Add RFC forwarded header as hint to backend server

[timkelty]

Fixes #1089

changeOrigin: true

Quickly looking around, it seems like it causes confusion no matter which way you default it:

• proxy changeOrigin set to true by default facebook/create-react-app#4302
• Document devServer.proxy default values for changeOrigin etc.  vuejs/vue-cli#1856
• Changing changeOrigin to be true by default http-party/node-http-proxy#1132

Originally I was inclined to remove it just to keep the defaults from webpack-dev-sever, as I was the one who added it, and since am not sure why I needed it 😝

However, it seems like perhaps it is more useful as true for more people?

CRA, for example, sets this to true, but then again there are people asking that they don't.

So, I left it as-is. Seems maybe like a toss-up. Any input welcome.

X-Dev-Server-Proxy/ Forwarded

This PR removes the invented/non-standard X-Dev-Server-Proxy in favor of a Forwarded header to indicate to the proxied server that this request has been proxied by webpack-dev-server.

I think I've read this too many times and proxies, being proxies, confuse me quickly…
I'm not 💯 if this should be for: or by:. Anyone good at reading spec-language? 😁

• https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Forwarded
• https://tools.ietf.org/html/rfc7239#section-4

[timkelty]

@neutrinojs/core-contributors can anyone do a sanity-check and verify we should be using by: and not for: here?

[edmorley]

So, I left it as-is. Seems maybe like a toss-up. Any input welcome.

CRA, for example, sets this to true, but then again there are people asking that they don't.

So, I left it as-is. Seems maybe like a toss-up. Any input welcome.

I think we should leave it enabled. There seems to only be one person asking for CRA to change the default, and presumably given the issues mentioned in some of the other linked issues/SO posts, there would be many more filed for the reverse, were CRA to ever change their default.

can anyone do a sanity-check and verify we should be using by: and not for: here?

Reading the spec I'm pretty sure by: is the correct one :-)

[edmorley]

👍