Metacat

/*

 * HarvesterRegistration.java

 *

 * Created on March 23, 2004, 4:44 PM

 */

package edu.ucsb.nceas.metacat.harvesterClient;

import com.oreilly.servlet.ParameterParser;

import java.io.File;

import java.io.InputStream;

import java.io.IOException;

import java.io.PrintWriter;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.SQLWarning;

import java.sql.Statement;

import java.text.ParseException;

import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.Enumeration;

import java.util.Properties;

import javax.servlet.ServletContext;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

/**

 * HarvesterRegistration is a servlet that implements harvester registration.

 * The servlet reads parameters that were entered in a harvester registration

 * form, checks the validity of the values, stores the values in the database

 * by either inserting, updating, or removing a record in the 

 * HARVEST_SITE_SCHEDULE table.

 * 

 * @author    costa

 * 

 */

public class HarvesterRegistration extends HttpServlet {

  /*

   * Object fields

   */

  final private long millisecondsPerDay = (1000 * 60 * 60 * 24);

  private String password;      // database password, from properties file

  private String url;           // database url, from properties file

  private String user;          // database user, from properties file

  /*

   * Object methods

   */

  /**

   * Checks validity of user input values.

   * 

   * @param out             the PrintWriter output object

   * @param documentListURL the Harvest Document List URL specified by the user

   * @param updateFrequency the Harvest Frequency specified by the user

   * @return validValues    true if all values are valid, else false

   */

  private boolean checkValues(PrintWriter out,

                              String documentListURL,

                              int updateFrequency

                             ) {

    boolean validValues = true;

    // Check validity of the Harvest Document List URL field    

    if (documentListURL.equals("")) {

      out.println(

              "A value must be specified in the Harvest Document List URL field"

                 );

      validValues = false;

    }

    // Check validity of the Harvest Frequency field    

    if ((updateFrequency < 1) || (updateFrequency > 99)) {

      out.println("Harvest Frequency should be in the range 1 to 99");

      validValues = false;

    }

    return validValues;

  }

  /**

   * Closes the database connection.

   * 

   * @param conn  The connection.

   */

  private void closeConnection(Connection conn) {

    try {

      if (conn != null) {

        conn.close();

      }

    }

    catch (SQLException e) {

      // ignored

    }

  }

  /**

   * Inserts a record to the HARVEST_SITE_SCHEDULE table.

   * 

   * @param out             the PrintWriter output object

   * @param conn            the Connection

   * @param siteScheduleID  the primary key for the table

   * @param contactEmail    contact email address of the site user

   * @param documentListURL the URL of the harvester document list at the site

   * @param ldapDN          the site user's LDAP DN

   * @param ldapPwd         the site user's LDAP password

   * @param unit            the update frequency unit, e.g. "days", "weeks"

   * @param updateFrequency the update frequency, an integer in range 1-99

   */

  private void dbInsert(PrintWriter out,

                        Connection conn,

                        int siteScheduleID,

                        String contactEmail,

                        String documentListURL,

                        String ldapDN,

                        String ldapPwd,

                        String unit,

                        int updateFrequency

                       ) {

    String dateNextHarvest;

    long delta;

    Date dnh;                          // Date of next harvest

    Date now;                          // Today's date

    String query;

		Statement stmt;

    long timeNextHarvest;

    SimpleDateFormat writeFormat = new SimpleDateFormat("dd-MMM-yyyy");

    // Calculate the value of delta, the number of milliseconds between the

    // last harvest date and the next harvest date.

    delta = updateFrequency * millisecondsPerDay;

    if (unit.equals("weeks")) {

      delta *= 7;

    }

    else if (unit.equals("months")) {

      delta *= 30;

    }

    now = new Date();

    timeNextHarvest = now.getTime();

    dnh = new Date(timeNextHarvest);

    dateNextHarvest = writeFormat.format(dnh);

		try {

			stmt = conn.createStatement();							

			query = "insert into HARVEST_SITE_SCHEDULE " +

      "(SITE_SCHEDULE_ID, CONTACT_EMAIL, DOCUMENTLISTURL, LDAPDN, LDAPPWD, " +

      "UNIT, UPDATEFREQUENCY, DATENEXTHARVEST) " +

      "values(" + siteScheduleID + "," +

                  quoteString(contactEmail) + "," +

                  quoteString(documentListURL) + "," +

                  quoteString(ldapDN) + "," +

                  quoteString(ldapPwd) + "," +

                  quoteString(unit) + "," +

                  updateFrequency + "," +

                  quoteString(dateNextHarvest) + ")";

      System.out.println(query);

      stmt.executeUpdate(query);

			stmt.close();

      reportResults(out, ldapDN, contactEmail, documentListURL, updateFrequency,

                    unit, dateNextHarvest);

		}

    catch(SQLException e) {

			System.out.println("SQLException: " + e.getMessage());

		}

   }

  /**

   * Removes a record from the HARVEST_SITE_SCHEDULE table.

   * 

   * @param out            the PrintWriter output object

   * @param conn           the Connection

   * @param siteScheduleID the primary key for the table

   * @param ldapDN          the site user's LDAP DN

   */

  private void dbRemove(PrintWriter out,

                        Connection conn,

                        int siteScheduleID,

                        String ldapDN

                       ) {

    String query = "DELETE FROM HARVEST_SITE_SCHEDULE WHERE " +

                   "SITE_SCHEDULE_ID=" + siteScheduleID;

    int nRecords = 0;

		Statement stmt;

		try {

			stmt = conn.createStatement();

      System.out.println(query);

      nRecords = stmt.executeUpdate(query);

      stmt.close();

      System.out.println(nRecords + " record(s) removed.");

      if (nRecords > 0) {

        out.println("Harvester registration removed for user " + ldapDN);

      }

      else {

        out.println("A problem was encountered removing registration for user " 

                    + ldapDN);

      }

		}

    catch(SQLException e) {

			System.out.println("SQLException: " + e.getMessage());

		}

   }

  /**

   * Updates a record in the HARVEST_SITE_SCHEDULE table.

   * 

   * @param out             the PrintWriter output object

   * @param conn            the Connection

   * @param siteScheduleID  the primary key for the table

   * @param contactEmail    contact email address of the site user

   * @param documentListURL the URL of the harvester document list at the site

   * @param ldapDN          the site user's LDAP DN

   * @param ldapPwd         the site user's LDAP password

   * @param unit            the update frequency unit, e.g. "days", "weeks"

   * @param updateFrequency the update frequency, an integer in range 1-99

   * @param dateLastHarvest the date of last harvest, 

   *                        e.g. "2004-04-30 00:00:00.0" or ""

   */

   private void dbUpdate(PrintWriter out,

                         Connection conn,

                         int siteScheduleID,

                         String contactEmail,

                         String documentListURL,

                         String ldapDN,

                         String ldapPwd,

                         String unit,

                         int updateFrequency,

                         String dateLastHarvest

                        ) {

    String dateNextHarvest;

    long delta;

    Date dlh;                          // Date of last harvest

    Date dnh;                          // Date of next harvest

    Date now = new Date();             // Today's date

    SimpleDateFormat readFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.S");

    SimpleDateFormat writeFormat = new SimpleDateFormat("dd-MMM-yyyy");

		Statement stmt;

    long timeLastHarvest;

    long timeNextHarvest;

    long timeNow = now.getTime();

    // Calculate the value of delta, the number of milliseconds between the

    // last harvest date and the next harvest date.

    delta = updateFrequency * millisecondsPerDay;

    if (unit.equals("weeks")) {

      delta *= 7;

    }

    else if (unit.equals("months")) {

      delta *= 30;

    }

    if (dateLastHarvest.equals("")) {

      timeNextHarvest = timeNow;

    }

    else {

      try {

        dlh = readFormat.parse(dateLastHarvest);

        timeLastHarvest = dlh.getTime();

        timeNextHarvest = timeLastHarvest + delta;

        timeNextHarvest = Math.max(timeNextHarvest, timeNow);

      }

      catch (ParseException e) {

        System.out.println("Error parsing date: " + dateLastHarvest +

                           " " + e.getMessage());

        timeNextHarvest = timeNow;

      }

    }

    dnh = new Date(timeNextHarvest);

    dateNextHarvest = writeFormat.format(dnh);

		try {

			stmt = conn.createStatement();							

			stmt.executeUpdate("UPDATE HARVEST_SITE_SCHEDULE SET CONTACT_EMAIL=" +

                         quoteString(contactEmail) +

                         " WHERE SITE_SCHEDULE_ID = " + siteScheduleID);

			stmt.executeUpdate("UPDATE HARVEST_SITE_SCHEDULE SET DOCUMENTLISTURL=" +

                         quoteString(documentListURL) +

                         " WHERE SITE_SCHEDULE_ID = " + siteScheduleID);

			stmt.executeUpdate("UPDATE HARVEST_SITE_SCHEDULE SET LDAPPWD=" +

                         quoteString(ldapPwd) +

                         " WHERE SITE_SCHEDULE_ID = " + siteScheduleID);

			stmt.executeUpdate("UPDATE HARVEST_SITE_SCHEDULE SET UNIT=" +

                         quoteString(unit) +

                         " WHERE SITE_SCHEDULE_ID = " + siteScheduleID);

			stmt.executeUpdate("UPDATE HARVEST_SITE_SCHEDULE SET UPDATEFREQUENCY=" +

                         updateFrequency +

                         " WHERE SITE_SCHEDULE_ID = " + siteScheduleID);

			stmt.executeUpdate("UPDATE HARVEST_SITE_SCHEDULE SET DATENEXTHARVEST=" +

                         quoteString(dateNextHarvest) +

                         " WHERE SITE_SCHEDULE_ID = " + siteScheduleID);

			stmt.close();

      reportResults(out, ldapDN, contactEmail, documentListURL, updateFrequency,

                    unit, dateNextHarvest);

		}

    catch(SQLException e) {

			System.out.println("SQLException: " + e.getMessage());

		}

  }

  /**

   * Handles GET method requests. Displays the current registration info for

   * this user (if any), then allows the user to make changes and register or

   * unregister.

   * 

   * @param req                the request

   * @param res                the response

   * @throws ServletException

   * @throws IOException

   */

  public void doGet(HttpServletRequest req, HttpServletResponse res)

                               throws ServletException, IOException {

    Connection conn = getConnection();

    String contactEmail = "";

    String documentListURL = "http://";

    HttpSession httpSession;

    String ldapDN;

    String ldapPwd;

    String query;

    int siteScheduleID;

		Statement stmt;

    String unit = "days";

    int updateFrequency = 1;

    httpSession = req.getSession(false);

    if (httpSession == null) {

      System.out.println("User did not log in.");

      return;

    }

    // The user name and password are stored as session attributes by the

    // HarvesterRegistrationLogin servlet.

    ldapDN = (String) httpSession.getAttribute("ldapDN");

    ldapPwd = (String) httpSession.getAttribute("ldapPwd");

    siteScheduleID = getSiteScheduleID(conn, ldapDN);

    // If the user is already registered, query the existing values and

    // initialize the form with them.

    if (siteScheduleID != 0) {

      query = "SELECT * FROM HARVEST_SITE_SCHEDULE WHERE SITE_SCHEDULE_ID=" +

              siteScheduleID;

		  try {

			  stmt = conn.createStatement();							

			  ResultSet rs = stmt.executeQuery(query);

			  while (rs.next()) {

          contactEmail = rs.getString("CONTACT_EMAIL");

          documentListURL = rs.getString("DOCUMENTLISTURL");

          updateFrequency = rs.getInt("UPDATEFREQUENCY");

          unit = rs.getString("UNIT");

        }

			  stmt.close();	

		  }

      catch (SQLException ex) {

			  System.out.println("SQLException: " + ex.getMessage());

		  }

    }

    res.setContentType("text/html");

    PrintWriter out = res.getWriter();

    // Print the registration form    

    out.println("<HTML>");

    out.println("<HEAD>");

    out.println("<TITLE>Metacat Harvester Registration</TITLE>");

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

    out.println("<BODY>");

    out.println("<H2><B>Metacat Harvester Registration</B></H2>");

    out.println("<FORM METHOD=POST>");   // posts to itself

    out.println("To register or changes values, enter all values ");

    out.println("below and click <B>Register</B>.<BR>");

    out.println("To unregister, simply click <B>Unregister</B>.<BR>");

    out.println("<BR><BR>");

    out.println("<pre>Email address:             </pre>");

    out.println("<INPUT TYPE=TEXT NAME=contactEmail VALUE=");

    out.println(contactEmail + ">");

    out.println("<BR><BR>");

    out.println("<pre>Harvest Document List URL: </pre>");

    out.println("<INPUT TYPE=TEXT NAME=documentListURL VALUE=");

    out.println(documentListURL + ">");

    out.println("<BR><BR>");

    out.println("<pre>Harvest Frequency (1-99):  </pre>");

    out.println("<INPUT TYPE=TEXT NAME=updateFrequency ");

    out.println("MAXLENGTH=2 SIZE=2 VALUE=");

    out.println(updateFrequency + ">");

    out.println("<BR><BR>");

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

    out.println("<INPUT TYPE=RADIO ");

    if (unit.equals("days")) out.println("CHECKED ");

    out.println("NAME=unit VALUE=days>day(s)");

    out.println("<INPUT TYPE=RADIO ");

    if (unit.equals("weeks")) out.println("CHECKED ");

    out.println("NAME=unit VALUE=weeks>week(s)");

    out.println("<INPUT TYPE=RADIO ");

    if (unit.equals("months")) out.println("CHECKED ");

    out.println("NAME=unit VALUE=months>month(s)");

    out.println("<BR><BR><BR>");

    out.println("<INPUT TYPE=SUBMIT NAME=register VALUE=Register>");

    out.println("<INPUT TYPE=SUBMIT NAME=unregister VALUE=Unregister>");

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

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

  }

  /**

   * Handles POST method requests. Reads values as entered by the user in the

   * harvester registration form and checks them for validity. Then either 

   * inserts, updates, or removes a record in the HARVEST_SITE_SCHEDULE table.

   * 

   * @param req                the request

   * @param res                the response

   * @throws ServletException

   * @throws IOException

   */

  public void doPost(HttpServletRequest req, HttpServletResponse res)

                               throws ServletException, IOException {

    Connection conn = getConnection();

    int maxValue;

    boolean remove = false;        // if true, remove record

    int siteScheduleID;

    String contactEmail;

    String dateLastHarvest;

    String dateNextHarvest;

    String documentListURL;

    HttpSession httpSession;

    String ldapDN;

    String ldapPwd;

    PrintWriter out;

    ParameterParser parameterParser = new ParameterParser(req);

    String register;

    String unit;

    String unregister;

    int updateFrequency;

    boolean validValues;

    httpSession = req.getSession(false);

    if (httpSession == null) {

      System.out.println("User did not log in.");

      return;

    }

    // The user name and password are stored as session attributes by the

    // HarvesterRegistrationLogin servlet

    ldapDN = (String) httpSession.getAttribute("ldapDN");

    ldapPwd = (String) httpSession.getAttribute("ldapPwd");

    contactEmail = parameterParser.getStringParameter("contactEmail", "None");

    documentListURL = parameterParser.getStringParameter("documentListURL", "");

    unit = parameterParser.getStringParameter("unit", "days");

    updateFrequency = parameterParser.getIntParameter("updateFrequency", 1);

    register = parameterParser.getStringParameter("register", "");

    unregister = parameterParser.getStringParameter("unregister", "");

    remove = (unregister.equalsIgnoreCase("Unregister"));

    siteScheduleID = getSiteScheduleID(conn, ldapDN);

    dateLastHarvest = getDateLastHarvest(conn, siteScheduleID);

    res.setContentType("text/plain");

    out = res.getWriter();

    if (!remove) {    

      validValues = checkValues(out, documentListURL, updateFrequency);

      if (!validValues) {

        return;

      }

    }

    if (siteScheduleID == 0) {

      if (remove) {

        // The user clicked Unregister, but no existing record was found

        System.out.println("Unable to remove record for user " + ldapDN);

        System.out.println("No matching record found in HARVEST_SITE_SCHEDULE");

        out.println("No record found for user " + ldapDN + ".");

        out.println("Since you were not registered, no action was taken.");

      }

      else {

        maxValue = getMaxValue(conn,

                               "HARVEST_SITE_SCHEDULE",

                               "SITE_SCHEDULE_ID");

        siteScheduleID = maxValue + 1;

        dbInsert(out, conn, siteScheduleID, contactEmail, documentListURL,

                 ldapDN, ldapPwd, unit, updateFrequency);

      }

    }

    else {

      // Either update or remove an existing record

      if (remove) {

        dbRemove(out, conn, siteScheduleID, ldapDN);

      }

      else {

        dbUpdate(out, conn, siteScheduleID, contactEmail, documentListURL,

                 ldapDN, ldapPwd, unit, updateFrequency, dateLastHarvest);

      }

    }

    closeConnection(conn);

  }

  /**

   * Gets a database connection.

   * 

   * @return  conn, the Connection object

   */

  private Connection getConnection() {

    Connection conn = null;

    SQLWarning warn;

    // Make the database connection

    try {

      System.out.println("Getting connection to Harvester tables");

      conn = DriverManager.getConnection(url, user, password);

      // If a SQLWarning object is available, print its warning(s).

      // There may be multiple warnings chained.

      warn = conn.getWarnings();

      if (warn != null) {

        while (warn != null) {

          System.out.println("SQLState: " + warn.getSQLState());

          System.out.println("Message:  " + warn.getMessage());

          System.out.println("Vendor: " + warn.getErrorCode());

          System.out.println("");

          warn = warn.getNextWarning();

        }

      }

    }

    catch (SQLException e) {

      System.out.println("Database access failed " + e);

    }

    return conn;

  }

  /**

   * Gets the date of last harvest value from the HARVEST_SITE_SCHEDULE table,

   * given a siteScheduleID value (the primary key).

   * 

   * @param  conn            the connection

   * @param  siteScheduleID  the primary key

   * @return dateLastHarvest the string stored in the table, e.g.

   *                         "2004-04-30 00:00:00.0" or ""

   */

  private String getDateLastHarvest(Connection conn, int siteScheduleID) {

    String dateLastHarvest = "";

    String query = "SELECT DATELASTHARVEST FROM HARVEST_SITE_SCHEDULE " +

                   "WHERE SITE_SCHEDULE_ID=" + siteScheduleID;

		Statement stmt;

		try {

			stmt = conn.createStatement();							

			ResultSet rs = stmt.executeQuery(query);

			while (rs.next()) {

        dateLastHarvest = rs.getString("DATELASTHARVEST");

        if (rs.wasNull()) {

          dateLastHarvest = "";  // Convert null value to empty string

        }

			}

			stmt.close();	

		}

    catch (SQLException ex) {

			System.out.println("SQLException: " + ex.getMessage());

		}

    return dateLastHarvest;

  }

  /** 

   * Gets the maximum value of an integer field from a table, given the table

   * name and the field name.

   * 

   * @param tableName  the database table name

   * @param fieldName  the field name of the integer field in the table

   * @return  the maximum integer stored in the fieldName field of tableName

   */

  private int getMaxValue(Connection conn, String tableName, String fieldName) {

    int maxValue = 0;

    int fieldValue;

		String query = "SELECT " + fieldName + " FROM " + tableName;

		Statement stmt;

		try {

			stmt = conn.createStatement();							

			ResultSet rs = stmt.executeQuery(query);

			while (rs.next()) {

				fieldValue = rs.getInt(fieldName);

        maxValue = Math.max(maxValue, fieldValue);

			}

			stmt.close();	

		} 

    catch (SQLException ex) {

			System.out.println("SQLException: " + ex.getMessage());

		}

    return maxValue;

  }

  /**

   * Gets the siteScheduleID value from the HARVEST_SITE_SCHEDULE table, given

   * the value of the ldapDN field.

   * 

   * @param conn   the database connection

   * @param ldapDN the ldap DN string

   * @return  siteScheduleID, an integer, the primary key

   */

  private int getSiteScheduleID(Connection conn, String ldapDN) {

    String ldapDNValue;                       // value of LDAPDN field

    String query = "SELECT * FROM HARVEST_SITE_SCHEDULE";

    int siteScheduleID = 0;

		Statement stmt;

		try {

			stmt = conn.createStatement();							

			ResultSet rs = stmt.executeQuery(query);

			while (rs.next()) {

        ldapDNValue = rs.getString("LDAPDN");

        if (ldapDNValue.equalsIgnoreCase(ldapDN)) {

				  siteScheduleID = rs.getInt("SITE_SCHEDULE_ID");

        }

			}

			stmt.close();	

		}

    catch (SQLException ex) {

			System.out.println("SQLException: " + ex.getMessage());

		}

    return siteScheduleID;

  }

  /**

   * Initializes the servlet. Reads properties and initializes object fields.

   * 

   * @throws ServletException

   */

  public void init() throws ServletException {

    String dbDriver;

    Properties properties = loadProperties();

    dbDriver = properties.getProperty("dbDriver");

    password = properties.getProperty("password");

    url = properties.getProperty("url");

    user = properties.getProperty("user");

    // Load the jdbc driver

    try {

      Class.forName(dbDriver);

    }

    catch (ClassNotFoundException e) {

      System.out.println("Can't load driver " + e);

    } 

  }

  /**

   * Loads Harvester properties from a configuration file.

   */

  private Properties loadProperties() {

    InputStream inputStream;

    String path = "/harvester/harvester.properties";

    Properties properties = new Properties();

    ServletContext servletContext = getServletContext();

    try {

      inputStream = servletContext.getResourceAsStream(path);

      properties.load(inputStream);

      properties.list(System.out);

    }

    catch (IOException e) {

      System.out.println("IOException: " + e.getMessage());

    }

    return properties;

  }

  /**

   * Surrounds a string with single quotes.

   * @param str  the original string

   * @return     the quoted string

   */

  private String quoteString(String str) {

    return "'" + str + "'";

  }

  /**

   * Reports the results of an insert or update to the client.

   * 

   * @param out               the PrintWriter

   * @param ldapDN            the LDAP DN string

   * @param contactEmail      the email address of the site contact

   * @param documentListURL   the URL of the harvester document list at the site

   * @param updateFrequency   the harvest update frequency

   * @param unit              the unit (e.g. "days", "weeks", "months"

   * @param dateNextHarvest   the date of the next scheduled harvest

   */

  private void reportResults(PrintWriter out,

                             String ldapDN,

                             String contactEmail,

                             String documentListURL,

                             int updateFrequency,

                             String unit,

                             String dateNextHarvest

                            ) {

    out.println("Harvester registration updated for " + ldapDN);

    out.println("  Email Address:             " + contactEmail);

    out.println("  Harvest Document List URL: " + documentListURL);

    out.println("  Harvest Frequency:         " + updateFrequency);

    out.println("  Unit:                      " + unit);

    out.println("");

    out.println("Next scheduled harvest date: " + dateNextHarvest);

  }

}