Guide to Setting the "Cross-Origin-Resource-Policy" Header

Contents

What Does This Header Do?

The Cross-Origin-Resource-Policy (CORP) header controls who can load resources (e.g., images, scripts, or styles) from your website. By restricting access to same-origin or trusted origins, this header helps prevent unauthorized usage of your resources.

Steps to Set the Header

1. If You Use a Web Server (e.g., Apache, Nginx, etc.)

For Apache:

  1. Open your website's configuration file (or .htaccess file if you use one).
  2. Add the following line, replacing same-origin with the appropriate policy: 
    Header set Cross-Origin-Resource-Policy "same-origin"
  3. Save the file and restart the Apache server to apply changes.

For Nginx:

  1. Open your website's configuration file (e.g., /etc/nginx/sites-available/your-site).
  2. Add the following line inside the server block, replacing same-origin with the appropriate policy: 
    add_header Cross-Origin-Resource-Policy "same-origin";
  3. Save the file and restart Nginx to apply changes using: 
    sudo systemctl restart nginx

2. If You Use a Programming Language:

For PHP:

header("Cross-Origin-Resource-Policy: same-origin");

For Node.js:

Use a middleware like helmet to set the header automatically:

const helmet = require('helmet');
app.use(helmet.crossOriginResourcePolicy({ policy: 'same-origin' }));

Or set it manually:

app.use((req, res, next) => {
  res.setHeader('Cross-Origin-Resource-Policy', 'same-origin');
  next();
});

For Python (Flask):

from flask import Flask, Response

app = Flask(__name__)

@app.after_request
def set_headers(response):
    response.headers['Cross-Origin-Resource-Policy'] = 'same-origin'
    return response

3. Verify the Header

After setting the header, test your website to ensure it’s working:

  1. Open your website in a browser.
  2. Use the developer tools (right-click > Inspect > Network tab) to view the HTTP headers.
  3. Look for the Cross-Origin-Resource-Policy header with the correct value.

Why It Matters

Setting this header protects your resources from being accessed or abused by unauthorized third parties, reducing potential misuse or security risks.

If you need further assistance, don't hesitate to reach out to your hosting provider or system administrator.