001/*
002 * Copyright 2012-2018 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.boot.autoconfigure.web.servlet.error;
018
019import java.util.ArrayList;
020import java.util.List;
021import java.util.Map;
022
023import javax.servlet.http.HttpServletRequest;
024import javax.servlet.http.HttpServletResponse;
025
026import org.springframework.boot.web.servlet.error.ErrorAttributes;
027import org.springframework.boot.web.servlet.error.ErrorController;
028import org.springframework.core.annotation.AnnotationAwareOrderComparator;
029import org.springframework.http.HttpStatus;
030import org.springframework.stereotype.Controller;
031import org.springframework.util.Assert;
032import org.springframework.web.context.request.ServletWebRequest;
033import org.springframework.web.context.request.WebRequest;
034import org.springframework.web.servlet.ModelAndView;
035
036/**
037 * Abstract base class for error {@link Controller} implementations.
038 *
039 * @author Dave Syer
040 * @author Phillip Webb
041 * @since 1.3.0
042 * @see ErrorAttributes
043 */
044public abstract class AbstractErrorController implements ErrorController {
045
046        private final ErrorAttributes errorAttributes;
047
048        private final List<ErrorViewResolver> errorViewResolvers;
049
050        public AbstractErrorController(ErrorAttributes errorAttributes) {
051                this(errorAttributes, null);
052        }
053
054        public AbstractErrorController(ErrorAttributes errorAttributes,
055                        List<ErrorViewResolver> errorViewResolvers) {
056                Assert.notNull(errorAttributes, "ErrorAttributes must not be null");
057                this.errorAttributes = errorAttributes;
058                this.errorViewResolvers = sortErrorViewResolvers(errorViewResolvers);
059        }
060
061        private List<ErrorViewResolver> sortErrorViewResolvers(
062                        List<ErrorViewResolver> resolvers) {
063                List<ErrorViewResolver> sorted = new ArrayList<>();
064                if (resolvers != null) {
065                        sorted.addAll(resolvers);
066                        AnnotationAwareOrderComparator.sortIfNecessary(sorted);
067                }
068                return sorted;
069        }
070
071        protected Map<String, Object> getErrorAttributes(HttpServletRequest request,
072                        boolean includeStackTrace) {
073                WebRequest webRequest = new ServletWebRequest(request);
074                return this.errorAttributes.getErrorAttributes(webRequest, includeStackTrace);
075        }
076
077        protected boolean getTraceParameter(HttpServletRequest request) {
078                String parameter = request.getParameter("trace");
079                if (parameter == null) {
080                        return false;
081                }
082                return !"false".equalsIgnoreCase(parameter);
083        }
084
085        protected HttpStatus getStatus(HttpServletRequest request) {
086                Integer statusCode = (Integer) request
087                                .getAttribute("javax.servlet.error.status_code");
088                if (statusCode == null) {
089                        return HttpStatus.INTERNAL_SERVER_ERROR;
090                }
091                try {
092                        return HttpStatus.valueOf(statusCode);
093                }
094                catch (Exception ex) {
095                        return HttpStatus.INTERNAL_SERVER_ERROR;
096                }
097        }
098
099        /**
100         * Resolve any specific error views. By default this method delegates to
101         * {@link ErrorViewResolver ErrorViewResolvers}.
102         * @param request the request
103         * @param response the response
104         * @param status the HTTP status
105         * @param model the suggested model
106         * @return a specific {@link ModelAndView} or {@code null} if the default should be
107         * used
108         * @since 1.4.0
109         */
110        protected ModelAndView resolveErrorView(HttpServletRequest request,
111                        HttpServletResponse response, HttpStatus status, Map<String, Object> model) {
112                for (ErrorViewResolver resolver : this.errorViewResolvers) {
113                        ModelAndView modelAndView = resolver.resolveErrorView(request, status, model);
114                        if (modelAndView != null) {
115                                return modelAndView;
116                        }
117                }
118                return null;
119        }
120
121}