org.springframework.web.context.support.WebApplicationContextUtils Maven / Gradle / Ivy
/*
* Copyright 2002-2018 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
*
* https://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.context.support;
import java.io.Serializable;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpSession;
import org.springframework.beans.factory.ObjectFactory;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.core.env.MutablePropertySources;
import org.springframework.core.env.PropertySource.StubPropertySource;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.web.context.ConfigurableWebApplicationContext;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.RequestScope;
import org.springframework.web.context.request.ServletRequestAttributes;
import org.springframework.web.context.request.ServletWebRequest;
import org.springframework.web.context.request.SessionScope;
import org.springframework.web.context.request.WebRequest;
/**
* Convenience methods for retrieving the root {@link WebApplicationContext} for
* a given {@link ServletContext}. This is useful for programmatically accessing
* a Spring application context from within custom web views or MVC actions.
*
* Note that there are more convenient ways of accessing the root context for
* many web frameworks, either part of Spring or available as an external library.
* This helper class is just the most generic way to access the root context.
*
* @author Juergen Hoeller
* @see org.springframework.web.context.ContextLoader
* @see org.springframework.web.servlet.FrameworkServlet
* @see org.springframework.web.servlet.DispatcherServlet
* @see org.springframework.web.jsf.FacesContextUtils
* @see org.springframework.web.jsf.el.SpringBeanFacesELResolver
*/
public abstract class WebApplicationContextUtils {
private static final boolean jsfPresent =
ClassUtils.isPresent("javax.faces.context.FacesContext", RequestContextHolder.class.getClassLoader());
/**
* Find the root {@code WebApplicationContext} for this web app, typically
* loaded via {@link org.springframework.web.context.ContextLoaderListener}.
*
Will rethrow an exception that happened on root context startup,
* to differentiate between a failed context startup and no context at all.
* @param sc the ServletContext to find the web application context for
* @return the root WebApplicationContext for this web app
* @throws IllegalStateException if the root WebApplicationContext could not be found
* @see org.springframework.web.context.WebApplicationContext#ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE
*/
public static WebApplicationContext getRequiredWebApplicationContext(ServletContext sc) throws IllegalStateException {
WebApplicationContext wac = getWebApplicationContext(sc);
if (wac == null) {
throw new IllegalStateException("No WebApplicationContext found: no ContextLoaderListener registered?");
}
return wac;
}
/**
* Find the root {@code WebApplicationContext} for this web app, typically
* loaded via {@link org.springframework.web.context.ContextLoaderListener}.
*
Will rethrow an exception that happened on root context startup,
* to differentiate between a failed context startup and no context at all.
* @param sc the ServletContext to find the web application context for
* @return the root WebApplicationContext for this web app, or {@code null} if none
* @see org.springframework.web.context.WebApplicationContext#ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE
*/
@Nullable
public static WebApplicationContext getWebApplicationContext(ServletContext sc) {
return getWebApplicationContext(sc, WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);
}
/**
* Find a custom {@code WebApplicationContext} for this web app.
* @param sc the ServletContext to find the web application context for
* @param attrName the name of the ServletContext attribute to look for
* @return the desired WebApplicationContext for this web app, or {@code null} if none
*/
@Nullable
public static WebApplicationContext getWebApplicationContext(ServletContext sc, String attrName) {
Assert.notNull(sc, "ServletContext must not be null");
Object attr = sc.getAttribute(attrName);
if (attr == null) {
return null;
}
if (attr instanceof RuntimeException) {
throw (RuntimeException) attr;
}
if (attr instanceof Error) {
throw (Error) attr;
}
if (attr instanceof Exception) {
throw new IllegalStateException((Exception) attr);
}
if (!(attr instanceof WebApplicationContext)) {
throw new IllegalStateException("Context attribute is not of type WebApplicationContext: " + attr);
}
return (WebApplicationContext) attr;
}
/**
* Find a unique {@code WebApplicationContext} for this web app: either the
* root web app context (preferred) or a unique {@code WebApplicationContext}
* among the registered {@code ServletContext} attributes (typically coming
* from a single {@code DispatcherServlet} in the current web application).
*
Note that {@code DispatcherServlet}'s exposure of its context can be
* controlled through its {@code publishContext} property, which is {@code true}
* by default but can be selectively switched to only publish a single context
* despite multiple {@code DispatcherServlet} registrations in the web app.
* @param sc the ServletContext to find the web application context for
* @return the desired WebApplicationContext for this web app, or {@code null} if none
* @since 4.2
* @see #getWebApplicationContext(ServletContext)
* @see ServletContext#getAttributeNames()
*/
@Nullable
public static WebApplicationContext findWebApplicationContext(ServletContext sc) {
WebApplicationContext wac = getWebApplicationContext(sc);
if (wac == null) {
Enumeration attrNames = sc.getAttributeNames();
while (attrNames.hasMoreElements()) {
String attrName = attrNames.nextElement();
Object attrValue = sc.getAttribute(attrName);
if (attrValue instanceof WebApplicationContext) {
if (wac != null) {
throw new IllegalStateException("No unique WebApplicationContext found: more than one " +
"DispatcherServlet registered with publishContext=true?");
}
wac = (WebApplicationContext) attrValue;
}
}
}
return wac;
}
/**
* Register web-specific scopes ("request", "session", "globalSession")
* with the given BeanFactory, as used by the WebApplicationContext.
* @param beanFactory the BeanFactory to configure
*/
public static void registerWebApplicationScopes(ConfigurableListableBeanFactory beanFactory) {
registerWebApplicationScopes(beanFactory, null);
}
/**
* Register web-specific scopes ("request", "session", "globalSession", "application")
* with the given BeanFactory, as used by the WebApplicationContext.
* @param beanFactory the BeanFactory to configure
* @param sc the ServletContext that we're running within
*/
public static void registerWebApplicationScopes(ConfigurableListableBeanFactory beanFactory,
@Nullable ServletContext sc) {
beanFactory.registerScope(WebApplicationContext.SCOPE_REQUEST, new RequestScope());
beanFactory.registerScope(WebApplicationContext.SCOPE_SESSION, new SessionScope());
if (sc != null) {
ServletContextScope appScope = new ServletContextScope(sc);
beanFactory.registerScope(WebApplicationContext.SCOPE_APPLICATION, appScope);
// Register as ServletContext attribute, for ContextCleanupListener to detect it.
sc.setAttribute(ServletContextScope.class.getName(), appScope);
}
beanFactory.registerResolvableDependency(ServletRequest.class, new RequestObjectFactory());
beanFactory.registerResolvableDependency(ServletResponse.class, new ResponseObjectFactory());
beanFactory.registerResolvableDependency(HttpSession.class, new SessionObjectFactory());
beanFactory.registerResolvableDependency(WebRequest.class, new WebRequestObjectFactory());
if (jsfPresent) {
FacesDependencyRegistrar.registerFacesDependencies(beanFactory);
}
}
/**
* Register web-specific environment beans ("contextParameters", "contextAttributes")
* with the given BeanFactory, as used by the WebApplicationContext.
* @param bf the BeanFactory to configure
* @param sc the ServletContext that we're running within
*/
public static void registerEnvironmentBeans(ConfigurableListableBeanFactory bf, @Nullable ServletContext sc) {
registerEnvironmentBeans(bf, sc, null);
}
/**
* Register web-specific environment beans ("contextParameters", "contextAttributes")
* with the given BeanFactory, as used by the WebApplicationContext.
* @param bf the BeanFactory to configure
* @param servletContext the ServletContext that we're running within
* @param servletConfig the ServletConfig
*/
public static void registerEnvironmentBeans(ConfigurableListableBeanFactory bf,
@Nullable ServletContext servletContext, @Nullable ServletConfig servletConfig) {
if (servletContext != null && !bf.containsBean(WebApplicationContext.SERVLET_CONTEXT_BEAN_NAME)) {
bf.registerSingleton(WebApplicationContext.SERVLET_CONTEXT_BEAN_NAME, servletContext);
}
if (servletConfig != null && !bf.containsBean(ConfigurableWebApplicationContext.SERVLET_CONFIG_BEAN_NAME)) {
bf.registerSingleton(ConfigurableWebApplicationContext.SERVLET_CONFIG_BEAN_NAME, servletConfig);
}
if (!bf.containsBean(WebApplicationContext.CONTEXT_PARAMETERS_BEAN_NAME)) {
Map parameterMap = new HashMap<>();
if (servletContext != null) {
Enumeration paramNameEnum = servletContext.getInitParameterNames();
while (paramNameEnum.hasMoreElements()) {
String paramName = (String) paramNameEnum.nextElement();
parameterMap.put(paramName, servletContext.getInitParameter(paramName));
}
}
if (servletConfig != null) {
Enumeration paramNameEnum = servletConfig.getInitParameterNames();
while (paramNameEnum.hasMoreElements()) {
String paramName = (String) paramNameEnum.nextElement();
parameterMap.put(paramName, servletConfig.getInitParameter(paramName));
}
}
bf.registerSingleton(WebApplicationContext.CONTEXT_PARAMETERS_BEAN_NAME,
Collections.unmodifiableMap(parameterMap));
}
if (!bf.containsBean(WebApplicationContext.CONTEXT_ATTRIBUTES_BEAN_NAME)) {
Map attributeMap = new HashMap<>();
if (servletContext != null) {
Enumeration attrNameEnum = servletContext.getAttributeNames();
while (attrNameEnum.hasMoreElements()) {
String attrName = (String) attrNameEnum.nextElement();
attributeMap.put(attrName, servletContext.getAttribute(attrName));
}
}
bf.registerSingleton(WebApplicationContext.CONTEXT_ATTRIBUTES_BEAN_NAME,
Collections.unmodifiableMap(attributeMap));
}
}
/**
* Convenient variant of {@link #initServletPropertySources(MutablePropertySources,
* ServletContext, ServletConfig)} that always provides {@code null} for the
* {@link ServletConfig} parameter.
* @see #initServletPropertySources(MutablePropertySources, ServletContext, ServletConfig)
*/
public static void initServletPropertySources(MutablePropertySources propertySources, ServletContext servletContext) {
initServletPropertySources(propertySources, servletContext, null);
}
/**
* Replace {@code Servlet}-based {@link StubPropertySource stub property sources} with
* actual instances populated with the given {@code servletContext} and
* {@code servletConfig} objects.
* This method is idempotent with respect to the fact it may be called any number
* of times but will perform replacement of stub property sources with their
* corresponding actual property sources once and only once.
* @param sources the {@link MutablePropertySources} to initialize (must not
* be {@code null})
* @param servletContext the current {@link ServletContext} (ignored if {@code null}
* or if the {@link StandardServletEnvironment#SERVLET_CONTEXT_PROPERTY_SOURCE_NAME
* servlet context property source} has already been initialized)
* @param servletConfig the current {@link ServletConfig} (ignored if {@code null}
* or if the {@link StandardServletEnvironment#SERVLET_CONFIG_PROPERTY_SOURCE_NAME
* servlet config property source} has already been initialized)
* @see org.springframework.core.env.PropertySource.StubPropertySource
* @see org.springframework.core.env.ConfigurableEnvironment#getPropertySources()
*/
public static void initServletPropertySources(MutablePropertySources sources,
@Nullable ServletContext servletContext, @Nullable ServletConfig servletConfig) {
Assert.notNull(sources, "'propertySources' must not be null");
String name = StandardServletEnvironment.SERVLET_CONTEXT_PROPERTY_SOURCE_NAME;
if (servletContext != null && sources.contains(name) && sources.get(name) instanceof StubPropertySource) {
sources.replace(name, new ServletContextPropertySource(name, servletContext));
}
name = StandardServletEnvironment.SERVLET_CONFIG_PROPERTY_SOURCE_NAME;
if (servletConfig != null && sources.contains(name) && sources.get(name) instanceof StubPropertySource) {
sources.replace(name, new ServletConfigPropertySource(name, servletConfig));
}
}
/**
* Return the current RequestAttributes instance as ServletRequestAttributes.
* @see RequestContextHolder#currentRequestAttributes()
*/
private static ServletRequestAttributes currentRequestAttributes() {
RequestAttributes requestAttr = RequestContextHolder.currentRequestAttributes();
if (!(requestAttr instanceof ServletRequestAttributes)) {
throw new IllegalStateException("Current request is not a servlet request");
}
return (ServletRequestAttributes) requestAttr;
}
/**
* Factory that exposes the current request object on demand.
*/
@SuppressWarnings("serial")
private static class RequestObjectFactory implements ObjectFactory, Serializable {
@Override
public ServletRequest getObject() {
return currentRequestAttributes().getRequest();
}
@Override
public String toString() {
return "Current HttpServletRequest";
}
}
/**
* Factory that exposes the current response object on demand.
*/
@SuppressWarnings("serial")
private static class ResponseObjectFactory implements ObjectFactory, Serializable {
@Override
public ServletResponse getObject() {
ServletResponse response = currentRequestAttributes().getResponse();
if (response == null) {
throw new IllegalStateException("Current servlet response not available - " +
"consider using RequestContextFilter instead of RequestContextListener");
}
return response;
}
@Override
public String toString() {
return "Current HttpServletResponse";
}
}
/**
* Factory that exposes the current session object on demand.
*/
@SuppressWarnings("serial")
private static class SessionObjectFactory implements ObjectFactory, Serializable {
@Override
public HttpSession getObject() {
return currentRequestAttributes().getRequest().getSession();
}
@Override
public String toString() {
return "Current HttpSession";
}
}
/**
* Factory that exposes the current WebRequest object on demand.
*/
@SuppressWarnings("serial")
private static class WebRequestObjectFactory implements ObjectFactory, Serializable {
@Override
public WebRequest getObject() {
ServletRequestAttributes requestAttr = currentRequestAttributes();
return new ServletWebRequest(requestAttr.getRequest(), requestAttr.getResponse());
}
@Override
public String toString() {
return "Current ServletWebRequest";
}
}
/**
* Inner class to avoid hard-coded JSF dependency.
*/
private static class FacesDependencyRegistrar {
public static void registerFacesDependencies(ConfigurableListableBeanFactory beanFactory) {
beanFactory.registerResolvableDependency(FacesContext.class, new ObjectFactory() {
@Override
public FacesContext getObject() {
return FacesContext.getCurrentInstance();
}
@Override
public String toString() {
return "Current JSF FacesContext";
}
});
beanFactory.registerResolvableDependency(ExternalContext.class, new ObjectFactory() {
@Override
public ExternalContext getObject() {
return FacesContext.getCurrentInstance().getExternalContext();
}
@Override
public String toString() {
return "Current JSF ExternalContext";
}
});
}
}
}