albertstill · March 6, 2018 00:59 · alexframe · Mar 6, 2018
diff --git a/node_pipe_example.js b/node_pipe_example.js
 const http = require('http');

 const server = http.createServer((req, res) => {
  res.writeHead(200, { 'Content-Type': 'text/html; charset=utf-8' });

  /*
    below is cool because the browser could download assets while we fetch data,
    BUT there is a huge web breaking caveat, it seems we have to know the HTTP response code at this
    moment in time. But we don't - what if there is a 500 during fetching? what happens if we actually need to 404?
    Defaulting to 200 would lead to undesirable outcomes, especially with web scrapers and APM tooling.

    I think this is the reason an RFC exists on Internet Engineering Task Force (IETF)
    titled "An HTTP Status Code for Indicating Hints" https://datatracker.ietf.org/doc/rfc8297/

    Most notably:

    "The dilemma here is that even though it is preferable for an origin
    server to send some header fields as soon as it receives a request,
    it cannot do so until the status code and the full header fields of
    the final HTTP response are determined."
  */
  res.write(`
    <!DOCTYPE html>
    <html>
      <head>
        <script src="https://cdnjs.cloudflare.com/ajax/libs/react/0.14.8/react.min.js" type="text/javascript"></script>
      </head>
  `);

  // imagine fetching data then rendering body
  setTimeout(
    () => { res.end('<body><h1>Foo bar</h1></body></html>'); },
    1000
  );
 });

 server.listen(3002);
	const http = require('http');

	const server = http.createServer((req, res) => {
	res.writeHead(200, { 'Content-Type': 'text/html; charset=utf-8' });

	/*
	below is cool because the browser could download assets while we fetch data,
	BUT there is a huge web breaking caveat, it seems we have to know the HTTP response code at this
	moment in time. But we don't - what if there is a 500 during fetching? what happens if we actually need to 404?
	Defaulting to 200 would lead to undesirable outcomes, especially with web scrapers and APM tooling.

	I think this is the reason an RFC exists on Internet Engineering Task Force (IETF)
	titled "An HTTP Status Code for Indicating Hints" https://datatracker.ietf.org/doc/rfc8297/

	Most notably:

	"The dilemma here is that even though it is preferable for an origin
	server to send some header fields as soon as it receives a request,
	it cannot do so until the status code and the full header fields of
	the final HTTP response are determined."
	*/
	res.write(`
	<!DOCTYPE html>
	<html>
	<head>
	<script src="https://cdnjs.cloudflare.com/ajax/libs/react/0.14.8/react.min.js" type="text/javascript"></script>
	</head>
	`);

	// imagine fetching data then rendering body
	setTimeout(
	() => { res.end('<body><h1>Foo bar</h1></body></html>'); },
	1000
	);
	});

	server.listen(3002);