Metacat

/**

 *  '$RCSfile$'

 *    Purpose: A Class that implements a metacat web front end as a java Servlet

 *  Copyright: 2009 Regents of the University of California and the

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Michael Daigle

 *

 *   '$Author: daigle $'

 *     '$Date: 2009-08-07 10:35:18 -0700 (Fri, 07 Aug 2009) $'

 * '$Revision: 5018 $'

 *

 * 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.web;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.Enumeration;

import java.util.Hashtable;

import javax.servlet.ServletConfig;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import org.apache.log4j.Logger;

import edu.ucsb.nceas.metacat.AuthSession;

import edu.ucsb.nceas.metacat.DBTransform;

import edu.ucsb.nceas.metacat.database.DBConnectionPool;

import edu.ucsb.nceas.metacat.service.SessionService;

import edu.ucsb.nceas.metacat.shared.BaseException;

import edu.ucsb.nceas.metacat.shared.ServiceException;

import edu.ucsb.nceas.metacat.util.ErrorSendingErrorException;

import edu.ucsb.nceas.metacat.util.RequestUtil;

import edu.ucsb.nceas.metacat.util.ResponseUtil;

import edu.ucsb.nceas.metacat.util.SessionData;

import edu.ucsb.nceas.metacat.workflow.WorkflowSchedulerClient;

/**

 * A workflow scheduling server implemented as a Java Servlet

 *

 * Valid actions are:

 * 

 * action=scheduleWorkflow -- Schedule a workflow to be run.  Scheduling a workflow 

 *                            registers it with the scheduling engine and creates a row

 *                            in the scheduled_job table.  Note that this may be 

 *                            extracted into a separate servlet.

 *     delay -- The amount of time from now before the workflow should be run.  The 

 *              delay can be expressed in number of seconds, minutes, hours and days, 

 *              for instance 30s, 2h, etc.

 *     starttime -- The time that the workflow should first run.  If both are provided

 *                  this takes precedence over delay.  The time should be expressed as: 

 *                  MM/dd/yyyy HH:mm:ss with the timezone assumed to be that of the OS.

 *     endtime -- The time when the workflow should end. The time should be expressed as: 

 *                  MM/dd/yyyy HH:mm:ss with the timezone assumed to be that of the OS.

 *     intervalvalue -- The numeric value of the interval between runs

 *     intervalunit -- The unit of the interval between runs.  Can be s, m, h, d for 

 *                     seconds, minutes, hours and days respectively

 *     workflowid -- The lsid of the workflow that we want to schedule.  This workflow

 *                   must already exist in the database.

 *     karid -- The karid for the workflow that we want to schedule.

 *     workflowname -- The name of the workflow.

 *     forwardto -- If provided, forward to this page when processing is done.

 *     qformat -- If provided, render results using the stylesheets associated with

 *                this skin.  Default is xml.

 * action=unscheduleWorkflow -- Unschedule a workflow.  Unscheduling a workflow 

 *                            removes it from the scheduling engine and changes the 

 *                            status in the scheduled_job table to " unscheduled.  Note 

 *                            that this may be extracted into a separate servlet.

 *     workflowjobid -- The job ID for the workflow run that we want to unschedule.  This

 *                      is held in the database as scheduled_job.name

 *     forwardto -- If provided, forward to this page when processing is done.

 *     qformat -- If provided, render results using the stylesheets associated with

 *                this skin.  Default is xml.

 * action=rescheduleWorkflow -- Unschedule a workflow.  Rescheduling a workflow 

 *                            registers it with the scheduling engine and changes the 

 *                            status in the scheduled_job table to " scheduled.  Note 

 *                            that this may be extracted into a separate servlet.

 *     workflowjobid -- The job ID for the workflow run that we want to reschedule.  This

 *                      is held in the database as scheduled_job.name

 *     forwardto -- If provided, forward to this page when processing is done.

 *     qformat -- If provided, render results using the stylesheets associated with

 *                this skin.  Default is xml.

 * action=deleteScheduledWorkflow -- Delete a workflow.  Deleting a workflow 

 *                            removes it from the scheduling engine and changes the 

 *                            status in the scheduled_job table to " deleted.  Note 

 *                            that this may be extracted into a separate servlet.

 *     workflowjobid -- The job ID for the workflow run that we want to delete.  This

 *                      is held in the database as scheduled_job.name

 *     forwardto -- If provided, forward to this page when processing is done.

 *     qformat -- If provided, render results using the stylesheets associated with

 *                this skin.  Default is xml.

 *     

 */

public class MetacatWebServlet extends HttpServlet {

	/**

	 * 

	 */

	private static final long serialVersionUID = 1L;

    /**

     * Initialize the servlet by creating appropriate database connections

     */

    public void init(ServletConfig config) throws ServletException {

    	super.init(config);

    }

    /**

	 * Close all db connections from the pool

	 */

    public void destroy() {

    	Logger logMetacat = Logger.getLogger(MetacatWebServlet.class);

        // Close all db connection

        logMetacat.warn("Destroying MetacatWebServlet");

    }

    /** Handle "GET" method requests from HTTP clients */

    public void doGet(HttpServletRequest request, HttpServletResponse response)

    throws ServletException, IOException {

        // Process the data and send back the response

        handleGetOrPost(request, response);

    }

    /** Handle "POST" method requests from HTTP clients */

    public void doPost(HttpServletRequest request, HttpServletResponse response)

    throws ServletException, IOException {

        // Process the data and send back the response

        handleGetOrPost(request, response);

    }

    /**

	 * Control servlet response depending on the action parameter specified

	 */

	private void handleGetOrPost(HttpServletRequest request,

			HttpServletResponse response) throws ServletException, IOException {

		Logger logMetacat = Logger.getLogger(MetacatWebServlet.class);

		// Update the last update time for this user if they are not new

		HttpSession httpSession = request.getSession(false);

		if (httpSession != null) {

			SessionService.touchSession(httpSession.getId());

		}

		try {

				String name = null;

				String[] value = null;

				Hashtable<String, String[]> params = new Hashtable<String, String[]>();

				Enumeration<String> paramlist =(Enumeration<String>)request.getParameterNames();

				while (paramlist.hasMoreElements()) {

					name = paramlist.nextElement();

					value = request.getParameterValues(name);

					params.put(name, value);

				}

				// handle param is emptpy

				if (params.isEmpty() || params == null) {

					return;

				}

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

				// was clicked then set the action.

				if (params.get("action") == null) {

					PrintWriter out = response.getWriter();

					response.setContentType("text/xml");

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

					out.println("<error>");

					out.println("Action not specified");

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

					out.close();

					return;

				}

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

				logMetacat.info("Action is: " + action);

				// 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[] groupNames = null;

				name = null;

				// handle login action

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

					PrintWriter out = response.getWriter();

					handleLoginAction(out, params, request, response);

					out.close();

					// handle logout action

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

					PrintWriter out = response.getWriter();

					handleLogoutAction(out, params, request, response);

					out.close();

					// handle shrink DBConnection request

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

					PrintWriter out = response.getWriter();

					boolean success = false;

					// If all DBConnection in the pool are free and DBConnection pool

					// size is greater than initial value, shrink the connection pool

					// size to initial value

					success = DBConnectionPool.shrinkConnectionPoolSize();

					if (success) {

						// if successfully shrink the pool size to initial value

						out.println("DBConnection Pool shrunk successfully.");

					}// if

					else {

						out.println("DBConnection pool not shrunk successfully.");

					}

					// close out put

					out.close();

					// aware of session expiration on every request

				} else {

					SessionData sessionData = RequestUtil.getSessionData(request);

					userName = sessionData.getUserName();

//					password = sessionData.getPassword();

					groupNames = sessionData.getGroupNames();

//					sessionId = sessionData.getId();

					logMetacat.info("The user is : " + userName);

				}

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

					try {

						WorkflowSchedulerClient.getInstance().scheduleJob(request, response, params, 

							userName, groupNames);

						return;

					} catch (BaseException be) {

						ResponseUtil.sendErrorXML(response, ResponseUtil.SCHEDULE_WORKFLOW_ERROR, be);

						return;						

					}

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

					try {

						WorkflowSchedulerClient.getInstance().unScheduleJob(request, response, params, 

							userName, groupNames);

						return;

					} catch (BaseException be) {

						ResponseUtil.sendErrorXML(response, ResponseUtil.UNSCHEDULE_WORKFLOW_ERROR, be);

						return;						

					}

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

					try {

						WorkflowSchedulerClient.getInstance().reScheduleJob(request, response, params, 

							userName, groupNames);

						return;

					} catch (BaseException be) {

						ResponseUtil.sendErrorXML(response, ResponseUtil.RESCHEDULE_WORKFLOW_ERROR, be);

						return;						

					}

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

					try {

						WorkflowSchedulerClient.getInstance().getJobs(request, response, params, 

								userName, groupNames);				

						return;

					} catch (BaseException be) {

						ResponseUtil.sendErrorXML(response, ResponseUtil.GET_SCHEDULED_WORKFLOW_ERROR, be);

						return;						

					}

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

					try {

						WorkflowSchedulerClient.getInstance().deleteJob(request, response, params, 

								userName, groupNames);				

						return;

					} catch (BaseException be) {

						ResponseUtil.sendErrorXML(response, ResponseUtil.DELETE_SCHEDULED_WORKFLOW_ERROR, be);

						return;						

					}

				} else {

					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>");

					out.close();

				}

		} catch (ErrorSendingErrorException esee) {

			String errorString = "Error sending error message: " + esee.getMessage();

			logMetacat.error(errorString);

			throw new ServletException(errorString);

		} 

	}

    // LOGIN & LOGOUT SECTION

    /**

	 * Handle the login request. Create a new session object. Do user

	 * authentication through the session.

	 */

    private void handleLoginAction(PrintWriter out, Hashtable<String, String[]> params,

            HttpServletRequest request, HttpServletResponse response) {

        Logger logMetacat = Logger.getLogger(MetacatWebServlet.class);

        AuthSession sess = null;

        if(params.get("username") == null){

            response.setContentType("text/xml");

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

            out.println("<error>");

            out.println("Username not specified");

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

            return;

        }

        // }

        if(params.get("password") == null){

            response.setContentType("text/xml");

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

            out.println("<error>");

            out.println("Password not specified");

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

            return;

        }

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

        logMetacat.info("user " + un + " is trying to login");

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

        String qformat = "xml";

        if(params.get("qformat") != null){

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

        }

        try {

            sess = new AuthSession();

        } catch (Exception e) {

        	String errorMsg = "Problem in MetacatWebServlet.handleLoginAction() authenicating session: "

                + e.getMessage();

            logMetacat.error(errorMsg);

            out.println(errorMsg);

            return;

        }

        boolean isValid = sess.authenticate(request, un, pw);

        //if it is authernticate is true, store the session

        if (isValid) {

            HttpSession session = sess.getSessions();

            String id = session.getId();

            logMetacat.debug("Store session id " + id

                    + " which has username" + session.getAttribute("username")

                    + " into hash in login method");

            try {

				SessionService.registerSession(id, (String) session

						.getAttribute("username"), (String[]) session

						.getAttribute("groupnames"), (String) session

						.getAttribute("password"));

			} catch (ServiceException se) {

				String errorMsg = "Problem in MetacatWebServlet.handleLoginAction() registering session: "

						+ se.getMessage();

				logMetacat.error(errorMsg);

				out.println(errorMsg);

				return;

			}

        }

        // format and transform the output

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

            response.setContentType("text/xml");

            out.println(sess.getMessage());

        } else {

            try {

                DBTransform trans = new DBTransform();

                response.setContentType("text/html");

                trans.transformXMLDocument(sess.getMessage(),

                        "-//NCEAS//login//EN", "-//W3C//HTML//EN", qformat,

                        out, null, null);

            } catch (Exception e) {               

                logMetacat.error("Error in MetacatWebServlet.handleLoginAction: "

                        + e.getMessage());

            }

        }

    }

    /**

     * Handle the logout request. Close the connection.

     */

    private void handleLogoutAction(PrintWriter out, Hashtable<String, String[]> params,

            HttpServletRequest request, HttpServletResponse response) {

        Logger logMetacat = Logger.getLogger(MetacatWebServlet.class);

        String qformat = "xml";

        if(params.get("qformat") != null){

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

        }

        // close the connection

        HttpSession sess = request.getSession(false);

        logMetacat.info("After get session in logout request");

        if (sess != null) {

            logMetacat.info("The session id " + sess.getId()

            + " will be invalidate in logout action");

            logMetacat.info("The session contains user "

                    + sess.getAttribute("username")

                    + " will be invalidate in logout action");

            sess.invalidate();

            SessionService.unRegisterSession(sess.getId());

        }

        // produce output

        StringBuffer output = new StringBuffer();

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

        output.append("<logout>");

        output.append("User logged out");

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

        //format and transform the output

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

            response.setContentType("text/xml");

            out.println(output.toString());

        } else {

            try {

                DBTransform trans = new DBTransform();

                response.setContentType("text/html");

                trans.transformXMLDocument(output.toString(),

                        "-//NCEAS//login//EN", "-//W3C//HTML//EN", qformat,

                        out, null, null);

            } catch (Exception e) {

                logMetacat.error(

                        "Error in MetacatWebServlet.handleLogoutAction"

                        + e.getMessage());

            }

        }

    }

}