Metacat

/**

 *  '$RCSfile$'

 *    Purpose: A Class that implements replication for metacat

 *  Copyright: 2000 Regents of the University of California and the

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Chad Berkley

 *    Release: @release@

 *

 *   '$Author$'

 *     '$Date$'

 * '$Revision$'

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

package edu.ucsb.nceas.metacat;

import java.util.*;

import java.io.*;

import java.sql.*;

import java.net.*;

import java.lang.*;

import java.text.*;

import javax.servlet.*;

import javax.servlet.http.*;

  private String deltaT;

  Timer replicationDaemon;

  private Vector fileLocks = new Vector();

  private Thread lockThread = null;

  /**

   * Initialize the servlet by creating appropriate database connections

   */

  public void init(ServletConfig config) throws ServletException

  {

    //initialize db connections to handle any update requests

    MetaCatUtil util = new MetaCatUtil();

    deltaT = util.getOption("deltaT");

    //create a thread to do the delta-T check but don't execute it yet

  }

  public void destroy()

  {

    replicationDaemon.cancel();

  public void doGet (HttpServletRequest request, HttpServletResponse response)

                     throws ServletException, IOException

  {

    // Process the data and send back the response

    handleGetOrPost(request, response);

  }

  public void doPost(HttpServletRequest request, HttpServletResponse response)

                     throws ServletException, IOException

  {

    // Process the data and send back the response

    handleGetOrPost(request, response);

  }

  private void handleGetOrPost(HttpServletRequest request,

                               HttpServletResponse response)

                               throws ServletException, IOException

  {

    //ServletOutputStream outPut = response.getOutputStream();

// REPLACED with running replication comminications over HTTPS

//    String requestingServerIP = request.getRemoteAddr();

//    InetAddress iaddr = InetAddress.getByName(requestingServerIP);

//    String requestingServer = iaddr.getHostName();

      String[] value = request.getParameterValues(name);

      params.put(name, value);

    }

    String server = null;

      // check if the server is included in the list of replicated servers

           !action.equals("stop") &&

           !action.equals("start") &&

           !action.equals("getall") ) {

        server = ((String[])params.get("server"))[0];

                             "\" rejected for server: " + server);

          return;

        } else {

          System.out.println("Action \"" + action +

                             "\" accepted for server: " + server);

        }

      System.out.println("Error in MetacatReplication.handleGetOrPost: " +

                         e.getMessage() );

    }

    {

      handleGetDataFileRequest(out, params, response);

      out.close();

    }

    {

      //read a specific docid from remote host, and store it into local host

      handleForceReplicateDataFileRequest(params);

    {

    PrintWriter out = response.getWriter();

      replicationDaemon.cancel();

      replicationDaemon = new Timer(true);

      out.println("Replication Handler Stopped");

      MetacatReplication.replLog("deltaT handler stopped");

      int rate;

      if ( params.containsKey("rate") ) {

        rate = new Integer(

               new String(((String[])params.get("rate"))[0])).intValue();

        if(rate < 30) {

        }

        rate = 1000;

      }

      out.println("New rate is: " + rate + " seconds.");

      replicationDaemon.cancel();

      replicationDaemon = new Timer(true);

      replicationDaemon.scheduleAtFixedRate(new ReplicationHandler(out), 0,

                                            rate * 1000);

      out.println("Replication Handler Started");

      MetacatReplication.replLog("deltaT handler started with rate=" +

      replicationDaemon.schedule(new ReplicationHandler(out), 0);

      response.setContentType("text/html");

      out.println("<html><body>\"Get All\" Done</body></html>");

      handleUpdateRequest(out, params, response);

      //note that this could be replaced by a call to metacatServlet

      //handleGetDocumentAction().

      handleGetDocumentRequest(out, params, response);

      response.setContentType("text/html");

      out.println("<html><body>Test successfully</body></html>");

    out.close();

   * This method can add, delete and list the servers currently included in

   * xml_replication.

   * action           subaction            other needed params

   * ---------------------------------------------------------

   * servercontrol    add                  server

   * servercontrol    delete               server

   * servercontrol    list

   */

  private void handleServerControlRequest(PrintWriter out, Hashtable params,

                                          HttpServletResponse response)

  {

    String subaction = ((String[])params.get("subaction"))[0];

    int serialNumber = -1;

    PreparedStatement pstmt = null;

    String server = null;

    String dataReplicate = null;

    String hub = null;

      dbConn=DBConnectionPool.

               getDBConnection("MetacatReplication.handleServerControlRequest");

      serialNumber=dbConn.getCheckOutSerialNumber();

      if ( subaction.equals("add") ) {

        server = ((String[])params.get("server"))[0];

        //Get data replication value

        dataReplicate = ((String[])params.get("datareplicate"))[0];

        //Get hub value

        hub = ((String[])params.get("hub"))[0];

                                      "'01/01/00', 'MM/DD/YY'), '" +

                                      + hub +"')");

        out.println("<html><body><table border=\"1\">");

        out.println("<tr><td><b>server</b></td><td><b>last_checked</b></td><td>");

        out.println("<td><b>datareplicate</b></td>");

        out.println("<td><b>hub</b></td></tr>");

        //increase dbconnection usage

        dbConn.increaseUsageCount(1);

        ResultSet rs = pstmt.getResultSet();

        boolean tablehasrows = rs.next();

          out.println(rs.getString(3) + "</td><td>");

          out.println(rs.getString(5) + "</td><td>");

          out.println(rs.getString(6) + "</td></tr>");

        }

        out.println("</table></body></html>");

        // download certificate with the public key on this server

        // and import it as a trusted certificate

        String certURL = ((String[])params.get("certificate"))[0];

        downloadCertificate(certURL);

      } else if ( subaction.equals("delete") ) {

        out.println("<html><body><table border=\"1\">");

        out.println("<tr><td><b>server</b></td><td><b>last_checked</b></td><td>");

        out.println("<td><b>datareplicate</b></td>");

        out.println("<td><b>hub</b></td></tr>");

        //increase dbconnection usage

        dbConn.increaseUsageCount(1);

        ResultSet rs = pstmt.getResultSet();

        boolean tablehasrows = rs.next();

        while(tablehasrows)

        {

          out.println("<tr><td>" + rs.getString(2) + "</td><td>");

          out.println(rs.getString(3) + "</td><td>");

          out.println(rs.getString(5) + "</td><td>");

          out.println(rs.getString(6) + "</td></tr>");

        }

        out.println("</table></body></html>");

      // list servers in server list

      } else if ( subaction.equals("list") ) {

        out.println("<html><body><table border=\"1\">");

        out.println("<td><b>datareplicate</b></td>");

        out.println("<td><b>hub</b></td></tr>");

        ResultSet rs = pstmt.getResultSet();

        boolean tablehasrows = rs.next();

          out.println(rs.getString(5) + "</td><td>");

          out.println(rs.getString(6) + "</td></tr>");

        }

        out.println("</table></body></html>");

      else

      {

        out.println("<error>Unkonwn subaction</error>");

    } catch(Exception e) {

      System.out.println("Error in " +

      e.printStackTrace(System.out);

    }

    {

      try

      {

        pstmt.close();

      }//try

      catch (SQLException ee)

      {

        MetaCatUtil.debugMessage("Error in " +

                "MetacatReplication.handleServerControlRequest to close pstmt "

      finally

      {

        DBConnectionPool.returnDBConnection(dbConn, serialNumber);

      }//finally

    }//finally

  // upload it onto this server; it then must be imported as a

  // trusted certificate

  private void downloadCertificate (String certURL)

                throws FileNotFoundException, IOException, MalformedURLException

  {

    MetaCatUtil util = new MetaCatUtil();

    String certPath = util.getOption("certPath"); //the path to be uploaded to

    // get filename from the URL of the certificate

    String filename = certURL;

    int slash = Math.max(filename.lastIndexOf('/'), filename.lastIndexOf('\\'));

    if ( slash > -1 ) {

      filename = filename.substring(slash + 1);

    }

    // open file output strem to write the input into it

    File f = new File(certPath, filename);

    synchronized (f) {

      try {

        if ( f.exists() ) {

          throw new IOException("File already exist: " + f.getCanonicalFile());

          //if ( f.exists() && !f.canWrite() ) {

          //  throw new IOException("Not writable: " + f.getCanonicalFile());

        }

      } catch (SecurityException se) {

        // if a security manager exists,

        // its checkRead method is called for f.exist()

        // or checkWrite method is called for f.canWrite()

        throw se;

      }

      // create a buffered byte output stream

      // that uses a default-sized output buffer

      FileOutputStream fos = new FileOutputStream(f);

      BufferedOutputStream out = new BufferedOutputStream(fos);

      // this should be http url

      URL url = new URL(certURL);

      BufferedInputStream bis = null;

      try {

        bis = new BufferedInputStream(url.openStream());

        byte[] buf = new byte[4 * 1024]; // 4K buffer

        int b = bis.read(buf);

        while (b != -1) {

          out.write(buf, 0, b);

          b = bis.read(buf);

        }

      } finally {

        if (bis != null) bis.close();

      }

      // the input and the output streams must be closed

      bis.close();

	    out.flush();

	    out.close();

	    fos.close();

    } // end of synchronized(f)

  }

   * to the requesting server (remote server) for the specified docid.

   * Then store it in local database.

                                           HttpServletResponse response)

  {

    String docid = ((String[])params.get("docid"))[0]; // sent the document

    String dbaction = "UPDATE"; // the default action is UPDATE

    int serverCode = 1;

    int serialNumber = -1;

      //if the url contains a dbaction then the default action is overridden

      if(params.containsKey("dbaction")) {

        //override = true; //we are now overriding the default action

      MetaCatUtil.debugMessage("Force replication request from: "+ server, 34);

      MetaCatUtil.debugMessage("Force replication docid: "+docid, 34);

      MetaCatUtil.debugMessage("Force replication action: "+dbaction, 34);

      // sending back read request to remote server

                +util.getLocalReplicationServerName()

                +"&action=read&docid=" + docid);

      URL docinfourl = new URL("https://" + server +

                               +"&action=getdocumentinfo&docid=" + docid);

      XMLReader docinfoParser = ReplicationHandler.initParser(dih);

      docinfoParser.parse(new InputSource(new StringReader(docInfoStr)));

      Hashtable docinfoHash = dih.getDocInfo();

      // Get user owner of this docid

      // Get DBConnection from pool

              getDBConnection("MetacatReplication.handleForceReplicateRequest");

      serialNumber=dbConn.getCheckOutSerialNumber();

                                 "action " + dbaction);

    catch(Exception e)

    {

                         "Request(): " + e.getMessage());

    {

    }//finally

   * readdata request to the requesting server (remote server) for the specified

   * docid. Then store it in local database and file system

   */

  private void handleForceReplicateDataFileRequest(Hashtable params)

  {

    if(params.isEmpty())

    {

      return;

    }

    String server = ((String[])params.get("server"))[0];

    // the docid should include rev number

    String docid = ((String[])params.get("docid"))[0];

    // Make sure there is a docid and server

    if (docid==null || server==null || server.equals(""))

                              , 20);

    }

    // Overide or not

    {

      int rev=MetaCatUtil.getVersionFromString(docid);

      if(params.containsKey("dbaction"))

      {

        dbaction = ((String[])params.get("dbaction"))[0];

      }

      else//default value is update

      {

        dbaction = "update";

      }

      MetaCatUtil.debugMessage("Force replication docid: "+docid, 34);

      MetaCatUtil.debugMessage("Force replication action: "+dbaction, 34);

      URL docinfourl = new URL("https://" + server +

                               "?server="+util.getLocalReplicationServerName()

                               +"&action=getdocumentinfo&docid=" + uniqueCode);

      String docInfoStr = MetacatReplication.getURLContent(docinfourl);

      //dih is the parser for the docinfo xml format

      DocInfoHandler dih = new DocInfoHandler();

      XMLReader docinfoParser = ReplicationHandler.initParser(dih);

      docinfoParser.parse(new InputSource(new StringReader(docInfoStr)));

      Hashtable docinfoHash = dih.getDocInfo();

      String user = (String)docinfoHash.get("user_owner");

      String docName = (String)docinfoHash.get("docname");

      String docType = (String)docinfoHash.get("doctype");

      //the xml_documents

      if (dbaction.equals("delete"))

      {

        DocumentImpl.delete(docid,user,null);

        //util.returnConnection(conn);

      else if (dbaction.equals("insert")||dbaction.equals("update"))

        //Get data file and store it into local file system.

        // sending back readdata request to server

        URL url = new URL("https://" + server + "?server="

                +util.getLocalReplicationServerName()

                +"&action=readdata&docid=" + docid);

        //register data file into xml_documents table and wite data file

        //into file system

                            docName, docType, docid, user,docHomeServer,server);

                                 "action " + dbaction);

    } catch(Exception e)

    {

              ("ERROR in MetacatReplication.handleForceDataFileReplicate" +

  }

  /**

   * The servlet parameters of interrest are:

   * docid: the docid of the file the lock is being requested for

   * currentdate: the timestamp of the document on the remote server

   *

   */

  private void handleGetLockRequest(PrintWriter out, Hashtable params,

                                    HttpServletResponse response)

  {

    {

      int remoteRevInt = Integer.parseInt(remoteRev);

      if(remoteRevInt >= localRevInt)

        if(!fileLocks.contains(docid))

          //send a message back to the the remote host authorizing the insert

          out.println("<lockgranted><docid>" +docid+ "</docid></lockgranted>");

          lockThread = new Thread(this);

          lockThread.setPriority(Thread.MIN_PRIORITY);

          lockThread.start();

        else

        { //deny the lock

          out.println("<filelocked><docid>" + docid + "</docid></filelocked>");

                                     "reason: file already locked");

      }

      else

      {//deny the lock.

        out.println("<outdatedfile><docid>" + docid + "</docid></filelocked>");