ID.java :  » HTTP » cipango » org » cipango » server » Java Open Source

// ========================================================================
// Copyright 2008-2009 NEXCOM Systems
// ------------------------------------------------------------------------
// 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.cipango.server;

import java.net.InetAddress;
import java.util.Random;

import org.cipango.sip.Via;
import org.cipango.util.HexString;

/**
 * All SIP-related IDs generation and parsing (call, session, transaction ...)
 */
public abstract class ID 
{
  public static final String APP_SESSION_ID_PARAMETER = "app-session-id";
  
  public static final String CONTEXT_ATTRIBUTE = "context";
  public static final String SESSION_KEY_ATTRIBUTE = "session.key";

  private static String __localhost;
  private static Random __random = new Random();
    public static final int MAX_CSEQ = (1 << 16);
  private static String __magicCookie = "aK5q9iC";
    
  static
  {
    try
    {
      __localhost = InetAddress.getLocalHost().getHostName();
    }
    catch (Exception e)
    {
      __localhost = "localhost";
    }
  }
  
  /** SipApplicationSession id */
    public static String newAppSessionId()
    {
      return newID(4);
    }
    
    /** SipSession id */
    public static String newSessionId()
    {
      return newID(4);
    }
    
    /** Call id */
    public static String newCallId()
    {
      return newID(4) + '@' + __localhost;
    }
    
    /** dialog tags (from/to) */
    public static String newTag() 
    {
      return newID(4); // RFC 3261: at least 32 bits of randomness
    }
    
    /** Digest cnonce */
    public static String newCNonce()
    {
      return newID(4);
    }
    
    /** transaction branch */ 
    public static String newBranch() 
    {
      return Via.MAGIC_COOKIE + newID(6);
    }
    
    /** cseq */
    public static int newCSeq()
    {
        synchronized (__random)
        {
            return (int) (__random.nextDouble() * MAX_CSEQ);
        }
    }
    
    /** 
      * Random ID generator
      * 
     * @param length  the number of bytes of randomness
     * @return  a new random ID as an hex-string  
     */
    public static String newID(int length) 
    {
      byte[] b = new byte[length];
      synchronized (__random) 
      {
          __random.nextBytes(b);
    }
      return HexString.toHexString(b);
    }
      
  public static String newCallId(String callId)
    {
      if (callId.startsWith(__magicCookie))
      {
        int i = callId.indexOf('*');
        
        StringBuilder sb = new StringBuilder(callId.length());
        sb.append(__magicCookie);
        sb.append('-');
        sb.append(ID.newID(3));
        sb.append('*');
        sb.append(callId.substring(i+1));
        return sb.toString();
      }
      else
      {
        StringBuilder sb = new StringBuilder(callId.length() + __localhost.length() + 14);
        sb.append(__magicCookie);
        sb.append('-');
        sb.append(ID.newID(3));
        sb.append('*');
        for (int i = 0; i < callId.length(); i++)
        {
          char c = callId.charAt(i);
          if (c == '@')
            sb.append('%');
          else if (c == '%')
            sb.append("%%");
          else
            sb.append(c);
        }
        sb.append('@');
        sb.append(__localhost);
        return sb.toString();
      }    
    }
  
  public static String getCallSessionId(String callId)
  {
       if (!callId.startsWith(__magicCookie))
         return callId;
       
       int i = callId.indexOf('*', __magicCookie.length() + 7);
       int j = callId.indexOf('@', i+1);
       
       StringBuilder sb = null;
       boolean escape = false;
       
       for (int k = i+1; k < j; k++)
       {
         char c = callId.charAt(k);
         if (c == '%')
         {
           if (sb == null)
           {
             sb = new StringBuilder(j-i);
             sb.append(callId.substring(i+1, k));
           }
           if (escape)
             sb.append('%');
           escape = ! escape;
         }
         else
         {
           if (escape)
           {
             sb.append('@');
             escape = false;
           }
           if (sb != null)
             sb.append(c);
         }
       }
       if (sb != null)
         return sb.toString();
       return callId.substring(i+1, j);
  }  
  
  public static String getIdFromKey(String applicationName, String sessionKey)
  {
    return "skey-" + applicationName + "-" + sessionKey;
  }
  
  public static boolean isKey(String id)
  {
    return id.startsWith("skey-");
  }
   
  public static void main(String[] args) throws Exception 
    {/*
    MessageDigest md = MessageDigest.getInstance("MD5");
    System.out.println(HexString.toHexString(new byte[] {'1', '.', '1'}));
      
    System.out.println(ID.newID(4));
    
    System.out.println("1.session-key".hashCode());*/
    long ts = (System.currentTimeMillis() / 1000) * 5;
    long hi = ts & 0xffffffffL;
    long id = hi << 32;
    System.out.println(ts);
    System.out.println(hi);
    System.out.println(Long.toHexString(ts));
    System.out.println(Long.toHexString(hi));
    
  }
}