/*
* Copyright 2002-2017 the original author or authors.
*
* 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.springframework.web.servlet.support;
import java.util.Locale;
import java.util.Map;
import java.util.TimeZone;
import javax.servlet.ServletContext;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.context.i18n.LocaleContext;
import org.springframework.context.i18n.TimeZoneAwareLocaleContext;
import org.springframework.ui.context.Theme;
import org.springframework.ui.context.ThemeSource;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;
import org.springframework.web.context.ContextLoader;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;
import org.springframework.web.servlet.DispatcherServlet;
import org.springframework.web.servlet.FlashMap;
import org.springframework.web.servlet.FlashMapManager;
import org.springframework.web.servlet.LocaleContextResolver;
import org.springframework.web.servlet.LocaleResolver;
import org.springframework.web.servlet.ThemeResolver;
import org.springframework.web.util.UriComponents;
import org.springframework.web.util.UriComponentsBuilder;
/**
* Utility class for easy access to request-specific state which has been
* set by the {@link org.springframework.web.servlet.DispatcherServlet}.
*
* <p>Supports lookup of current WebApplicationContext, LocaleResolver,
* Locale, ThemeResolver, Theme, and MultipartResolver.
*
* @author Juergen Hoeller
* @author Rossen Stoyanchev
* @since 03.03.2003
* @see RequestContext
* @see org.springframework.web.servlet.DispatcherServlet
*/
public abstract class RequestContextUtils {
/**
* The name of the bean to use to look up in an implementation of
* {@link RequestDataValueProcessor} has been configured.
* @since 4.2.1
*/
public static final String REQUEST_DATA_VALUE_PROCESSOR_BEAN_NAME = "requestDataValueProcessor";
/**
* Look for the WebApplicationContext associated with the DispatcherServlet
* that has initiated request processing, and for the global context if none
* was found associated with the current request. The global context will
* be found via the ServletContext or via ContextLoader's current context.
* <p>NOTE: This variant remains compatible with Servlet 2.5, explicitly
* checking a given ServletContext instead of deriving it from the request.
* @param request current HTTP request
* @param servletContext current servlet context
* @return the request-specific WebApplicationContext, or the global one
* if no request-specific context has been found, or {@code null} if none
* @since 4.2.1
* @see DispatcherServlet#WEB_APPLICATION_CONTEXT_ATTRIBUTE
* @see WebApplicationContextUtils#getWebApplicationContext(ServletContext)
* @see ContextLoader#getCurrentWebApplicationContext()
*/
public static WebApplicationContext findWebApplicationContext(
HttpServletRequest request, ServletContext servletContext) {
WebApplicationContext webApplicationContext = (WebApplicationContext) request.getAttribute(
DispatcherServlet.WEB_APPLICATION_CONTEXT_ATTRIBUTE);
if (webApplicationContext == null) {
if (servletContext != null) {
webApplicationContext = WebApplicationContextUtils.getWebApplicationContext(servletContext);
}
if (webApplicationContext == null) {
webApplicationContext = ContextLoader.getCurrentWebApplicationContext();
}
}
return webApplicationContext;
}
/**
* Look for the WebApplicationContext associated with the DispatcherServlet
* that has initiated request processing, and for the global context if none
* was found associated with the current request. The global context will
* be found via the ServletContext or via ContextLoader's current context.
* <p>NOTE: This variant requires Servlet 3.0+ and is generally recommended
* for forward-looking custom user code.
* @param request current HTTP request
* @return the request-specific WebApplicationContext, or the global one
* if no request-specific context has been found, or {@code null} if none
* @since 4.2.1
* @see #findWebApplicationContext(HttpServletRequest, ServletContext)
* @see ServletRequest#getServletContext()
* @see ContextLoader#getCurrentWebApplicationContext()
*/
public static WebApplicationContext findWebApplicationContext(HttpServletRequest request) {
return findWebApplicationContext(request, request.getServletContext());
}
/**
* Return the LocaleResolver that has been bound to the request by the
* DispatcherServlet.
* @param request current HTTP request
* @return the current LocaleResolver, or {@code null} if not found
*/
public static LocaleResolver getLocaleResolver(HttpServletRequest request) {
return (LocaleResolver) request.getAttribute(DispatcherServlet.LOCALE_RESOLVER_ATTRIBUTE);
}
/**
* Retrieve the current locale from the given request, using the
* LocaleResolver bound to the request by the DispatcherServlet
* (if available), falling back to the request's accept-header Locale.
* <p>This method serves as a straightforward alternative to the standard
* Servlet {@link javax.servlet.http.HttpServletRequest#getLocale()} method,
* falling back to the latter if no more specific locale has been found.
* <p>Consider using {@link org.springframework.context.i18n.LocaleContextHolder#getLocale()}
* which will normally be populated with the same Locale.
* @param request current HTTP request
* @return the current locale for the given request, either from the
* LocaleResolver or from the plain request itself
* @see #getLocaleResolver
* @see org.springframework.context.i18n.LocaleContextHolder#getLocale()
*/
public static Locale getLocale(HttpServletRequest request) {
LocaleResolver localeResolver = getLocaleResolver(request);
return (localeResolver != null ? localeResolver.resolveLocale(request) : request.getLocale());
}
/**
* Retrieve the current time zone from the given request, using the
* TimeZoneAwareLocaleResolver bound to the request by the DispatcherServlet
* (if available), falling back to the system's default time zone.
* <p>Note: This method returns {@code null} if no specific time zone can be
* resolved for the given request. This is in contrast to {@link #getLocale}
* where there is always the request's accept-header locale to fall back to.
* <p>Consider using {@link org.springframework.context.i18n.LocaleContextHolder#getTimeZone()}
* which will normally be populated with the same TimeZone: That method only
* differs in terms of its fallback to the system time zone if the LocaleResolver
* hasn't provided a specific time zone (instead of this method's {@code null}).
* @param request current HTTP request
* @return the current time zone for the given request, either from the
* TimeZoneAwareLocaleResolver or {@code null} if none associated
* @see #getLocaleResolver
* @see org.springframework.context.i18n.LocaleContextHolder#getTimeZone()
*/
public static TimeZone getTimeZone(HttpServletRequest request) {
LocaleResolver localeResolver = getLocaleResolver(request);
if (localeResolver instanceof LocaleContextResolver) {
LocaleContext localeContext = ((LocaleContextResolver) localeResolver).resolveLocaleContext(request);
if (localeContext instanceof TimeZoneAwareLocaleContext) {
return ((TimeZoneAwareLocaleContext) localeContext).getTimeZone();
}
}
return null;
}
/**
* Return the ThemeResolver that has been bound to the request by the
* DispatcherServlet.
* @param request current HTTP request
* @return the current ThemeResolver, or {@code null} if not found
*/
public static ThemeResolver getThemeResolver(HttpServletRequest request) {
return (ThemeResolver) request.getAttribute(DispatcherServlet.THEME_RESOLVER_ATTRIBUTE);
}
/**
* Return the ThemeSource that has been bound to the request by the
* DispatcherServlet.
* @param request current HTTP request
* @return the current ThemeSource
*/
public static ThemeSource getThemeSource(HttpServletRequest request) {
return (ThemeSource) request.getAttribute(DispatcherServlet.THEME_SOURCE_ATTRIBUTE);
}
/**
* Retrieves the current theme from the given request, using the ThemeResolver
* and ThemeSource bound to the request by the DispatcherServlet.
* @param request current HTTP request
* @return the current theme, or {@code null} if not found
* @see #getThemeResolver
*/
public static Theme getTheme(HttpServletRequest request) {
ThemeResolver themeResolver = getThemeResolver(request);
ThemeSource themeSource = getThemeSource(request);
if (themeResolver != null && themeSource != null) {
String themeName = themeResolver.resolveThemeName(request);
return themeSource.getTheme(themeName);
}
else {
return null;
}
}
/**
* Return read-only "input" flash attributes from request before redirect.
* @param request current request
* @return a read-only Map, or {@code null} if not found
* @see FlashMap
*/
@SuppressWarnings("unchecked")
public static Map<String, ?> getInputFlashMap(HttpServletRequest request) {
return (Map<String, ?>) request.getAttribute(DispatcherServlet.INPUT_FLASH_MAP_ATTRIBUTE);
}
/**
* Return "output" FlashMap to save attributes for request after redirect.
* @param request current request
* @return a {@link FlashMap} instance, never {@code null} within a
* {@code DispatcherServlet}-handled request
*/
public static FlashMap getOutputFlashMap(HttpServletRequest request) {
return (FlashMap) request.getAttribute(DispatcherServlet.OUTPUT_FLASH_MAP_ATTRIBUTE);
}
/**
* Return the {@code FlashMapManager} instance to save flash attributes.
* <p>As of 5.0 the convenience method {@link #saveOutputFlashMap} may be
* used to save the "output" FlashMap.
* @param request the current request
* @return a {@link FlashMapManager} instance, never {@code null} within a
* {@code DispatcherServlet}-handled request
*/
public static FlashMapManager getFlashMapManager(HttpServletRequest request) {
return (FlashMapManager) request.getAttribute(DispatcherServlet.FLASH_MAP_MANAGER_ATTRIBUTE);
}
/**
* Convenience method that retrieves the {@link #getOutputFlashMap "output"
* FlashMap}, updates it with the path and query params of the target URL,
* and then saves it using the {@link #getFlashMapManager FlashMapManager}.
*
* @param location the target URL for the redirect
* @param request the current request
* @param response the current response
* @since 5.0
*/
public static void saveOutputFlashMap(String location, HttpServletRequest request,
HttpServletResponse response) {
FlashMap flashMap = getOutputFlashMap(request);
if (CollectionUtils.isEmpty(flashMap)) {
return;
}
UriComponents uriComponents = UriComponentsBuilder.fromUriString(location).build();
flashMap.setTargetRequestPath(uriComponents.getPath());
flashMap.addTargetRequestParams(uriComponents.getQueryParams());
FlashMapManager manager = getFlashMapManager(request);
Assert.state(manager != null, "No FlashMapManager. Is this a DispatcherServlet handled request?");
manager.saveOutputFlashMap(flashMap, request, response);
}
}