java.fedora.server.access.MethodParameterResolverServlet Maven / Gradle / Ivy

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The Fedora Client is a Java Library that allows API access to a Fedora Repository. The client is typically one part of a full Fedora installation.
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/*
 * -----------------------------------------------------------------------------
 *
 * License and Copyright: The contents of this file are subject to the
 * Apache License, Version 2.0 (the "License"); you may not use 
 * this file except in compliance with the License. You may obtain a copy of 
 * the License at 
 * http://www.fedora-commons.org/licenses.
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
 * the specific language governing rights and limitations under the License.
 *
 * The entire file consists of original code.
 * Copyright © 2008 Fedora Commons, Inc.

 * 
Copyright © 2002-2007 The Rector and Visitors of the University of 
 * Virginia and Cornell University
 
 * All rights reserved.
 *
 * -----------------------------------------------------------------------------
 */
package fedora.server.access;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.IOException;
import java.net.URLEncoder;
import java.util.Enumeration;
import java.util.Hashtable;

import org.apache.log4j.Logger;

import fedora.common.Constants;
import fedora.server.Server;
import fedora.server.errors.InitializationException;

/**
 * 
 * Title: MethodParameterResolverServlet.java
 * 
 * 
 * 
 * Description: This servlet accepts the result of a posted web form
 * containing information about which method parameter values were selected for
 * a dissemination request. The information is read from the form and translated
 * into the corresponding API-A-LITE interface dissemination request in the form
 * of a URI. The initial request is then redirected to the API-A-LITE interface
 * to execute the dissemination request.
 * 
 * 
 * @author [email protected]
 * @version $Id: MethodParameterResolverServlet.java,v 1.15 2006/09/06 20:06:00
 *          cwilper Exp $
 */
public class MethodParameterResolverServlet extends HttpServlet {

    /** Logger for this class. */
    private static final Logger LOG = Logger.getLogger(
            MethodParameterResolverServlet.class.getName());

	private static final long serialVersionUID = 1L;

	/** A string constant for the html MIME type */
	private static final String HTML_CONTENT_TYPE = "text/html; charset=UTF-8";

	/** The Fedora API-A-Lite servlet path. */
	private static final String API_A_LITE_SERVLET_PATH = "/fedora/get/";

	/** An instance of the Fedora server. */
	private static Server s_server = null;

	public void init() throws ServletException {
		try {
			s_server = Server.getInstance(new File(Constants.FEDORA_HOME),
                    false);
		} catch (InitializationException ie) {
			throw new ServletException(
					"Unable to get Fedora Server instance. -- "
							+ ie.getMessage());
		}
	}

	/**
	 * 
	 * Treat Get request identical to Post request.
	 * 
	 * 
	 * @param request
	 *            The servlet request.
	 * @param response
	 *            The servlet response.
	 * @throws ServletException
	 *             If an error occurs that affects the servlet's basic
	 *             operation.
	 * @throws IOException
	 *             If an error occurs within an input or output operation.
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doPost(request, response);
	}

	/**
	 * 
	 * Process Post request from web form.
	 * 
	 * 
	 * @param request
	 *            The servlet request.
	 * @param response
	 *            The servlet response.
	 * @throws ServletException
	 *             If an error occurs that affects the servlet's basic
	 *             operation.
	 * @throws IOException
	 *             If an error occurs within an input or output operation.
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		String PID = null;
		String bDefPID = null;
		String methodName = null;
		String versDateTime = null;
		StringBuffer methodParms = new StringBuffer();
		response.setContentType(HTML_CONTENT_TYPE);
		Hashtable h_methodParms = new Hashtable();

		// Get parameters passed from web form.
		Enumeration parms = request.getParameterNames();
		while (parms.hasMoreElements()) {
			String name = new String((String) parms.nextElement());
			if (name.equals("PID")) {
				PID = request.getParameter(name);
			} else if (name.equals("bDefPID")) {
				bDefPID = request.getParameter(name);
			} else if (name.equals("methodName")) {
				methodName = request.getParameter(name);
			} else if (name.equals("asOfDateTime")) {
				versDateTime = request.getParameter(name).trim();
				if (versDateTime.equalsIgnoreCase("null")
						|| versDateTime.equalsIgnoreCase("")) {
					versDateTime = null;
				}
			} else if (name.equals("Submit")) {
				// Submit parameter is ignored.
			} else {
				// Any remaining parameters are assumed to be method parameters
				// so
				// decode and place in hashtable.
				h_methodParms.put(name, request.getParameter(name));
			}
		}

		// Check that all required parameters are present.
		if ((PID == null || PID.equalsIgnoreCase(""))
				|| (bDefPID == null || bDefPID.equalsIgnoreCase(""))
				|| (methodName == null || methodName.equalsIgnoreCase(""))) {
			String message = "[MethodParameterResolverServlet] Insufficient "
					+ "information to construct dissemination request. Parameters "
					+ "received from web form were: PID: " + PID
					+ " -- bDefPID: " + bDefPID + " -- methodName: "
					+ methodName + " -- methodParms: " + methodParms.toString()
					+ "\".  ";
            LOG.error(message);
			response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
			response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
					message);
		} else {
			// Translate web form parameters into dissemination request.
			StringBuffer redirectURL = new StringBuffer();
			redirectURL.append(API_A_LITE_SERVLET_PATH + PID + "/" + bDefPID
					+ "/" + methodName);

			// Add method parameters.
			int i = 0;
			for (Enumeration e = h_methodParms.keys(); e.hasMoreElements();) {
				String name = URLEncoder.encode((String) e.nextElement(),
						"UTF-8");
				String value = URLEncoder.encode((String) h_methodParms
						.get(name), "UTF-8");
				i++;
				if (i == h_methodParms.size()) {
					methodParms.append(name + "=" + value);
				} else {
					methodParms.append(name + "=" + value + "&");
				}

			}
			if (h_methodParms.size() > 0) {
				if (versDateTime == null || versDateTime.equalsIgnoreCase("")) {
					redirectURL.append("?" + methodParms.toString());

				} else {
					redirectURL.append("/" + versDateTime + "?"
							+ methodParms.toString());
				}
			} else {
				if (versDateTime == null || versDateTime.equalsIgnoreCase("")) {
					redirectURL.append("/");
				} else {
					redirectURL.append("/" + versDateTime + "/");
				}
			}

			// Redirect request back to FedoraAccessServlet.
			response.sendRedirect(redirectURL.toString());
		}
	}

	// Clean up resources
	public void destroy() {
	}

}