org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext Maven / Gradle / Ivy
/*
* Copyright 2012-2018 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.boot.web.servlet.context;
import java.util.Collection;
import java.util.Collections;
import java.util.EventListener;
import java.util.HashMap;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;
import javax.servlet.Filter;
import javax.servlet.Servlet;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.config.Scope;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.boot.web.context.ConfigurableWebServerApplicationContext;
import org.springframework.boot.web.server.WebServer;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletContextInitializer;
import org.springframework.boot.web.servlet.ServletContextInitializerBeans;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.boot.web.servlet.server.ServletWebServerFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextException;
import org.springframework.core.io.Resource;
import org.springframework.util.StringUtils;
import org.springframework.web.context.ContextLoader;
import org.springframework.web.context.ContextLoaderListener;
import org.springframework.web.context.ServletContextAware;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.GenericWebApplicationContext;
import org.springframework.web.context.support.ServletContextAwareProcessor;
import org.springframework.web.context.support.ServletContextResource;
import org.springframework.web.context.support.ServletContextScope;
import org.springframework.web.context.support.WebApplicationContextUtils;
/**
* A {@link WebApplicationContext} that can be used to bootstrap itself from a contained
* {@link ServletWebServerFactory} bean.
*
* This context will create, initialize and run an {@link WebServer} by searching for a
* single {@link ServletWebServerFactory} bean within the {@link ApplicationContext}
* itself. The {@link ServletWebServerFactory} is free to use standard Spring concepts
* (such as dependency injection, lifecycle callbacks and property placeholder variables).
*
* In addition, any {@link Servlet} or {@link Filter} beans defined in the context will be
* automatically registered with the web server. In the case of a single Servlet bean, the
* '/' mapping will be used. If multiple Servlet beans are found then the lowercase bean
* name will be used as a mapping prefix. Any Servlet named 'dispatcherServlet' will
* always be mapped to '/'. Filter beans will be mapped to all URLs ('/*').
*
* For more advanced configuration, the context can instead define beans that implement
* the {@link ServletContextInitializer} interface (most often
* {@link ServletRegistrationBean}s and/or {@link FilterRegistrationBean}s). To prevent
* double registration, the use of {@link ServletContextInitializer} beans will disable
* automatic Servlet and Filter bean registration.
*
* Although this context can be used directly, most developers should consider using the
* {@link AnnotationConfigServletWebServerApplicationContext} or
* {@link XmlServletWebServerApplicationContext} variants.
*
* @author Phillip Webb
* @author Dave Syer
* @see AnnotationConfigServletWebServerApplicationContext
* @see XmlServletWebServerApplicationContext
* @see ServletWebServerFactory
*/
public class ServletWebServerApplicationContext extends GenericWebApplicationContext
implements ConfigurableWebServerApplicationContext {
private static final Log logger = LogFactory
.getLog(ServletWebServerApplicationContext.class);
/**
* Constant value for the DispatcherServlet bean name. A Servlet bean with this name
* is deemed to be the "main" servlet and is automatically given a mapping of "/" by
* default. To change the default behavior you can use a
* {@link ServletRegistrationBean} or a different bean name.
*/
public static final String DISPATCHER_SERVLET_NAME = "dispatcherServlet";
private volatile WebServer webServer;
private ServletConfig servletConfig;
private String serverNamespace;
/**
* Create a new {@link ServletWebServerApplicationContext}.
*/
public ServletWebServerApplicationContext() {
}
/**
* Create a new {@link ServletWebServerApplicationContext} with the given
* {@code DefaultListableBeanFactory}.
* @param beanFactory the DefaultListableBeanFactory instance to use for this context
*/
public ServletWebServerApplicationContext(DefaultListableBeanFactory beanFactory) {
super(beanFactory);
}
/**
* Register ServletContextAwareProcessor.
* @see ServletContextAwareProcessor
*/
@Override
protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {
beanFactory.addBeanPostProcessor(
new WebApplicationContextServletContextAwareProcessor(this));
beanFactory.ignoreDependencyInterface(ServletContextAware.class);
registerWebApplicationScopes();
}
@Override
public final void refresh() throws BeansException, IllegalStateException {
try {
super.refresh();
}
catch (RuntimeException ex) {
stopAndReleaseWebServer();
throw ex;
}
}
@Override
protected void onRefresh() {
super.onRefresh();
try {
createWebServer();
}
catch (Throwable ex) {
throw new ApplicationContextException("Unable to start web server", ex);
}
}
@Override
protected void finishRefresh() {
super.finishRefresh();
WebServer webServer = startWebServer();
if (webServer != null) {
publishEvent(new ServletWebServerInitializedEvent(webServer, this));
}
}
@Override
protected void onClose() {
super.onClose();
stopAndReleaseWebServer();
}
private void createWebServer() {
WebServer webServer = this.webServer;
ServletContext servletContext = getServletContext();
if (webServer == null && servletContext == null) {
ServletWebServerFactory factory = getWebServerFactory();
this.webServer = factory.getWebServer(getSelfInitializer());
}
else if (servletContext != null) {
try {
getSelfInitializer().onStartup(servletContext);
}
catch (ServletException ex) {
throw new ApplicationContextException("Cannot initialize servlet context",
ex);
}
}
initPropertySources();
}
/**
* Returns the {@link ServletWebServerFactory} that should be used to create the
* embedded {@link WebServer}. By default this method searches for a suitable bean in
* the context itself.
* @return a {@link ServletWebServerFactory} (never {@code null})
*/
protected ServletWebServerFactory getWebServerFactory() {
// Use bean names so that we don't consider the hierarchy
String[] beanNames = getBeanFactory()
.getBeanNamesForType(ServletWebServerFactory.class);
if (beanNames.length == 0) {
throw new ApplicationContextException(
"Unable to start ServletWebServerApplicationContext due to missing "
+ "ServletWebServerFactory bean.");
}
if (beanNames.length > 1) {
throw new ApplicationContextException(
"Unable to start ServletWebServerApplicationContext due to multiple "
+ "ServletWebServerFactory beans : "
+ StringUtils.arrayToCommaDelimitedString(beanNames));
}
return getBeanFactory().getBean(beanNames[0], ServletWebServerFactory.class);
}
/**
* Returns the {@link ServletContextInitializer} that will be used to complete the
* setup of this {@link WebApplicationContext}.
* @return the self initializer
* @see #prepareWebApplicationContext(ServletContext)
*/
private org.springframework.boot.web.servlet.ServletContextInitializer getSelfInitializer() {
return this::selfInitialize;
}
private void selfInitialize(ServletContext servletContext) throws ServletException {
prepareWebApplicationContext(servletContext);
registerApplicationScope(servletContext);
WebApplicationContextUtils.registerEnvironmentBeans(getBeanFactory(),
servletContext);
for (ServletContextInitializer beans : getServletContextInitializerBeans()) {
beans.onStartup(servletContext);
}
}
private void registerApplicationScope(ServletContext servletContext) {
ServletContextScope appScope = new ServletContextScope(servletContext);
getBeanFactory().registerScope(WebApplicationContext.SCOPE_APPLICATION, appScope);
// Register as ServletContext attribute, for ContextCleanupListener to detect it.
servletContext.setAttribute(ServletContextScope.class.getName(), appScope);
}
private void registerWebApplicationScopes() {
ExistingWebApplicationScopes existingScopes = new ExistingWebApplicationScopes(
getBeanFactory());
WebApplicationContextUtils.registerWebApplicationScopes(getBeanFactory());
existingScopes.restore();
}
/**
* Returns {@link ServletContextInitializer}s that should be used with the embedded
* web server. By default this method will first attempt to find
* {@link ServletContextInitializer}, {@link Servlet}, {@link Filter} and certain
* {@link EventListener} beans.
* @return the servlet initializer beans
*/
protected Collection getServletContextInitializerBeans() {
return new ServletContextInitializerBeans(getBeanFactory());
}
/**
* Prepare the {@link WebApplicationContext} with the given fully loaded
* {@link ServletContext}. This method is usually called from
* {@link ServletContextInitializer#onStartup(ServletContext)} and is similar to the
* functionality usually provided by a {@link ContextLoaderListener}.
* @param servletContext the operational servlet context
*/
protected void prepareWebApplicationContext(ServletContext servletContext) {
Object rootContext = servletContext.getAttribute(
WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);
if (rootContext != null) {
if (rootContext == this) {
throw new IllegalStateException(
"Cannot initialize context because there is already a root application context present - "
+ "check whether you have multiple ServletContextInitializers!");
}
return;
}
Log logger = LogFactory.getLog(ContextLoader.class);
servletContext.log("Initializing Spring embedded WebApplicationContext");
try {
servletContext.setAttribute(
WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE, this);
if (logger.isDebugEnabled()) {
logger.debug(
"Published root WebApplicationContext as ServletContext attribute with name ["
+ WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE
+ "]");
}
setServletContext(servletContext);
if (logger.isInfoEnabled()) {
long elapsedTime = System.currentTimeMillis() - getStartupDate();
logger.info("Root WebApplicationContext: initialization completed in "
+ elapsedTime + " ms");
}
}
catch (RuntimeException | Error ex) {
logger.error("Context initialization failed", ex);
servletContext.setAttribute(
WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE, ex);
throw ex;
}
}
private WebServer startWebServer() {
WebServer webServer = this.webServer;
if (webServer != null) {
webServer.start();
}
return webServer;
}
private void stopAndReleaseWebServer() {
WebServer webServer = this.webServer;
if (webServer != null) {
try {
webServer.stop();
this.webServer = null;
}
catch (Exception ex) {
throw new IllegalStateException(ex);
}
}
}
@Override
protected Resource getResourceByPath(String path) {
if (getServletContext() == null) {
return new ClassPathContextResource(path, getClassLoader());
}
return new ServletContextResource(getServletContext(), path);
}
@Override
public String getServerNamespace() {
return this.serverNamespace;
}
@Override
public void setServerNamespace(String serverNamespace) {
this.serverNamespace = serverNamespace;
}
@Override
public void setServletConfig(ServletConfig servletConfig) {
this.servletConfig = servletConfig;
}
@Override
public ServletConfig getServletConfig() {
return this.servletConfig;
}
/**
* Returns the {@link WebServer} that was created by the context or {@code null} if
* the server has not yet been created.
* @return the embedded web server
*/
@Override
public WebServer getWebServer() {
return this.webServer;
}
/**
* Utility class to store and restore any user defined scopes. This allow scopes to be
* registered in an ApplicationContextInitializer in the same way as they would in a
* classic non-embedded web application context.
*/
public static class ExistingWebApplicationScopes {
private static final Set SCOPES;
static {
Set scopes = new LinkedHashSet<>();
scopes.add(WebApplicationContext.SCOPE_REQUEST);
scopes.add(WebApplicationContext.SCOPE_SESSION);
SCOPES = Collections.unmodifiableSet(scopes);
}
private final ConfigurableListableBeanFactory beanFactory;
private final Map scopes = new HashMap<>();
public ExistingWebApplicationScopes(ConfigurableListableBeanFactory beanFactory) {
this.beanFactory = beanFactory;
for (String scopeName : SCOPES) {
Scope scope = beanFactory.getRegisteredScope(scopeName);
if (scope != null) {
this.scopes.put(scopeName, scope);
}
}
}
public void restore() {
this.scopes.forEach((key, value) -> {
if (logger.isInfoEnabled()) {
logger.info("Restoring user defined scope " + key);
}
this.beanFactory.registerScope(key, value);
});
}
}
}