CORS headers in action
When a web app wants to fetch data from an API on a different domain, CORS headers step in to manage the communication between them. their working is as follows:-
- Request with CORS Headers: The web app sends a request to the API, and the browser tags along with CORS headers, like “Origin”, saying where the request came from, such as “https://example.com”.
- Response with CORS Headers: The API gets the request and checks its CORS policy. If it’s okay with requests from the origin mentioned in the “Origin” header, it adds CORS headers like “Access-Control-Allow-Origin” in its response, giving permission to that domain (like “https://localhost.3001”).
- Handling Preflight Requests (Optional): Sometimes, for complex requests, the browser first sends an “OPTIONS” request (a preflight) to check if the actual request is safe. The API then responds with CORS headers indicating if it’s allowed.
- Access Control: If the CORS headers in the response say it’s okay, the browser lets the web app access the response data. If not, it stops the request, and the web app might see an error. This system helps keep things secure while allowing different domains to talk to each other.
How to use CORS in Next.js to Handle Cross-origin Requests ?
NextJS simplifies server-side logic with its API routes, reducing the need for separate server maintenance. CORS, usually configured on the server, can be handled within NextJS API routes directly. These routes, integrated into the application codebase, allow control over request origins. By implementing CORS in API routes, NextJS ensures secure and controlled access to server resources. This approach aligns with NextJS’s server-side rendering capabilities. Developers benefit from reduced complexity and streamlined maintenance.
NextJS emerges as a favorable framework for building applications with server-side rendering needs. Its integration of CORS management within API routes enhances security and flexibility. This model offers a unified solution for both client and server-side needs, promoting efficient development practices.
We Will discuss the different approaches to handling cross-origin requests using NextJS:
Table of Content
- Using Server-side configuration
- Enabling CORS for all API routes