    001package org.apache.turbine.services.jsp;
    002
    003
    004/*
    005 * Licensed to the Apache Software Foundation (ASF) under one
    006 * or more contributor license agreements.  See the NOTICE file
    007 * distributed with this work for additional information
    008 * regarding copyright ownership.  The ASF licenses this file
    009 * to you under the Apache License, Version 2.0 (the
    010 * "License"); you may not use this file except in compliance
    011 * with the License.  You may obtain a copy of the License at
    012 *
    013 *   http://www.apache.org/licenses/LICENSE-2.0
    014 *
    015 * Unless required by applicable law or agreed to in writing,
    016 * software distributed under the License is distributed on an
    017 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    018 * KIND, either express or implied.  See the License for the
    019 * specific language governing permissions and limitations
    020 * under the License.
    021 */
    022
    023
    024import java.io.File;
    025import java.io.IOException;
    026
    027import javax.servlet.RequestDispatcher;
    028import javax.servlet.http.HttpServletRequest;
    029
    030import org.apache.commons.configuration.Configuration;
    031import org.apache.commons.lang.StringUtils;
    032import org.apache.commons.logging.Log;
    033import org.apache.commons.logging.LogFactory;
    034import org.apache.turbine.Turbine;
    035import org.apache.turbine.pipeline.PipelineData;
    036import org.apache.turbine.services.InitializationException;
    037import org.apache.turbine.services.pull.ApplicationTool;
    038import org.apache.turbine.services.pull.tools.TemplateLink;
    039import org.apache.turbine.services.template.BaseTemplateEngineService;
    040import org.apache.turbine.util.RunData;
    041import org.apache.turbine.util.TurbineException;
    042
    043/**
    044 * This is a Service that can process JSP templates from within a Turbine
    045 * screen.
    046 *
    047 * @author <a href="mailto:john.mcnally@clearink.com">John D. McNally</a>
    048 * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
    049 * @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
    050 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
    051 */
    052public class TurbineJspService
    053        extends BaseTemplateEngineService
    054        implements JspService
    055{
    056    /** The base path[s] prepended to filenames given in arguments */
    057    private String[] templatePaths;
    058
    059    /** The relative path[s] prepended to filenames */
    060    private String[] relativeTemplatePaths;
    061
    062    /** The buffer size for the output stream. */
    063    private int bufferSize;
    064
    065    /** Logging */
    066    private static Log log = LogFactory.getLog(TurbineJspService.class);
    067
    068    /**
    069     * Load all configured components and initialize them. This is
    070     * a zero parameter variant which queries the Turbine Servlet
    071     * for its config.
    072     *
    073     * @throws InitializationException Something went wrong in the init
    074     *         stage
    075     */
    076    @Override
    077    public void init()
    078        throws InitializationException
    079    {
    080        try
    081        {
    082            initJsp();
    083            registerConfiguration(JspService.JSP_EXTENSION);
    084            setInit(true);
    085        }
    086        catch (Exception e)
    087        {
    088            throw new InitializationException(
    089                "TurbineJspService failed to initialize", e);
    090        }
    091    }
    092
    093    /**
    094     * Adds some convenience objects to the request.  For example an instance
    095     * of TemplateLink which can be used to generate links to other templates.
    096     *
    097     * @param pipelineData the Turbine PipelineData object
    098     */
    099    @Override
    100    public void addDefaultObjects(PipelineData pipelineData)
    101    {
    102        HttpServletRequest req = pipelineData.get(Turbine.class, HttpServletRequest.class);
    103
    104        //
    105        // This is a place where an Application Pull Tool is used
    106        // in a regular Java Context. We have no Pull Service with the
    107        // Jsp Paging stuff, but we can run our Application Tool by Hand:
    108        //
    109        ApplicationTool templateLink = new TemplateLink();
    110        templateLink.init(pipelineData);
    111
    112        req.setAttribute(LINK, templateLink);
    113        req.setAttribute(PIPELINE_DATA, pipelineData);
    114    }
    115
    116    /**
    117     * Returns the default buffer size of the JspService
    118     *
    119     * @return The default buffer size.
    120     */
    121    @Override
    122    public int getDefaultBufferSize()
    123    {
    124        return bufferSize;
    125    }
    126
    127    /**
    128     * executes the JSP given by templateName.
    129     *
    130     * @param pipelineData A PipelineData Object
    131     * @param templateName The template to execute
    132     * @param isForward whether to perform a forward or include.
    133     *
    134     * @throws TurbineException If a problem occurred while executing the JSP
    135     */
    136    @Override
    137    public void handleRequest(PipelineData pipelineData, String templateName, boolean isForward)
    138        throws TurbineException
    139    {
    140        if(!(pipelineData instanceof RunData))
    141        {
    142            throw new RuntimeException("Can't cast to rundata from pipeline data.");
    143        }
    144
    145        RunData data = (RunData)pipelineData;
    146
    147        /** template name with relative path */
    148        String relativeTemplateName = getRelativeTemplateName(templateName);
    149
    150        if (StringUtils.isEmpty(relativeTemplateName))
    151        {
    152            throw new TurbineException(
    153                "Template " + templateName + " not found in template paths");
    154        }
    155
    156        // get the RequestDispatcher for the JSP
    157        RequestDispatcher dispatcher = data.getServletContext()
    158            .getRequestDispatcher(relativeTemplateName);
    159
    160        try
    161        {
    162            if (isForward)
    163            {
    164                // forward the request to the JSP
    165                dispatcher.forward(data.getRequest(), data.getResponse());
    166            }
    167            else
    168            {
    169                data.getResponse().getWriter().flush();
    170                // include the JSP
    171                dispatcher.include(data.getRequest(), data.getResponse());
    172            }
    173        }
    174        catch (Exception e)
    175        {
    176            // Let's try hard to send the error message to the browser, to speed up debugging
    177            try
    178            {
    179                data.getResponse().getWriter().print("Error encountered processing a template: "
    180                    + templateName);
    181                e.printStackTrace(data.getResponse().getWriter());
    182            }
    183            catch (IOException ignored)
    184            {
    185                // ignore
    186            }
    187
    188            // pass the exception to the caller according to the general
    189            // contract for templating services in Turbine
    190            throw new TurbineException(
    191                "Error encountered processing a template: " + templateName, e);
    192        }
    193    }
    194
    195    /**
    196     * executes the JSP given by templateName.
    197     *
    198     * @param pipelineData A PipelineData Object
    199     * @param templateName The template to execute
    200     *
    201     * @throws TurbineException If a problem occurred while executing the JSP
    202     */
    203    @Override
    204    public void handleRequest(PipelineData pipelineData, String templateName)
    205        throws TurbineException
    206    {
    207        handleRequest(pipelineData, templateName, false);
    208    }
    209
    210    /**
    211     * This method sets up the template cache.
    212     */
    213    private void initJsp()
    214        throws Exception
    215    {
    216        Configuration config = getConfiguration();
    217
    218        // Set relative paths from config.
    219        // Needed for javax.servlet.RequestDispatcher
    220        relativeTemplatePaths = config.getStringArray(TEMPLATE_PATH_KEY);
    221
    222        // Use Turbine Servlet to translate the template paths.
    223        templatePaths = new String [relativeTemplatePaths.length];
    224        for (int i=0; i < relativeTemplatePaths.length; i++)
    225        {
    226            relativeTemplatePaths[i] = warnAbsolute(relativeTemplatePaths[i]);
    227
    228            templatePaths[i] = Turbine.getRealPath(relativeTemplatePaths[i]);
    229        }
    230
    231        bufferSize = config.getInt(JspService.BUFFER_SIZE_KEY,
    232            JspService.BUFFER_SIZE_DEFAULT);
    233    }
    234
    235    /**
    236     * Determine whether a given template is available on the
    237     * configured template pathes.
    238     *
    239     * @param template The name of the requested Template
    240     * @return True if the template is available.
    241     */
    242    @Override
    243    public boolean templateExists(String template)
    244    {
    245        for (int i = 0; i < templatePaths.length; i++)
    246        {
    247            if (templateExists(templatePaths[i], template))
    248            {
    249                return true;
    250            }
    251        }
    252        return false;
    253    }
    254
    255    /**
    256     * Determine whether a given template exists on the supplied
    257     * template path. This service ATM only supports file based
    258     * templates so it simply checks for file existence.
    259     *
    260     * @param path The absolute (file system) template path
    261     * @param template The name of the requested Template
    262     * @return True if the template is available.
    263     */
    264    private boolean templateExists(String path, String template)
    265    {
    266        return new File(path, template).exists();
    267    }
    268
    269    /**
    270     * Searches for a template in the default.template path[s] and
    271     * returns the template name with a relative path which is
    272     * required by <a href="http://java.sun.com/products/servlet/2.3/javadoc/javax/servlet/ServletContext.html#getRequestDispatcher(java.lang.String)">
    273     * javax.servlet.RequestDispatcher</a>
    274     *
    275     * @param template the name of the template
    276     * @return String
    277     */
    278    @Override
    279    public String getRelativeTemplateName(String template)
    280    {
    281        template = warnAbsolute(template);
    282
    283        // Find which template path the template is in
    284        // We have a 1:1 match between relative and absolute
    285        // pathes so we can use the index for translation.
    286        for (int i = 0; i < templatePaths.length; i++)
    287        {
    288            if (templateExists(templatePaths[i], template))
    289            {
    290                return relativeTemplatePaths[i] + "/" + template;
    291            }
    292        }
    293        return null;
    294    }
    295
    296    /**
    297     * Warn if a template name or path starts with "/".
    298     *
    299     * @param template The template to test
    300     * @return The template name with a leading / stripped off
    301     */
    302    private String warnAbsolute(String template)
    303    {
    304        if (template.startsWith("/"))
    305        {
    306            log.warn("Template " + template
    307                + " has a leading /, which is wrong!");
    308            return template.substring(1);
    309        }
    310        return template;
    311    }
    312}