JsonErrorView.java

/*******************************************************************************
 * Copyright 2017 The MIT Internet Trust Consortium
 *
 * Portions copyright 2011-2013 The MITRE Corporation
 *
 * 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.
 *******************************************************************************/
package org.mitre.openid.connect.view;

import java.io.IOException;
import java.io.Writer;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Component;
import org.springframework.validation.BeanPropertyBindingResult;
import org.springframework.web.servlet.view.AbstractView;

import com.google.common.base.Strings;
import com.google.gson.ExclusionStrategy;
import com.google.gson.FieldAttributes;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonObject;

/**
 * @author aanganes, jricher
 *
 */
@Component(JsonErrorView.VIEWNAME)
public class JsonErrorView extends AbstractView {

    /**
     *
     */
    public static final String ERROR_MESSAGE = "errorMessage";

    /**
     *
     */
    public static final String ERROR = "error";

    /**
     * Logger for this class
     */
    private static final Logger logger = LoggerFactory.getLogger(JsonErrorView.class);

    public static final String VIEWNAME = "jsonErrorView";

    private Gson gson = new GsonBuilder()
            .setExclusionStrategies(new ExclusionStrategy() {

                @Override
                public boolean shouldSkipField(FieldAttributes f) {

                    return false;
                }

                @Override
                public boolean shouldSkipClass(Class<?> clazz) {
                    // skip the JPA binding wrapper
                    if (clazz.equals(BeanPropertyBindingResult.class)) {
                        return true;
                    }
                    return false;
                }

            })
            .serializeNulls()
            .setDateFormat("yyyy-MM-dd'T'HH:mm:ssZ")
            .create();

    @Override
    protected void renderMergedOutputModel(Map<String, Object> model, HttpServletRequest request, HttpServletResponse response) {

        response.setContentType(MediaType.APPLICATION_JSON_VALUE);


        HttpStatus code = (HttpStatus) model.get(HttpCodeView.CODE);
        if (code == null) {
            code = HttpStatus.INTERNAL_SERVER_ERROR; // default to 500
        }

        response.setStatus(code.value());

        try {

            Writer out = response.getWriter();

            String errorTitle = (String) model.get(ERROR);
            if (Strings.isNullOrEmpty(errorTitle)) {
                errorTitle = "mitreid_error";
            }
            String errorMessage = (String) model.get(ERROR_MESSAGE);
            JsonObject obj = new JsonObject();
            obj.addProperty("error", errorTitle);
            obj.addProperty("error_description", errorMessage);
            gson.toJson(obj, out);

        } catch (IOException e) {

            logger.error("IOException in JsonErrorView.java: ", e);

        }
    }

}