[FIXED] how to force hostname when behind a chain of 2 revese proxy

Issue

An spring boot application is hosted behind 2 reverse proxy (chained).

reverse-proxy 1 --> reverse-proxy 2 --> spring boot app

And the host and forward headers are not chain correctly. there is a way to force the host to a fixed value? like the hostname of the "reverse proxy 1"?

Solution

i have fixed my issue by changing the serverName in incoming request.

i have add a valve to tomcat:

public class HostForceValve extends ValveBase {

private final String proxyName;

public HostForceValve(String proxyName) {
    this.proxyName = proxyName;
}

@Override public void invoke(Request request, Response response) throws IOException, ServletException {
    org.apache.coyote.Request coyoteRequest = request.getCoyoteRequest();
    MimeHeaders mimeHeaders = coyoteRequest.getMimeHeaders();
    mimeHeaders.removeHeader("host");
    final MessageBytes host = mimeHeaders.addValue("host");
    host.setString(proxyName);
    request.setRemoteHost(proxyName);
    request.getCoyoteRequest().serverName().setString(proxyName);
    try {
        Valve next = getNext();
        if (null == next) {
            return;
        }
        next.invoke(request, response);
    } finally {
        request.setRemoteHost(proxyName);
    }

}
}

And add this value to the tomcat embedded server:

@Component
public class MyTomcatCustomizer implements WebServerFactoryCustomizer<TomcatServletWebServerFactory> {

@Value("${proxyName:}")
private String proxyName;

@Override
public void customize(TomcatServletWebServerFactory factory) {
    final Collection<Valve> currents = factory.getEngineValves();
    final ArrayList<Valve> addValves = new ArrayList<>(currents);
    if (StringUtils.hasLength(proxyName)) {
        addValves.add(0, new HostForceValve(proxyName));
    }
    factory.setEngineValves(addValves);
}
}

Answered By - RJO

Answer Checked By - Willingham (PHPFixing Volunteer)