http headers

HTTP headers are key-value pairs sent between a client (like a web browser) and a server during an HTTP request or response.

does an iframe that displays a pdf use an http header and more specifically a cors header

When an iframe is used to display a PDF, the browser makes an HTTP request to fetch the PDF file from the server.

This request includes HTTP headers, and the server’s response will also contain HTTP headers.

Whether CORS headers are involved depends on the origin of the PDF file relative to the web page containing the iframe:
• Same-Origin: If the PDF is hosted on the same origin as the web page, CORS headers are generally not needed.
• Cross-Origin: If the PDF is hosted on a different origin, the server must include appropriate CORS headers (e.g., Access-Control-Allow-Origin) in its response to allow the PDF to be displayed in the iframe.

Without the correct CORS headers, the browser may block the PDF from being displayed due to security restrictions.

if the pdf asset is served by backblaze private repository and that a cloudfare worker is used to supply the key to obtain the asset, will consideration need to b e made towards cors header

Yes, considerations for CORS headers are necessary in this scenario.

When using a Cloudflare Worker to supply a key for accessing a PDF asset from a Backblaze private repository, the following should be considered:

1 Cloudflare Worker Response: Ensure that the Cloudflare Worker includes appropriate CORS headers in its response to the client. This typically involves setting the Access-Control-Allow-Origin header to allow the requesting origin.
2 Backblaze Response: If the PDF is fetched directly from Backblaze by the client, Backblaze must also include the necessary CORS headers in its response. If the Cloudflare Worker fetches the PDF and then serves it to the client, the Worker should handle CORS.
3 Security: Ensure that the CORS policy is configured to allow only trusted origins to access the resource, minimizing security risks.

By properly configuring CORS headers, you can ensure that the PDF is accessible while maintaining security.