CommonStatusService.java

package com.sixsq.slipstream.application;

/*
 * +=================================================================+
 * SlipStream Server (WAR)
 * =====
 * Copyright (C) 2013 SixSq Sarl (sixsq.com)
 * =====
 * Licensed under 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.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * -=================================================================-
 */

import static org.restlet.data.MediaType.APPLICATION_JSON;
import static org.restlet.data.MediaType.APPLICATION_XHTML;
import static org.restlet.data.MediaType.APPLICATION_XML;
import static org.restlet.data.MediaType.TEXT_HTML;
import static org.restlet.data.MediaType.TEXT_PLAIN;

import java.util.List;

import org.restlet.Request;
import org.restlet.Response;
import org.restlet.data.ClientInfo;
import org.restlet.data.Cookie;
import org.restlet.data.MediaType;
import org.restlet.data.Preference;
import org.restlet.data.Status;
import org.restlet.representation.Representation;
import org.restlet.representation.StringRepresentation;
import org.restlet.security.Verifier;
import org.restlet.service.StatusService;
import org.simpleframework.xml.Attribute;
import org.simpleframework.xml.Root;
import org.simpleframework.xml.Text;
import org.w3c.dom.Document;

import com.sixsq.slipstream.configuration.Configuration;
import com.sixsq.slipstream.cookie.CookieUtils;
import com.sixsq.slipstream.exceptions.ConfigurationException;
import com.sixsq.slipstream.exceptions.Util;
import com.sixsq.slipstream.exceptions.ValidationException;
import com.sixsq.slipstream.persistence.ServiceConfiguration;
import com.sixsq.slipstream.persistence.ServiceConfigurationParameter;
import com.sixsq.slipstream.persistence.User;
import com.sixsq.slipstream.util.HtmlUtil;
import com.sixsq.slipstream.util.ResourceUriUtil;
import com.sixsq.slipstream.util.SerializationUtil;
import com.sixsq.slipstream.util.XmlUtil;

public class CommonStatusService extends StatusService {

	@Root(name="error")
	private static class ErrorElement {
		@Attribute
		private int code;
		@Attribute
		private String reason;
		@Attribute
		private String detail;
		@Attribute
		private String specificationUri;
		@Text
		private String text;

		public ErrorElement(Status status) {
			this(status.getCode(), status.getReasonPhrase(), status.getDescription(), status.getUri(),
					status.getDescription());
		}

		public ErrorElement(int code, String reason, String detail, String specificationUri, String text) {
			this.code = code;
			this.reason = reason;
			this.detail = detail;
			this.specificationUri = specificationUri;
			this.text = "\n" + text + "\n";
		}
    }

	@Override
	public Representation getRepresentation(Status status, Request request, Response response) {

		try {
			reloadParameters();
		} catch (ConfigurationException e) {
			Util.throwConfigurationException(e);
		} catch (ValidationException e) {
			Util.throwClientValidationError(e.getMessage());
		}

		Representation representation = null;

		User user = null;
		Cookie cookie = CookieUtils.extractAuthnCookie(request);
		if (CookieUtils.verifyAuthnCookie(cookie) == Verifier.RESULT_VALID) {
			String username = CookieUtils.getCookieUsername(cookie);
			try {
				user = User.loadByName(username);
			} catch (Exception e) {
				e.printStackTrace();
			}
		}

		String baseUrlSlash = ResourceUriUtil.getBaseUrlSlash(request);

		ClientInfo clientInfo = request.getClientInfo();
		List<Preference<MediaType>> mediaTypes = clientInfo.getAcceptedMediaTypes();

		for (Preference<MediaType> preference : mediaTypes) {

			MediaType desiredMediaType = preference.getMetadata();

			if (TEXT_HTML.isCompatible(desiredMediaType)) {
				return toXhtml(status, request, response, user, baseUrlSlash);

			} else if (APPLICATION_XHTML.isCompatible(desiredMediaType)) {
				return toXhtml(status, request, response, user, baseUrlSlash);

			} else if (APPLICATION_JSON.isCompatible(desiredMediaType)) {
				return toJson(status);

			} else if (TEXT_PLAIN.isCompatible(desiredMediaType)) {
				return toTxt(status);

			} else if (APPLICATION_XML.isCompatible(desiredMediaType)) {
				return toXml(status);
			}
		}

		return representation;
	}

	private Representation toXhtml(Status status, Request request, Response response, User user, String baseUrlSlash) {

		String metadata = "";

		if (user != null) {
			Document doc = SerializationUtil.toXmlDocument(user);
			XmlUtil.addUser(doc, user);
			metadata = SerializationUtil.documentToString(doc);
		}

		return new StringRepresentation(HtmlUtil.toHtmlError(metadata, status.getDescription(), status.getCode(),
				request), MediaType.TEXT_HTML);
	}

	private Representation toJson(Status status) {

		StringBuilder json = new StringBuilder();

		json.append("{\n");
		json.append("    \"error\": {\n");
		json.append("        \"code\": \"" + status.getCode() + "\"");

		if (status.getReasonPhrase() != null)
			json.append(",\n        \"reason\": \"" + status.getReasonPhrase() + "\"");

		if (status.getDescription() != null)
			json.append(",\n        \"detail\": \"" + status.getDescription() + "\"");

		if (status.getUri() != null)
			json.append(",\n        \"specificationUri\": \"" + status.getUri() + "\"");

		json.append("\n    }\n");
		json.append("}");

		Representation representation = new StringRepresentation(json.toString());
		representation.setMediaType(APPLICATION_JSON);

		return representation;
	}

	private Representation toTxt(Status status) {
		StringBuilder txt = new StringBuilder();
		txt.append(status.getCode());

		if (status.getReasonPhrase() != null)
			txt.append(" - " + status.getReasonPhrase());

		if (status.getDescription() != null)
			txt.append("\n" + status.getDescription());

		Representation representation;
		representation = new StringRepresentation(txt.toString());
		representation.setMediaType(TEXT_PLAIN);
		return representation;
	}

	private Representation toXml(Status status) {
		String xml = SerializationUtil.toXmlString(new ErrorElement(status));
		Representation representation = new StringRepresentation(xml);
		representation.setMediaType(APPLICATION_XML);
		return representation;
	}

	private void reloadParameters() throws ConfigurationException, ValidationException {
		Configuration configuration = Configuration.getInstance();

		String key = ServiceConfiguration.RequiredParameters.SLIPSTREAM_SUPPORT_EMAIL.getName();
		ServiceConfigurationParameter parameter = configuration.getParameters().getParameter(key);
		String email = parameter.getValue();

		setContactEmail(email);
	}

}