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Groovy: A powerful, dynamic language for the JVM
/*
* Copyright 2003-2007 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
*
* 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.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 common ground dealing with the HTTP servlet API wrinkles.
*
* Resource name mangling (pattern replacement)
*
*
* Also implements Groovy's {@link groovy.util.ResourceConnector} in dynamic
* manner. It allows to modifiy 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:
*
* 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
*/
public abstract class AbstractHttpServlet extends HttpServlet implements ResourceConnector {
/**
* 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;
/**
* Null or compiled pattern matcher read from "resource.name.regex"
* and used in {@link AbstractHttpServlet#getResourceConnection(String)}.
*/
protected Matcher resourceNameMatcher;
/**
* 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;
/**
* Initializes all fields with default values.
*/
public AbstractHttpServlet() {
this.servletContext = null;
this.resourceNameMatcher = null;
this.resourceNameReplacement = null;
this.resourceNameReplaceAll = true;
this.verbose = false;
this.reflection = false;
this.logGROOVY861 = false;
}
/**
* Interface method for ResourceContainer. This is used by the GroovyScriptEngine.
*/
public URLConnection getResourceConnection(String name) throws ResourceException {
/*
* First, mangle resource name with the compiled pattern.
*/
Matcher matcher = resourceNameMatcher;
if (matcher != null) {
matcher.reset(name);
String replaced;
if (resourceNameReplaceAll) {
replaced = resourceNameMatcher.replaceAll(resourceNameReplacement);
} else {
replaced = resourceNameMatcher.replaceFirst(resourceNameReplacement);
}
if (!name.equals(replaced)) {
if (verbose) {
log("Replaced resource name \"" + name + "\" with \"" + replaced + "\".");
}
name = replaced;
}
}
/*
* 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 http://jira.codehaus.org/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 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 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
*/
protected File getScriptUriAsFile(HttpServletRequest request) {
String uri = getScriptUri(request);
String real = servletContext.getRealPath(uri);
File file = new File(real).getAbsoluteFile();
return file;
}
/**
* Overrides the generic init method to set some debug flags.
*
* @param config
* the servlet coniguration 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).booleanValue();
}
// 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("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);
}
int flags = 0; // TODO : Parse pattern compile flags.
this.resourceNameMatcher = Pattern.compile(regex, flags).matcher("");
this.resourceNameReplacement = replacement;
String all = config.getInitParameter("resource.name.replace.all");
if (all != null) {
this.resourceNameReplaceAll = Boolean.valueOf(all).booleanValue();
}
}
value = config.getInitParameter("logGROOVY861");
if (value != null) {
this.logGROOVY861 = Boolean.valueOf(value).booleanValue();
// nothing else to do here
}
/*
* If verbose, log the parameter values.
*/
if (verbose) {
log("(Abstract) init done. Listing some parameter name/value pairs:");
log("verbose = " + verbose); // this *is* verbose! ;)
log("reflection = " + reflection);
log("logGROOVY861 = " + logGROOVY861);
if (resourceNameMatcher != null) {
log("resource.name.regex = " + resourceNameMatcher.pattern().pattern());
}
else {
log("resource.name.regex = null");
}
log("resource.name.replacement = " + resourceNameReplacement);
}
}
/**
* Override this method to set your variables to the Groovy binding.
*
* 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 implicite 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 Mytlet 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
}
}