public void dap2ExceptionHandler(DAP2Exception de, ReqState rs) {
   rs.getResponse().setHeader("Content-Description", "dods-error");
   rs.getResponse().setContentType("text/plain");
   try {
     de.print(rs.getResponse().getOutputStream());
   } catch (Exception e) {
     System.err.println("dap2ExceptionHandler: " + e);
   }
 }
  public void doGetDDS(ReqState rs) throws Exception {
    HttpServletResponse response = rs.getResponse();

    GuardedDataset ds = null;
    try {
      ds = getDataset(rs);
      if (null == ds) return;

      response.setContentType("text/plain");
      response.setHeader("XDODS-Server", getServerVersion());
      response.setHeader("Content-Description", "dods-dds");

      OutputStream out = new BufferedOutputStream(response.getOutputStream());
      ServerDDS myDDS = ds.getDDS();

      if (rs.getConstraintExpression().equals("")) { // No Constraint Expression?
        // Send the whole DDS
        myDDS.print(out);
        out.flush();

      } else { // Otherwise, send the constrained DDS
        // Instantiate the CEEvaluator and parse the constraint expression
        CEEvaluator ce = new CEEvaluator(myDDS);
        ce.parseConstraint(rs);

        // Send the constrained DDS back to the client
        PrintWriter pw = new PrintWriter(new OutputStreamWriter(out));
        myDDS.printConstrained(pw);
        pw.flush();
      }

    } finally { // release lock if needed
      if (ds != null) ds.release();
    }
  }
  public void doGetHELP(ReqState rs) throws Exception {
    HttpServletResponse response = rs.getResponse();

    response.setContentType("text/html");
    response.setHeader("XDODS-Server", getServerVersion());
    response.setHeader("Content-Description", "dods-help");

    PrintWriter pw = new PrintWriter(new OutputStreamWriter(response.getOutputStream()));
    printHelpPage(pw);
    pw.flush();
  }
  // any time the server needs access to the dataset, it gets a "GuardedDataset" which allows us to
  // add caching
  // optionally, a session may be established, which allows us to reserve the dataset for that
  // session.
  protected GuardedDataset getDataset(ReqState preq) throws Exception {
    HttpServletRequest req = preq.getRequest();
    String reqPath = preq.getDataSet();

    // see if the client wants sessions
    boolean acceptSession = false;
    String s = req.getHeader("X-Accept-Session");
    if (s != null && s.equalsIgnoreCase("true") && allowSessions) acceptSession = true;

    HttpSession session = null;
    if (acceptSession) {
      // see if theres already a session established, create one if not
      session = req.getSession();
      if (!session.isNew()) {
        GuardedDataset gdataset = (GuardedDataset) session.getAttribute(reqPath);
        if (null != gdataset) {
          if (debugSession)
            System.out.printf(" found gdataset %s in session %s %n", reqPath, session.getId());
          if (log.isDebugEnabled())
            log.debug(" found gdataset " + gdataset + " in session " + session.getId());
          return gdataset;
        }
      }
    }

    NetcdfFile ncd = DatasetHandler.getNetcdfFile(req, preq.getResponse(), reqPath);
    if (null == ncd) return null;

    GuardedDataset gdataset = new GuardedDatasetCacheAndClone(reqPath, ncd, acceptSession);
    // GuardedDataset gdataset = new GuardedDatasetImpl(reqPath, ncd, acceptSession);

    if (acceptSession) {
      String cookiePath = req.getRequestURI();
      String suffix = "." + preq.getRequestSuffix();
      if (cookiePath.endsWith(suffix)) // snip off the suffix
      cookiePath = cookiePath.substring(0, cookiePath.length() - suffix.length());
      session.setAttribute(reqPath, gdataset);
      session.setAttribute(CookieFilter.SESSION_PATH, cookiePath);
      // session.setAttribute("dataset", ncd.getLocation());  // for UsageValve
      // session.setMaxInactiveInterval(30); // 30 second timeout !!
      if (debugSession)
        System.out.printf(
            " added gdataset %s in session %s cookiePath %s %n",
            reqPath, session.getId(), cookiePath);
      if (log.isDebugEnabled())
        log.debug(" added gdataset " + gdataset + " in session " + session.getId());
    } /* else {
        session = req.getSession();
        session.setAttribute("dataset", ncd.getLocation()); // for UsageValve
      } */

    return gdataset;
  }
  public void doGetDIR(ReqState rs) throws Exception {
    // rather dangerous here, since you can go into an infinite loop
    // so we're going to insist that there's  no suffix
    HttpServletResponse response = rs.getResponse();
    HttpServletRequest request = rs.getRequest();
    if ((rs.getRequestSuffix() == null) || (rs.getRequestSuffix().length() == 0)) {
      ServletUtil.forwardToCatalogServices(request, response);
      return;
    }

    sendErrorResponse(response, 0, "Unrecognized request");
  }
  public void doGetVER(ReqState rs) throws Exception {
    HttpServletResponse response = rs.getResponse();

    response.setContentType("text/plain");
    response.setHeader("XDODS-Server", getServerVersion());
    response.setHeader("Content-Description", "dods-version");

    PrintWriter pw = new PrintWriter(new OutputStreamWriter(response.getOutputStream()));

    pw.println("Server Version: " + getServerVersion());
    pw.flush();
  }
  public void doGetDAP2Data(ReqState rs) throws Exception {
    HttpServletResponse response = rs.getResponse();

    GuardedDataset ds = null;
    try {
      ds = getDataset(rs);
      if (null == ds) return;

      response.setContentType("application/octet-stream");
      response.setHeader("XDODS-Server", getServerVersion());
      response.setHeader("Content-Description", "dods-data");

      ServletOutputStream sOut = response.getOutputStream();
      OutputStream bOut;
      DeflaterOutputStream dOut = null;
      if (rs.getAcceptsCompressed() && allowDeflate) {
        response.setHeader("Content-Encoding", "deflate");
        dOut = new DeflaterOutputStream(sOut);
        bOut = new BufferedOutputStream(dOut);

      } else {
        bOut = new BufferedOutputStream(sOut);
      }

      ServerDDS myDDS = ds.getDDS();
      CEEvaluator ce = new CEEvaluator(myDDS);
      ce.parseConstraint(rs);
      checkSize(myDDS, false);

      // Send the constrained DDS back to the client
      PrintWriter pw = new PrintWriter(new OutputStreamWriter(bOut));
      myDDS.printConstrained(pw);

      // Send the Data delimiter back to the client
      pw.flush();
      bOut.write("\nData:\n".getBytes());
      bOut.flush();

      // Send the binary data back to the client
      DataOutputStream sink = new DataOutputStream(bOut);
      ce.send(myDDS.getEncodedName(), sink, ds);
      sink.flush();

      // Finish up sending the compressed stuff, but don't
      // close the stream (who knows what the Servlet may expect!)
      if (null != dOut) dOut.finish();
      bOut.flush();

    } finally { // release lock if needed
      if (ds != null) ds.release();
    }
  }
  public void doGetINFO(ReqState rs) throws Exception {
    HttpServletResponse response = rs.getResponse();
    GuardedDataset ds = null;
    try {
      ds = getDataset(rs);
      if (null == ds) return;

      PrintStream pw = new PrintStream(response.getOutputStream());
      response.setHeader("XDODS-Server", getServerVersion());
      response.setContentType("text/html");
      response.setHeader("Content-Description", "dods-description");

      GetInfoHandler di = new GetInfoHandler();
      di.sendINFO(pw, ds, rs);

    } finally { // release lock if needed
      if (ds != null) ds.release();
    }
  }
  private void doClose(ReqState rs) throws Exception {
    HttpServletResponse response = rs.getResponse();
    HttpServletRequest request = rs.getRequest();
    String reqPath = rs.getDataSet();
    HttpSession session = request.getSession();
    session.removeAttribute(reqPath); // work done in the listener

    response.setHeader("XDODS-Server", getServerVersion()); // needed by client

    /* if (path.endsWith(".close")) {
      closeSession(request, response);
      response.setContentLength(0);
      log.info("doGet(): " + UsageLog.closingMessageForRequestContext(HttpServletResponse.SC_OK, 0));
      return;

    }

    // so we need to worry about deleting sessions?
    session.invalidate();  */
  }
  public void doGetDAS(ReqState rs) throws Exception {
    HttpServletResponse response = rs.getResponse();

    GuardedDataset ds = null;
    try {
      ds = getDataset(rs);
      if (ds == null) return;

      response.setContentType("text/plain");
      response.setHeader("XDODS-Server", getServerVersion());
      response.setHeader("Content-Description", "dods-das");

      OutputStream Out = new BufferedOutputStream(response.getOutputStream());

      DAS myDAS = ds.getDAS();
      myDAS.print(Out);

    } finally { // release lock if needed
      if (ds != null) ds.release();
    }
  }
  public void doGetHTML(ReqState rs) throws Exception {
    HttpServletResponse response = rs.getResponse();
    HttpServletRequest request = rs.getRequest();
    GuardedDataset ds = null;
    try {
      ds = getDataset(rs);
      if (ds == null) return;

      response.setHeader("XDODS-Server", getServerVersion());
      response.setContentType("text/html");
      response.setHeader("Content-Description", "dods-form");

      // Utilize the getDDS() method to get	a parsed and populated DDS
      // for this server.
      ServerDDS myDDS = ds.getDDS();
      DAS das = ds.getDAS();
      GetHTMLInterfaceHandler2 di = new GetHTMLInterfaceHandler2();
      di.sendDataRequestForm(request, response, rs.getDataSet(), myDDS, das);

    } finally { // release lock if needed
      if (ds != null) ds.release();
    }
  }
  public void doGetASC(ReqState rs) throws Exception {
    HttpServletResponse response = rs.getResponse();

    GuardedDataset ds = null;
    try {
      ds = getDataset(rs);
      if (ds == null) return;

      response.setHeader("XDODS-Server", getServerVersion());
      response.setContentType("text/plain");
      response.setHeader("Content-Description", "dods-ascii");

      log.debug(
          "Sending OPeNDAP ASCII Data For: " + rs + "  CE: '" + rs.getConstraintExpression() + "'");

      ServerDDS dds = ds.getDDS();
      CEEvaluator ce = new CEEvaluator(dds);
      ce.parseConstraint(rs);
      checkSize(dds, true);

      PrintWriter pw = new PrintWriter(response.getOutputStream());
      dds.printConstrained(pw);
      pw.println("---------------------------------------------");

      AsciiWriter writer = new AsciiWriter(); // could be static
      writer.toASCII(pw, dds, ds);

      // the way that getDAP2Data works
      // DataOutputStream sink = new DataOutputStream(bOut);
      // ce.send(myDDS.getName(), sink, ds);

      pw.flush();

    } finally { // release lock if needed
      if (ds != null) ds.release();
    }
  }