Category Archives: Recipes

Using the geolocation API

The following instructions are valid for al SFS2X prior to version 2.12. See the last section at the bottom for more recent releases.

SmartFoxServer 2X comes with a geolocation API and database that are used mainly in the AdminTool’s Analytics module to aggregate and show statistics based on geographical positions. The API is not directly exposed to developers but since it’s been requested several times here is a quick recipe on how to use geolocation in your Extension code.

For starters we need to add lib/logs-analysis-app.jar to our project’s dependencies and import a couple of classes:

import com.maxmind.geoip.Country;
import com.smartfoxserver.v2.admin.utils.IpGeoLocator;

NOTE: starting from SmartFoxServer 2X v2.12, the com.maxmind.geoip.Country class has been replaced by com.maxmind.geoip2.record.Country; change the above import accordingly.

Next we instantiate and initialize the IpGeoLocator class:

IpGeoLocator geo = new IpGeoLocator();
geo.init("data/", false);

This tells the geolocation service to load the relative database, located under SFS2X/data/. Finally we can test the service with an IP address:

String ipAdr = ""; // wikipedia's IP

// Locate address
Country country = geo.locateIP(adr);

if (country == null)
   System.out.println("Not found for address: " + ipAdr);
   System.out.println(ipAdr + ": " + countrt.getName() + ", " + country.getCode();

Running the code results in this output: United States, US

NOTE: it is important to always check that the returned Country object is not null. If it is, the geolocation service was not able to resolve the IP to a specific country.

» SFS2X 2.12.x and higher

SFS2X 2.12 introduced automatic geolocation for every client. The setting is configurable per-Zone from the AdminTool > Zone Configurator > Enable Geolocation.

When the service is active we can access the geolocation data with a few lines of server side code:

import com.smartfoxserver.v2.util.Country;

class MyHandler extends BaseClientRequestHandler
	void handleClientRequest(User sender, ISFSObject params)
		Country ctry = sender.getCountry();
		if (ctry != null)
			trace("User's country: " + ctry.getName());
			trace("Country ISO code: " + ctry.getIsoCode());


HTTP Request and Extensions integration

In this new recipe we’re going to take a look at how we can integrate regular HTTP calls with the SmartFoxServer runtime and specifically how to communicate with Extension code via HTTP GET/POST requests.

Common applications of the HTTP/Extension interoperability are debugging interfaces and administration UIs. With this approach developers can easily build a simple web interface that reports that game state, monitors data structures, users etc… allowing to quickly debug problems while testing, triggering events and so on.

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Fine tuning Room Lists

In this new recipe we will take a look at how to optimize the Room List that SmartFoxServer 2X sends to each client.

Room Lists are very important to show players what is going on in the server and allow them to quickly find games to join. Sometimes, however, they can get too big and result in a waste of bandwidth and information overload for clients.

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Using the trace(…) command from anywhere in your Extension code

The trace(…) method is a useful little tool to log any information in the log files for debugging your Extension code.

It is available in the main Extension class and in every Request or Event handler. However, often times, developers need to log messages from other places in their code such as data classes, or any other object that doesn’t extend the Request/Event base classes.

How can we call trace(…) from somewhere else? Continue reading