//AbstractService.java 
//------------------------
//part of YaCy
//(C) by Michael Peter Christen; mc@anomic.de
//first published on http://www.anomic.de
//Frankfurt, Germany, 2005
//
//this file was contributed by Martin Thelian
//last major change: $LastChangedDate$ by $LastChangedBy$
//Revision: $LastChangedRevision$
//
//This program 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 2 of the License, or
//(at your option) any later version.
//
//This program 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 this program; if not, write to the Free Software
//Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
//Using this software in any meaning (reading, learning, copying, compiling,
//running) means that you agree that the Author(s) is (are) not responsible
//for cost, loss of data or any harm that may be caused directly or indirectly
//by usage of this softare or this documentation. The usage of this software
//is on your own risk. The installation and usage (starting/running) of this
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//the software.
//
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package de.anomic.soap;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.lang.reflect.Method;
import java.util.HashMap;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.apache.axis.AxisFault;
import org.apache.axis.Message;
import org.apache.axis.MessageContext;
import org.apache.axis.message.SOAPEnvelope;
import org.apache.axis.message.SOAPHeaderElement;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

import de.anomic.http.httpHeader;
import de.anomic.http.httpTemplate;
import de.anomic.http.httpd;
import de.anomic.server.serverClassLoader;
import de.anomic.server.serverObjects;
import de.anomic.server.serverSwitch;

public abstract class AbstractService {
    protected String rootPath;
    protected serverClassLoader provider;
    protected HashMap templates;
    protected serverSwitch switchboard;
    protected httpHeader requestHeader;
    protected MessageContext messageContext;
    
    protected static final boolean NO_AUTHENTICATION = false;
    protected static final boolean AUTHENTICATION_NEEDED = true;
    
    
    /**
     * This function is called by the available service functions to
     * extract all needed informations from the SOAP message context.
     * @throws AxisFault 
     */
    protected void extractMessageContext(boolean authenticate) throws AxisFault {        
        this.messageContext = MessageContext.getCurrentContext();
        
        this.rootPath      = (String) this.messageContext.getProperty(httpdSoapHandler.MESSAGE_CONTEXT_HTTP_ROOT_PATH);       
        this.provider      = (serverClassLoader) this.messageContext.getProperty(httpdSoapHandler.MESSAGE_CONTEXT_SERVER_CLASSLOADER);
        this.templates     = (HashMap) this.messageContext.getProperty(httpdSoapHandler.MESSAGE_CONTEXT_TEMPLATES);
        this.switchboard   = (serverSwitch) this.messageContext.getProperty(httpdSoapHandler.MESSAGE_CONTEXT_SERVER_SWITCH);
        this.requestHeader = (httpHeader) this.messageContext.getProperty(httpdSoapHandler.MESSAGE_CONTEXT_HTTP_HEADER);
        
        if (authenticate) {
            String authInfo = this.doAuthentication();
            
            // modify headers
            // This is needed for plasmaSwitchboard.adminAuthenticated to work
            this.requestHeader.put(httpHeader.AUTHORIZATION,"Basic " + authInfo);
            this.requestHeader.put("CLIENTIP","localhost");
            
        }                        
    }
    

    
    /**
     * This function is called by the service functions to
     * invoke the desired server-internal method and to generate
     * a output document using one of the available templates.
     * 
     * @param templateName
     * @param args
     * @return the output document
     * @throws AxisFault
     */
    protected byte[] writeTemplate(String templateName, serverObjects args) throws AxisFault {
        try {
        	// invoke servlet
        	serverObjects tp = invokeServlet(templateName,args);
            
        	// generate output
        	byte[] result = buildServletOutput(templateName, tp);
            return result; 
        } catch (Exception e) {
    		if (e instanceof AxisFault) throw (AxisFault) e;
    		
    		// create a new AxisFault Object
    		throw new AxisFault(e.getMessage());
        }
    }        
    
    protected byte[] buildServletOutput(String templateName, serverObjects tp) throws AxisFault {
            try {
            	File templateFile = getTemplateFile(templateName);
            	
                // generating the output document
                ByteArrayOutputStream o = new ByteArrayOutputStream();
                FileInputStream fis = new FileInputStream(templateFile);
                httpTemplate.writeTemplate(fis, o, tp, "-UNRESOLVED_PATTERN-".getBytes("UTF-8"));
                o.close();
                fis.close();
                
                // convert it into a byte array and send it back as result
                byte[] result = o.toByteArray();            
                return result; 
            } catch (Exception e) {
        		if (e instanceof AxisFault) throw (AxisFault) e;
        		
        		// create a new AxisFault Object
        		throw new AxisFault(e.getMessage());
            }    	
    }
    
    protected serverObjects invokeServlet(String templateName, serverObjects args) throws AxisFault {
    	try {
    		// getting the template class file
    		File rc = getServletClassFile(templateName);
    		
    		// invoke the desired method
    		serverObjects tp = (serverObjects) rewriteMethod(rc).invoke(null, new Object[] {this.requestHeader, args, this.switchboard});
    		
    		// testing if a authentication was needed by the invoked method
    		validateAuthentication(tp);
    		
    		// adding all available templates
    		tp.putAll(this.templates);
    		
    		// return result
    		return tp;
    	} catch (Exception e) {
    		if (e instanceof AxisFault) throw (AxisFault) e;
    		
    		e.printStackTrace();
    		
    		// create a new AxisFault Object
    		throw new AxisFault(e.getMessage());
    	}        
    }
    
    protected File getTemplateFile(String templateName) {
        // determining the proper class that should be invoked
        File file = new File(this.rootPath, templateName);     
        return file;
    }
    
    protected File getServletClassFile(String templateName) {
    	File templateFile = getTemplateFile(templateName);
    	File templateClassFile = getServletClassFile(templateFile);
    	return templateClassFile;
    }
    
    protected File getServletClassFile(File templateFile) {    	 
        File templateClassFile = rewriteClassFile(templateFile);    	
        return templateClassFile;
    }
    
    
    /**
     * This function is used to test if an invoked method requires authentication
     * 
     * @param tp the properties returned by a previous method invocation
     * 
     * @throws AxisFault if an authentication was required.
     */
    protected void validateAuthentication(serverObjects tp) throws AxisFault {
        // check if the servlets requests authentification
        if (tp.containsKey("AUTHENTICATE")) {
            throw new AxisFault("log-in required");
        }             
    }    
    
    /**
     * Doing the user authentication. To improve security, this client
     * accepts the base64 encoded and md5 hashed password directly. 
     * 
     * @throws AxisFault if the authentication could not be done successfully
     */
    protected String doAuthentication() throws AxisFault {
        // accessing the SOAP request message
        Message message = this.messageContext.getRequestMessage();
        
        // getting the contained soap envelope
        SOAPEnvelope envelope = message.getSOAPEnvelope();
        
        // getting the proper soap header containing the authorization field
        SOAPHeaderElement authElement = envelope.getHeaderByName(httpdSoapHandler.serviceHeaderNamespace, "Authorization");
        if (authElement != null) {        
            // the base64 encoded and md5 hashed authentication string 
            String authString = authElement.getValue();
            
            String adminAccountBase64MD5 = this.switchboard.getConfig(httpd.ADMIN_ACCOUNT_B64MD5,"");
            if (authString.length() == 0) {
                throw new AxisFault("log-in required");
            } else if (!(adminAccountBase64MD5.equals(authString))) {
                throw new AxisFault("log-in required");
            }
            return adminAccountBase64MD5;
        }
		throw new AxisFault("log-in required");
    }
    
    /**
     * This method was copied from the {@link httpdFileHandler httpdFileHandler-class}
     * @param template
     * @return the .class-{@link File} belonging to the given template or <code>null</code>
     * if no fitting .class-{@link File} does exist
     */
    protected File rewriteClassFile(File template) {
        try {
            String f = template.getCanonicalPath();
            int p = f.lastIndexOf(".");
            if (p < 0) return null;
            f = f.substring(0, p) + ".class";
            //System.out.println("constructed class path " + f);
            File cf = new File(f);
            if (cf.exists()) return cf;
            return null;
        } catch (IOException e) {
            return null;
        }
    }    
    
    /**
     * This method was copied from the {@link httpdFileHandler httpdFileHandler-class}
     * @param classFile
     * @return the <code>resond({@link httpHeader}, {@link serverObjects}, {@link serverSwitch})</code>
     * {@link Method} of the specified class file or <code>null</code> if this file doesn't contain
     * such a method
     */    
    protected Method rewriteMethod(File classFile) {
        Method m = null;
        // now make a class out of the stream
        try {
            //System.out.println("**DEBUG** loading class file " + classFile);
            Class c = this.provider.loadClass(classFile);
            Class[] params = new Class[] {
                    httpHeader.class,     // Class.forName("de.anomic.http.httpHeader"),
                    serverObjects.class,  // Class.forName("de.anomic.server.serverObjects"),
                    serverSwitch.class }; // Class.forName("de.anomic.server.serverSwitch")};
            m = c.getMethod("respond", params);
        } catch (ClassNotFoundException e) {
            System.out.println("INTERNAL ERROR: class " + classFile + " is missing:" + e.getMessage()); 
        } catch (NoSuchMethodException e) {
            System.out.println("INTERNAL ERROR: method respond not found in class " + classFile + ": " + e.getMessage());
        }
        //System.out.println("found method: " + m.toString());
        return m;
    }        
    
    protected Document convertContentToXML(String contentString) throws Exception {
        return convertContentToXML(contentString.getBytes("UTF-8"));
    }    
    
    protected Document convertContentToXML(byte[] content) throws Exception {
        Document doc = null;
        try {
            DocumentBuilderFactory newDocBuilderFactory = DocumentBuilderFactory.newInstance();
            
//            // disable dtd validation
//            newDocBuilderFactory.setValidating(false);
//            newDocBuilderFactory.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
//            newDocBuilderFactory.setFeature("http://xml.org/sax/features/validation", false);
//            
            DocumentBuilder newDocBuilder = newDocBuilderFactory.newDocumentBuilder();
            
            ByteArrayInputStream byteIn = new ByteArrayInputStream(content);
            doc = newDocBuilder.parse(byteIn);                      
        }  catch (Exception e) {
            String errorMessage = "Unable to parse the search result XML data. " + e.getClass().getName() + ". " + e.getMessage();
            throw new Exception(errorMessage);
        }       
        
        return doc;
    }        
    
    public Document createNewXMLDocument(String rootElementName) throws ParserConfigurationException {
    	// creating a new document builder factory
    	DocumentBuilderFactory newDocBuilderFactory = DocumentBuilderFactory.newInstance();

    	// creating a new document builder
    	DocumentBuilder newDocBuilder = newDocBuilderFactory.newDocumentBuilder();

    	// creating a new xml document
    	Document newXMLDocument = newDocBuilder.newDocument();

    	if (rootElementName != null) {
    		// creating the xml root document
    		Element rootElement = newXMLDocument.createElement(rootElementName);    
    		newXMLDocument.appendChild(rootElement);
    	}

    	return newXMLDocument;
    }

        
}