Jabaco Source

import static com.emobus.stuff.LoggerConstants.facebookUserId;
import static com.emobus.stuff.LoggerConstants.ipAddress;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.slf4j.MDC;
import org.w3c.dom.Document;

import com.google.code.facebookapi.FacebookException;
import com.google.code.facebookapi.FacebookWebappHelper;
import com.google.code.facebookapi.FacebookXmlRestClient;
import com.google.code.facebookapi.IFacebookRestClient;

/**
 * The Facebook User Filter ensures that a Facebook client that pertains to
 * the logged in user is available in the session object named "facebook.user.client".
 * 
 * The session ID is stored as "facebook.user.session". It's important to get
 * the session ID only when the application actually needs it. The user has to 
 * authorise to give the application a session key.
 * 
 * @author Dave
 */

public class FacebookUserFilter implements Filter {

    	private static final Logger logger = LoggerFactory.getLogger(FacebookUserFilter.class);
    	
    	private String api_key;
    	private String secret;
    	
    	private static final String FACEBOOK_USER_CLIENT = "facebook.user.client";
    	
    	public void init(FilterConfig filterConfig) throws ServletException {
            	api_key = filterConfig.getServletContext().getInitParameter("facebook_api_key");
            	secret = filterConfig.getServletContext().getInitParameter("facebook_secret");
            	if(api_key == null || secret == null) {
                    	throw new ServletException("Cannot initialise Facebook User Filter because the " +
                                                       	"facebook_api_key or facebook_secret context init " +
                                                       	"params have not been set. Check that they're there " +
                                                       	"in your servlet context descriptor.");
            	} else {
                    	logger.info("Using facebook API key: " + api_key);
            	}
    	}

public void destroy() {
}

public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
try {
MDC.put(ipAddress, req.getRemoteAddr());

HttpServletRequest request = (HttpServletRequest)req;
HttpServletResponse response = (HttpServletResponse)res;

HttpSession session = request.getSession(true);
IFacebookRestClient<Document> userClient = getUserClient(session); 
if(userClient == null) {
logger.debug("User session doesn't have a Facebook API client setup yet. Creating one and storing it in the user's session.");
userClient = new FacebookXmlRestClient(api_key, secret);
session.setAttribute(FACEBOOK_USER_CLIENT, userClient);
}

logger.trace("Creating a FacebookWebappHelper, which copies fb_ request param data into the userClient");
FacebookWebappHelper<Document> facebook = new FacebookWebappHelper<Document>(request, response, api_key, secret, userClient);
String nextPage = request.getRequestURI();
nextPage = nextPage.substring(nextPage.indexOf("/", 1) + 1); //cut out the first /, the context path and the 2nd /
logger.trace(nextPage); 
boolean redirectOccurred = facebook.requireLogin(nextPage);
if(redirectOccurred) {
return;
}
redirectOccurred = facebook.requireFrame(nextPage);
if(redirectOccurred) {
return;
}

long facebookUserID;
try {
facebookUserID = userClient.users_getLoggedInUser();
} catch(FacebookException ex) {
response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "Error while fetching user's facebook ID");
logger.error("Error while getting cached (supplied by request params) value " +
"of the user's facebook ID or while fetching it from the Facebook service " +
"if the cached value was not present for some reason. Cached value = {}", userClient.getCacheUserId());
return;
}

MDC.put(facebookUserId, String.valueOf(facebookUserID));

chain.doFilter(request, response);
} finally {
MDC.remove(ipAddress);
MDC.remove(facebookUserId);
}
}

public static FacebookXmlRestClient getUserClient(HttpSession session) {
return (FacebookXmlRestClient)session.getAttribute(FACEBOOK_USER_CLIENT);
}
}



public class SetUsersStatus

if (client.users_hasAppPermission(Permission.STATUS_UPDATE)) {
client.users_setStatus("developing Facebook apps in Java because the new Java client kicks the PHP client's ... !", false);
}

}