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Groovy: A powerful, dynamic language for the JVM
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* 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
* "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 groovy.servlet;
import groovy.util.ResourceConnector;
import groovy.util.ResourceException;
import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLConnection;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
/**
* A base class dealing with common HTTP servlet API housekeeping aspects.
*
*
Resource name mangling (pattern replacement)
*
* Also implements Groovy's {@link groovy.util.ResourceConnector} in a dynamic
* manner. It allows you to modify the resource name that is searched for with a
* replace all operation. See {@link java.util.regex.Pattern} and
* {@link java.util.regex.Matcher} for details.
* The servlet init parameter names are:
*
* {@value #INIT_PARAM_RESOURCE_NAME_REGEX} = empty - defaults to null
* resource.name.replacement = empty - defaults to null
* resource.name.replace.all = true (default) | false means replaceFirst()
*
* Note: If you specify a regex, you have to specify a replacement string too!
* Otherwise an exception gets raised.
*
*
Logging and bug-hunting options
*
* This implementation provides a verbosity flag switching log statements.
* The servlet init parameter name is:
*
* verbose = false(default) | true
*
*
* In order to support class-loading-troubles-debugging with Tomcat 4 or
* higher, you can log the class loader responsible for loading some classes.
* See GROOVY-861 for details.
* The servlet init parameter name is:
*
* log.GROOVY861 = false(default) | true
*
*
* If you experience class-loading-troubles with Tomcat 4 (or higher) or any
* other servlet container using custom class loader setups, you can fallback
* to use (slower) reflection in Groovy's MetaClass implementation. Please
* contact the dev team with your problem! Thanks.
* The servlet init parameter name is:
*
* reflection = false(default) | true
*
*
* @author Christian Stein
* @author Roshan Dawrani (roshandawrani)
*/
public abstract class AbstractHttpServlet extends HttpServlet implements ResourceConnector {
public static final String INIT_PARAM_RESOURCE_NAME_REGEX = "resource.name.regex";
public static final String INIT_PARAM_RESOURCE_NAME_REGEX_FLAGS = "resource.name.regex.flags";
/**
* Content type of the HTTP response.
*/
public static final String CONTENT_TYPE_TEXT_HTML = "text/html";
/**
* Servlet API include key name: path_info
*/
public static final String INC_PATH_INFO = "javax.servlet.include.path_info";
/* *** Not used, yet. See comments in getScriptUri(HttpServletRequest). ***
* Servlet API include key name: request_uri
*/
public static final String INC_REQUEST_URI = "javax.servlet.include.request_uri";
/**
* Servlet API include key name: servlet_path
*/
public static final String INC_SERVLET_PATH = "javax.servlet.include.servlet_path";
/**
* Servlet (or the web application) context.
*/
protected ServletContext servletContext;
/**
* Either null or a compiled pattern read from "{@value #INIT_PARAM_RESOURCE_NAME_REGEX}"
* and used in {@link AbstractHttpServlet#getScriptUri(HttpServletRequest)}.
*/
protected Pattern resourceNamePattern;
/**
* The replacement used by the resource name matcher.
*/
protected String resourceNameReplacement;
/**
* The replace method to use on the matcher.
*
* true - replaceAll(resourceNameReplacement); (default)
* false - replaceFirst(resourceNameReplacement);
*
*/
protected boolean resourceNameReplaceAll;
/**
* Controls almost all log output.
*/
protected boolean verbose;
/**
* Encoding to use, becomes charset part of contentType.
*/
protected String encoding = "UTF-8";
/**
* Mirrors the static value of the reflection flag in MetaClass.
* See AbstractHttpServlet#logGROOVY861
*/
protected boolean reflection;
/**
* Debug flag logging the class the class loader of the request.
*/
private boolean logGROOVY861;
/** a.fink: it was in {@link #removeNamePrefix}, but was extracted to var for optimization*/
protected String namePrefix;
/**
* Initializes all fields with default values.
*/
public AbstractHttpServlet () {
this.servletContext = null;
this.resourceNameReplacement = null;
this.resourceNameReplaceAll = true;
this.verbose = false;
this.reflection = false;
this.logGROOVY861 = false;
}
protected void generateNamePrefixOnce () {
URI uri = null;
String realPath = servletContext.getRealPath("/");
if (realPath != null) { uri = new File(realPath).toURI();}//prevent NPE if in .war
try {
URL res = servletContext.getResource("/");
if (res != null) { uri = res.toURI(); }
} catch (MalformedURLException ignore) {
} catch (URISyntaxException ignore) {
}
if (uri != null) {
try {
namePrefix = uri.toURL().toExternalForm();
return;
} catch (MalformedURLException e) {
log("generateNamePrefixOnce [ERROR] Malformed URL for base path / == '"+ uri +'\'', e);
}
}
namePrefix = "";
}
protected String removeNamePrefix(String name) throws ResourceException {
if (namePrefix == null) {
generateNamePrefixOnce();
}
if (name.startsWith(namePrefix)) {//usualy name has text
return name.substring(namePrefix.length());
}
return name;
}
/**
* Interface method for ResourceContainer. This is used by the GroovyScriptEngine.
*/
public URLConnection getResourceConnection (String name) throws ResourceException {
name = removeNamePrefix(name).replace('\\', '/');
//remove the leading / as we are trying with a leading / now
if (name.startsWith("WEB-INF/groovy/")) {
name = name.substring(15);//just for uniformity
} else if (name.startsWith("/")) {
name = name.substring(1);
}
/*
* Try to locate the resource and return an opened connection to it.
*/
try {
URL url = servletContext.getResource('/' + name);
if (url == null) {
url = servletContext.getResource("/WEB-INF/groovy/" + name);
}
if (url == null) {
throw new ResourceException("Resource \"" + name + "\" not found!");
}
return url.openConnection();
} catch (IOException e) {
throw new ResourceException("Problems getting resource named \"" + name + "\"!", e);
}
}
/**
* Returns the include-aware uri of the script or template file.
*
* @param request the http request to analyze
* @return the include-aware uri either parsed from request attributes or
* hints provided by the servlet container
*/
protected String getScriptUri(HttpServletRequest request) {
/*
* Log some debug information for https://issues.apache.org/jira/browse/GROOVY-861
*/
if (logGROOVY861) {
log("Logging request class and its class loader:");
log(" c = request.getClass() :\"" + request.getClass() + "\"");
log(" l = c.getClassLoader() :\"" + request.getClass().getClassLoader() + "\"");
log(" l.getClass() :\"" + request.getClass().getClassLoader().getClass() + "\"");
/*
* Keep logging, if we're verbose. Else turn it off.
*/
logGROOVY861 = verbose;
}
//
// NOTE: This piece of code is heavily inspired by Apaches Jasper2!
//
// http://cvs.apache.org/viewcvs.cgi/jakarta-tomcat-jasper/jasper2/ \
// src/share/org/apache/jasper/servlet/JspServlet.java?view=markup
//
// Why doesn't it use request.getRequestURI() or INC_REQUEST_URI?
//
String uri = null;
String info = null;
//
// Check to see if the requested script/template source file has been the
// target of a RequestDispatcher.include().
//
uri = (String) request.getAttribute(INC_SERVLET_PATH);
if (uri != null) {
//
// Requested script/template file has been target of
// RequestDispatcher.include(). Its path is assembled from the relevant
// javax.servlet.include.* request attributes and returned!
//
info = (String) request.getAttribute(INC_PATH_INFO);
if (info != null) {
uri += info;
}
return applyResourceNameMatcher(uri);
}
//
// Requested script/template file has not been the target of a
// RequestDispatcher.include(). Reconstruct its path from the request's
// getServletPath() and getPathInfo() results.
//
uri = request.getServletPath();
info = request.getPathInfo();
if (info != null) {
uri += info;
}
/*
* TODO : Enable auto ".groovy" extension replacing here!
* http://cvs.groovy.codehaus.org/viewrep/groovy/groovy/groovy-core/src/main/groovy/servlet/GroovyServlet.java?r=1.10#l259
*/
return applyResourceNameMatcher(uri);
}
protected String applyResourceNameMatcher (String uri) {
if (resourceNamePattern != null) {// mangle resource name with the compiled pattern.
Matcher matcher = resourceNamePattern.matcher(uri);
String replaced;
if (resourceNameReplaceAll) {
replaced = matcher.replaceAll(resourceNameReplacement);
} else {
replaced = matcher.replaceFirst(resourceNameReplacement);
}
if (!uri.equals(replaced)) {
if (verbose) {
log("Replaced resource name \"" + uri + "\" with \"" + replaced + "\".");
}
return replaced;
}
}
return uri;
}
/**
* Parses the http request for the real script or template source file.
*
* @param request
* the http request to analyze
* @return a file object using an absolute file path name, or null if the
* servlet container cannot translate the virtual path to a real
* path for any reason (such as when the content is being made
* available from a .war archive).
*/
protected File getScriptUriAsFile(HttpServletRequest request) {
String uri = getScriptUri(request);
String real = servletContext.getRealPath(uri);
if (real == null) {
return null;
}
return new File(real).getAbsoluteFile();
}
/**
* Overrides the generic init method to set some debug flags.
*
* @param config the servlet configuration provided by the container
* @throws ServletException if init() method defined in super class
* javax.servlet.GenericServlet throws it
*/
public void init(ServletConfig config) throws ServletException {
/*
* Never forget super.init()!
*/
super.init(config);
/*
* Grab the servlet context.
*/
this.servletContext = config.getServletContext();
// Get verbosity hint.
String value = config.getInitParameter("verbose");
if (value != null) {
this.verbose = Boolean.valueOf(value);
}
// get encoding
value = config.getInitParameter("encoding");
if (value != null) {
this.encoding = value;
}
// And now the real init work...
if (verbose) {
log("Parsing init parameters...");
}
String regex = config.getInitParameter(INIT_PARAM_RESOURCE_NAME_REGEX);
if (regex != null) {
String replacement = config.getInitParameter("resource.name.replacement");
if (replacement == null) {
Exception npex = new NullPointerException("resource.name.replacement");
String message = "Init-param 'resource.name.replacement' not specified!";
log(message, npex);
throw new ServletException(message, npex);
} else if ("EMPTY_STRING".equals(replacement)) {//
* All variables bound the binding are passed to the template source text,
* e.g. the HTML file, when the template is merged.
*
* The binding provided by TemplateServlet does already include some default
* variables. As of this writing, they are (copied from
* {@link groovy.servlet.ServletBinding}):
*
* - "request" : HttpServletRequest
* - "response" : HttpServletResponse
* - "context" : ServletContext
* - "application" : ServletContext
* - "session" : request.getSession(false)
*
*
* And via implicit hard-coded keywords:
*
* - "out" : response.getWriter()
* - "sout" : response.getOutputStream()
* - "html" : new MarkupBuilder(response.getWriter())
*
*
* The binding also provides convenient methods:
*
* - "forward(String path)" : request.getRequestDispatcher(path).forward(request, response);
* - "include(String path)" : request.getRequestDispatcher(path).include(request, response);
* - "redirect(String location)" : response.sendRedirect(location);
*
*
*
Example binding all servlet context variables:
*
* class MyServlet extends TemplateServlet {
*
* protected void setVariables(ServletBinding binding) {
* // Bind a simple variable
* binding.setVariable("answer", new Long(42));
*
* // Bind all servlet context attributes...
* ServletContext context = (ServletContext) binding.getVariable("context");
* Enumeration enumeration = context.getAttributeNames();
* while (enumeration.hasMoreElements()) {
* String name = (String) enumeration.nextElement();
* binding.setVariable(name, context.getAttribute(name));
* }
* }
* }
*
*
* @param binding to be modified
*/
protected void setVariables(ServletBinding binding) {
// empty
}
}