Metacat

/**

 *  '$RCSfile$'

 *    Purpose: A Class that represents an document in remote metacat server

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

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Jing Tao

 *

 *   '$Author: jones $'

 *     '$Date: 2006-11-10 10:25:38 -0800 (Fri, 10 Nov 2006) $'

 * '$Revision: 3077 $'

 *

 * 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 edu.ucsb.nceas.utilities.HttpMessage;

import javax.servlet.ServletOutputStream;

import org.apache.log4j.Logger;

import java.io.*;

import java.net.*;

import java.util.*;

import java.util.zip.*;

/**

 * A class represents a document in remote metacat server. During the 

 * replication between two metacats, metadata (xml documents) might be 

 * replicated from Metacat A to Metacat B. But data file didn't. 

 * Sometime, user in Metacat B might query the data file which doesn't riside in

 * Metacat B. We need to download it from remote metacat server A and output it

 * to user. But it still doesn't reside in Metacat B.

 */

public class RemoteDocument

{

  private String docIdWithoutRevision = null; //Docid for this document

  private String revision = null; // Reviseion number for this document

  private String dataSetId = null; // Data set document Id which contains

                                   // this document

  private String documentHomeServerURL = null; // Home metacat server url

                                               // for this document

  private String docType = null; //String to store docType

  private String userName = null; // User name to require this document

  private String passWord = null; // The user's passwd

  private String zipEntry = null; // For zip entry

  private String revisionAndDocType; // String to store this info

  private Logger logMetacat = Logger.getLogger(RemoteDocument.class);

  /**

   * Constructor of RemoteDcoument

   * @param myDocIdWithoutRevision, Docid for this document

   * @param myRevision, revision number for this document

   * @param myUserName, the user who require this document

   * @param myGroup, the gourps the user belong to

   * @param myPassWord, the password of the user

   * @param myOutPut, the output stream the document will be put

   * @param myZipEntryPath, the base line for zip entry

   */

  public RemoteDocument ( String myDocIdWithoutRevision, String myRevision,

                    String myUserName, String myPassWord, String myZipEntryPath)

                          throws Exception

  {

    docIdWithoutRevision = myDocIdWithoutRevision;

    // Get data set id for the given docid

    dataSetId = DBUtil.findDataSetDocIdForGivenDocument(docIdWithoutRevision);

    documentHomeServerURL = getMetacatURLForGivenDocId(dataSetId);

    // Get revisionAndDocType

    getRevisionAndDocTypeString();

    revision = myRevision;

    // If rev is null or empty (user didn't specify it,

    // then set it current one in remote metacat

    if (revision == null ||revision.equals(""))

    {

      revision = setRevision();

    }

    docType = setDocType();

    userName = myUserName;

    passWord = myPassWord;

    zipEntry = myZipEntryPath+ docIdWithoutRevision + 

                MetaCatUtil.getOption("accNumSeparator") + revision;

  }// Constructor

  /**

   * Method to get docidWithout revision

   */

  public String getDocIdWithoutRevsion()

  {

    return docIdWithoutRevision;

  }//getDocIdWithoutRevsion

  /**

   * Method to get revsion

   */

  public String getRevision()

  {

    return revision;

  }//getRevision

  /**

   * Method to get docType

   */

  public String getDocType()

  {

    return docType;

  }//getDocType

  /**

   * Set revision if client didn't specify the revision number.

   * It come from revsionAndDocType String. This String look like "rev;doctype"

   * Rule: 

   *      1) Get current revision number from remote metacat

   *      2) If couldn't get, set revision number 1

   */

  private String setRevision()

  {

    // String to store the result

    String revision = null;

    // Int to store the index of ";" in revision

    int index = -1;

    // If String revisionAndDocType is null, revision set to 1

    if (revisionAndDocType == null || revisionAndDocType.equals(""))

    {

      revision = "1";

    }//if

    else

    {

      // Get the index of ";" in String revisionAndDocType

      index = revisionAndDocType.indexOf(";");

      // Get the subString about rev in String revisionAndDocType

      revision = revisionAndDocType.substring(0, index);

      // If revision is null or empty set revision 1

      if (revision == null || revision.equals(""))

      {

        revision = "1";

      }//if

    }//else

    return revision;

  }//setRevision

  /**

   * Set docType for this document base on the information from retmote metacat

   * It come from revsionAndDocType String. This String look like "rev;doctype"

   * If we couldn't get it from remote metacat, null will be set

   */

  private String setDocType()

  {

    // String to store the result

    String remoteDocType = null;

    // Int to store the index of ";" in revision

    int index = -1;

    // If String revisionAndDocType is null, revision set to 1

    if (revisionAndDocType == null || revisionAndDocType.equals(""))

    {

      remoteDocType = null;

    }//if

    else

    {

      // Get the index of ";" in String revisionAndDocType

      index = revisionAndDocType.indexOf(";");

      // Get the subString about doctype in String revisionAndDocType

      remoteDocType = revisionAndDocType.substring(index+1);

    }//else

    return remoteDocType;

  }//setDocType

  /**

   * Method to get a metacat url for dataset document id.

   * First, get replication document home server for dataset document.

   * Second, transfer a doc home server from replication servlet to metacat 

   * servlet. The reseaon is when we use read action to get the document, the

   * url is metacat servlet. Note: the protocol should be https. Because

   * replication is using https. If we use http and maybe access wrong port 

   * number.

   * @param dataSetId, the document id for which we need to find metacat url

   */

  private String getMetacatURLForGivenDocId( String givenDocId) throws Exception

  {

    // DocumentImpl object of this given docid

    DocumentImpl document = null;

    // Replication home server

    String replicationDocHomeServer = null;

    // String metacat url

    String metacatURL = null;

    // Check the given Docid is not null or empty

    if (givenDocId == null || givenDocId.equals(""))

    {

      throw new Exception ("Couldn't find a dataset docid for the required id");

    }

    // Create a documentImpl object

    String accNumber = givenDocId + MetaCatUtil.getOption("accNumSeparator") +

    DBUtil.getLatestRevisionInDocumentTable(givenDocId);

    document = new DocumentImpl(accNumber, false);

    // get the replication home server (it come from xml_replication table)

    replicationDocHomeServer = document.getDocHomeServer();

    // If replication doc home server is local host. throws a exception

    if (replicationDocHomeServer.

                           equals(MetaCatUtil.getLocalReplicationServerName()))

    {

      throw new Exception ("Couldn't find the docid: "

                                          +docIdWithoutRevision+"."+revision);

    }//if

    // replicationDocHomeServer looks like 

    // "pine.nceas.ucsb.edu:8443/tao/servlet/replication" and we should transfer

    // it to"https://pine.nceas.ucsb.edu:8443/tao/servlet/metacat"

    // get index of "replication" ocurrence

    int index = replicationDocHomeServer.indexOf("replication");

    // Get the subString from 0 to the index

    String subString = replicationDocHomeServer.substring(0, index);

    // Add https at head and append metacat 

    metacatURL = "https://" + subString +"metacat";

    logMetacat.info("metacatURL: "+metacatURL);

    return metacatURL;

  }//getMetacatURLForGivenDocId

  /**

   * Method to get revisionAndDocType String from remote metacat

   */

  private void getRevisionAndDocTypeString()

  {

    // Set property for login action

    Properties prop = new Properties();

    // Set action = getrevisionanddoctype

    prop.put("action", "getrevisionanddoctype");

    prop.put("docid", docIdWithoutRevision);

    // Now contact metacat and login.

    String response = getMetacatString(prop);

    // response contains error information

    if (response.indexOf("<error>")!=-1)

    {

      // Set response null

      response = null;

    }

    // Set revisionAndDocType equals reponse which get rid of white space

    if ( response != null)

    {

      revisionAndDocType = response.trim();

    }//if

    else

    {

      revisionAndDocType = response;

    }//else

  }//getRevisionAndDocTypeString

  /**

   * Method to read both xml and data file from remote server

   * and put the output into the given output stream

   * @param outPut, the serverlstoutputStream which the remote document or

   *                data file need to put.

   */

  public void readDocumentFromRemoteServer(ServletOutputStream outPut)

                                              throws Exception

  {

    // Set properties

    Properties prop = new Properties();

    // qformat set to be xml. Data file will be handle in MetaCatServlet class

    String qformat = "xml";

    // Action set to read

    String action = "read";

    // Input stream from remote metacat

    InputStream remoteResponse = null;

    // Check docIdWithoutRevision is not null or empty

    if (docIdWithoutRevision ==null || docIdWithoutRevision.equals(""))

    {

      throw new Exception("User didn't specify the required docid");

    }

    // User specified docid (including revision number

    String specifiedDocId = docIdWithoutRevision + 

                MetaCatUtil.getOption("accNumSeparator") +revision;

    logMetacat.info("The requried docid is: "+ specifiedDocId);

    // At first login to remote metacat server. 

    logIn(userName, passWord);

    // Set action  

    prop.put("action", action);

    // Set qformat xml

    prop.put("qformat", qformat);

    // Set the docid

    prop.put("docid", specifiedDocId);

    // Get remote metacat response

    try

    {

      remoteResponse = getMetacatInputStream(prop);

    }//try

    catch (Exception e)

    {

      // If has a exception throws it again

      throw e;

    }//catch

    // Read content from the remote input and write the content into

    // the given output

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

     // Read remote input into buffer

     int index = remoteResponse.read(buf);

     // If index is -1, this meams remote input ended

     while (index != -1) 

     {

        // Write the content of butter to given output

        outPut.write(buf, 0, index);

        // Read next bytes to the buffer from remote input stream

        index = remoteResponse.read(buf);

     }//while

     // Close remote reponse

     if (remoteResponse != null)

     {

       remoteResponse.close();

     }//if

  }//readDocumentFormRemoteServer

    /**

   * Method to read both xml and data file from remote server by zip output

   * and put the output into the given output stream

   * @param outPut, the serverlstoutputStream which the remote document or

   *                data file need to put.

   */

  public void readDocumentFromRemoteServerByZip(ZipOutputStream outPut)

                                              throws Exception

  {

    // Set properties

    Properties prop = new Properties();

    // qformat set to be xml. Data file will be handle in MetaCatServlet class

    String qformat = "xml";

    // Action set to read

    String action = "read";

    // Input stream from remote metacat

    InputStream remoteResponse = null;

    // Check docIdWithoutRevision is not null or empty

    if (docIdWithoutRevision ==null || docIdWithoutRevision.equals(""))

    {

      throw new Exception("User didn't specify the required docid");

    }

    // User specified docid (including revision number

    String specifiedDocId = docIdWithoutRevision + 

                MetaCatUtil.getOption("accNumSeparator") +revision;

    logMetacat.info("The requried docid is: "+ specifiedDocId);

    // At first login to remote metacat server.

    logIn(userName, passWord);

    // Set action  

    prop.put("action", action);

    // Set qformat xml

    prop.put("qformat", qformat);

    // Set the docid

    prop.put("docid", specifiedDocId);

    // Get remote metacat response

    try

    {

      remoteResponse = getMetacatInputStream(prop);

    }//try

    catch (Exception e)

    {

      // If has a exception throws it again

      throw e;

    }//catch

    // Create a zip entry

    ZipEntry zentry = new ZipEntry(zipEntry);

    outPut.putNextEntry(zentry);

    // Read content from the remote input and write the content into

    // the given output

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

     // Read remote input into buffer

     int index = remoteResponse.read(buf);

     // If index is -1, this meams remote input ended

     while (index != -1) 

     {

        // Write the content of butter to given output

        outPut.write(buf, 0, index);

        // Read next bytes to the buffer from remote input stream

        index = remoteResponse.read(buf);

     }//while

     // Close remote reponse

     if (remoteResponse != null)

     {

       remoteResponse.close();

     }//if

     // Close zip entry

     outPut.closeEntry();

  }//readDocumentFormRemoteServerByZip

  /**

   * Method to do login action. set cookie for it

   * @param usrerName, the DN name of the test method

   * @param passWord, the passwd of the user

   */

  private void logIn(String userName, String passWord)

  {

     // Make sure userName and password are not null 

    if ( userName == null || passWord == null || 

                                  userName.equals("") || passWord.equals(""))

    {

      return;

    }

    // Set property for login action

    Properties prop = new Properties();

    prop.put("action", "login");

    prop.put("qformat", "xml");

    prop.put("username", userName);

    prop.put("password", passWord);

    // Now contact metacat and login.

    String response = getMetacatString(prop);

    logMetacat.info("Login Message: "+response);

  }//login

  /**

   * Method to do logout action

   */

  private void logOut()

  {

    // Set property

    Properties prop = new Properties();

    prop.put("action", "logout");

    prop.put("qformat", "xml");

    // Send it to remote metacat

    String response = getMetacatString(prop);

    logMetacat.debug("Logout Message: "+response);

    // Set cookie to null

    HttpMessage.setCookie(null);

  }//logout

  /**

   * Send a request to Metacat and the return is a string from remote

   * Metacat.

   * @param prop the properties to be sent to Metacat

   */

  private String getMetacatString(Properties prop)

  {

    // Variable to store the response

    String response = null;

    // Now contact metacat and send the request

    try

    {

      InputStreamReader returnStream = 

                        new InputStreamReader(getMetacatInputStream(prop));

      StringWriter sw = new StringWriter();

      int len;

      char[] characters = new char[512];

      // Write inputstream into String

      while ((len = returnStream.read(characters, 0, 512)) != -1)

      {

        sw.write(characters, 0, len);

      }

      // Close the input stream reader

      returnStream.close();

      // Transfer string writer to String

      response = sw.toString();

      // close string wirter

      sw.close();

    }

    catch(Exception e)

    {

      logMetacat.error("Error in RemoteDocument.getMetacatString: "+

                               e.getMessage());

      // If there is some exception return null

      return null;

    }

    return response;

  }// getMetaCatString

  /**

   * Send a request to Metacat and the return is a input stream from remote

   * Metacat.

   * @param prop the properties to be sent to Metacat

   */

  private InputStream getMetacatInputStream(Properties prop) throws Exception

  {

    // Variable to store the returned input stream

    InputStream returnStream = null;

    // Create a URL for remtate

    URL url = new URL(documentHomeServerURL);

    HttpMessage msg = new HttpMessage(url);

    // Now contact metacat and send the request

    returnStream = msg.sendPostMessage(prop);

    return returnStream;

  }//getMetacatInputStream

}//Class RemoteDocument