Getting Request And Response Using BrowserMobProxy, Selenium, Firefox, marionette/gecko

Question

I'm trying to get response and request using BMP's RequestFilter and ResponseFilter. However, when the webpage loads, nothing gets printed in the console.
Everything else seems to work though. Maybe BMP is not watching GeckoDriver?
I'm using Firefox 50.0, BrowserMobProxy 2.1.2, Selenium 3.0.1, and GeckoDriver 0.11.1
The testing code is below. Could someone please help me?
Thank you very much!

BrowserMobProxy server = new BrowserMobProxyServer();
server.enableHarCaptureTypes(CaptureType.REQUEST_CONTENT, CaptureType.RESPONSE_CONTENT);
server.start();
int port = server.getPort();
server.addRequestFilter((request, content, info) -> {
    String q = URLDecoder.decode(info.getOriginalUrl(), "UTF-8");
    System.out.println("Request: "+q);
    return null;
});

server.addResponseFilter((response, content, info) -> {
    String type = response.headers().get("Content-Type");
    System.out.println("Response: "+info.getOriginalRequest());
    System.out.println(type);
});

Proxy proxy = ClientUtil.createSeleniumProxy(server);
DesiredCapabilities capabilities = DesiredCapabilities.firefox();
capabilities.setCapability(CapabilityType.PROXY, proxy);
capabilities.setCapability("marionette", true);
capabilities.setCapability(CapabilityType.ACCEPT_SSL_CERTS, true);
capabilities.setCapability(CapabilityType.SUPPORTS_JAVASCRIPT, true);
FirefoxProfile fp = new FirefoxProfile();
capabilities.setCapability(FirefoxDriver.PROFILE, fp);
String gecko = "d:/Programming/java/geckodriver.exe";
System.setProperty("webdriver.gecko.driver", gecko);
driver = new FirefoxDriver(capabilities);                    
driver.get("https://google.com");;

Answer 1

In Firefox 51 and lower, there is a bug/missing feature in Selenium 3's GeckoDriver that prevents Firefox from picking up the proxy settings when setting CapabilityType.PROXY on the DesiredCapabilities object.

However, you can still set the proxy settings directly on the FirefoxProfile. There's an example of this in one of BMP's tests. Since you're already using a FirefoxProfile object, this would probably be a sensible solution for you. It would look something like this (replace localhost with a hostname/ip address as appropriate):

FirefoxProfile fp = new FirefoxProfile();
fp.setPreference("network.proxy.http", "localhost");
fp.setPreference("network.proxy.http_port", server.getPort());
fp.setPreference("network.proxy.ssl", "localhost");
fp.setPreference("network.proxy.ssl_port", server.getPort());
fp.setPreference("network.proxy.type", 1);
fp.setPreference("network.proxy.no_proxies_on", "");

This geckodriver issue also discusses a few other alternatives to using CapabilityType.PROXY on the DesiredCapabilities object.

UPDATE

According to the mozilla bug report, this issue is fixed in Firefox 52, which is scheduled to be released on March 7, 2017. In the meantime, the solution with the FirefoxProfile should work with 51 (and lower), and should also continue to work with 52+.