Instant Stream Resumption implementation

documentation/extensions/index.md

@@ -22,6 +22,7 @@ Currently supported XEPs of smack-tcp
 | Name                                        | XEP                                                      | Description |
 |---------------------------------------------|----------------------------------------------------------|----------------------------------------------------------------------------------------------------------|
 | [Stream Management](streammanagement.md)  | [XEP-0198](http://xmpp.org/extensions/xep-0198.html) | Allows active management of an XML Stream between two XMPP entities (stanza acknowledgement, stream resumption). |
+| Instant Stream Resumption 				| [XEP-xxxx](http://xmpp.org/extensions/inbox/isr.html) | Allows XMPP entities to instantaneously resume an XMPP stream.. |
 
 
 Smack Extensions and currently supported XEPs of smack-extensions

smack-tcp/src/main/java/org/jivesoftware/smack/isr/HMAC.java

@@ -0,0 +1,75 @@
+/**
+ *
+ * Copyright © 2016 Fernando Ramirez
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jivesoftware.smack.isr;
+
+import java.io.UnsupportedEncodingException;
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
+
+import javax.crypto.Mac;
+import javax.crypto.spec.SecretKeySpec;
+
+/**
+ * Instant Stream Resumption HMAC class.
+ * 
+ * @author Fernando Ramirez
+ * @see <a href="http://xmpp.org/extensions/inbox/isr.html">XEP-xxxx: Instant
+ *      Stream Resumption</a>
+ * 
+ */
+public class HMAC {
+
+    /**
+     * Get the HMAC digest.
+     * 
+     * @param msg
+     * @param keyString
+     * @param algo
+     * @return the HMAC digest
+     */
+    public static String hmacDigest(String msg, String keyString, String algo) {
+        String digest = null;
+        try {
+            SecretKeySpec key = new SecretKeySpec((keyString).getBytes("UTF-8"), algo);
+
+            String algorithm;
+            if (!algo.toLowerCase().startsWith("hmac")) {
+                algorithm = "hmac" + algo.toLowerCase();
+            } else {
+                algorithm = algo.toLowerCase();
+            }
+
+            Mac mac = Mac.getInstance(algorithm);
+            mac.init(key);
+
+            byte[] bytes = mac.doFinal(msg.getBytes("ASCII"));
+
+            StringBuffer hash = new StringBuffer();
+            for (int i = 0; i < bytes.length; i++) {
+                String hex = Integer.toHexString(0xFF & bytes[i]);
+                if (hex.length() == 1) {
+                    hash.append('0');
+                }
+                hash.append(hex);
+            }
+            digest = hash.toString();
+        } catch (UnsupportedEncodingException | InvalidKeyException | NoSuchAlgorithmException e) {
+            throw new IllegalStateException("HMAC digest could not be obtained correctly.", e);
+        }
+        return digest;
+    }
+}

smack-tcp/src/main/java/org/jivesoftware/smack/isr/ISRUtils.java

@@ -0,0 +1,49 @@
+/**
+ *
+ * Copyright © 2016 Fernando Ramirez
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jivesoftware.smack.isr;
+
+import java.io.IOException;
+
+import org.jivesoftware.smack.isr.element.InstantStreamResumption;
+import org.xmlpull.v1.XmlPullParser;
+import org.xmlpull.v1.XmlPullParserException;
+
+/**
+ * Instant Stream Resumption utils.
+ * 
+ * @author Fernando Ramirez
+ * @see <a href="http://xmpp.org/extensions/inbox/isr.html">XEP-xxxx: Instant
+ *      Stream Resumption</a>
+ * 
+ */
+public class ISRUtils {
+
+    /**
+     * Check if is a nonza from Instant Stream Resumption.
+     * 
+     * @param parser
+     * @return true if is a nonza from Instant Stream Resumption
+     * @throws XmlPullParserException
+     * @throws IOException
+     */
+    public static boolean isISRNonza(XmlPullParser parser) throws XmlPullParserException, IOException {
+        String isrNamespace = parser.getNamespace(InstantStreamResumption.NAMESPACE_PREFIX);
+        return (isrNamespace != null && isrNamespace.equals(InstantStreamResumption.NAMESPACE))
+                || parser.getNamespace().equals(InstantStreamResumption.NAMESPACE);
+    }
+
+}