start to finish. By the end, you’ll have a working implementation with proper error handling, testing, and deployment considerations.

Prerequisites

Before starting, ensure you have:

  • A modern programming language runtime (Python 3.10+, Node.js 18+, or Go 1.20+)
  • An API key for the services you’ll use
  • Basic understanding of HTTP APIs and JSON
  • A code editor and terminal access

Step 1: Project Setup

Create a new project directory and initialize it:

mkdir build-api-pagination-handler
cd build-api-pagination-handler
python -m venv venv
source venv/bin/activate  # On Windows: venv\Scripts\activate
pip install requests python-dotenv

Create a .env file to store your API keys:

API_KEY=your_api_key_here
BASE_URL=https://api.example.com

Step 2: Configure Authentication

Set up secure authentication using environment variables:

import os
from dotenv import load_dotenv

load_dotenv()

API_KEY = os.environ.get("API_KEY")
BASE_URL = os.environ.get("BASE_URL", "https://api.example.com")

if not API_KEY:
    raise ValueError("API_KEY environment variable is required")

headers = {
    "Authorization": f"Bearer {API_KEY}",
    "Content-Type": "application/json"
}

Step 3: Implement Core Functionality

Build the main logic for build an api pagination handler:

import requests
import logging
from typing import Optional, Dict, Any

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

class BuildApiPaginationHandler:
    def __init__(self, api_key: str, base_url: str):
        self.api_key = api_key
        self.base_url = base_url.rstrip("/")
        self.session = requests.Session()
        self.session.headers.update({
            "Authorization": f"Bearer {api_key}",
            "Content-Type": "application/json"
        })

    def create_resource(self, data: Dict[str, Any]) -> Optional[Dict]:
        """Create a new resource via the API."""
        try:
            response = self.session.post(
                f"{self.base_url}/v1/resources",
                json=data,
                timeout=30
            )
            response.raise_for_status()
            logger.info("Resource created successfully")
            return response.json()
        except requests.exceptions.RequestException as e:
            logger.error(f"Failed to create resource: {e}")
            return None

    def list_resources(self, params: Dict = None) -> Optional[list]:
        """List resources with optional filtering."""
        try:
            response = self.session.get(
                f"{self.base_url}/v1/resources",
                params=params,
                timeout=30
            )
            response.raise_for_status()
            return response.json().get("data", [])
        except requests.exceptions.RequestException as e:
            logger.error(f"Failed to list resources: {e}")
            return None

# Usage
client = BuildApiPaginationHandler(API_KEY, BASE_URL)
new_resource = client.create_resource({"name": "Test Resource"})
resources = client.list_resources(params={"limit": 10})

Step 4: Add Error Handling and Retries

Implement robust error handling with exponential backoff:

import time
import random

def retry_with_backoff(func, max_retries=3, base_delay=1.0):
    """Retry a function with exponential backoff and jitter."""
    for attempt in range(max_retries + 1):
        try:
            return func()
        except Exception as e:
            if attempt == max_retries:
                raise
            delay = base_delay * (2 ** attempt) + random.random()
            logger.warning(f"Attempt {attempt + 1} failed, retrying in {delay:.1f}s: {e}")
            time.sleep(delay)

# Usage
result = retry_with_backoff(lambda: client.list_resources())

Step 5: Test Your Implementation

Write tests to verify your integration:

import pytest
from unittest.mock import patch, MagicMock

class TestBuildApiPaginationHandler:
    def setup_method(self):
        self.client = BuildApiPaginationHandler("test_key", "https://api.example.com")

    @patch("requests.Session.get")
    def test_list_resources_success(self, mock_get):
        mock_response = MagicMock()
        mock_response.status_code = 200
        mock_response.json.return_value = {"data": [{"id": 1}]}
        mock_response.raise_for_status = MagicMock()
        mock_get.return_value = mock_response

        result = self.client.list_resources()
        assert result == [{"id": 1}]

    @patch("requests.Session.get")
    def test_list_resources_failure(self, mock_get):
        mock_get.side_effect = requests.exceptions.ConnectionError
        result = self.client.list_resources()
        assert result is None

Step 6: Deploy to Production

Consider these deployment best practices:

  1. Use a WSGI/ASGI server (Gunicorn, Uvicorn) for Python web apps
  2. Set up monitoring with structured logging
  3. Configure health checks and alerting
  4. Use a secrets manager for API keys (AWS Secrets Manager, HashiCorp Vault)
  5. Implement circuit breakers for downstream API calls

Best Practices

  • Security: Never expose API keys in client-side code or logs
  • Performance: Use connection pooling and async I/O for high throughput
  • Reliability: Implement retries, circuit breakers, and fallbacks
  • Observability: Log request IDs, latencies, and error rates
  • Testing: Write unit and integration tests with mocked API responses

Summary

You’ve now built a production-ready implementation for build an api pagination handler. The code includes authentication, error handling, retries, testing, and deployment considerations. Adapt the patterns shown here to your specific requirements.

Further Reading

Other languages