Servlet.java

package org.h3270.web;

/*
 * Copyright (C) 2003-2008 akquinet tech@spree
 *
 * This file is part of h3270.
 *
 * h3270 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 3 of the License, or
 * (at your option) any later version.
 *
 * h3270 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 h3270; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
 * MA 02110-1301 USA
 */

import java.io.File;
import java.io.IOException;
import java.net.*;
import java.util.Iterator;

import javax.servlet.ServletException;
import javax.servlet.http.*;

import org.apache.avalon.framework.configuration.Configuration;
import org.apache.avalon.framework.configuration.ConfigurationException;
import org.h3270.host.*;
import org.h3270.logicalunit.*;
import org.h3270.render.*;

/**
 * @author Andre Spiegel spiegel@gnu.org
 * @version $Id: Servlet.java,v 1.36 2008/11/21 14:50:33 spiegel Exp $
 */
public class Servlet extends AbstractServlet {

  private static final long serialVersionUID = 1L;

  private static final String STYLE_JSP = "/screen.jsp";

  private static final String DEFAULT_JSP = "/simple-screen.jsp";

  private String targetHost;

  private boolean autoconnect;

  private String execPath;

  private String templateDir;

  private final HtmlRenderer basicRenderer = new HtmlRenderer();

  private Engine engine = null;

  private H3270Configuration configuration;

  private String mainJSP = DEFAULT_JSP;

  private LogicalUnitPool logicalUnitPool;

  public void init() throws ServletException {
    super.init();

    configuration = getConfiguration();
    Configuration styleConfig = configuration.getChild("style");

    try {
      if (styleConfig.getValue() != null) {
        mainJSP = STYLE_JSP;
      }
    } catch (ConfigurationException e) {
      logger.info("Set main jsp to default");
    }

    targetHost = configuration.getChild("target-host").getValue(null);
    if (targetHost != null) {
      autoconnect = configuration.getChild("target-host")
          .getAttributeAsBoolean("autoconnect", false);
    }

    Configuration dirConfig = configuration.getChild("template-dir");
    templateDir = getRealPath(dirConfig.getValue("/WEB-INF/templates"));
    engine = new Engine(templateDir);

    execPath = configuration.getChild("exec-path").getValue("/usr/local/bin");

    logicalUnitPool = LogicalUnitPoolFactory
        .createLogicalUnitPool(configuration);
    if (logicalUnitPool != null) {
      getServletContext().setAttribute(LogicalUnitPool.SERVLET_CONTEXT_KEY,
          logicalUnitPool);
    }

    if (logger.isDebugEnabled()) {
      logger.info("Using main JSP: " + mainJSP);
      logger.info("Set template-dir to " + templateDir);
      logger.info("Set exec-path to " + execPath);
      logger.info("Use Logical Unit Pool " + (logicalUnitPool != null));
    }
  }

  protected void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {

    SessionState state = getSessionState(request);

    if (state.getTerminal(request) == null && autoconnect) {
      connect(request, state, targetHost);
    }

    if (state.getTerminal(request) != null) {
      state.getTerminal(request).updateScreen();
      Screen s = state.getTerminal(request).getScreen();

      Renderer r = (state.useRenderers() && engine.canRender(s)) ? (Renderer) engine
          : (Renderer) basicRenderer;
      state.setScreen(request, r.render(s, "", state.getTerminalId(request)));
    }
    getServletContext().getRequestDispatcher(mainJSP)
        .forward(request, response);
  }

  protected void doPost(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {

    SessionState state = getSessionState(request);
    state.setException(request, null);
    handlePreferences(state, request, response);

    Terminal terminal = state.getTerminal(request);

    if (request.getParameter("connect") != null) {
      String hostname = (targetHost == null) ? request.getParameter("hostname")
          : targetHost;
      // TODO message to user if no hostname specified
      if (!hostname.equals("")) {
        connect(request, state, hostname);
      }
    } else if (request.getParameter("disconnect") != null) {
      disconnect(request, state, terminal);
    } else if (request.getParameter("refresh") != null) {
      terminal.updateScreen();
    } else if (request.getParameter("dumpfile") != null
        && !request.getParameter("dumpfile").equals("")) {
      String filename = new File(getRealPath("/WEB-INF/dump"), request
          .getParameter("dumpfile")).toString();
      terminal.dumpScreen(filename);
    } else if (request.getParameter("keypad") != null) {
      state.useKeypad(request, !state.useKeypad(request));
    } else if (terminal != null) {
      submitScreen(request);
      String key = request.getParameter("key");
      if (key != null)
        terminal.doKey(key);
    }
    doGet(request, response);
  }

  private void disconnect(HttpServletRequest request, SessionState state,
      Terminal terminal) {
    if (terminal != null)
      terminal.disconnect();
    String logicalUnit = terminal.getLogicalUnit();
    releaseLogicalUnit(logicalUnit);
    state.setTerminal(request, null);
    state.setScreen(request, null);
  }

  private void connect(HttpServletRequest request, SessionState state,
      String hostname) throws IOException, MalformedURLException {
    try {
      if (logger.isInfoEnabled()) {
        logger.info("Connecting to " + hostname);
      }

      if (hostname.startsWith("file:")) {
        String filename = new File(getRealPath("/WEB-INF/dump"), hostname
            .substring(5)).toString();
        state.setTerminal(request,
            new FileTerminal(new URL("file:" + filename)));
      } else {
        state.setTerminal(request, new S3270(leaseLogicalUnit(), hostname,
            configuration));
      }
      state.useKeypad(request, false);

    } catch (Exception ex) {
      state.setException(request, ex);
    }
  }

  private String leaseLogicalUnit() throws LogicalUnitException {
    if (logicalUnitPool != null) {
      return logicalUnitPool.leaseLogicalUnit();
    }
    return null;
  }

  private void releaseLogicalUnit(String logicalUnit) {
    if (logicalUnit != null) {
      logicalUnitPool.releaseLogicalUnit(logicalUnit);
    }
  }

  /**
   * If any preferences have been changed by the user in this request, take the
   * appropriate action.
   */
  private void handlePreferences(SessionState state,
      HttpServletRequest request, HttpServletResponse response)
      throws IOException {

    String colorscheme = request.getParameter("colorscheme");
    String render = request.getParameter("render");
    String font = request.getParameter("font");
    boolean modified = false;

    response.setContentType("text/html");

    if (colorscheme != null) {
      colorscheme = URLDecoder.decode(request.getParameter("colorscheme"),
          "UTF-8");
      modified = state.setActiveColorScheme(request, colorscheme);
    }

    if (render != null) {
      if (render.equals("true")) {
        if (!state.useRenderers()) {
          engine = new Engine(templateDir);
        }
        state.useRenderers(true);
      } else if (render.equals("false")) {
        state.useRenderers(false);
      }
      modified = true;
    }

    if (font != null && !font.equals("")) {
      state.setFontName(font);

      modified = true;
    }

    if (modified) {
      Cookie cookie = new Cookie(SessionState.COOKIE_NAME, state
          .getSavedState());

      if (logger.isDebugEnabled()) {
        logger.debug("Sending Cookie: " + state);
      }

      cookie.setMaxAge(Integer.MAX_VALUE);

      response.addCookie(cookie);
    }
  }

  /**
   * Gets the input field parameters from the request and fills them into the
   * Fields of the Screen, then submits them back to s3270.
   */
  private void submitScreen(HttpServletRequest request) throws IOException {
    SessionState state = getSessionState(request);
    Screen s = state.getTerminal(request).getScreen();
    if (s.isFormatted()) {
      for (Iterator i = s.getFields().iterator(); i.hasNext();) {
        Field f = (Field) i.next();
        if (f instanceof InputField) {
          if (!f.isMultiline()) {
            String value = request.getParameter("field_" + f.getStartX() + "_"
                + f.getStartY());
            if (value != null) {
              ((InputField) f).setValue(value);
            }
          } else { // multi-line field
            for (int j = 0; j < f.getHeight(); j++) {
              String value = request.getParameter("field_" + f.getStartX()
                  + "_" + f.getStartY() + "_" + j);
              if (value != null) {
                ((InputField) f).setValue(j, value);
              }
            }
          }
        }
      }
      state.getTerminal(request).submitScreen();
    } else {
      state.getTerminal(request).submitUnformatted(
          (String) request.getParameter("field"));
    }
  }

  /**
   * Returns the SessionState object that is associated with the given request,
   * creates the object if it doesn't already exist.
   */
  private SessionState getSessionState(HttpServletRequest request)
      throws IOException {
    boolean forceNewSession = request.getParameter("dump.session") != null;

    HttpSession session = request.getSession(forceNewSession);

    if (session == null) {
      session = request.getSession();
    }

    if (this.targetHost != null) {
      String targetHost = (String) session.getAttribute("targetHost");
      if (targetHost == null) {
        session.setAttribute("targetHost", this.targetHost);
      }
    }

    SessionState result = (SessionState) session.getAttribute("sessionState");
    if (result == null) {
      String savedState = getSavedSessionState(request);

      result = new SessionState(configuration, savedState);
      session.setAttribute("sessionState", result);
    }
    return result;
  }

  private String getSavedSessionState(HttpServletRequest request) {
    Cookie cookie = getCookie(request);

    if (cookie != null) {
      return cookie.getValue();
    }

    return "";
  }

  private Cookie getCookie(HttpServletRequest request) {
    Cookie[] cookies = request.getCookies();

    if (cookies != null) {
      for (int x = 0; x < cookies.length; ++x) {
        if (SessionState.COOKIE_NAME.equals(cookies[x].getName())) {
          return cookies[x];
        }
      }
    }
    return null;
  }

}