content-length request header is removed when parseReqBody is false

[mdmower-csnw]

Problem
When option {parseReqBody: false} is used, the original request content-length header is lost when the request is forwarded to the target origin.

Analysis
It looks like the header is removed here:

express-http-proxy/lib/requestOptions.js

Lines 52 to 65 in b05cb04

	function reqHeaders(req, options) {
	var headers = options.headers || {};
	var skipHdrs = [ 'connection', 'content-length' ];
	if (!options.preserveHostHdr) {
	skipHdrs.push('host');
	}
	var hds = extend(headers, req.headers, skipHdrs);
	hds.connection = 'close';
	return hds;
	}

But then is only recalculated when parseReqBody is true, here:

express-http-proxy/app/steps/sendProxyRequest.js

Line 57 in b05cb04

proxyReq.setHeader('Content-Length', Buffer.byteLength(body));

Potential solution
When {parseReqBody: false}...

1. If bodyContent is provided, then content-length could be determined from the size of bodyContent
2. If bodyContent is not provided (i.e. proxyReq is piped), then the original content-length header could be restored (if defined)

Supposing number item 1 is handled (content-length determined from size of bodyContent), then it may not be necessary to remove content-length from the original request at all. It would be overwritten in sendProxyRequest when appropriate and left alone otherwise.

[monkpow]

@mdmower-csnw Thanks for this detailed report. I'll take a look.

[monkpow]

@mdmower-csnw Thanks for the report. I ended up following your parenthetical advice and not removing content-length at all.

[mdmower-csnw]

Thanks for the quick attention on this, @monkpow!