path: root/projects/net.wotonomy.web/src/main/java/net/wotonomy/web/xml/XMLRPCServlet.java

/*
Wotonomy: OpenStep design patterns for pure Java applications.
Copyright (C) 2001 Intersect Software Corporation

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library 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
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, see http://www.gnu.org
*/

package net.wotonomy.web.xml;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Hashtable;

import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import net.wotonomy.foundation.NSSelector;
import net.wotonomy.foundation.internal.WotonomyException;

/**
 * A servlet that can make any java object into an XML-RPC server. Simply pass
 * in the object to the constructor and XML-RPC requests to this servlet will
 * call the appropriate methods and convert the results to an XML-RPC response.
 * <br>
 * <br>
 *
 * Depending on your servlet container, it may be necessary to create a simple
 * subclass that creates your handler object in its constructor and then calls
 * setHandler(). <br>
 * <br>
 *
 * Responses are in the specification's standard response format.<br>
 * <br>
 *
 * Faults are returned if any exception is thrown in the method, or if the
 * specified method is not found on the object. The fault string is the toString
 * value of the exception, and the fault code is the hasCode value of the
 * exception. <br>
 * <br>
 *
 * Remember that this servlet only responds to POSTs, per the XML-RPC spec.
 */
public class XMLRPCServlet extends HttpServlet {
	protected Object handler;
	protected boolean synchronizing;
	private Hashtable selectorCache = new Hashtable(); // thread safe
	private boolean copyStream = false;

	/**
	 * Default constructor initializes internal state.
	 */
	public XMLRPCServlet() {
		handler = null;
		synchronizing = false;
	}

	/**
	 * Constructor takes any java object and allows its methods to be invoked via
	 * XMLRPC requests to this servlet. Simply calls setHandler().
	 */
	public XMLRPCServlet(Object aHandler) {
		this();
		setHandler(aHandler);
	}

	/**
	 * Gets the object whose methods will be invoked to handle incoming requests.
	 */
	public Object getHandler() {
		return handler;
	}

	/**
	 * Sets the object whose methods will be invoked to handle incoming requests.
	 */
	public void setHandler(Object aHandler) {
		handler = aHandler;
	}

	/**
	 * Gets whether the servlet should synchonize on the object before invoking
	 * methods on it. Defaults to false.
	 */
	public boolean isSynchronizing() {
		return synchronizing;
	}

	/**
	 * Sets whether the servlet should synchonize on the object before invoking
	 * methods on it. Defaults to false.
	 */
	public void setSynchronizing(boolean willSynchronize) {
		synchronizing = willSynchronize;
	}

	/**
	 * Overridden to service the request.
	 */
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		if (getHandler() != null) {
			InputStream input = req.getInputStream();
			byte[] copyOfRequest = null;

			if (copyStream) {
				ByteArrayOutputStream byteArray = new ByteArrayOutputStream();
				int b;
				while ((b = input.read()) != -1) {
					byteArray.write(b);
				}
				copyOfRequest = byteArray.toByteArray();
				input = new ByteArrayInputStream(copyOfRequest);
			}

			try {
				new XMLRPCDecoder().decode(input, new Receiver(this, resp));
			} catch (WotonomyException exc) {
				if (copyOfRequest != null) {
					System.out.println(new String(copyOfRequest));
					exc.printStackTrace();
				}
				// catches io exceptions thrown in handleRequest.
				Throwable t = exc.getWrappedThrowable();
				if (t instanceof IOException) {
					throw (IOException) t;
				}
				throw exc;
			}
		}
	}

	/**
	 * Called by doPost after parsing an incoming request, and is responsible for
	 * invoking the specified method with the specified parameters on the handler
	 * object. (This implementation calls getOutputStream() on the response.)
	 * Override to customize the handling of the request.
	 */
	protected void handleRequest(String aMethodName, Object[] aParameterArray, HttpServletResponse aResponse) {
		OutputStream output = null;

		try {
			output = aResponse.getOutputStream();
			aResponse.setStatus(HttpServletResponse.SC_OK); // always 200
			aResponse.setContentType("text/xml");
		} catch (IOException exc) {
			// caught in doPost
			throw new WotonomyException(exc);
		}

		// get the array of types
		XMLRPCEncoder encoder = new XMLRPCEncoder();
		Class[] types = new Class[aParameterArray.length];
		for (int i = 0; i < aParameterArray.length; i++) {
			types[i] = aParameterArray[i].getClass();
		}

		// TODO: selectors should be cached if possible

		Object handler = getHandler();
		if (isSynchronizing()) {
			synchronized (handler) {
				execute(encoder, handler, output, new NSSelector(aMethodName, types), aParameterArray);
			}
		} else {
			execute(encoder, handler, output, new NSSelector(aMethodName, types), aParameterArray);
		}
	}

	private void execute(XMLRPCEncoder anEncoder, Object aHandler, OutputStream output, NSSelector aSelector,
			Object[] aParameterArray) {
		try {
			Object result = aSelector.invoke(aHandler, aParameterArray);
			anEncoder.encodeResponse(result, output);
		} catch (Exception exc) {
			anEncoder.encodeFault(exc.hashCode(), exc.toString(), output);
		}
	}

	private class Receiver implements XMLRPCReceiver {
		XMLRPCServlet controller;
		HttpServletResponse response;

		public Receiver(XMLRPCServlet aController, HttpServletResponse aResponse) {
			controller = aController;
			response = aResponse;
		}

		public void request(String aMethodName, Object[] aParameterArray) {
			controller.handleRequest(aMethodName, aParameterArray, response);
		}

		public void response(Object aResult) {
			// does nothing
		}

		public void fault(int aFaultCode, String aFaultString) {
			// does nothing
		}
	}
}

/*
 * $Log$ Revision 1.1 2006/02/19 01:44:02 cgruber Add xmlrpc files Remove jclark
 * and replace with dom4j and javax.xml.sax stuff Re-work dependencies and
 * imports so it all compiles.
 *
 * Revision 1.1 2006/02/16 13:22:22 cgruber Check in all sources in
 * eclipse-friendly maven-enabled packages.
 *
 * Revision 1.1 2001/02/07 19:24:28 mpowers Moved XML classes to separate
 * package.
 *
 */