XMPP with Java Asmack library supporting X-FACEBOOK-PLATFORM

Question

I'm trying to make a Facebook Chat on Android with the Smack library. I've read the Chat API from Facebook, but I cannot understand how I have to authenticate with Facebook using this library.

Can anyone point me how to accomplish this?

Update: According to the no.good.at.coding answer, I have this code adapted to the Asmack library. All works fine except I receive as response to the login: not-authorized. Here is the code I use:

public class SASLXFacebookPlatformMechanism extends SASLMechanism
{

    private static final String NAME              = "X-FACEBOOK-PLATFORM";

    private String              apiKey            = "";
    private String              applicationSecret = "";
    private String              sessionKey        = "";

    /**
     * Constructor.
     */
    public SASLXFacebookPlatformMechanism(SASLAuthentication saslAuthentication)
    {
        super(saslAuthentication);
    }

    @Override
    protected void authenticate() throws IOException, XMPPException
    {

        getSASLAuthentication().send(new AuthMechanism(NAME, ""));
    }

    @Override
    public void authenticate(String apiKeyAndSessionKey, String host,
            String applicationSecret) throws IOException, XMPPException
    {
        if (apiKeyAndSessionKey == null || applicationSecret == null)
        {
            throw new IllegalArgumentException("Invalid parameters");
        }

        String[] keyArray = apiKeyAndSessionKey.split("\\|", 2);
        if (keyArray.length < 2)
        {
            throw new IllegalArgumentException(
                    "API key or session key is not present");
        }

        this.apiKey = keyArray[0];
        Log.d("API_KEY", apiKey);
        this.applicationSecret = applicationSecret;
        Log.d("SECRET_KEY", applicationSecret);
        this.sessionKey = keyArray[1];
        Log.d("SESSION_KEY", sessionKey);

        this.authenticationId = sessionKey;
        this.password = applicationSecret;
        this.hostname = host;

        String[] mechanisms = { "DIGEST-MD5" };
        Map<String, String> props = new HashMap<String, String>();
        this.sc =
                Sasl.createSaslClient(mechanisms, null, "xmpp", host, props,
                        this);
        authenticate();
    }

    @Override
    protected String getName()
    {
        return NAME;
    }

    @Override
    public void challengeReceived(String challenge) throws IOException
    {
        byte[] response = null;

        if (challenge != null)
        {
            String decodedChallenge = new String(Base64.decode(challenge));
            Log.d("DECODED", decodedChallenge);
            Map<String, String> parameters = getQueryMap(decodedChallenge);

            String version = "1.0";
            String nonce = parameters.get("nonce");
            String method = parameters.get("method");

            long callId = new GregorianCalendar().getTimeInMillis() / 1000L;

            String sig =
                    "api_key=" + apiKey + "call_id=" + callId + "method="
                            + method + "nonce=" + nonce + "session_key="
                            + sessionKey + "v=" + version + applicationSecret;

            try
            {
                sig = md5(sig);
                sig = sig.toUpperCase();
            } catch (NoSuchAlgorithmException e)
            {
                throw new IllegalStateException(e);
            }

            String composedResponse =
                    "api_key=" + URLEncoder.encode(apiKey, "utf-8")
                            + "&call_id=" + callId + "&method="
                            + URLEncoder.encode(method, "utf-8") + "&nonce="
                            + URLEncoder.encode(nonce, "utf-8")
                            + "&session_key="
                            + URLEncoder.encode(sessionKey, "utf-8") + "&v="
                            + URLEncoder.encode(version, "utf-8") + "&sig="
                            + URLEncoder.encode(sig, "utf-8");

            Log.d("COMPOSED", composedResponse);

            response = composedResponse.getBytes("utf-8");
        }

        String authenticationText = "";

        if (response != null)
        {
            authenticationText =
                    Base64.encodeBytes(response, Base64.DONT_BREAK_LINES);
        }

        // Send the authentication to the server
        getSASLAuthentication().send(new Response(authenticationText));
    }

    private Map<String, String> getQueryMap(String query)
    {
        Map<String, String> map = new HashMap<String, String>();
        String[] params = query.split("\\&");

        for (String param : params)
        {
            String[] fields = param.split("=", 2);
            map.put(fields[0], (fields.length > 1 ? fields[1] : null));
        }

        return map;
    }

    private String md5(String text) throws NoSuchAlgorithmException,
            UnsupportedEncodingException
    {
        MessageDigest md = MessageDigest.getInstance("MD5");
        md.update(text.getBytes("utf-8"), 0, text.length());
        return convertToHex(md.digest());
    }

    private String convertToHex(byte[] data)
    {
        StringBuilder buf = new StringBuilder();
        int len = data.length;

        for (int i = 0; i < len; i++)
        {
            int halfByte = (data[i] >>> 4) & 0xF;
            int twoHalfs = 0;

            do
            {
                if (0 <= halfByte && halfByte <= 9)
                {
                    buf.append((char) ('0' + halfByte));
                }
                else
                {
                    buf.append((char) ('a' + halfByte - 10));
                }
                halfByte = data[i] & 0xF;
            } while (twoHalfs++ < 1);
        }

        return buf.toString();
    }
}

And this, is the communication with the server with the sent and received messages:

PM SENT (1132418216): <stream:stream to="chat.facebook.com" xmlns="jabber:client" xmlns:stream="http://etherx.jabber.org/streams" version="1.0">


PM RCV  (1132418216): <?xml version="1.0"?><stream:stream id="C62D0F43" from="chat.facebook.com" xmlns="jabber:client" xmlns:stream="http://etherx.jabber.org/streams" version="1.0" xml:lang="en"><stream:features><mechanisms xmlns="urn:ietf:params:xml:ns:xmpp-sasl"><mechanism>X-FACEBOOK-PLATFORM</mechanism><mechanism>DIGEST-MD5</mechanism></mechanisms></stream:features>


PM SENT (1132418216): <auth mechanism="X-FACEBOOK-PLATFORM" xmlns="urn:ietf:params:xml:ns:xmpp-sasl"></auth>


PM RCV  (1132418216): <challenge xmlns="urn:ietf:params:xml:ns:xmpp-sasl">dmVyc2lvbj0xJm1ldGhvZD1hdXRoLnhtcHBfbG9naW4mbm9uY2U9NzFGNkQ3Rjc5QkIyREJCQ0YxQTkwMzA0QTg3OTlBMzM=</challenge>


PM SENT (1132418216): <response xmlns="urn:ietf:params:xml:ns:xmpp-sasl">YXBpX2tleT0zMWYzYjg1ZjBjODYwNjQ3NThiZTZhOTQyNjVjZmNjMCZjYWxsX2lkPTEzMDA0NTYxMzUmbWV0aG9kPWF1dGgueG1wcF9sb2dpbiZub25jZT03MUY2RDdGNzlCQjJEQkJDRjFBOTAzMDRBODc5OUEzMyZzZXNzaW9uX2tleT0yNjUzMTg4ODNkYWJhOGRlOTRiYTk4ZDYtMTAwMDAwNTAyNjc2Nzc4JnY9MS4wJnNpZz04RkRDRjRGRTgzMENGOEQ3QjgwNjdERUQyOEE2RERFQw==</response>


PM RCV  (1132418216): <failure xmlns="urn:ietf:params:xml:ns:xmpp-sasl"><not-authorized/></failure>

As read in the developers Facebook forum, it is needed to disable the "Disable Deprecated Auth Methods" setting from the Facebook settings page of your app. But, even doing that, I can't login. And the session key is the second part of the OAuth token in the form AAA|BBB|CCC, I mean, BBB.

Answer 1

Finally, thanks to the no.good.at.coding code and the suggestion of harism, I've been able to connect to the Facebook chat. This code is the Mechanism for the Asmack library (the Smack port for Android). For the Smack library is necessary to use the no.good.at.coding mechanism.

SASLXFacebookPlatformMechanism.java:

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.GregorianCalendar;
import java.util.HashMap;
import java.util.Map;

import org.apache.harmony.javax.security.auth.callback.CallbackHandler;
import org.apache.harmony.javax.security.sasl.Sasl;
import org.jivesoftware.smack.SASLAuthentication;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.sasl.SASLMechanism;
import org.jivesoftware.smack.util.Base64;

public class SASLXFacebookPlatformMechanism extends SASLMechanism
{

    private static final String NAME              = "X-FACEBOOK-PLATFORM";

    private String              apiKey            = "";
    private String              applicationSecret = "";
    private String              sessionKey        = "";

    /**
     * Constructor.
     */
    public SASLXFacebookPlatformMechanism(SASLAuthentication saslAuthentication)
    {
        super(saslAuthentication);
    }

    @Override
    protected void authenticate() throws IOException, XMPPException
    {

        getSASLAuthentication().send(new AuthMechanism(NAME, ""));
    }

    @Override
    public void authenticate(String apiKeyAndSessionKey, String host,
            String applicationSecret) throws IOException, XMPPException
    {
        if (apiKeyAndSessionKey == null || applicationSecret == null)
        {
            throw new IllegalArgumentException("Invalid parameters");
        }

        String[] keyArray = apiKeyAndSessionKey.split("\\|", 2);
        if (keyArray.length < 2)
        {
            throw new IllegalArgumentException(
                    "API key or session key is not present");
        }

        this.apiKey = keyArray[0];
        this.applicationSecret = applicationSecret;
        this.sessionKey = keyArray[1];

        this.authenticationId = sessionKey;
        this.password = applicationSecret;
        this.hostname = host;

        String[] mechanisms = { "DIGEST-MD5" };
        Map<String, String> props = new HashMap<String, String>();
        this.sc =
                Sasl.createSaslClient(mechanisms, null, "xmpp", host, props,
                        this);
        authenticate();
    }

    @Override
    public void authenticate(String username, String host, CallbackHandler cbh)
            throws IOException, XMPPException
    {
        String[] mechanisms = { "DIGEST-MD5" };
        Map<String, String> props = new HashMap<String, String>();
        this.sc =
                Sasl.createSaslClient(mechanisms, null, "xmpp", host, props,
                        cbh);
        authenticate();
    }

    @Override
    protected String getName()
    {
        return NAME;
    }

    @Override
    public void challengeReceived(String challenge) throws IOException
    {
        byte[] response = null;

        if (challenge != null)
        {
            String decodedChallenge = new String(Base64.decode(challenge));
            Map<String, String> parameters = getQueryMap(decodedChallenge);

            String version = "1.0";
            String nonce = parameters.get("nonce");
            String method = parameters.get("method");

            long callId = new GregorianCalendar().getTimeInMillis();

            String sig =
                    "api_key=" + apiKey + "call_id=" + callId + "method="
                            + method + "nonce=" + nonce + "session_key="
                            + sessionKey + "v=" + version + applicationSecret;

            try
            {
                sig = md5(sig);
            } catch (NoSuchAlgorithmException e)
            {
                throw new IllegalStateException(e);
            }

            String composedResponse =
                    "api_key=" + URLEncoder.encode(apiKey, "utf-8")
                            + "&call_id=" + callId + "&method="
                            + URLEncoder.encode(method, "utf-8") + "&nonce="
                            + URLEncoder.encode(nonce, "utf-8")
                            + "&session_key="
                            + URLEncoder.encode(sessionKey, "utf-8") + "&v="
                            + URLEncoder.encode(version, "utf-8") + "&sig="
                            + URLEncoder.encode(sig, "utf-8");

            response = composedResponse.getBytes("utf-8");
        }

        String authenticationText = "";

        if (response != null)
        {
            authenticationText =
                    Base64.encodeBytes(response, Base64.DONT_BREAK_LINES);
        }

        // Send the authentication to the server
        getSASLAuthentication().send(new Response(authenticationText));
    }

    private Map<String, String> getQueryMap(String query)
    {
        Map<String, String> map = new HashMap<String, String>();
        String[] params = query.split("\\&");

        for (String param : params)
        {
            String[] fields = param.split("=", 2);
            map.put(fields[0], (fields.length > 1 ? fields[1] : null));
        }

        return map;
    }

    private String md5(String text) throws NoSuchAlgorithmException,
            UnsupportedEncodingException
    {
        MessageDigest md = MessageDigest.getInstance("MD5");
        md.update(text.getBytes("utf-8"), 0, text.length());
        return convertToHex(md.digest());
    }

    private String convertToHex(byte[] data)
    {
        StringBuilder buf = new StringBuilder();
        int len = data.length;

        for (int i = 0; i < len; i++)
        {
            int halfByte = (data[i] >>> 4) & 0xF;
            int twoHalfs = 0;

            do
            {
                if (0 <= halfByte && halfByte <= 9)
                {
                    buf.append((char) ('0' + halfByte));
                }
                else
                {
                    buf.append((char) ('a' + halfByte - 10));
                }
                halfByte = data[i] & 0xF;
            } while (twoHalfs++ < 1);
        }

        return buf.toString();
    }
}

To use it:

ConnectionConfiguration config = new ConnectionConfiguration("chat.facebook.com", 5222);
config.setSASLAuthenticationEnabled(true);
XMPPConnection xmpp = new XMPPConnection(config);
try
{
    SASLAuthentication.registerSASLMechanism("X-FACEBOOK-PLATFORM", SASLXFacebookPlatformMechanism.class);
    SASLAuthentication.supportSASLMechanism("X-FACEBOOK-PLATFORM", 0);
    xmpp.connect();
    xmpp.login(apiKey + "|" + sessionKey, sessionSecret, "Application");
} catch (XMPPException e)
{
    xmpp.disconnect();
    e.printStackTrace();
}

apiKey is the API key given in the application settings page in Facebook. sessionKey is the second part of the access token. If the token is in this form, AAA|BBB|CCC, the BBB is the session key. sessionSecret is obtained using the old REST API with the method auth.promoteSession. To use it, it's needed to make a Http get to this url:

https://api.facebook.com/method/auth.promoteSession?access_token=yourAccessToken

Despite of the Facebook Chat documentation says that it's needed to use your application secret key, only when I used the key that returned that REST method I was able to make it works. To make that method works, you have to disable the Disable Deprecated Auth Methods option in the Advance tab in your application settings.

Answer 2

I'd used this about 6 months ago with Smack (not asmack) so I'm not sure how it'll hold up now but here goes, hope it helps!

I found an implementation of Facebook's X-FACEBOOK-PLATFORM authentication mechanism on the Ignite Realtime Smack forum where someone got it from the fbgc project. You'll find the a ZIP with the SASLXFacebookPlatformMechanism.java source in the answer I linked to. You can use it as follows:

public void login() throws XMPPException
{
    SASLAuthentication.registerSASLMechanism(SASLXFacebookPlatformMechanism.NAME,
            SASLXFacebookPlatformMechanism.class);
    SASLAuthentication.supportSASLMechanism(SASLXFacebookPlatformMechanism.NAME, 0);

    ConnectionConfiguration connConfig = new ConnectionConfiguration(host, port);

    XMPPConnection connection = new XMPPConnection(connConfig);
    connection.connect();
    log.info("XMPP client connected");

    connection.login(Utils.FB_APP_ID + "|" + this.user.sessionId, Utils.FB_APP_SECRET, "app_name");
    log.info("XMPP client logged in");
}

I was doing this on the server without an SDK. I don't remember the details (and the Facebook documentation isn't very good) but from what I can tell from my code, after getting the user to authorize the app, I get a callback request from Facebook with a code parameter. I open a URLConnection to https://graph.facebook.com/oauth/access_token?client_id=<app_id>&redirect_uri=http://myserver/context/path/&client_secret=<app_secret>&code=<code>. The response should be the access token where the session id is the part after the | - something of the form XXX|<sessionId>.

Answer 3

Here's code I've been using successfully for authentication. Maybe this helps even though this is not related to Smack in any way. You can get sessionKey from access token received from FB, and for getting sessionSecret I've been using oldish REST API;

http://developers.facebook.com/docs/reference/rest/auth.promoteSession/

private final void processChallenge(XmlPullParser parser, Writer writer,
        String sessionKey, String sessionSecret) throws IOException,
        NoSuchAlgorithmException, XmlPullParserException {

    parser.require(XmlPullParser.START_TAG, null, "challenge");
    String challenge = new String(Base64.decode(parser.nextText(),
            Base64.DEFAULT));

    String params[] = challenge.split("&");
    HashMap<String, String> paramMap = new HashMap<String, String>();
    for (int i = 0; i < params.length; ++i) {
        String p[] = params[i].split("=");
        p[0] = URLDecoder.decode(p[0]);
        p[1] = URLDecoder.decode(p[1]);
        paramMap.put(p[0], p[1]);
    }

    String api_key = "YOUR_API_KEY";
    String call_id = "" + System.currentTimeMillis();
    String method = paramMap.get("method");
    String nonce = paramMap.get("nonce");
    String v = "1.0";

    StringBuffer sigBuffer = new StringBuffer();
    sigBuffer.append("api_key=" + api_key);
    sigBuffer.append("call_id=" + call_id);
    sigBuffer.append("method=" + method);
    sigBuffer.append("nonce=" + nonce);
    sigBuffer.append("session_key=" + sessionKey);
    sigBuffer.append("v=" + v);
    sigBuffer.append(sessionSecret);

    MessageDigest md = MessageDigest.getInstance("MD5");
    md.update(sigBuffer.toString().getBytes());
    byte[] digest = md.digest();

    StringBuffer sig = new StringBuffer();
    for (int i = 0; i < digest.length; ++i) {
        sig.append(Integer.toHexString(0xFF & digest[i]));
    }

    StringBuffer response = new StringBuffer();
    response.append("api_key=" + URLEncoder.encode(api_key));
    response.append("&call_id=" + URLEncoder.encode(call_id));
    response.append("&method=" + URLEncoder.encode(method));
    response.append("&nonce=" + URLEncoder.encode(nonce));
    response.append("&session_key=" + URLEncoder.encode(sessionKey));
    response.append("&v=" + URLEncoder.encode(v));
    response.append("&sig=" + URLEncoder.encode(sig.toString()));

    StringBuilder out = new StringBuilder();
    out.append("<response xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>");
    out.append(Base64.encodeToString(response.toString().getBytes(),
            Base64.NO_WRAP));
    out.append("</response>");

    writer.write(out.toString());
    writer.flush();
}

Answer 4

I'm sorry to make new answer but I had to include the new code @YShinkarev sorry for being late
By modifying @Adrian answer to make challengeReceived we can use APIKey and accessToken all I modified was the composedResponse

@Override
public void challengeReceived(String challenge) throws IOException {
    byte[] response = null;

    if (challenge != null) {
        String decodedChallenge = new String(Base64.decode(challenge));
        Map<String, String> parameters = getQueryMap(decodedChallenge);

        String version = "1.0";
        String nonce = parameters.get("nonce");
        String method = parameters.get("method");

        long callId = new GregorianCalendar().getTimeInMillis();

        String composedResponse = "api_key="
                + URLEncoder.encode(apiKey, "utf-8") + "&call_id=" + callId
                + "&method=" + URLEncoder.encode(method, "utf-8")
                + "&nonce=" + URLEncoder.encode(nonce, "utf-8")
                + "&access_token="
                + URLEncoder.encode(access_token, "utf-8") + "&v="
                + URLEncoder.encode(version, "utf-8");

        response = composedResponse.getBytes("utf-8");
    }

    String authenticationText = "";

    if (response != null) {
        authenticationText = Base64.encodeBytes(response,
                Base64.DONT_BREAK_LINES);
    }

    // Send the authentication to the server
    getSASLAuthentication().send(new Response(authenticationText));
}