Revise charset by location support for static resources

Author: rstoyanchev

spring-webmvc/src/main/java/org/springframework/web/servlet/config/MvcNamespaceUtils.java

@@ -16,19 +16,14 @@
 
 package org.springframework.web.servlet.config;
 
-import java.nio.charset.Charset;
 import java.util.LinkedHashMap;
-import java.util.List;
 import java.util.Map;
 
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.config.RuntimeBeanReference;
 import org.springframework.beans.factory.parsing.BeanComponentDefinition;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.beans.factory.xml.ParserContext;
-import org.springframework.core.io.Resource;
-import org.springframework.core.io.ResourceLoader;
-import org.springframework.core.io.UrlResource;
 import org.springframework.util.AntPathMatcher;
 import org.springframework.util.PathMatcher;
 import org.springframework.web.cors.CorsConfiguration;
@@ -64,8 +59,6 @@ public abstract class MvcNamespaceUtils {
 
 	private static final String HANDLER_MAPPING_INTROSPECTOR_BEAN_NAME = "mvcHandlerMappingIntrospector";
 
-	private static final String URL_RESOURCE_CHARSET_PREFIX = "[charset=";
-
 
 	public static void registerDefaultComponents(ParserContext parserContext, Object source) {
 		registerBeanNameUrlHandlerMapping(parserContext, source);
@@ -228,40 +221,4 @@ public static Object getContentNegotiationManager(ParserContext context) {
 		return null;
 	}
 
-	/**
-	 * Load the {@link Resource}'s for the given locations with the given
-	 * {@link ResourceLoader} and add them to the output list. Also for
-	 * {@link org.springframework.core.io.UrlResource URL-based resources} (e.g. files,
-	 * HTTP URLs, etc) this method supports a special prefix to indicate the charset
-	 * associated with the URL so that relative paths appended to it can be encoded
-	 * correctly, e.g. {@code [charset=Windows-31J]http://example.org/path}.
-	 * The charsets, if any, are added to the output map.
-	 * @since 4.3.13
-	 */
-	public static void loadResourceLocations(String[] locations, ResourceLoader resourceLoader,
-			List<Resource> outputLocations, Map<Resource, Charset> outputLocationCharsets) {
-
-		for (String location : locations) {
-			Charset charset = null;
-			location = location.trim();
-			if (location.startsWith(URL_RESOURCE_CHARSET_PREFIX)) {
-				int endIndex = location.indexOf("]", URL_RESOURCE_CHARSET_PREFIX.length());
-				if (endIndex == -1) {
-					throw new IllegalArgumentException("Invalid charset syntax in location: " + location);
-				}
-				String value = location.substring(URL_RESOURCE_CHARSET_PREFIX.length(), endIndex);
-				charset = Charset.forName(value);
-				location = location.substring(endIndex + 1);
-			}
-			Resource resource = resourceLoader.getResource(location);
-			outputLocations.add(resource);
-			if (charset != null) {
-				if (!(resource instanceof UrlResource)) {
-					throw new IllegalArgumentException("Unexpected charset for non-UrlResource: " + resource);
-				}
-				outputLocationCharsets.put(resource, charset);
-			}
-		}
-	}
-
 }

spring-webmvc/src/main/java/org/springframework/web/servlet/config/ResourcesBeanDefinitionParser.java

@@ -16,19 +16,13 @@
 
 package org.springframework.web.servlet.config;
 
-import java.nio.charset.Charset;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 
 import org.w3c.dom.Element;
 
 import org.springframework.beans.MutablePropertyValues;
 import org.springframework.beans.factory.config.BeanDefinition;
-import org.springframework.beans.factory.config.ConfigurableBeanFactory;
 import org.springframework.beans.factory.config.ConstructorArgumentValues;
 import org.springframework.beans.factory.config.RuntimeBeanReference;
 import org.springframework.beans.factory.parsing.BeanComponentDefinition;
@@ -39,8 +33,6 @@
 import org.springframework.beans.factory.xml.ParserContext;
 import org.springframework.cache.concurrent.ConcurrentMapCache;
 import org.springframework.core.Ordered;
-import org.springframework.core.io.Resource;
-import org.springframework.core.io.ResourceLoader;
 import org.springframework.http.CacheControl;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.StringUtils;
@@ -170,35 +162,13 @@ private String registerResourceHandler(
 			return null;
 		}
 
-		String[] locationValues = StringUtils.commaDelimitedListToStringArray(locationAttr);
-		if (context.getRegistry() instanceof ConfigurableBeanFactory) {
-			ConfigurableBeanFactory cbf = ((ConfigurableBeanFactory) context.getRegistry());
-			for (int i = 0; i < locationValues.length; i++) {
-				locationValues[i] = cbf.resolveEmbeddedValue(locationValues[i]);
-			}
-		}
-
-		ManagedList<Object> locations = new ManagedList<Object>();
-		Map<Resource, Charset> locationCharsets = new HashMap<Resource, Charset>();
-		ResourceLoader resourceLoader = context.getReaderContext().getResourceLoader();
-
-		if (resourceLoader != null) {
-			List<Resource> resources = new ArrayList<Resource>();
-			MvcNamespaceUtils.loadResourceLocations(locationValues, resourceLoader, resources, locationCharsets);
-			locations.addAll(resources);
-		}
-		else {
-			locations.addAll(Arrays.asList(locationValues));
-		}
-
 		RootBeanDefinition resourceHandlerDef = new RootBeanDefinition(ResourceHttpRequestHandler.class);
 		resourceHandlerDef.setSource(source);
 		resourceHandlerDef.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
 
 		MutablePropertyValues values = resourceHandlerDef.getPropertyValues();
 		values.add("urlPathHelper", pathHelperRef);
-		values.add("locations", locations);
-		values.add("locationCharsets", locationCharsets);
+		values.add("locationValues", StringUtils.commaDelimitedListToStringArray(locationAttr));
 
 		String cacheSeconds = element.getAttribute("cache-period");
 		if (StringUtils.hasText(cacheSeconds)) {

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/ResourceHandlerRegistration.java

@@ -16,18 +16,13 @@
 
 package org.springframework.web.servlet.config.annotation;
 
-import java.nio.charset.Charset;
 import java.util.ArrayList;
-import java.util.HashMap;
+import java.util.Arrays;
 import java.util.List;
-import java.util.Map;
 
 import org.springframework.cache.Cache;
-import org.springframework.core.io.Resource;
-import org.springframework.core.io.ResourceLoader;
 import org.springframework.http.CacheControl;
 import org.springframework.util.Assert;
-import org.springframework.web.servlet.config.MvcNamespaceUtils;
 import org.springframework.web.servlet.resource.PathResourceResolver;
 import org.springframework.web.servlet.resource.ResourceHttpRequestHandler;
 
@@ -41,13 +36,9 @@
  */
 public class ResourceHandlerRegistration {
 
-	private final ResourceLoader resourceLoader;
-
 	private final String[] pathPatterns;
 
-	private final List<Resource> locations = new ArrayList<Resource>();
-
-	private final Map<Resource, Charset> locationCharsets = new HashMap<Resource, Charset>();
+	private final List<String> locationValues = new ArrayList<String>(4);
 
 	private Integer cachePeriod;
 
@@ -58,12 +49,10 @@ public class ResourceHandlerRegistration {
 
 	/**
 	 * Create a {@link ResourceHandlerRegistration} instance.
-	 * @param resourceLoader a resource loader for turning a String location into a {@link Resource}
 	 * @param pathPatterns one or more resource URL path patterns
 	 */
-	public ResourceHandlerRegistration(ResourceLoader resourceLoader, String... pathPatterns) {
+	public ResourceHandlerRegistration(String... pathPatterns) {
 		Assert.notEmpty(pathPatterns, "At least one path pattern is required for resource handling.");
-		this.resourceLoader = resourceLoader;
 		this.pathPatterns = pathPatterns;
 	}
 
@@ -86,8 +75,7 @@ public ResourceHandlerRegistration(ResourceLoader resourceLoader, String... path
 	 * chained method invocation
 	 */
 	public ResourceHandlerRegistration addResourceLocations(String... resourceLocations) {
-		MvcNamespaceUtils.loadResourceLocations(
-				resourceLocations, this.resourceLoader, this.locations, this.locationCharsets);
+		this.locationValues.addAll(Arrays.asList(resourceLocations));
 		return this;
 	}
 
@@ -177,8 +165,7 @@ protected ResourceHttpRequestHandler getRequestHandler() {
 			handler.setResourceResolvers(this.resourceChainRegistration.getResourceResolvers());
 			handler.setResourceTransformers(this.resourceChainRegistration.getResourceTransformers());
 		}
-		handler.setLocations(this.locations);
-		handler.setLocationCharsets(this.locationCharsets);
+		handler.setLocationValues(this.locationValues);
 		if (this.cacheControl != null) {
 			handler.setCacheControl(this.cacheControl);
 		}

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/ResourceHandlerRegistry.java

@@ -114,8 +114,7 @@ public ResourceHandlerRegistry(ApplicationContext applicationContext, ServletCon
 	 * registered resource handler
 	 */
 	public ResourceHandlerRegistration addResourceHandler(String... pathPatterns) {
-		ResourceHandlerRegistration registration =
-				new ResourceHandlerRegistration(this.applicationContext, pathPatterns);
+		ResourceHandlerRegistration registration = new ResourceHandlerRegistration(pathPatterns);
 		this.registrations.add(registration);
 		return registration;
 	}

spring-webmvc/src/main/java/org/springframework/web/servlet/resource/ResourceHttpRequestHandler.java

@@ -20,7 +20,6 @@
 import java.net.URLDecoder;
 import java.nio.charset.Charset;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -33,7 +32,10 @@
 import org.apache.commons.logging.LogFactory;
 
 import org.springframework.beans.factory.InitializingBean;
+import org.springframework.beans.factory.config.ConfigurableBeanFactory;
+import org.springframework.context.ApplicationContext;
 import org.springframework.core.io.Resource;
+import org.springframework.core.io.UrlResource;
 import org.springframework.core.io.support.ResourceRegion;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
@@ -101,11 +103,15 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
 
 	private static final Log logger = LogFactory.getLog(ResourceHttpRequestHandler.class);
 
+	private static final String URL_RESOURCE_CHARSET_PREFIX = "[charset=";
+
 
 	private final List<Resource> locations = new ArrayList<Resource>(4);
 
 	private final Map<Resource, Charset> locationCharsets = new HashMap<Resource, Charset>(4);
 
+	private final List<String> locationValues = new ArrayList<String>(4);
+
 	private final List<ResourceResolver> resourceResolvers = new ArrayList<ResourceResolver>(4);
 
 	private final List<ResourceTransformer> resourceTransformers = new ArrayList<ResourceTransformer>(4);
@@ -129,8 +135,9 @@ public ResourceHttpRequestHandler() {
 
 
 	/**
-	 * Set the {@code List} of {@code Resource} paths to use as sources
+	 * Set the {@code List} of {@code Resource} locations to use as sources
 	 * for serving static resources.
+	 * @see #setLocationValues(List)
 	 */
 	public void setLocations(List<Resource> locations) {
 		Assert.notNull(locations, "Locations list must not be null");
@@ -139,35 +146,27 @@ public void setLocations(List<Resource> locations) {
 	}
 
 	/**
-	 * Return the {@code List} of {@code Resource} paths to use as sources
-	 * for serving static resources.
+	 * Return the configured {@code List} of {@code Resource} locations.
+	 * Note that if {@link #setLocationValues(List) locationValues} are provided,
+	 * instead of loaded Resource-based locations, this method will return
+	 * empty until after initialization via {@link #afterPropertiesSet()}.
 	 */
 	public List<Resource> getLocations() {
 		return this.locations;
 	}
 
 	/**
-	 * Specify charsets associated with the configured {@link #setLocations(List)
-	 * locations}. This is supported for
-	 * {@link org.springframework.core.io.UrlResource URL resources} such as a
-	 * file or an HTTP URL location and is used in {@link PathResourceResolver}
-	 * to correctly encode paths relative to the location.
-	 * <p><strong>Note:</strong> The charset is used only if the
-	 * {@link #setUrlPathHelper urlPathHelper} property is also configured and
-	 * its {@code urlDecode} property is set to {@code true}.
-	 * @since 4.3.13
-	 */
-	public void setLocationCharsets(Map<Resource,Charset> locationCharsets) {
-		this.locationCharsets.clear();
-		this.locationCharsets.putAll(locationCharsets);
-	}
-
-	/**
-	 * Return charsets associated with static resource locations.
+	 * An alternative to {@link #setLocations(List)} that accepts a list of
+	 * String-based location values, with support for {@link UrlResource}'s
+	 * (e.g. files or HTTP URLs) with a special prefix to indicate the charset
+	 * to use when appending relative paths. For example
+	 * {@code "[charset=Windows-31J]http://example.org/path"}.
 	 * @since 4.3.13
 	 */
-	public Map<Resource, Charset> getLocationCharsets() {
-		return Collections.unmodifiableMap(this.locationCharsets);
+	public void setLocationValues(List<String> locationValues) {
+		Assert.notNull(locationValues, "Location values list must not be null");
+		this.locationValues.clear();
+		this.locationValues.addAll(locationValues);
 	}
 
 	/**
@@ -297,6 +296,9 @@ public UrlPathHelper getUrlPathHelper() {
 
 	@Override
 	public void afterPropertiesSet() throws Exception {
+
+		loadResourceLocations();
+
 		if (logger.isWarnEnabled() && CollectionUtils.isEmpty(this.locations)) {
 			logger.warn("Locations list is empty. No resources will be served unless a " +
 					"custom ResourceResolver is configured as an alternative to PathResourceResolver.");
@@ -305,6 +307,7 @@ public void afterPropertiesSet() throws Exception {
 		if (this.resourceResolvers.isEmpty()) {
 			this.resourceResolvers.add(new PathResourceResolver());
 		}
+
 		initAllowedLocations();
 
 		if (this.resourceHttpMessageConverter == null) {
@@ -317,6 +320,46 @@ public void afterPropertiesSet() throws Exception {
 		this.contentNegotiationStrategy = initContentNegotiationStrategy();
 	}
 
+	private void loadResourceLocations() {
+		if (!CollectionUtils.isEmpty(this.locations) && !CollectionUtils.isEmpty(this.locationValues)) {
+			throw new IllegalArgumentException("Please set either Resource-based \"locations\" or " +
+					"String-based \"locationValues\", but not both.");
+		}
+		if (CollectionUtils.isEmpty(this.locationValues)) {
+			return;
+		}
+		ApplicationContext appContext = getApplicationContext();
+		ConfigurableBeanFactory beanFactory = null;
+		if (appContext.getAutowireCapableBeanFactory() instanceof ConfigurableBeanFactory) {
+			beanFactory = ((ConfigurableBeanFactory) appContext.getAutowireCapableBeanFactory());
+		}
+		for (String location : this.locationValues) {
+			if (beanFactory != null) {
+				location = beanFactory.resolveEmbeddedValue(location);
+				Assert.notNull(location, "Null location");
+			}
+			Charset charset = null;
+			location = location.trim();
+			if (location.startsWith(URL_RESOURCE_CHARSET_PREFIX)) {
+				int endIndex = location.indexOf("]", URL_RESOURCE_CHARSET_PREFIX.length());
+				if (endIndex == -1) {
+					throw new IllegalArgumentException("Invalid charset syntax in location: " + location);
+				}
+				String value = location.substring(URL_RESOURCE_CHARSET_PREFIX.length(), endIndex);
+				charset = Charset.forName(value);
+				location = location.substring(endIndex + 1);
+			}
+			Resource resource = appContext.getResource(location);
+			this.locations.add(resource);
+			if (charset != null) {
+				if (!(resource instanceof UrlResource)) {
+					throw new IllegalArgumentException("Unexpected charset for non-UrlResource: " + resource);
+				}
+				this.locationCharsets.put(resource, charset);
+			}
+		}
+	}
+
 	/**
 	 * Look for a {@code PathResourceResolver} among the configured resource
 	 * resolvers and set its {@code allowedLocations} property (if empty) to