source: greenstone3/trunk/src/java/org/greenstone/gsdl3/core/TransformingReceptionist.java@ 18433

package org.greenstone.gsdl3.core;

import org.greenstone.gsdl3.util.*;
import org.greenstone.gsdl3.action.*;
// XML classes
import org.w3c.dom.Node; 
import org.w3c.dom.NodeList; 
import org.w3c.dom.Document; 
import org.w3c.dom.Element;
import org.xml.sax.InputSource;

// other java classes
import java.io.File;
import java.io.StringWriter;
import java.io.FileReader;
import java.io.FileNotFoundException;
import java.util.HashMap;
import java.util.Enumeration;

import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.*;
import javax.xml.transform.stream.*;
import org.apache.log4j.*;
import org.apache.xerces.dom.*;
import org.apache.xerces.parsers.DOMParser;

/** A receptionist that uses xslt to transform the page_data before returning it. . Receives requests consisting
 * of an xml representation of cgi args, and returns the page of data - in 
 * html by default. The requests are processed by the appropriate action class
 *
 * @see Action
 */
public class TransformingReceptionist extends Receptionist{
    
    static Logger logger = Logger.getLogger(org.greenstone.gsdl3.core.TransformingReceptionist.class.getName());
    
    /** The preprocess.xsl file is in a fixed location */
    static final String preprocess_xsl_filename = GlobalProperties.getGSDL3Home() + File.separatorChar 
        + "ui" + File.separatorChar + "xslt" + File.separatorChar + "preProcess.xsl";   
        
    /** the list of xslt to use for actions */
    protected HashMap xslt_map = null;
    
    /** a transformer class to transform xml using xslt */
    protected XMLTransformer transformer=null;

    protected TransformerFactory transformerFactory=null;
    protected DOMParser parser = null;
    public TransformingReceptionist() {
    super();
    this.xslt_map = new HashMap();
    this.transformer = new XMLTransformer();
        try {
            transformerFactory = org.apache.xalan.processor.TransformerFactoryImpl.newInstance();
            this.converter = new XMLConverter();
            //transformerFactory.setURIResolver(new MyUriResolver()) ;

            parser = new DOMParser();
            parser.setFeature("http://xml.org/sax/features/validation", false);
            // don't try and load external DTD - no need if we are not validating, and may cause connection errors if a proxy is not set up.
            parser.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
            // a performance test showed that having this on lead to increased 
            // memory use for small-medium docs, and not much gain for large 
            // docs.
            // http://www.sosnoski.com/opensrc/xmlbench/conclusions.html
            parser.setFeature("http://apache.org/xml/features/dom/defer-node-expansion", false);
            parser.setFeature("http://apache.org/xml/features/continue-after-fatal-error", true);
            // setting a handler for when fatal errors, errors or warnings happen during xml parsing
            // call XMLConverter's getParseErrorMessage() to get the errorstring that can be rendered as web page
            this.parser.setErrorHandler(new XMLConverter.ParseErrorHandler());
        }
        catch (Exception e) {
            e.printStackTrace();
        }

    }
    
    /** configures the receptionist - overwrite this to set up the xslt map*/
    public boolean configure() {
    
        if (this.config_params==null) {
            logger.error(" config variables must be set before calling configure");
            return false;
        }
        if (this.mr==null) {       
            logger.error(" message router must be set  before calling configure");
            return false;
        }
        
        // find the config file containing a list of actions
        File interface_config_file = new File(GSFile.interfaceConfigFile(GSFile.interfaceHome(GlobalProperties.getGSDL3Home(), (String)this.config_params.get(GSConstants.INTERFACE_NAME))));
        if (!interface_config_file.exists()) {
            logger.error(" interface config file: "+interface_config_file.getPath()+" not found!");
            return false;
        }
        Document config_doc = this.converter.getDOM(interface_config_file, "utf-8");
        if (config_doc == null) {
            logger.error(" could not parse interface config file: "+interface_config_file.getPath());
            return false;
        }
        Element config_elem = config_doc.getDocumentElement();
        String base_interface = config_elem.getAttribute("baseInterface");
        setUpBaseInterface(base_interface);
        setUpInterfaceOptions(config_elem);

        Element action_list = (Element)GSXML.getChildByTagName(config_elem, GSXML.ACTION_ELEM+GSXML.LIST_MODIFIER);
        NodeList actions = action_list.getElementsByTagName(GSXML.ACTION_ELEM);

        for (int i=0; i<actions.getLength(); i++) {
            Element action = (Element) actions.item(i);
            String class_name = action.getAttribute("class");
            String action_name = action.getAttribute("name");
            Action ac = null;
            try {
                ac = (Action)Class.forName("org.greenstone.gsdl3.action."+class_name).newInstance();
            } catch (Exception e) {
                logger.error(" couldn't load in action "+class_name);
                e.printStackTrace();
                continue;
            }
            ac.setConfigParams(this.config_params);
            ac.setMessageRouter(this.mr);
            ac.configure();
            ac.getActionParameters(this.params);
            this.action_map.put(action_name, ac);

            // now do the xslt map
            String xslt = action.getAttribute("xslt");
            if (!xslt.equals("")) {
                this.xslt_map.put(action_name, xslt);
            }
            NodeList subactions = action.getElementsByTagName(GSXML.SUBACTION_ELEM);
            for (int j=0; j<subactions.getLength(); j++) {
                Element subaction = (Element)subactions.item(j);
                String subname = subaction.getAttribute(GSXML.NAME_ATT);
                String subxslt = subaction.getAttribute("xslt");
                
                String map_key = action_name+":"+subname;
                logger.debug("adding in to xslt map, "+map_key+"->"+subxslt);
                this.xslt_map.put(map_key, subxslt);
            }
        }
        Element lang_list = (Element)GSXML.getChildByTagName(config_elem, "languageList");
        if (lang_list == null) {
            logger.error(" didn't find a language list in the config file!!");
        } else {
            this.language_list = (Element) this.doc.importNode(lang_list, true);
        }

        return true;
    }


    protected Node postProcessPage(Element page) {
        // might need to add some data to the page
        addExtraInfo(page);
        // transform the page using xslt
        Node transformed_page = transformPage(page);
        
        return transformed_page;
    }
    
    /** overwrite this to add any extra info that might be needed in the page before transformation */
    protected void addExtraInfo(Element page) {}

    /** transform the page using xslt
         * we need to get any format element out of the page and add it to the xslt
         * before transforming */
    protected Node transformPage(Element page) {

        logger.debug("page before transfomring:");
        logger.debug(this.converter.getPrettyString(page));

        Element request = (Element)GSXML.getChildByTagName(page, GSXML.PAGE_REQUEST_ELEM);
        String action = request.getAttribute(GSXML.ACTION_ATT);
        String subaction = request.getAttribute(GSXML.SUBACTION_ATT);
        
        String output = request.getAttribute(GSXML.OUTPUT_ATT);
        // we should choose how to transform the data based on output, eg diff
        // choice for html, and wml??
        // for now, if output=xml, we don't transform the page, we just return 
        // the page xml
        if (output.equals("xml")) {
            return page;
        }
        

        Element cgi_param_list = (Element)GSXML.getChildByTagName(request, GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER);
        String collection = "";
        if (cgi_param_list != null) {
            HashMap params = GSXML.extractParams(cgi_param_list, false);
            collection = (String)params.get(GSParams.COLLECTION);
            if (collection == null) collection = "";
        }
        
        String xslt_file = getXSLTFileName(action, subaction, collection);
        if (xslt_file==null) {
            // returning file not found error page to indicate which file is missing
            return fileNotFoundErrorPage(xslt_file);
        }
        
        Document style_doc = this.converter.getDOM(new File(xslt_file), "UTF-8");
        String errorPage = this.converter.getParseErrorMessage();
        if(errorPage != null) {
            return XMLTransformer.constructErrorXHTMLPage(
                "Cannot parse the xslt file: " + xslt_file + "\n" + errorPage);
        }
        if (style_doc == null) {
            logger.error(" cant parse the xslt file needed, so returning the original page!");
            return page;
        }
        
        // put the page into a document - this is necessary for xslt to get
        // the paths right if you have paths relative to the document root
        // eg /page.
        Document doc = this.converter.newDOM();
        doc.appendChild(doc.importNode(page, true));
        Element page_response = (Element)GSXML.getChildByTagName(page, GSXML.PAGE_RESPONSE_ELEM);
        Element format_elem = (Element)GSXML.getChildByTagName(page_response, GSXML.FORMAT_ELEM);
        if (output.equals("formatelem")) {
            return format_elem;
        }
        if (format_elem != null) {
            //page_response.removeChild(format_elem);
            logger.debug("format elem="+this.converter.getPrettyString(format_elem));
            // need to transform the format info
            String configStylesheet_file = GSFile.stylesheetFile(GlobalProperties.getGSDL3Home(), (String)this.config_params.get(GSConstants.SITE_NAME), collection, (String)this.config_params.get(GSConstants.INTERFACE_NAME), base_interfaces,   "config_format.xsl");
            Document configStylesheet_doc = this.converter.getDOM(new File(configStylesheet_file));
            if (configStylesheet_doc != null) {
                Document format_doc = this.converter.newDOM();
                format_doc.appendChild(format_doc.importNode(format_elem, true));
                Node result = this.transformer.transform(configStylesheet_doc, format_doc);
                
                // Since we started creating documents with DocTypes, we can end up with 
                // Document objects here. But we will be working with an Element instead, 
                // so we grab the DocumentElement() of the Document object in such a case.
                Element new_format;
                if(result.getNodeType() == Node.DOCUMENT_NODE) {
                    new_format = ((Document)result).getDocumentElement();
                } else {
                    new_format = (Element)result;
                }
                logger.debug("new format elem="+this.converter.getPrettyString(new_format));
                if (output.equals("newformat")) {
                    return new_format;
                }
                
                // add extracted GSF statements in to the main stylesheet
                GSXSLT.mergeStylesheets(style_doc, new_format);
                //System.out.println("added extracted GSF statements into the main stylesheet") ;
                
                // add extracted GSF statements in to the debug test stylesheet
                //GSXSLT.mergeStylesheets(oldStyle_doc, new_format);
            } else {
                logger.error(" couldn't parse the config_format stylesheet, adding the format info as is");
                GSXSLT.mergeStylesheets(style_doc, format_elem);
            //  GSXSLT.mergeStylesheets(oldStyle_doc, format_elem);
            }
            logger.debug("the converted stylesheet is:");
            logger.debug(this.converter.getPrettyString(style_doc.getDocumentElement()));
        }
        //for debug purposes only
        Document oldStyle_doc = style_doc;


        Document preprocessingXsl  ;
        try {
            preprocessingXsl = getPreprocessDoc();
            String errMsg = ((XMLConverter.ParseErrorHandler)parser.getErrorHandler()).getErrorMessage();
            if(errMsg != null) {
                return XMLTransformer.constructErrorXHTMLPage("error loading preprocess xslt file: " 
                + preprocess_xsl_filename + "\n" + errMsg);
            } 
        } catch (java.io.FileNotFoundException e) {
            return fileNotFoundErrorPage(e.getMessage());
        } catch (Exception e) {
            e.printStackTrace() ;
            System.out.println("error loading preprocess xslt") ;
            return XMLTransformer.constructErrorXHTMLPage("error loading preprocess xslt\n" + e.getMessage());
        }

        Document libraryXsl = null;
        try {
            libraryXsl = getLibraryDoc() ;
            String errMsg = ((XMLConverter.ParseErrorHandler)parser.getErrorHandler()).getErrorMessage();
            if(errMsg != null) {
                return XMLTransformer.constructErrorXHTMLPage("Error loading xslt file: " 
                + this.getLibraryXSLFilename() + "\n" + errMsg);
            } 
        } catch (java.io.FileNotFoundException e) {
            return fileNotFoundErrorPage(e.getMessage());
        } catch (Exception e) {
            e.printStackTrace() ;
            System.out.println("error loading library xslt") ;
            return constructErrorXHTMLPage("error loading library xslt\n" + e.getMessage()) ;
        }
        
        //   Combine the skin file and library variables/templates into one document. 
        //   Please note: We dont just use xsl:import because the preprocessing stage  
        //   needs to know what's available in the library.

        Document skinAndLibraryXsl = null ;
        Document skinAndLibraryDoc = converter.newDOM();
        try {
            
            skinAndLibraryXsl = converter.newDOM();
            Element root = skinAndLibraryXsl.createElement("skinAndLibraryXsl") ;
            skinAndLibraryXsl.appendChild(root) ;
            
            Element s = skinAndLibraryXsl.createElement("skinXsl") ;
            s.appendChild(skinAndLibraryXsl.importNode(style_doc.getDocumentElement(), true)) ;
            root.appendChild(s) ;
            
            Element l = skinAndLibraryXsl.createElement("libraryXsl") ;
            Element libraryXsl_el = libraryXsl.getDocumentElement();
            l.appendChild(skinAndLibraryXsl.importNode(libraryXsl_el, true)) ;
            root.appendChild(l) ;
            //System.out.println("Skin and Library XSL are now together") ;
            
            
            //System.out.println("Pre-processing the skin file...") ;
            
            //pre-process the skin style sheet
            //In other words, apply the preProcess.xsl to 'skinAndLibraryXsl' in order to
            //expand all GS-Lib statements into complete XSL statements and also to create
            //a valid  xsl style sheet document.

            Transformer preProcessor = transformerFactory.newTransformer(new DOMSource(preprocessingXsl));
            preProcessor.setErrorListener(new XMLTransformer.TransformErrorListener());
            DOMResult result = new DOMResult();
            result.setNode(skinAndLibraryDoc);
            preProcessor.transform(new DOMSource(skinAndLibraryXsl), result);
            System.out.println("GS-Lib statements are now expanded") ;      
            
        }   
        catch (TransformerException e) {
            e.printStackTrace() ;
            System.out.println("TransformerException while preprocessing the skin xslt") ;
            return XMLTransformer.constructErrorXHTMLPage(e.getMessage()) ;
        }
        catch (Exception e) {
            e.printStackTrace() ;
            System.out.println("Error while preprocessing the skin xslt") ;
            return XMLTransformer.constructErrorXHTMLPage(e.getMessage()) ;
        }
    
    // there is a thing called a URIResolver which you can set for a
    // transformer or transformer factory. may be able to use this
    // instead of this absoluteIncludepaths hack

        GSXSLT.absoluteIncludePaths(skinAndLibraryDoc, GlobalProperties.getGSDL3Home(), 
                (String)this.config_params.get(GSConstants.SITE_NAME), 
                collection, (String)this.config_params.get(GSConstants.INTERFACE_NAME), 
                base_interfaces);


        //Same but for the debug version when we want the do the transformation like we use to do
        //without any gslib elements.
        GSXSLT.absoluteIncludePaths(oldStyle_doc, GlobalProperties.getGSDL3Home(), 
                (String)this.config_params.get(GSConstants.SITE_NAME), 
                collection, (String)this.config_params.get(GSConstants.INTERFACE_NAME), 
                base_interfaces);
                
        //Send different stages of the skin xslt to the browser for debug purposes only
        //using &o=skindoc or &o=skinandlib etc...
        if (output.equals("skindoc")) {
            return converter.getDOM(getStringFromDocument(style_doc));
        }
        if (output.equals("skinandlib")) {
            return converter.getDOM(getStringFromDocument(skinAndLibraryXsl));
        }
        if (output.equals("skinandlibdoc")) {
            return converter.getDOM(getStringFromDocument(skinAndLibraryDoc));
        }
        if (output.equals("oldskindoc")) {
            return converter.getDOM(getStringFromDocument(oldStyle_doc));
        }

        // DocType defaults in case the skin doesn't have an "xsl:output" element
        String qualifiedName = "html";
        String publicID = "-//W3C//DTD HTML 4.01 Transitional//EN";
        String systemID = "http://www.w3.org/TR/html4/loose.dtd";
        
        // Try to get the system and public ID from the current skin xsl document
        // otherwise keep the default values.
        Element root = skinAndLibraryDoc.getDocumentElement();
        NodeList nodes = root.getElementsByTagName("xsl:output");
        // If there is at least one "xsl:output" command in the final xsl then...
        if(nodes.getLength() != 0) {
            // There should be only one element called xsl:output, 
            // but if this is not the case get the last one
            Element xsl_output = (Element)nodes.item(nodes.getLength()-1);
            if (xsl_output != null) {
                // Qualified name will always be html even for xhtml pages
                //String attrValue = xsl_output.getAttribute("method");
                //qualifiedName = attrValue.equals("") ? qualifiedName : attrValue;
                
                String attrValue = xsl_output.getAttribute("doctype-system");
                systemID = attrValue.equals("") ? systemID : attrValue;
                
                attrValue = xsl_output.getAttribute("doctype-public");
                publicID = attrValue.equals("") ? publicID : attrValue;
            }
        }
        
        // We need to create an empty document with a predefined DocType,
        // that will then be used for the transformation by the DOMResult
        Document docWithDoctype = converter.newDOM(qualifiedName, publicID, systemID);
        
        //System.out.println(converter.getPrettyString(docWithDoctype));
        //System.out.println("Doctype vals: " + qualifiedName + " " + publicID + " " + systemID) ;
        
        //System.out.println("Generate final HTML from current skin") ;
        //Transformation of the XML message from the receptionist to HTML with doctype
        return this.transformer.transform(skinAndLibraryDoc, doc, config_params, docWithDoctype);
        
        
        // The line below will do the transformation like we use to do before having Skin++ implemented,
        // it will not contain any GS-Lib statements expanded, and the result will not contain any doctype.

        //return (Element)this.transformer.transform(style_doc, doc, config_params);  

    }
    
    
    // method to convert Document to a proper XML string for debug purposes only
    protected String getStringFromDocument(Document doc)
    {
        String content = "";
        try
        {
           DOMSource domSource = new DOMSource(doc);
           StringWriter writer = new StringWriter();
           StreamResult result = new StreamResult(writer);
           TransformerFactory tf = TransformerFactory.newInstance();
           Transformer transformer = tf.newTransformer();
           transformer.transform(domSource, result);
           content = writer.toString();
           System.out.println("Change the & to &Amp; for proper debug dispay") ;
           content = content.replaceAll("&", "&amp;");
           writer.flush();
        }
        catch(TransformerException ex)
        {
           ex.printStackTrace();
           return null;
        }
        return content;
    } 


    protected Document getPreprocessDoc() throws Exception {

        File xslt_file = new File(preprocess_xsl_filename) ;

        FileReader reader = new FileReader(xslt_file);
        InputSource xml_source = new InputSource(reader);
        this.parser.parse(xml_source);
        Document doc = this.parser.getDocument();

        return doc ;        
    }

    protected Document getLibraryDoc() throws Exception {
        Document doc = null;
        File xslt_file = new File(this.getLibraryXSLFilename()) ;

        FileReader reader = new FileReader(xslt_file);
        InputSource xml_source = new InputSource(reader);
        this.parser.parse(xml_source);
        
        doc = this.parser.getDocument();
        return doc ;        
    }   

    protected String getXSLTFileName(String action, String subaction,
                    String collection) {

    String name = null;
    if (!subaction.equals("")) {
        String key = action+":"+subaction;
        name = (String) this.xslt_map.get(key);
    }
    // try the action by itself
    if (name==null) {
        name = (String) this.xslt_map.get(action);
    }
    // now find the absolute path
    String stylesheet = GSFile.stylesheetFile(GlobalProperties.getGSDL3Home(), (String)this.config_params.get(GSConstants.SITE_NAME), collection, (String)this.config_params.get(GSConstants.INTERFACE_NAME), base_interfaces, name);
    if (stylesheet==null) {
        logger.info(" cant find stylesheet for "+name);
    }
    return stylesheet;
    }

    // returns the library.xsl path of the library file that is applicable for the current interface
    protected String getLibraryXSLFilename() {
        return GSFile.xmlTransformDir(GSFile.interfaceHome(
            GlobalProperties.getGSDL3Home(), (String)this.config_params.get(GSConstants.INTERFACE_NAME)))
            + File.separatorChar + "library.xsl";
    }
    
    // Call this when a FileNotFoundException could be thrown when loading an xsl (xml) file.
    // Returns an error xhtml page indicating which xsl (or other xml) file is missing.
    protected Document fileNotFoundErrorPage(String filenameMessage) {
        String errorMessage = "ERROR missing file: " + filenameMessage;
        Element errPage = XMLTransformer.constructErrorXHTMLPage(errorMessage);
        logger.error(errorMessage);
        System.err.println("****" + errorMessage);
        return errPage.getOwnerDocument();
    }
}