Is there a way to forward certain HTTP request headers when we're using Codespaces in the browser?

[imballinst]

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Hello! I have a question here:

Is it possible to forward certain headers in the forward proxy (the one that maps preview.app.github.dev to localhost)? So my case is, I am creating an app using https://remix.run and I am using cookies. I could set cookie just fine from my server to the browser, but all cookies sent from the browser aren't received by the server.

I somewhat have a suspicion that the cookie is lost in the forwarding process, since request.headers.Cookie is not defined. Is it because the Codespaces intentionally not forward cookies from the proxy to the local server...?

So... yeah, I'm not sure, could someone help me point out where I am doing it wrong? Thanks!

[hrishikesh-kocharekar-dev]

in the forward proxy, it depends on the specific configuration and capabilities of the proxy server being used. In the case of the Codespaces forward proxy that maps preview.app.github.dev to localhost, the proxy might not forward certain headers, such as cookies, by default. This behavior is often implemented for security reasons, as forwarding cookies from an external client to a local server can have potential security implications.

Check the proxy server's configuration: Look for any configuration options or documentation related to forwarding headers, specifically cookies. It's possible that the proxy server can be configured to forward certain headers, including cookies, if needed.

Modify your application to handle cookies differently: If forwarding cookies through the proxy is not an option, you can consider modifying your application to handle cookies in a different way. One approach is to use alternative methods of authentication and session management, such as using tokens or session IDs passed through query parameters or custom headers.

[imballinst]

Thanks for the reply!

This behavior is often implemented for security reasons, as forwarding cookies from an external client to a local server can have potential security implications.

This part somewhat makes sense, but also doesn't at the same time. If security is a concern, then there's already a feature called private/public port. When it's private, only us (the codespace owner) can access the port.

Check the proxy server's configuration: Look for any configuration options or documentation related to forwarding headers, specifically cookies. It's possible that the proxy server can be configured to forward certain headers, including cookies, if needed.

I believe I already did and I couldn't find the information that I seek, like for example, this page https://docs.github.com/en/codespaces/developing-in-codespaces/forwarding-ports-in-your-codespace. Any chance you could point me to a better keyword? I tried these keywords but no avail, not even AI chatbots could help me:

1. request header
2. proxy
3. github codespaces

What is the proxy server used by GitHub Codespaces, anyway? I think that might be a better question.

Modify your application to handle cookies differently: If forwarding cookies through the proxy is not an option, you can consider modifying your application to handle cookies in a different way. One approach is to use alternative methods of authentication and session management, such as using tokens or session IDs passed through query parameters or custom headers.

This one is interesting, it might be my last resort. My issue with this approach is, if it works outside of GitHub Codespaces (I tried in another Codespaces equivalent product and it worked out of the box), I don't see the reason why I must adapt my web app only to Codespaces.

[RihanArfan]

I'm facing the same thing, but only when the port is set to "private". For the monolythic I'm working with (.NET Core), auth is handled via session cookies. I can see the session cookies are set, but cannot be read it seems.