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 com.oreilly.servlet.multipart.MultipartParser;

import com.oreilly.servlet.multipart.ParamPart;

import com.oreilly.servlet.multipart.Part;

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;

 * 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= -- export a zip format for data packadge<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 String xmlcatalogfile = null;

  private String saxparser = null;

  private File dataDirectory = null;

  private MetaCatUtil util = null;

   * Initialize the servlet by creating appropriate database connections

   */

    try {

      super.init( config );

      this.config = config;

      xmlcatalogfile = util.getOption("xmlcatalogfile");

      saxparser = util.getOption("saxparser");

      dataDirectory = new File(datafilepath);

      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

                               throws ServletException, IOException

  {

        util = new MetaCatUtil();

    }

    /*if ( connectionPool.isEmpty() ) {

      } catch (Exception e) {

                            " MetaCatServlet.handleGetOrPost");

      }

    // Deal with forms that are encoded as "multipart/form-data" differently

    // this is mainly used for uploading non-xml files using that may be binary

    if (ctype != null && ctype.startsWith("multipart/form-data")) {

    } else {

      String[] value = null;

      String[] docid = new String[3];

      Hashtable params = new Hashtable();

      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";

          name = "xpos";

        }

        params.put(name,value);

      //if the user clicked on the input images, decode which image

      //was clicked then set the action.

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

      // This block handles session management for the servlet

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

      // other than "login" and "logout"

      String username = null;

      String password = null;

      // handle login action

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

        handleLoginAction(response.getWriter(), params, request, response);

      // handle logout action

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

        handleLogoutAction(response.getWriter(), params, request, response);

      // aware of session expiration on every request

      } else {

        HttpSession sess = request.getSession(true);

        if (sess.isNew()) {

          // session expired or has not been stored b/w user requests

          username = "public";

          sess.setAttribute("username", username);

        } else {

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

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

            sess_id = (String)sess.getId();

          } catch(IllegalStateException ise) {

            System.out.println("error in handleGetOrPost: this shouldn't " +

                               "happen: the session should be valid: " +

                               ise.getMessage());

          }

        }

      }

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

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

          PrintWriter out = response.getWriter();

          out.println("Illegal action squery without \"query\" parameter");

        }

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

        }

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

        PrintWriter out = response.getWriter();

        if ( (username != null) &&  !username.equals("public") ) {

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

        }

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

        PrintWriter out = response.getWriter();

        handleValidateAction(out, params, response);

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

        PrintWriter out = response.getWriter();

        PrintWriter out = response.getWriter();

        handleGetPrincipalsAction(out, username, password);

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

        PrintWriter out = response.getWriter();

        handleGetDoctypesAction(out, params, response);

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

        PrintWriter out = response.getWriter();

        handleGetDTDSchemaAction(out, params, response);

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

        PrintWriter out = response.getWriter();

        handleGetDataGuideAction(out, params, response);

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

        PrintWriter out = response.getWriter();

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

        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("</body>");

          out.close();

        } catch (MalformedURLException mue) {

          System.out.println("bad url from MetacatServlet.handleGetOrPost");

          out.println(mue.getMessage());

          mue.printStackTrace(out);

          out.close();

        PrintWriter out = response.getWriter();

        out.println("<?xml version=\"1.0\"?>");

        out.println("<error>");

        out.println("Error: action not registered.  Please report this error.");

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

      util.closeConnections();

      // Close the stream to the client

      // 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

      response.setContentType("text/xml");

      out.println(sess.getMessage());

    } else {

        DBTransform trans = new DBTransform(conn);

        response.setContentType("text/html");

      } catch(Exception e) {

        util.returnConnection(conn);

      }

    // any output is returned

  /**

   * 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

      response.setContentType("text/xml");

      out.println(output.toString());

    } else {

      try {

        conn = util.getConnection();

        DBTransform trans = new DBTransform(conn);

        response.setContentType("text/html");

      } catch(Exception e) {

        util.returnConnection(conn);

      }

    }

  }

   *

   * @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];

      out.println(resultdoc);

    } else {

   /**

    *

    * @param out the output stream to the client

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

    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

   */

    Hashtable doclist=null;

    Connection conn = null;

    try

    {

      DBQuery queryobj = new DBQuery(conn, saxparser);

      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,

    Connection conn = null;

      DBTransform trans = new DBTransform(conn);

      response.setContentType("text/html");

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

    }

    catch(Exception e)

    {

  }

   * Transforms a hashtable of documents to an xml or html 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 "export" request of data package from Metacat in zip format

   * @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 groups the user's groupnames

   */

  private void handleExportAction(Hashtable params,

                    HttpServletResponse response, String user, String[] groups)

  {

    ServletOutputStream out = null;

    ZipOutputStream zOut = null;

    DocumentImpl docImpls=null;

    DBQuery queryObj=null;

    Connection conn = null;

    String[] docs = new String[10];

    String docId = "";

    try

    {

      // read the params

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

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

      }

      //get the connection to database

      conn = util.getConnection();

      queryObj = new DBQuery(conn, saxparser);//"saxparser" have to use though

                                              //it is not standard

      docId=docs[0];

      out = response.getOutputStream();

      response.setContentType("application/zip"); //MIME type

      zOut = new ZipOutputStream(out);

      zOut =queryObj.getZippedPackage(docId, out, user, groups);