Function preStringToSignV2

pkg/signer/request-signature-v2.go:171–180

From the Amazon docs: StringToSign = HTTP-Verb + "\n" + Content-Md5 + "\n" + Content-Type + "\n" + Expires + "\n" + CanonicalizedProtocolHeaders + CanonicalizedResource;

(req http.Request, virtualHost bool)

//	CanonicalizedProtocolHeaders +
//	CanonicalizedResource;
func preStringToSignV2(req http.Request, virtualHost bool) string {
	buf := new(bytes.Buffer)
	// Write standard headers.
	writePreSignV2Headers(buf, req)
	// Write canonicalized protocol headers if any.
	writeCanonicalizedHeaders(buf, req)
	// Write canonicalized Query resources if any.
	writeCanonicalizedResource(buf, req, virtualHost)
	return buf.String()
}

// writePreSignV2Headers - write preSign v2 required headers.
func writePreSignV2Headers(buf *bytes.Buffer, req http.Request) {