How to send headers in deno?

[scientific-dev]

I am working with an socket api where i need to send headers with the socket connections. However in nodejs it allows me to input headers in the second param. But as deno uses the browser like WebSocket api. I can't send headers with it. Any way so how can i send it with deno?

[crowlKats]

You can't set headers for the WebSocket API, as the spec doesnt allow such. See https://github.com/whatwg/html/issues/3062

[justinmchase]

Hey guess what! I poked the bear yesterday and it said we were free to make our own WebSocket standard for non-browser environments! 🤣

https://github.com/whatwg/html/issues/3062#issuecomment-881056952

[justinmchase]

Also here are some relevant links in code I found yesterday while investigating this:

Here is a link to the signature of the main WebSocket library in nodejs, which does include support for headers:
https://github.com/websockets/ws/blob/HEAD/doc/ws.md#new-websocketaddress-protocols-options

Here is the starting point in kubernetes codebase:
https://github.com/kubernetes/kubectl/blob/master/pkg/cmd/exec/exec.go#L366

Here is the official nodejs kubernetes client exec api, which uses ws:
https://github.com/kubernetes-client/javascript/blob/master/src/exec.ts#L53

Here it is applying the authorization header to the options object:
https://github.com/kubernetes-client/javascript/blob/master/src/config.ts#L435

Here it creates the WebSocket with those options:
https://github.com/kubernetes-client/javascript/blob/master/src/web-socket-handler.ts#L174

[kitsonk]

Sending headers over a web socket is, well, just using the socket to .send(). This is as simple has having a utility class in std which accepts a web browser standard WebSocket and sends headers over it. There is no need to re-implement, modify or change the web standard. It might make sense to continue to have it as a "sidecar", something like this:

interface SockeetHeadersOptions {
  headers?: Headers;
  autoSend?: boolean;
}

export class SocketHeaders {
  constructor(websocket: WebSocket, options: SocketHeadersOptions);
  get(key: string): string | undefined;
  set(key: string, value: string): void;
  send(): Promise<void>;
}

Deviating from the web standards should only be done when there is no other realistic alternative, because when/if we do it, it decreases portability of code. Using this sort of "side car" class increases portability because this code can likely be used on other platforms.

[crowlKats]

@kitsonk that doesn't make much sense; this would assume that the server would need to interpret websocket messages as headers themselves. What is asked here is to set additional headers during the initial handshake

[justinmchase]

@kitsonk I think that's partially right, the websocket standards maintainers certainly think that all communication should happen that way but the send happens after the handshake I believe and in this case the server wants to observe the headers before upgrading the connection and doing the handshake.

[scientific-dev]

I have viewed all of those and finally ended up here. So is there any other way?

[scientific-dev]

Well i managed making a ws module which supports custom headers...
https://github.com/scientific-dev/custom-socket