org.apache.shiro.web.env.EnvironmentLoader Maven / Gradle / Ivy
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* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.shiro.web.env;
import org.apache.shiro.config.ConfigurationException;
import org.apache.shiro.config.ResourceConfigurable;
import org.apache.shiro.util.ClassUtils;
import org.apache.shiro.util.LifecycleUtils;
import org.apache.shiro.util.StringUtils;
import org.apache.shiro.util.UnknownClassException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.servlet.ServletContext;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.ServiceLoader;
/**
* An {@code EnvironmentLoader} is responsible for loading a web application's Shiro {@link WebEnvironment}
* (which includes the web app's {@link org.apache.shiro.web.mgt.WebSecurityManager WebSecurityManager}) into the
* {@code ServletContext} at application startup.
*
* In Shiro 1.1 and earlier, the Shiro ServletFilter was responsible for creating the {@code WebSecurityManager} and
* any additional objects (security filters, etc). However, any component not filtered by the Shiro Filter (such
* as other context listeners) was not able to easily acquire the these objects to perform security operations.
*
* Due to this, in Shiro 1.2 and later, this {@code EnvironmentLoader} (or more likely, the
* {@link EnvironmentLoaderListener} subclass) is the preferred mechanism to initialize
* a Shiro environment. The Shiro Filter, while still required for request filtering, will not perform this
* initialization at startup if the {@code EnvironmentLoader} (or listener) runs first.
* Usage
* This implementation will look for two servlet context {@code context-param}s in {@code web.xml}:
* {@code shiroEnvironmentClass} and {@code shiroConfigLocations} that customize how the {@code WebEnvironment} instance
* will be initialized.
* shiroEnvironmentClass
* The {@code shiroEnvironmentClass} {@code context-param}, if it exists, allows you to specify the
* fully-qualified implementation class name of the {@link WebEnvironment} to instantiate. For example:
*
* <context-param>
* <param-name>shiroEnvironmentClass</param-name>
* <param-value>com.foo.bar.shiro.MyWebEnvironment</param-value>
* </context-param>
*
* If not specified, the default value is the {@link IniWebEnvironment} class, which assumes Shiro's default
* INI configuration format
* shiroConfigLocations
* The {@code shiroConfigLocations} {@code context-param}, if it exists, allows you to specify the config location(s)
* (resource path(s)) that will be relayed to the instantiated {@link WebEnvironment}. For example:
*
* <context-param>
* <param-name>shiroConfigLocations</param-name>
* <param-value>/WEB-INF/someLocation/shiro.ini</param-value>
* </context-param>
*
* The {@code WebEnvironment} implementation must implement the {@link ResourceConfigurable} interface if it is to
* acquire the {@code shiroConfigLocations} value.
*
* If this {@code context-param} is not specified, the {@code WebEnvironment} instance determines default resource
* lookup behavior. For example, the {@link IniWebEnvironment} will check the following two locations for INI config
* by default (in order):
*
* - /WEB-INF/shiro.ini
* - classpath:shiro.ini
*
* Web Security Enforcement
* Using this loader will only initialize Shiro's environment in a web application - it will not filter web requests or
* perform web-specific security operations. To do this, you must ensure that you have also configured the
* {@link org.apache.shiro.web.servlet.ShiroFilter ShiroFilter} in {@code web.xml}.
*
* Finally, it should be noted that this implementation was based on ideas in Spring 3's
* {@code org.springframework.web.context.ContextLoader} implementation - no need to reinvent the wheel for this common
* behavior.
*
* @see EnvironmentLoaderListener
* @see org.apache.shiro.web.servlet.ShiroFilter ShiroFilter
* @since 1.2
*/
public class EnvironmentLoader {
/**
* Servlet Context config param for specifying the {@link WebEnvironment} implementation class to use:
* {@code shiroEnvironmentClass}
*/
public static final String ENVIRONMENT_CLASS_PARAM = "shiroEnvironmentClass";
/**
* Servlet Context config param for the resource path to use for configuring the {@link WebEnvironment} instance:
* {@code shiroConfigLocations}
*/
public static final String CONFIG_LOCATIONS_PARAM = "shiroConfigLocations";
public static final String ENVIRONMENT_ATTRIBUTE_KEY = EnvironmentLoader.class.getName() + ".ENVIRONMENT_ATTRIBUTE_KEY";
private static final Logger log = LoggerFactory.getLogger(EnvironmentLoader.class);
/**
* Initializes Shiro's {@link WebEnvironment} instance for the specified {@code ServletContext} based on the
* {@link #CONFIG_LOCATIONS_PARAM} value.
*
* @param servletContext current servlet context
* @return the new Shiro {@code WebEnvironment} instance.
* @throws IllegalStateException if an existing WebEnvironment has already been initialized and associated with
* the specified {@code ServletContext}.
*/
public WebEnvironment initEnvironment(ServletContext servletContext) throws IllegalStateException {
if (servletContext.getAttribute(ENVIRONMENT_ATTRIBUTE_KEY) != null) {
String msg = "There is already a Shiro environment associated with the current ServletContext. " +
"Check if you have multiple EnvironmentLoader* definitions in your web.xml!";
throw new IllegalStateException(msg);
}
servletContext.log("Initializing Shiro environment");
log.info("Starting Shiro environment initialization.");
long startTime = System.currentTimeMillis();
try {
WebEnvironment environment = createEnvironment(servletContext);
servletContext.setAttribute(ENVIRONMENT_ATTRIBUTE_KEY,environment);
log.debug("Published WebEnvironment as ServletContext attribute with name [{}]",
ENVIRONMENT_ATTRIBUTE_KEY);
if (log.isInfoEnabled()) {
long elapsed = System.currentTimeMillis() - startTime;
log.info("Shiro environment initialized in {} ms.", elapsed);
}
return environment;
} catch (RuntimeException ex) {
log.error("Shiro environment initialization failed", ex);
servletContext.setAttribute(ENVIRONMENT_ATTRIBUTE_KEY, ex);
throw ex;
} catch (Error err) {
log.error("Shiro environment initialization failed", err);
servletContext.setAttribute(ENVIRONMENT_ATTRIBUTE_KEY, err);
throw err;
}
}
/**
* Return the WebEnvironment implementation class to use, either the default
* {@link IniWebEnvironment} or a custom class if specified.
*
* @param servletContext current servlet context
* @return the WebEnvironment implementation class to use
* @see #ENVIRONMENT_CLASS_PARAM
* @see IniWebEnvironment
* @see #determineWebEnvironment(ServletContext)
* @see #getDefaultWebEnvironmentClass()
* @deprecated This method is not longer used by Shiro, and will be removed in future versions,
* use {@link #determineWebEnvironment(ServletContext)} or {@link #determineWebEnvironment(ServletContext)}
*/
@Deprecated
protected Class determineWebEnvironmentClass(ServletContext servletContext) {
Class webEnvironmentClass = webEnvironmentClassFromServletContext(servletContext);
if( webEnvironmentClass != null) {
return webEnvironmentClass;
} else {
return getDefaultWebEnvironmentClass();
}
}
private Class webEnvironmentClassFromServletContext(ServletContext servletContext) {
Class webEnvironmentClass = null;
String className = servletContext.getInitParameter(ENVIRONMENT_CLASS_PARAM);
if (className != null) {
try {
webEnvironmentClass = ClassUtils.forName(className);
} catch (UnknownClassException ex) {
throw new ConfigurationException(
"Failed to load custom WebEnvironment class [" + className + "]", ex);
}
}
return webEnvironmentClass;
}
private WebEnvironment webEnvironmentFromServiceLoader() {
WebEnvironment webEnvironment = null;
// try to load WebEnvironment as a service
ServiceLoader serviceLoader = ServiceLoader.load(WebEnvironment.class);
Iterator iterator = serviceLoader.iterator();
// Use the first one
if (iterator.hasNext()) {
webEnvironment = iterator.next();
}
// if there are others, throw an error
if (iterator.hasNext()) {
List allWebEnvironments = new ArrayList();
allWebEnvironments.add(webEnvironment.getClass().getName());
while (iterator.hasNext()) {
allWebEnvironments.add(iterator.next().getClass().getName());
}
throw new ConfigurationException("ServiceLoader for class [" + WebEnvironment.class + "] returned more then one " +
"result. ServiceLoader must return zero or exactly one result for this class. Select one using the " +
"servlet init parameter '"+ ENVIRONMENT_CLASS_PARAM +"'. Found: " + allWebEnvironments);
}
return webEnvironment;
}
/**
* Returns the default WebEnvironment class, which is unless overridden: {@link IniWebEnvironment}.
* @return the default WebEnvironment class.
*/
protected Class getDefaultWebEnvironmentClass() {
return IniWebEnvironment.class;
}
/**
* Return the WebEnvironment implementation class to use, based on the order of:
*
* - A custom WebEnvironment class - specified in the {@code servletContext} {@link #ENVIRONMENT_ATTRIBUTE_KEY} property
* - {@code ServiceLoader.load(WebEnvironment.class)} - (if more then one instance is found a {@link ConfigurationException} will be thrown
* - A call to {@link #getDefaultWebEnvironmentClass()} (default: {@link IniWebEnvironment})
*
*
* @param servletContext current servlet context
* @return the WebEnvironment implementation class to use
* @see #ENVIRONMENT_CLASS_PARAM
* @param servletContext the {@code servletContext} to query the {@code ENVIRONMENT_ATTRIBUTE_KEY} property from
* @return the {@code WebEnvironment} to be used
*/
protected WebEnvironment determineWebEnvironment(ServletContext servletContext) {
Class webEnvironmentClass = webEnvironmentClassFromServletContext(servletContext);
WebEnvironment webEnvironment = null;
// try service loader next
if (webEnvironmentClass == null) {
webEnvironment = webEnvironmentFromServiceLoader();
}
// if webEnvironment is not set, and ENVIRONMENT_CLASS_PARAM prop was not set, use the default
if (webEnvironmentClass == null && webEnvironment == null) {
webEnvironmentClass = getDefaultWebEnvironmentClass();
}
// at this point, we anything is set for the webEnvironmentClass, load it.
if (webEnvironmentClass != null) {
webEnvironment = (WebEnvironment) ClassUtils.newInstance(webEnvironmentClass);
}
return webEnvironment;
}
/**
* Instantiates a {@link WebEnvironment} based on the specified ServletContext.
*
* This implementation {@link #determineWebEnvironmentClass(javax.servlet.ServletContext) determines} a
* {@link WebEnvironment} implementation class to use. That class is instantiated, configured, and returned.
*
* This allows custom {@code WebEnvironment} implementations to be specified via a ServletContext init-param if
* desired. If not specified, the default {@link IniWebEnvironment} implementation will be used.
*
* @param sc current servlet context
* @return the constructed Shiro WebEnvironment instance
* @see MutableWebEnvironment
* @see ResourceConfigurable
*/
protected WebEnvironment createEnvironment(ServletContext sc) {
WebEnvironment webEnvironment = determineWebEnvironment(sc);
if (!MutableWebEnvironment.class.isInstance(webEnvironment)) {
throw new ConfigurationException("Custom WebEnvironment class [" + webEnvironment.getClass().getName() +
"] is not of required type [" + MutableWebEnvironment.class.getName() + "]");
}
String configLocations = sc.getInitParameter(CONFIG_LOCATIONS_PARAM);
boolean configSpecified = StringUtils.hasText(configLocations);
if (configSpecified && !(ResourceConfigurable.class.isInstance(webEnvironment))) {
String msg = "WebEnvironment class [" + webEnvironment.getClass().getName() + "] does not implement the " +
ResourceConfigurable.class.getName() + "interface. This is required to accept any " +
"configured " + CONFIG_LOCATIONS_PARAM + "value(s).";
throw new ConfigurationException(msg);
}
MutableWebEnvironment environment = (MutableWebEnvironment) webEnvironment;
environment.setServletContext(sc);
if (configSpecified && (environment instanceof ResourceConfigurable)) {
((ResourceConfigurable) environment).setConfigLocations(configLocations);
}
customizeEnvironment(environment);
LifecycleUtils.init(environment);
return environment;
}
/**
* Any additional customization of the Environment can be by overriding this method. For example setup shared
* resources, etc. By default this method does nothing.
* @param environment
*/
protected void customizeEnvironment(WebEnvironment environment) {
}
/**
* Destroys the {@link WebEnvironment} for the given servlet context.
*
* @param servletContext the ServletContext attributed to the WebSecurityManager
*/
public void destroyEnvironment(ServletContext servletContext) {
servletContext.log("Cleaning up Shiro Environment");
try {
Object environment = servletContext.getAttribute(ENVIRONMENT_ATTRIBUTE_KEY);
if (environment instanceof WebEnvironment) {
finalizeEnvironment((WebEnvironment) environment);
}
LifecycleUtils.destroy(environment);
} finally {
servletContext.removeAttribute(ENVIRONMENT_ATTRIBUTE_KEY);
}
}
/**
* Any additional cleanup of the Environment can be done by overriding this method. For example clean up shared
* resources, etc. By default this method does nothing.
* @param environment
* @since 1.3
*/
protected void finalizeEnvironment(WebEnvironment environment) {
}
}
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