最后，感谢 no.good.at.coding 代码和 harism 的建议，我已经能够连接到 Facebook 聊天了。此代码是 Asmack 库（Android 的 Smack 端口）的机制。对于Smack库来说有必要使用no.good.at.coding机制。
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();
}
}
使用方法：
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 是 Facebook 的应用程序设置页面中给出的 API 密钥。 sessionKey 是访问令牌的第二部分。如果令牌采用以下形式：AAA|BBB|CCC，则 BBB 是会话密钥。 sessionSecret 是使用旧的 REST API 和 auth.promoteSession 方法获得的。要使用它，需要通过 Http 访问此 url：
https://api.facebook.com/method/auth.promoteSession?access_token=yourAccessToken https://api.facebook.com/method/auth.promoteSession?access_token=yourAccessToken
尽管 Facebook 聊天文档说需要使用您的应用程序密钥，但只有当我使用返回 REST 方法的密钥时，我才能使其工作。要使该方法起作用，您必须禁用禁用已弃用的身份验证方法应用程序设置中“高级”选项卡中的选项。
