source: trunk/gsdl3/src/java/org/greenstone/gsdl3/LibraryServlet.java@ 3766

package org.greenstone.gsdl3;

import org.greenstone.gsdl3.core.*;
import org.greenstone.gsdl3.util.*;
import org.greenstone.gsdl3.action.PageAction; // used to get the default action
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.Enumeration;
import java.io.File;

/** a servlet to serve the greenstone library - we are using servlets instead
 * of cgi
 * the init method is called only once - the first time the servlet classes
 * are loaded. Each time a request comes in to the servlet, the session()
 * method is called in a new thread (calls doGet/doPut etc)
 * takes the a=p&p=home type args and builds a simple request to send to 
 * its receptionist, which returns a result in html, cos output=html
 * is set in the request
 * @see Receptionist
 */
public class LibraryServlet extends HttpServlet {
    
    /** the receptionist to send messages to */
    protected Receptionist recept_=null;
    /** the default language - is specified by setting a servlet param,
     * otherwise DEFUALT_LANG is used*/
    protected String default_lang_= null;
    /** The default default - used if a default lang is not specified 
     * in the servlet params */
    protected final String DEFAULT_LANG = "en";
    /** container Document to create XML Nodes */
    protected Document doc_=null;    
    /** a converter class to parse XML and create Docs */
    protected XMLConverter converter_=null;

    /** initialise the servlet
     */
    public void init(ServletConfig config) throws ServletException {
    // always call super.init;
    super.init(config);

    ConfigVars config_vars = new ConfigVars();
    String library_name = config.getInitParameter("libraryname");
    String gsdl3_home = config.getInitParameter("gsdl3home");
    String site_name = config.getInitParameter("sitename");
    String interface_name = config.getInitParameter("interfacename");
    default_lang_ = config.getInitParameter("defaultlang");
    if (library_name == null || gsdl3_home == null || site_name ==null ||  interface_name ==null) {
        // must have this
        System.err.println("initialisation parameters not all set!");
        System.err.println(" you must have libraryname, gsdl3home, sitename,  interfacename");
        System.exit(1);
    }

    if (default_lang_ == null) {
        // choose english
        default_lang_ = DEFAULT_LANG;
    }

    config_vars.library_name_ = library_name;
    config_vars.gsdl3_home_ = gsdl3_home;
    config_vars.site_name_ = site_name;
    config_vars.interface_name_ =interface_name;
    config_vars.default_language_ = default_lang_;
    config_vars.createXML();
    
    // new message router - create it and pass reference to recept.
    // the servlet wont use this directly
    MessageRouter message_router = new MessageRouter();
    message_router.setSiteHome(GSFile.siteHome(config_vars.gsdl3_home_, 
                            config_vars.site_name_));
    message_router.configure();

    // the receptionist -the servlet will talk to this
    recept_ = new Receptionist();
    recept_.setConfigVars(config_vars);
    recept_.setMessageRouter(message_router);
    recept_.configure();

    converter_ = new XMLConverter();
    doc_ = converter_.newDOM();

    }
    
    public void doGet(HttpServletRequest request,
              HttpServletResponse response)
    throws ServletException, IOException {
    
    request.setCharacterEncoding("UTF-8");
    response.setContentType("text/html;charset=UTF-8");
    PrintWriter out = response.getWriter();

    String lang = request.getParameter(GSCGI.LANGUAGE_ARG);
    if (lang==null || lang.equals("")) {
        lang = default_lang_; // the default
    }
    String output = request.getParameter(GSCGI.OUTPUT_ARG);
    if (output==null || output.equals("")) {
        output = "html"; // uses html by default
    }

    // the request to the receptionist  
    Element xml_message = doc_.createElement(GSXML.MESSAGE_ELEM);
    Element xml_request = doc_.createElement(GSXML.REQUEST_ELEM);
    xml_message.appendChild(xml_request);
    xml_request.setAttribute(GSXML.LANG_ATT, lang);
    xml_request.setAttribute(GSXML.TYPE_ATT, GSXML.REQUEST_TYPE_CGI);
    xml_request.setAttribute(GSXML.OUTPUT_ATT, output);
    
    String action = request.getParameter(GSCGI.ACTION_ARG);
    String subaction = request.getParameter(GSCGI.SUBACTION_ARG);
    if (action==null || action.equals("")) {
        // should we do all the following stuff if using default page?
        // display the home page  - the default page
        action = "p";
        subaction = PageAction.HOME_PAGE;
        xml_request.setAttribute(GSXML.ACTION_ATT, action);
        xml_request.setAttribute(GSXML.SUBACTION_ATT, subaction);
        
        Element xml_result = recept_.process(xml_message);
        out.println(converter_.getString(xml_result));
        return;
    } 
    
    xml_request.setAttribute(GSXML.ACTION_ATT, action);
    if (subaction != null) {
        xml_request.setAttribute(GSXML.SUBACTION_ATT, subaction);
    }
    Element xml_param_list = doc_.createElement(GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER);
    xml_request.appendChild(xml_param_list);
    Enumeration params = request.getParameterNames();
    while(params.hasMoreElements()) {
        String name = (String)params.nextElement();
        if (!name.equals(GSCGI.ACTION_ARG) && !name.equals(GSCGI.SUBACTION_ARG) && !name.equals(GSCGI.LANGUAGE_ARG) && !name.equals(GSCGI.OUTPUT_ARG)) { // these ones are in the header so leave out
        String value="";
        String []values = request.getParameterValues(name);
        value = values[0];
        if (values.length > 1) {
            for (int i=1; i< values.length; i++) {
            value += ","+values[i];
            }
        }
        Element param = doc_.createElement(GSXML.PARAM_ELEM);
        param.setAttribute(GSXML.NAME_ATT, name);
        param.setAttribute(GSXML.VALUE_ATT, GSXML.xmlSafe(value));
        xml_param_list.appendChild(param);
        
        }
    }

    if (!output.equals("html")) {
        response.setContentType("text/xml"); // for now use text
    }
    
    Element xml_result = recept_.process(xml_message);
    out.println(converter_.getString(xml_result));
    }
}