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
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*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
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* KIND, either express or implied. See the License for the
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* under the License.
*/
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.util.VelocityStrutsUtil;
import org.apache.struts2.views.TagLibraryDirectiveProvider;
import org.apache.struts2.views.jsp.ui.OgnlTool;
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.view.ToolboxManager;
import org.apache.velocity.tools.view.context.ChainedContext;
import org.apache.velocity.tools.view.servlet.ServletToolboxManager;
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.*;
/**
* Manages the environment for Velocity result types
*/
public class VelocityManager {
private static final Logger LOG = LogManager.getLogger(VelocityManager.class);
public static final String STRUTS = "struts";
private ObjectFactory objectFactory;
public static final String KEY_VELOCITY_STRUTS_CONTEXT = ".KEY_velocity.struts2.context";
/**
* the parent JSP tag
*/
public static final String PARENT = "parent";
/**
* the current JSP tag
*/
public static final String TAG = "tag";
private VelocityEngine velocityEngine;
/**
* A reference to the toolbox manager.
*/
protected ToolboxManager toolboxManager = null;
private String toolBoxLocation;
/**
* Names of contexts that will be chained on every request
*/
private String[] chainedContextNames;
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 = new ArrayList<>();
Set prefixes = container.getInstanceNames(TagLibraryDirectiveProvider.class);
for (String prefix : prefixes) {
list.add(container.getInstance(TagLibraryDirectiveProvider.class, prefix));
}
this.tagLibraries = Collections.unmodifiableList(list);
}
/**
* @return a reference to the VelocityEngine used by all struts velocity thingies with the exception of
* directly accessed *.vm pages
*/
public VelocityEngine getVelocityEngine() {
return velocityEngine;
}
/**
*
* This method is responsible for creating the standard VelocityContext used by all WW2 velocity views. The
* following context parameters are defined:
*
*
*
* - request - the current HttpServletRequest
* - response - the current HttpServletResponse
* - stack - the current {@link ValueStack}
* - ognl - an {@link OgnlTool}
* - struts - an instance of {@link org.apache.struts2.util.StrutsUtil}
* - action - the current Struts action
*
*
* @param stack the current {@link ValueStack}
* @param req the current HttpServletRequest
* @param res the current HttpServletResponse
* @return a new StrutsVelocityContext
*/
public Context createContext(ValueStack stack, HttpServletRequest req, HttpServletResponse res) {
Context result = null;
VelocityContext[] chainedContexts = prepareChainedContexts(req, res, stack.getContext());
StrutsVelocityContext context = new StrutsVelocityContext(chainedContexts, stack);
Map standardMap = ContextUtil.getStandardContext(stack, req, res);
for (Iterator iterator = standardMap.entrySet().iterator(); iterator.hasNext();) {
Map.Entry entry = (Map.Entry) iterator.next();
context.put((String) entry.getKey(), entry.getValue());
}
context.put(STRUTS, new VelocityStrutsUtil(velocityEngine, context, stack, req, res));
ServletContext ctx = null;
try {
ctx = ServletActionContext.getServletContext();
} catch (NullPointerException npe) {
// in case this was used outside the lifecycle of struts servlet
LOG.debug("internal toolbox context ignored");
}
if (toolboxManager != null && ctx != null) {
ChainedContext chained = new ChainedContext(context, velocityEngine, req, res, ctx);
chained.setToolbox(toolboxManager.getToolbox(chained));
result = chained;
} else {
result = context;
}
req.setAttribute(KEY_VELOCITY_STRUTS_CONTEXT, result);
return result;
}
/**
* 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 an VelocityContext[] of contexts to chain
*/
protected VelocityContext[] prepareChainedContexts(HttpServletRequest servletRequest, HttpServletResponse servletResponse, Map extraContext) {
if (this.chainedContextNames == null) {
return null;
}
List contextList = new ArrayList();
for (int i = 0; i < chainedContextNames.length; i++) {
String className = chainedContextNames[i];
try {
VelocityContext velocityContext = (VelocityContext) objectFactory.buildBean(className, null);
contextList.add(velocityContext);
} catch (Exception e) {
LOG.warn("Warning. {} caught while attempting to instantiate a chained VelocityContext, {} -- skipping", e.getClass().getName(), className);
}
}
if (contextList.size() > 0) {
VelocityContext[] extraContexts = new VelocityContext[contextList.size()];
contextList.toArray(extraContexts);
return extraContexts;
} else {
return null;
}
}
/**
* 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
*/
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 e) {
}
}
}
// overide with programmatically set properties
if (this.velocityProperties != null) {
Iterator keys = this.velocityProperties.keySet().iterator();
while (keys.hasNext()) {
String key = (String) keys.next();
properties.setProperty(key, this.velocityProperties.getProperty(key));
}
}
String userdirective = properties.getProperty("userdirective");
if ((userdirective == null) || userdirective.trim().equals("")) {
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 (Iterator iter = properties.keySet().iterator(); iter.hasNext(); ) {
String key = (String) iter.next();
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 ToolboxManager 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) {
// we expect contexts to be a comma separated list of classnames
StringTokenizer st = new StringTokenizer(contexts, ",");
List contextList = new ArrayList<>();
while (st.hasMoreTokens()) {
String classname = st.nextToken();
contextList.add(classname);
}
if (contextList.size() > 0) {
String[] chainedContexts = new String[contextList.size()];
contextList.toArray(chainedContexts);
this.chainedContextNames = chainedContexts;
}
}
/**
* Initializes the ServletToolboxManager for this servlet's
* toolbox (if any).
*
* @param context the servlet context
*/
protected void initToolbox(ServletContext context) {
/* if we have a toolbox, get a manager for it */
if (StringUtils.isNotBlank(toolBoxLocation)) {
toolboxManager = ServletToolboxManager.getInstance(context, toolBoxLocation);
} else {
Velocity.info("VelocityViewServlet: No toolbox entry in configuration.");
}
}
/**
*
* 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) {
String gripe = "Error attempting to create a new VelocityEngine from a null ServletContext!";
LOG.error(gripe);
throw new IllegalArgumentException(gripe);
}
Properties p = loadConfiguration(context);
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(p);
} 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
/**
* Load a default resource loader definition if there isn't one present.
* Ben Hall (22/08/2003)
*/
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.indexOf("strutsfile,") != -1) {
prop = replace(prop, "strutsfile,", "");
} else if (prop.indexOf(", strutsfile") != -1) {
prop = replace(prop, ", strutsfile", "");
} else if (prop.indexOf("strutsfile") != -1) {
prop = replace(prop, "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
* Matt Ho - Mon Mar 17 00:21:46 PST 2003
*/
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
StringBuilder sb = new StringBuilder();
for (TagLibraryDirectiveProvider tagLibrary : tagLibraries) {
List directives = tagLibrary.getDirectiveClasses();
for (Class directive : directives) {
addDirective(sb, directive);
}
}
String directives = sb.toString();
String userdirective = properties.getProperty("userdirective");
if ((userdirective == null) || userdirective.trim().equals("")) {
userdirective = directives;
} else {
userdirective = userdirective.trim() + "," + directives;
}
properties.setProperty("userdirective", userdirective);
}
private void addDirective(StringBuilder sb, Class clazz) {
sb.append(clazz.getName()).append(",");
}
private static final String replace(String string, String oldString, String newString) {
if (string == null) {
return null;
}
// If the newString is null, just return the string since there's nothing to replace.
if (newString == null) {
return string;
}
int i = 0;
// Make sure that oldString appears at least once before doing any processing.
if ((i = string.indexOf(oldString, i)) >= 0) {
// Use char []'s, as they are more efficient to deal with.
char[] string2 = string.toCharArray();
char[] newString2 = newString.toCharArray();
int oLength = oldString.length();
StringBuilder buf = new StringBuilder(string2.length);
buf.append(string2, 0, i).append(newString2);
i += oLength;
int j = i;
// Replace all remaining instances of oldString with newString.
while ((i = string.indexOf(oldString, i)) > 0) {
buf.append(string2, j, i - j).append(newString2);
i += oLength;
j = i;
}
buf.append(string2, j, string2.length - j);
return buf.toString();
}
return string;
}
/**
* @return the velocityProperties
*/
public Properties getVelocityProperties() {
return velocityProperties;
}
/**
* @param velocityProperties the velocityProperties to set
*/
public void setVelocityProperties(Properties velocityProperties) {
this.velocityProperties = velocityProperties;
}
}