where the date in response header be set?

Question

I want to know at where the date in response is be set. Considering the date is not the standard property of SeverletResponse.

And our server are nginx+tomcat, and inside the tomcat, it is the spring framework.

I look into the org.apache.catalina.core.ApplicationHttpResponse which implements javax.servlet.http.HttpServletResponse, but cannot find the result. there are some sort of setXXX() methods, even setDateHeader(), by which spring can set "Expires" value.

And maybe the date is be set at nginx layer?

Answer 1

I had a same questions like you, and found it.

See org.apache.coyote.http11.Http11Processor.java 1246:1 (org.apache.tomat.embed:tomcat-embed-core:8.5.15)

// Add date header unless application has already set one (e.g. in a
// Caching Filter)
if (headers.getValue("Date") == null) {
    headers.addValue("Date").setString(FastHttpDateFormat.getCurrentDate());
}