Metacat

/**

 *    Purpose: A Class that implements a metadata catalog as a java Servlet

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

 *             National Center for Ecological Analysis and Synthesis

 *     '$Date$'

 * '$Revision$'

 * 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.io.IOException;

import java.util.Hashtable;

import java.net.MalformedURLException;

import java.sql.ResultSet;

import javax.servlet.ServletConfig;

import javax.servlet.ServletContext;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import oracle.xml.parser.v2.XSLException;

import oracle.xml.parser.v2.XMLDocumentFragment;

import oracle.xml.parser.v2.XSLProcessor;

 * A metadata catalog server implemented as a Java Servlet

 * <p>Valid parameters are:<br>

 * action=query -- query the values of all elements and attributes

 *                     and return a result set of nodes<br>

 * action=update -- update an XML document that is in the database store<br>

 * action=delete --  delete an XML document from the database store<br>

 * action=validate -- vallidate the xml contained in valtext<br>

 * doctype -- document type list returned by the query (publicID)<br>

 * qformat=html -- display resultset from query in HTML<br>

 * dtdtext -- XML DTD text for a new DTD to load into Metacat XML Catalog<br>

 * action=getdoctypes -- retrieve all doctypes (publicID)<br>

 * <p>

 * The particular combination of parameters that are valid for each

 * particular action value is quite specific.  This documentation

 * will be reorganized to reflect this information.

public class MetaCatServlet extends HttpServlet {

  private ServletContext context = null;

  private Hashtable connectionPool = new Hashtable();

  private String resultStyleURL = null;

  private String xmlcatalogfile = null;

  private String saxparser = null;

  private String defaultdatapath = null;

  private String servletpath = null;

  private MetaCatUtil util = null;

  // path to directory where data files

  // that can be downloaded will be stored

  // in defaultdocpath dir

   * Initialize the servlet by creating appropriate database connections

   */

    try {

      super.init( config );

      this.config = config;

      xmlcatalogfile = util.getOption("xmlcatalogfile");

      saxparser = util.getOption("saxparser");

      defaultdatapath = util.getOption("defaultdatapath");

      htmlpath = util.getOption("htmlpath");

//        // Open a pool of db connections

//        connectionPool = util.getConnectionPool();

//      } catch (Exception e) {

//        System.err.println("Error creating pool of database connections");

//        System.err.println(e.getMessage());

//      }

      throw ex;

    }

  }

   * Close all db connections from the pool

   */

  public void destroy() {

    if (util != null) {

        util.closeConnections();

    }

  }

    throws ServletException, IOException {

    throws ServletException, IOException {

    // Process the data and send back the response

 {

        util = new MetaCatUtil();

    }

        // Open a pool of db connections

        connectionPool = util.getConnectionPool();

      } catch (Exception e) {

                            " MetaCatServlet.handleGetOrPost");

      }

    }

    String[] value = null;

    Enumeration paramlist = request.getParameterNames();

    while (paramlist.hasMoreElements()) {

      name = (String)paramlist.nextElement();

      value = request.getParameterValues(name);

      // Decode the docid and mouse click information

      if (name.endsWith(".y")) {

        docid[0] = name.substring(0,name.length()-2);

        params.put("docid", docid);

        name = "ypos";

      }

      if (name.endsWith(".x")) {

        name = "xpos";

    }

    //was clicked then set the action.

    util.debugMessage("Line 213: Action is: " + action);

    // by looking up the current session information for all actions

    // handle login action

    if (action.equals("login")) {

      if (sess.isNew()) {

        username = (String)sess.getAttribute("username");

                             "happen: the session should be valid: " +

                             ise.getMessage());

        }

    // to a particular action handler

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

      }

      handleReadAction(params, response, username, groupname);

    } else if (action.equals("insert") || action.equals("update")) {

      } else {

        out.println("Permission denied for " + action);

      }

      } else {

        out.println("Permission denied for " + action);

      }

      PrintWriter out = response.getWriter();

                              sess_id);

        out.println("You must be authenticated to perform the getdataport " +

                    "action!");

      }

      PrintWriter out = response.getWriter();

      handleGetAccessControlAction(out, params, response, username, groupname);

    } else if (action.equals("getprincipals")) {

      PrintWriter out = response.getWriter();

      handleGetPrincipalsAction(out, username, password);

    } else if (action.equals("getdoctypes")) {

      PrintWriter out = response.getWriter();

      handleGetDoctypesAction(out, params, response);

      PrintWriter out = response.getWriter();

      handleGetDTDSchemaAction(out, params, response);

      String testURL = "metacat://dev.nceas.ucsb.edu/NCEAS.897766.9";

      try {

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

      } catch (Throwable t) {

      }

      String phandler = System.getProperty("java.protocol.handler.pkgs");

      response.setContentType("text/html");

      PrintWriter out = response.getWriter();

      out.println("<body bgcolor=\"white\">");

      out.println("<p>Handler property: <code>" + phandler + "</code></p>");

      out.println("<p>Starting test for:<br>");

      out.println("    " + testURL + "</p>");

      try {

        URL u = new URL(testURL);

        out.println("<pre>");

        out.println("Protocol: " + u.getProtocol());

        out.println("    Host: " + u.getHost());

        out.println("    Port: " + u.getPort());

        out.println("    Path: " + u.getPath());

        out.println("     Ref: " + u.getRef());

        String pquery = u.getQuery();

        out.println("   Query: " + pquery);

        out.println("  Params: ");

        if (pquery != null) {

          Hashtable qparams = util.parseQuery(u.getQuery());

          for (Enumeration en = qparams.keys(); en.hasMoreElements(); ) {

            String pname = (String)en.nextElement();

            String pvalue = (String)qparams.get(pname);

            out.println("    " + pname + ": " + pvalue);

          }

        }

        out.println("</pre>");

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

        out.close();

      } catch (MalformedURLException mue) {

        mue.printStackTrace(out);

        out.close();

      }

  private void handleLoginAction(PrintWriter out, Hashtable params,

               HttpServletRequest request, HttpServletResponse response) {

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

                          e.getMessage());

    // format and transform the output

    if (qformat.equals("html")) {

      Connection conn = null;

        DBTransform trans = new DBTransform(conn);

        response.setContentType("text/html");

                                   "-//W3C//HTML//EN", out);

      } catch(Exception e) {

        util.returnConnection(conn);

      }

    // any output is returned

    } else {

      response.setContentType("text/xml");

      out.println(sess.getMessage());

  /**

   * Handle the logout request. Close the connection.

   */

  private void handleLogoutAction(PrintWriter out, Hashtable params,

               HttpServletRequest request, HttpServletResponse response) {

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

    // close the connection

    HttpSession sess = request.getSession(false);

    if (sess != null) { sess.invalidate();  }

    // produce output

    StringBuffer output = new StringBuffer();

    output.append("<?xml version=\"1.0\"?>");

    output.append("User logged out");

    output.append("</logout>");

    //format and transform the output

    if (qformat.equals("html")) {

      Connection conn = null;

      try {

        conn = util.getConnection();

        DBTransform trans = new DBTransform(conn);

        response.setContentType("text/html");

                                   "-//W3C//HTML//EN", out);

      } catch(Exception e) {

        util.returnConnection(conn);

      }

    // any output is returned

    } else {

      response.setContentType("text/xml");

      out.println(output.toString());

    }

  }

   *

   * @param out the output stream to the client

   * @param params the Hashtable of parameters that should be included

   * in the squery.

   * @param response the response object linked to the client

   * @param conn the database connection

   */

  protected void handleSQuery(PrintWriter out, Hashtable params,

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

    String[] returndoc = null;

    if(params.contains("returndoc"))

    {

      returndoc = (String[])params.get("returndoc");

    }

    Hashtable doclist = runQuery(xmlquery, user, group, returndoc);

    //String resultdoc = createResultDocument(doclist, transformQuery(xmlquery));

    if(qformat.equals("html")) {

      transformResultset(resultdoc, response, out);

    } else if(qformat.equals("xml")) {

      response.setContentType("text/xml");

      out.println(resultdoc);

    } else {

      out.println("invalid qformat: " + qformat);

    }

   /**

    *

    * @param out the output stream to the client

    * @param params the Hashtable of parameters that should be included

    if(params.containsKey("returndoc"))

    {

      returndoc = (String[])params.get("returndoc");

    }

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

    String resultdoc = null;

    resultdoc = createResultDocument(doclist, transformQuery(params));

      out.println(resultdoc);

    }

  /**

   * so it can properly be placed in the <query> tag of the resultset.

   * This method is overwritable so that other applications can customize

   * the structure of what is in the <query> tag.

   *

   * @param xmlquery is the query to remove the <?xml version="x"?> tag from.

   */

  protected String transformQuery(Hashtable params)

  {

    //DBQuery.createSQuery is a re-calling of a previously called

    //function but it is necessary

    //so that overriding methods have access to the params hashtable

    String xmlquery = DBQuery.createSQuery(params);

    //the <?xml version="1.0"?> tag is the first 22 characters of the

    xmlquery = xmlquery.trim();

    int index = xmlquery.indexOf("?>");

    return xmlquery.substring(index + 2, xmlquery.length());

  }

  /**

   * string as a param instead of a hashtable.

   *

   * @param xmlquery a string representing a query.

   */

  protected String transformQuery(String xmlquery)

  {

    xmlquery = xmlquery.trim();

    int index = xmlquery.indexOf("?>");

    return xmlquery.substring(index + 2, xmlquery.length());

  }

  /**

   *

   * @param xmlquery the query to run

   */

                             String[] returndoc)

    Hashtable doclist=null;

    Connection conn = null;

    try

    {

      DBQuery queryobj = new DBQuery(conn, saxparser);

                                       returndoc);

      return doclist;

    catch (Exception e)

    {

      return doclist;

    }

  }

   * to be transformed.

   * @param response the HttpServletResponse object bound to the client.

   * @param out the output stream to the client

  protected void transformResultset(String resultdoc,

                                    PrintWriter out)

    Connection conn = null;

      DBTransform trans = new DBTransform(conn);

      response.setContentType("text/html");

      trans.transformXMLDocument(resultdoc, "-//NCEAS//resultset//EN",

                                 "-//W3C//HTML//EN", out);

    }

    catch(Exception e)

    {

  }

   * Transforms a hashtable of documents to an xml or html result.

   * whatever type returndoc represents.  If a result is found in a document

   * that is not of type returndoc then this attempts to find a relation

   * between this document and one that satifies the returndoc doctype.

   * @param xmlquery- the query that returned the dolist result

    // Create a buffer to hold the xml result

    StringBuffer resultset = new StringBuffer();

    String document = null;

    resultset.append("<?xml version=\"1.0\"?>\n");

    resultset.append("<resultset>\n");

    if(doclist != null)

      while (doclistkeys.hasMoreElements())

      {

        docid = (String)doclistkeys.nextElement();

        document = (String)doclist.get(docid);

        resultset.append("  <document>" + document + "</document>");

      }

    }

  /**

   * Handle the "read" request of metadata/data files from Metacat

   * or any files from Internet;

   * transformed metadata XML document into HTML presentation if requested;

   * zip files when more than one were requested.

   *

   * @param params the Hashtable of HTTP request parameters

   * @param response the HTTP response object linked to the client

   * @param user the username sent the request

   * @param group the user's groupname

                                String user, String group)