1+ /*
2+ * Copyright 2002-2016 the original author or authors.
3+ *
4+ * Licensed under the Apache License, Version 2.0 (the "License");
5+ * you may not use this file except in compliance with the License.
6+ * You may obtain a copy of the License at
7+ *
8+ * http://www.apache.org/licenses/LICENSE-2.0
9+ *
10+ * Unless required by applicable law or agreed to in writing, software
11+ * distributed under the License is distributed on an "AS IS" BASIS,
12+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13+ * See the License for the specific language governing permissions and
14+ * limitations under the License.
15+ */
16+ package org .springframework .web .servlet .support ;
17+
18+ import java .io .IOException ;
19+ import java .util .ArrayList ;
20+ import java .util .List ;
21+ import java .util .Map ;
22+ import java .util .Properties ;
23+ import javax .servlet .http .HttpServletRequest ;
24+ import javax .servlet .http .HttpServletRequestWrapper ;
25+
26+ import org .springframework .beans .factory .BeanFactoryUtils ;
27+ import org .springframework .context .ApplicationContext ;
28+ import org .springframework .core .annotation .AnnotationAwareOrderComparator ;
29+ import org .springframework .core .io .ClassPathResource ;
30+ import org .springframework .core .io .Resource ;
31+ import org .springframework .core .io .support .PropertiesLoaderUtils ;
32+ import org .springframework .util .ClassUtils ;
33+ import org .springframework .util .StringUtils ;
34+ import org .springframework .web .cors .CorsConfiguration ;
35+ import org .springframework .web .cors .CorsConfigurationSource ;
36+ import org .springframework .web .servlet .DispatcherServlet ;
37+ import org .springframework .web .servlet .HandlerExecutionChain ;
38+ import org .springframework .web .servlet .HandlerInterceptor ;
39+ import org .springframework .web .servlet .HandlerMapping ;
40+
41+ /**
42+ * Helper class to get information from the {@code HandlerMapping} that would
43+ * serve a specific request.
44+ *
45+ * <p>Provides the following methods:
46+ * <ul>
47+ * <li>{@link #getMatchableHandlerMapping} -- obtain a {@code HandlerMapping}
48+ * to check request-matching criteria against.
49+ * <li>{@link #getCorsConfiguration} -- obtain the CORS configuration for the
50+ * request.
51+ * </ul>
52+ *
53+ * @author Rossen Stoyanchev
54+ * @since 4.3
55+ */
56+ public class HandlerMappingIntrospector implements CorsConfigurationSource {
57+
58+ private final List <HandlerMapping > handlerMappings ;
59+
60+
61+ /**
62+ * Constructor that detects the configured {@code HandlerMapping}s in the
63+ * given {@code ApplicationContext} or falling back on
64+ * "DispatcherServlet.properties" like the {@code DispatcherServlet}.
65+ */
66+ public HandlerMappingIntrospector (ApplicationContext context ) {
67+ this .handlerMappings = initHandlerMappings (context );
68+ }
69+
70+
71+ private static List <HandlerMapping > initHandlerMappings (ApplicationContext context ) {
72+
73+ Map <String , HandlerMapping > beans = BeanFactoryUtils .beansOfTypeIncludingAncestors (
74+ context , HandlerMapping .class , true , false );
75+
76+ if (!beans .isEmpty ()) {
77+ List <HandlerMapping > mappings = new ArrayList <HandlerMapping >(beans .values ());
78+ AnnotationAwareOrderComparator .sort (mappings );
79+ return mappings ;
80+ }
81+
82+ return initDefaultHandlerMappings (context );
83+ }
84+
85+ private static List <HandlerMapping > initDefaultHandlerMappings (ApplicationContext context ) {
86+ Properties props ;
87+ String path = "DispatcherServlet.properties" ;
88+ try {
89+ Resource resource = new ClassPathResource (path , DispatcherServlet .class );
90+ props = PropertiesLoaderUtils .loadProperties (resource );
91+ }
92+ catch (IOException ex ) {
93+ throw new IllegalStateException ("Could not load '" + path + "': " + ex .getMessage ());
94+ }
95+
96+ String value = props .getProperty (HandlerMapping .class .getName ());
97+ String [] names = StringUtils .commaDelimitedListToStringArray (value );
98+ List <HandlerMapping > result = new ArrayList <HandlerMapping >(names .length );
99+ for (String name : names ) {
100+ try {
101+ Class <?> clazz = ClassUtils .forName (name , DispatcherServlet .class .getClassLoader ());
102+ Object mapping = context .getAutowireCapableBeanFactory ().createBean (clazz );
103+ result .add ((HandlerMapping ) mapping );
104+ }
105+ catch (ClassNotFoundException ex ) {
106+ throw new IllegalStateException ("Could not find default HandlerMapping [" + name + "]" );
107+ }
108+ }
109+ return result ;
110+ }
111+
112+
113+ /**
114+ * Return the configured HandlerMapping's.
115+ */
116+ public List <HandlerMapping > getHandlerMappings () {
117+ return this .handlerMappings ;
118+ }
119+
120+
121+ /**
122+ * Find the {@link HandlerMapping} that would handle the given request and
123+ * return it as a {@link MatchableHandlerMapping} that can be used to
124+ * test request-matching criteria. If the matching HandlerMapping is not an
125+ * instance of {@link MatchableHandlerMapping}, an IllegalStateException is
126+ * raised.
127+ *
128+ * @param request the current request
129+ * @return the resolved matcher, or {@code null}
130+ * @throws Exception if any of the HandlerMapping's raise an exception
131+ */
132+ public MatchableHandlerMapping getMatchableHandlerMapping (HttpServletRequest request ) throws Exception {
133+ HttpServletRequest wrapper = new RequestAttributeChangeIgnoringWrapper (request );
134+ for (HandlerMapping handlerMapping : this .handlerMappings ) {
135+ Object handler = handlerMapping .getHandler (wrapper );
136+ if (handler == null ) {
137+ continue ;
138+ }
139+ if (handlerMapping instanceof MatchableHandlerMapping ) {
140+ return ((MatchableHandlerMapping ) handlerMapping );
141+ }
142+ throw new IllegalStateException ("HandlerMapping is not a MatchableHandlerMapping" );
143+ }
144+ return null ;
145+ }
146+
147+ @ Override
148+ public CorsConfiguration getCorsConfiguration (HttpServletRequest request ) {
149+ HttpServletRequest wrapper = new RequestAttributeChangeIgnoringWrapper (request );
150+ for (HandlerMapping handlerMapping : this .handlerMappings ) {
151+ HandlerExecutionChain handler = null ;
152+ try {
153+ handler = handlerMapping .getHandler (wrapper );
154+ }
155+ catch (Exception ex ) {
156+ // Ignore
157+ }
158+ if (handler == null ) {
159+ continue ;
160+ }
161+ if (handler .getInterceptors () != null ) {
162+ for (HandlerInterceptor interceptor : handler .getInterceptors ()) {
163+ if (interceptor instanceof CorsConfigurationSource ) {
164+ return ((CorsConfigurationSource ) interceptor ).getCorsConfiguration (wrapper );
165+ }
166+ }
167+ }
168+ if (handler .getHandler () instanceof CorsConfigurationSource ) {
169+ return ((CorsConfigurationSource ) handler .getHandler ()).getCorsConfiguration (wrapper );
170+ }
171+ }
172+ return null ;
173+ }
174+
175+
176+ /**
177+ * Request wrapper that ignores request attribute changes.
178+ */
179+ private static class RequestAttributeChangeIgnoringWrapper extends HttpServletRequestWrapper {
180+
181+
182+ private RequestAttributeChangeIgnoringWrapper (HttpServletRequest request ) {
183+ super (request );
184+ }
185+
186+ @ Override
187+ public void setAttribute (String name , Object value ) {
188+ // Ignore attribute change
189+ }
190+ }
191+
192+ }
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