org.apache.struts2.views.velocity.VelocityManager Maven / Gradle / Ivy
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* to you 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
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* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
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package org.apache.struts2.views.velocity;
import com.opensymphony.xwork2.ObjectFactory;
import com.opensymphony.xwork2.inject.Container;
import com.opensymphony.xwork2.inject.Inject;
import com.opensymphony.xwork2.util.ValueStack;
import org.apache.commons.lang3.StringUtils;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.struts2.ServletActionContext;
import org.apache.struts2.StrutsConstants;
import org.apache.struts2.StrutsException;
import org.apache.struts2.views.TagLibraryDirectiveProvider;
import org.apache.struts2.views.util.ContextUtil;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.Velocity;
import org.apache.velocity.app.VelocityEngine;
import org.apache.velocity.context.Context;
import org.apache.velocity.tools.ToolContext;
import org.apache.velocity.tools.ToolManager;
import org.apache.velocity.tools.ToolboxFactory;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import static java.lang.String.format;
import static java.util.Collections.emptyList;
import static java.util.stream.Collectors.joining;
import static java.util.stream.Collectors.toList;
import static org.apache.struts2.views.util.ContextUtil.STRUTS;
/**
* Manages the environment for Velocity result types
*/
public class VelocityManager implements VelocityManagerInterface {
private static final Logger LOG = LogManager.getLogger(VelocityManager.class);
private ObjectFactory objectFactory;
public static final String KEY_VELOCITY_STRUTS_CONTEXT = ".KEY_velocity.struts2.context";
private VelocityEngine velocityEngine;
/**
* A reference to the toolbox manager.
*/
protected ToolManager toolboxManager = null;
private String toolBoxLocation;
/**
* Names of contexts that will be chained on every request
*/
private List chainedContextNames = emptyList();
private Properties velocityProperties;
private String customConfigFile;
private List tagLibraries;
@Inject
public void setObjectFactory(ObjectFactory fac) {
this.objectFactory = fac;
}
@Inject
public void setContainer(Container container) {
List list = container.getInstanceNames(TagLibraryDirectiveProvider.class).stream()
.map(prefix -> container.getInstance(TagLibraryDirectiveProvider.class, prefix)).collect(toList());
this.tagLibraries = Collections.unmodifiableList(list);
}
/**
* @return a reference to the VelocityEngine used by all Struts Velocity results except directly
* accessed *.vm pages (unless otherwise configured)
*/
@Override
public VelocityEngine getVelocityEngine() {
return velocityEngine;
}
/**
* This method is responsible for creating the standard VelocityContext used by all Struts Velocity views.
*
* @param stack the current {@link ValueStack}
* @param req the current HttpServletRequest
* @param res the current HttpServletResponse
* @return a new StrutsVelocityContext
*/
@Override
public Context createContext(ValueStack stack, HttpServletRequest req, HttpServletResponse res) {
Context context = buildToolContext();
if (context == null) {
context = buildContext(stack, req, res);
}
req.setAttribute(KEY_VELOCITY_STRUTS_CONTEXT, context);
return context;
}
protected Context buildContext(ValueStack stack, HttpServletRequest req, HttpServletResponse res) {
List chainedContexts = prepareChainedContexts(req, res, stack.getContext());
Context context = new StrutsVelocityContext(chainedContexts, stack);
ContextUtil.getStandardContext(stack, req, res).forEach(context::put);
VelocityStrutsUtil util = new VelocityStrutsUtil(velocityEngine, context, stack, req, res);
context.put(STRUTS, util);
return context;
}
protected Context buildToolContext() {
if (toolboxManager == null) {
return null;
}
ServletContext ctx;
try {
ctx = ServletActionContext.getServletContext();
} catch (NullPointerException e) {
return null;
}
if (ctx == null) {
return null;
}
ToolContext toolContext = new ToolContext(velocityEngine);
toolContext.addToolbox(toolboxManager.getToolboxFactory().createToolbox(ToolboxFactory.DEFAULT_SCOPE));
return toolContext;
}
/**
* constructs contexts for chaining on this request. This method does not
* perform any initialization of the contexts. All that must be done in the
* context itself.
*
* @param servletRequest the servlet request object
* @param servletResponse the servlet response object
* @param extraContext map with extra context
* @return a List of contexts to chain or an empty list
*/
protected List prepareChainedContexts(HttpServletRequest servletRequest, HttpServletResponse servletResponse, Map extraContext) {
List contextList = new ArrayList<>();
for (String className : chainedContextNames) {
try {
VelocityContext velocityContext = (VelocityContext) objectFactory.buildBean(className, extraContext);
contextList.add(velocityContext);
} catch (Exception e) {
LOG.warn(format("Unable to instantiate chained VelocityContext %s, skipping", className), e);
}
}
return contextList;
}
/**
* initializes the VelocityManager. this should be called during the initialization process, say by
* ServletDispatcher. this may be called multiple times safely although calls beyond the first won't do anything
*
* @param context the current servlet context
*/
@Override
public synchronized void init(ServletContext context) {
if (velocityEngine == null) {
velocityEngine = newVelocityEngine(context);
}
this.initToolbox(context);
}
/**
* load optional velocity properties using the following loading strategy
*
* - relative to the servlet context path
* - relative to the WEB-INF directory
* - on the classpath
*
*
* @param context the current ServletContext. may not be null
* @return the optional properties if struts.velocity.configfile was specified, an empty Properties file otherwise
*/
public Properties loadConfiguration(ServletContext context) {
if (context == null) {
String gripe = "Error attempting to create a loadConfiguration from a null ServletContext!";
LOG.error(gripe);
throw new IllegalArgumentException(gripe);
}
Properties properties = new Properties();
// now apply our systemic defaults, then allow user to override
applyDefaultConfiguration(context, properties);
String defaultUserDirective = properties.getProperty("userdirective");
/*
if the user has specified an external velocity configuration file, we'll want to search for it in the
following order
1. relative to the context path
2. relative to /WEB-INF
3. in the class path
*/
String configfile;
if (customConfigFile != null) {
configfile = customConfigFile;
} else {
configfile = "velocity.properties";
}
configfile = configfile.trim();
InputStream in = null;
String resourceLocation = null;
try {
if (context.getRealPath(configfile) != null) {
// 1. relative to context path, i.e. /velocity.properties
String filename = context.getRealPath(configfile);
if (filename != null) {
File file = new File(filename);
if (file.isFile()) {
resourceLocation = file.getCanonicalPath() + " from file system";
in = new FileInputStream(file);
}
// 2. if nothing was found relative to the context path, search relative to the WEB-INF directory
if (in == null) {
file = new File(context.getRealPath("/WEB-INF/" + configfile));
if (file.isFile()) {
resourceLocation = file.getCanonicalPath() + " from file system";
in = new FileInputStream(file);
}
}
}
}
// 3. finally, if there's no physical file, how about something in our classpath
if (in == null) {
in = VelocityManager.class.getClassLoader().getResourceAsStream(configfile);
if (in != null) {
resourceLocation = configfile + " from classloader";
}
}
// if we've got something, load 'er up
if (in != null) {
LOG.info("Initializing velocity using {}", resourceLocation);
properties.load(in);
}
} catch (IOException e) {
LOG.warn("Unable to load velocity configuration {}", resourceLocation, e);
} finally {
if (in != null) {
try {
in.close();
} catch (IOException ignore) {
}
}
}
// overide with programmatically set properties
if (velocityProperties != null) {
for (Object o : velocityProperties.keySet()) {
String key = (String) o;
properties.setProperty(key, this.velocityProperties.getProperty(key));
}
}
String userdirective = properties.getProperty("userdirective");
if (userdirective == null || userdirective.trim().isEmpty()) {
userdirective = defaultUserDirective;
} else {
userdirective = userdirective.trim() + "," + defaultUserDirective;
}
properties.setProperty("userdirective", userdirective);
// for debugging purposes, allows users to dump out the properties that have been configured
if (LOG.isDebugEnabled()) {
LOG.debug("Initializing Velocity with the following properties ...");
for (Object o : properties.keySet()) {
String key = (String) o;
String value = properties.getProperty(key);
LOG.debug(" '{}' = '{}'", key, value);
}
}
return properties;
}
@Inject(StrutsConstants.STRUTS_VELOCITY_CONFIGFILE)
public void setCustomConfigFile(String val) {
this.customConfigFile = val;
}
@Inject(StrutsConstants.STRUTS_VELOCITY_TOOLBOXLOCATION)
public void setToolBoxLocation(String toolboxLocation) {
this.toolBoxLocation = toolboxLocation;
}
public ToolManager getToolboxManager() {
return toolboxManager;
}
/**
* allow users to specify via the struts.properties file a set of additional VelocityContexts to chain to the
* the StrutsVelocityContext. The intent is to allow these contexts to store helper objects that the ui
* developer may want access to. Examples of reasonable VelocityContexts would be an IoCVelocityContext, a
* SpringReferenceVelocityContext, and a ToolboxVelocityContext
*
* @param contexts comma separated velocity context's
*/
@Inject(StrutsConstants.STRUTS_VELOCITY_CONTEXTS)
public void setChainedContexts(String contexts) {
this.chainedContextNames = Arrays.stream(contexts.split(",")).filter(StringUtils::isNotBlank).collect(toList());
}
/**
* Initializes the ServletToolboxManager for this servlet's
* toolbox (if any).
*/
protected void initToolbox(ServletContext servletContext) {
if (StringUtils.isBlank(toolBoxLocation)) {
LOG.debug("Skipping ToolManager initialisation, [{}] was not defined", StrutsConstants.STRUTS_VELOCITY_TOOLBOXLOCATION);
return;
}
LOG.debug("Configuring Velocity ToolManager with {}", toolBoxLocation);
toolboxManager = new ToolManager();
toolboxManager.configure(toolBoxLocation);
}
/**
*
* Instantiates a new VelocityEngine.
*
*
* The following is the default Velocity configuration
*
*
*
* resource.loader = file, class
* file.resource.loader.path = real path of webapp
* class.resource.loader.description = Velocity Classpath Resource Loader
* class.resource.loader.class = org.apache.struts2.views.velocity.StrutsResourceLoader
*
*
* this default configuration can be overridden by specifying a struts.velocity.configfile property in the
* struts.properties file. the specified config file will be searched for in the following order:
*
*
*
* - relative to the servlet context path
* - relative to the WEB-INF directory
* - on the classpath
*
*
* @param context the current ServletContext. may not be null
* @return the new velocity engine
*/
protected VelocityEngine newVelocityEngine(ServletContext context) {
if (context == null) {
throw new IllegalArgumentException("Error attempting to create a new VelocityEngine from a null ServletContext!");
}
VelocityEngine velocityEngine = new VelocityEngine();
// Set the velocity attribute for the servlet context, if this is not set the webapp loader WILL NOT WORK
velocityEngine.setApplicationAttribute(ServletContext.class.getName(), context);
try {
velocityEngine.init(loadConfiguration(context));
} catch (Exception e) {
throw new StrutsException("Unable to instantiate VelocityEngine!", e);
}
return velocityEngine;
}
/**
* once we've loaded up the user defined configurations, we will want to apply Struts specification configurations.
*
* - if Velocity.RESOURCE_LOADER has not been defined, then we will use the defaults which is a joined file,
* class loader for unpackaed wars and a straight class loader otherwise
* - we need to define the various Struts custom user directives such as #param, #tag, and #bodytag
*
*
* @param context the servlet context
* @param properties velocity properties
*/
private void applyDefaultConfiguration(ServletContext context, Properties properties) {
// ensure that caching isn't overly aggressive
LOG.debug("Load a default resource loader definition if there isn't one present.");
if (properties.getProperty(Velocity.RESOURCE_LOADER) == null) {
properties.setProperty(Velocity.RESOURCE_LOADER, "strutsfile, strutsclass");
}
/*
* If there's a "real" path add it for the strutsfile resource loader.
* If there's no real path and they haven't configured a loader then we change
* resource loader property to just use the strutsclass loader
* Ben Hall (22/08/2003)
*/
if (context.getRealPath("") != null) {
properties.setProperty("strutsfile.resource.loader.description", "Velocity File Resource Loader");
properties.setProperty("strutsfile.resource.loader.class", "org.apache.velocity.runtime.resource.loader.FileResourceLoader");
properties.setProperty("strutsfile.resource.loader.path", context.getRealPath(""));
properties.setProperty("strutsfile.resource.loader.modificationCheckInterval", "2");
properties.setProperty("strutsfile.resource.loader.cache", "true");
} else {
// remove strutsfile from resource loader property
String prop = properties.getProperty(Velocity.RESOURCE_LOADER);
if (prop.contains("strutsfile,")) {
prop = prop.replace("strutsfile,", "");
} else if (prop.contains(", strutsfile")) {
prop = prop.replace(", strutsfile", "");
} else if (prop.contains("strutsfile")) {
prop = prop.replace("strutsfile", "");
}
properties.setProperty(Velocity.RESOURCE_LOADER, prop);
}
/*
* Refactored the Velocity templates for the Struts taglib into the classpath from the web path. This will
* enable Struts projects to have access to the templates by simply including the Struts jar file.
* Unfortunately, there does not appear to be a macro for the class loader keywords
*/
properties.setProperty("strutsclass.resource.loader.description", "Velocity Classpath Resource Loader");
properties.setProperty("strutsclass.resource.loader.class", "org.apache.struts2.views.velocity.StrutsResourceLoader");
properties.setProperty("strutsclass.resource.loader.modificationCheckInterval", "2");
properties.setProperty("strutsclass.resource.loader.cache", "true");
// components
String directives = tagLibraries.stream().map(TagLibraryDirectiveProvider::getDirectiveClasses).flatMap(
Collection::stream).map(directive -> directive.getName() + ",").collect(joining());
String userdirective = properties.getProperty("userdirective");
if (userdirective == null || userdirective.trim().isEmpty()) {
userdirective = directives;
} else {
userdirective = userdirective.trim() + "," + directives;
}
properties.setProperty("userdirective", userdirective);
}
/**
* @return the velocityProperties
*/
public Properties getVelocityProperties() {
return velocityProperties;
}
/**
* @param velocityProperties the velocityProperties to set
*/
public void setVelocityProperties(Properties velocityProperties) {
this.velocityProperties = velocityProperties;
}
}