Repository: caddyserver/caddy
File: modules/caddyhttp/reverseproxy/reverseproxy.go (Go)

Code before:
// proxying) regardless of proxy retries. This assumes that no mutations
// of the cloned request are performed by h during or after proxying.
func (h Handler) prepareRequest(req *http.Request, repl *caddy.Replacer) (*http.Request, error) {
	req = cloneRequest(req)

	// if enabled, perform rewrites on the cloned request; if
	// the method is GET or HEAD, prevent the request body
	// from being copied to the upstream
	if h.Rewrite != nil {
		changed := h.Rewrite.Rewrite(req, repl)
		if changed && (h.Rewrite.Method == "GET" || h.Rewrite.Method == "HEAD") {
			req.ContentLength = 0
			req.Body = nil
		}
	}

	// if enabled, buffer client request; this should only be
	// enabled if the upstream requires it and does not work
	// with "slow clients" (gunicorn, etc.) - this obviously
	// has a perf overhead and makes the proxy at risk of
	// exhausting memory and more susceptible to slowloris
	// attacks, so it is strongly recommended to only use this
	// feature if absolutely required, if read timeouts are
	// set, and if body size is limited
	if h.ResponseBuffers != 0 && req.Body != nil {
		req.Body, _ = h.bufferedBody(req.Body, h.ResponseBuffers)
	}

	if req.ContentLength == 0 {
		req.Body = nil // Issue golang/go#16036: nil Body for http.Transport retries
	}

	req.Close = false

	// if User-Agent is not set by client, then explicitly
	// disable it so it's not set to default value by std lib
	if _, ok := req.Header["User-Agent"]; !ok {
		req.Header.Set("User-Agent", "")
	}

	reqUpType := upgradeType(req.Header)
	removeConnectionHeaders(req.Header)

	// Remove hop-by-hop headers to the backend. Especially
	// important is "Connection" because we want a persistent
	// connection, regardless of what the client sent to us.
	// Issue golang/go#46313: don't skip if field is empty.
	for _, h := range hopHeaders {
		// Issue golang/go#21096: tell backend applications that care about trailer support
		// that we support trailers. (We do, but we don't go out of our way to
		// advertise that unless the incoming client request thought it was worth

Review comment (suggestion):
And so on that
```suggestion
		req.Body, _ = h.bufferedBody(req.Body, h.RequestBuffers)
```

Code after:
// proxying) regardless of proxy retries. This assumes that no mutations
// of the cloned request are performed by h during or after proxying.
func (h Handler) prepareRequest(req *http.Request, repl *caddy.Replacer) (*http.Request, error) {
	req = cloneRequest(req)

	// if enabled, perform rewrites on the cloned request; if
	// the method is GET or HEAD, prevent the request body
	// from being copied to the upstream
	if h.Rewrite != nil {
		changed := h.Rewrite.Rewrite(req, repl)
		if changed && (h.Rewrite.Method == "GET" || h.Rewrite.Method == "HEAD") {
			req.ContentLength = 0
			req.Body = nil
		}
	}

	// if enabled, buffer client request; this should only be
	// enabled if the upstream requires it and does not work
	// with "slow clients" (gunicorn, etc.) - this obviously
	// has a perf overhead and makes the proxy at risk of
	// exhausting memory and more susceptible to slowloris
	// attacks, so it is strongly recommended to only use this
	// feature if absolutely required, if read timeouts are
	// set, and if body size is limited
	if h.RequestBuffers != 0 && req.Body != nil {
		req.Body, _ = h.bufferedBody(req.Body, h.RequestBuffers)
	}

	if req.ContentLength == 0 {
		req.Body = nil // Issue golang/go#16036: nil Body for http.Transport retries
	}

	req.Close = false

	// if User-Agent is not set by client, then explicitly
	// disable it so it's not set to default value by std lib
	if _, ok := req.Header["User-Agent"]; !ok {
		req.Header.Set("User-Agent", "")
	}

	reqUpType := upgradeType(req.Header)
	removeConnectionHeaders(req.Header)

	// Remove hop-by-hop headers to the backend. Especially
	// important is "Connection" because we want a persistent
	// connection, regardless of what the client sent to us.
	// Issue golang/go#46313: don't skip if field is empty.
	for _, h := range hopHeaders {
		// Issue golang/go#21096: tell backend applications that care about trailer support
		// that we support trailers. (We do, but we don't go out of our way to
		// advertise that unless the incoming client request thought it was worth