How to use the Node.js axios library for making HTTP requests with interceptors for automatic JSON parsing in Koa

  Arif Babu

         

  NodeJS



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To use the Node.js Axios library for making HTTP requests with interceptors for automatic JSON parsing in Koa, you can create a custom middleware in your Koa application. Here's how you can do it:

  1. Install Axios and Koa: If you haven't already, install the axios and koa packages.
bash
npm install axios koa
  1. Create Axios Middleware: Implement a custom middleware that integrates Axios with Koa and automatically parses JSON responses.
javascript
const axios = require('axios');

function axiosMiddleware() {
  return async (ctx, next) => {
    ctx.axios = axios.create({
      baseURL: 'https://api.example.com', // Adjust base URL according to your API
      timeout: 5000, // Adjust timeout as needed
      headers: {
        'Content-Type': 'application/json',
        // Add any other default headers here
      },
    });

    // Add response interceptor for automatic JSON parsing
    ctx.axios.interceptors.response.use(
      (response) => {
        if (response.headers['content-type'] === 'application/json') {
          response.data = response.data ? JSON.parse(response.data) : {};
        }
        return response;
      },
      (error) => {
        return Promise.reject(error);
      }
    );

    await next();
  };
}

module.exports = axiosMiddleware;
  1. Integrate Middleware with Koa Application: Use the middleware in your Koa application.
javascript
const Koa = require('koa');
const axiosMiddleware = require('./axiosMiddleware');

const app = new Koa();

// Use Axios middleware
app.use(axiosMiddleware());

// Example route
app.use(async (ctx) => {
  try {
    // Make a GET request using ctx.axios
    const response = await ctx.axios.get('/data');
    ctx.body = response.data;
  } catch (error) {
    ctx.status = error.response.status || 500;
    ctx.body = error.response.data || 'Internal Server Error';
  }
});

// Start the server
const port = process.env.PORT || 3000;
app.listen(port, () => {
  console.log(`Server running on port ${port}`);
});

In this example:

  • We create a custom middleware axiosMiddleware that attaches an Axios instance to the Koa context (ctx) with default configurations such as base URL, timeout, and headers.
  • We add a response interceptor to the Axios instance to automatically parse JSON responses.
  • In the Koa application, we use axiosMiddleware() to apply the middleware.
  • Inside the Koa route handler, we make HTTP requests using ctx.axios with automatic JSON parsing for responses.

Adjust the middleware and configurations according to your specific requirements and API endpoints. This setup provides a convenient way to use Axios for making HTTP requests with automatic JSON parsing in a Koa application.

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