    001package org.apache.turbine.services.velocity;
    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.ByteArrayOutputStream;
    025import java.io.IOException;
    026import java.io.OutputStream;
    027import java.io.OutputStreamWriter;
    028import java.io.Writer;
    029import java.util.Iterator;
    030import java.util.List;
    031
    032import org.apache.commons.collections.ExtendedProperties;
    033import org.apache.commons.configuration.Configuration;
    034import org.apache.commons.lang.StringUtils;
    035import org.apache.commons.logging.Log;
    036import org.apache.commons.logging.LogFactory;
    037import org.apache.turbine.Turbine;
    038import org.apache.turbine.pipeline.PipelineData;
    039import org.apache.turbine.services.InitializationException;
    040import org.apache.turbine.services.pull.PullService;
    041import org.apache.turbine.services.pull.TurbinePull;
    042import org.apache.turbine.services.template.BaseTemplateEngineService;
    043import org.apache.turbine.util.RunData;
    044import org.apache.turbine.util.TurbineException;
    045import org.apache.velocity.VelocityContext;
    046import org.apache.velocity.app.VelocityEngine;
    047import org.apache.velocity.app.event.EventCartridge;
    048import org.apache.velocity.app.event.MethodExceptionEventHandler;
    049import org.apache.velocity.context.Context;
    050import org.apache.velocity.runtime.RuntimeConstants;
    051import org.apache.velocity.runtime.log.CommonsLogLogChute;
    052
    053/**
    054 * This is a Service that can process Velocity templates from within a
    055 * Turbine Screen. It is used in conjunction with the templating service
    056 * as a Templating Engine for templates ending in "vm". It registers
    057 * itself as translation engine with the template service and gets
    058 * accessed from there. After configuring it in your properties, it
    059 * should never be necessary to call methods from this service directly.
    060 *
    061 * Here's an example of how you might use it from a
    062 * screen:<br>
    063 *
    064 * <code>
    065 * Context context = TurbineVelocity.getContext(data);<br>
    066 * context.put("message", "Hello from Turbine!");<br>
    067 * String results = TurbineVelocity.handleRequest(context,"helloWorld.vm");<br>
    068 * data.getPage().getBody().addElement(results);<br>
    069 * </code>
    070 *
    071 * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
    072 * @author <a href="mailto:krzewski@e-point.pl">Rafal Krzewski</a>
    073 * @author <a href="mailto:jvanzyl@periapt.com">Jason van Zyl</a>
    074 * @author <a href="mailto:sean@informage.ent">Sean Legassick</a>
    075 * @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
    076 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
    077 * @author <a href="mailto:epugh@upstate.com">Eric Pugh</a>
    078 * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
    079 * @version $Id: TurbineVelocityService.java 1695634 2015-08-13 00:35:47Z tv $
    080 */
    081public class TurbineVelocityService
    082        extends BaseTemplateEngineService
    083        implements VelocityService,
    084                   MethodExceptionEventHandler
    085{
    086    /** The generic resource loader path property in velocity.*/
    087    private static final String RESOURCE_LOADER_PATH = ".resource.loader.path";
    088
    089    /** Default character set to use if not specified in the RunData object. */
    090    private static final String DEFAULT_CHAR_SET = "ISO-8859-1";
    091
    092    /** The prefix used for URIs which are of type <code>jar</code>. */
    093    private static final String JAR_PREFIX = "jar:";
    094
    095    /** The prefix used for URIs which are of type <code>absolute</code>. */
    096    private static final String ABSOLUTE_PREFIX = "file://";
    097
    098    /** Logging */
    099    private static final Log log = LogFactory.getLog(TurbineVelocityService.class);
    100
    101    /** Encoding used when reading the templates. */
    102    private String defaultInputEncoding;
    103
    104    /** Encoding used by the outputstream when handling the requests. */
    105    private String defaultOutputEncoding;
    106
    107    /** Is the pullModelActive? */
    108    private boolean pullModelActive = false;
    109
    110    /** Shall we catch Velocity Errors and report them in the log file? */
    111    private boolean catchErrors = true;
    112
    113    /** Velocity runtime instance */
    114    private VelocityEngine velocity = null;
    115
    116    /** Internal Reference to the pull Service */
    117    private PullService pullService = null;
    118
    119
    120    /**
    121     * Load all configured components and initialize them. This is
    122     * a zero parameter variant which queries the Turbine Servlet
    123     * for its config.
    124     *
    125     * @throws InitializationException Something went wrong in the init
    126     *         stage
    127     */
    128    @Override
    129    public void init()
    130            throws InitializationException
    131    {
    132        try
    133        {
    134            initVelocity();
    135
    136            // We can only load the Pull Model ToolBox
    137            // if the Pull service has been listed in the TR.props
    138            // and the service has successfully been initialized.
    139            if (TurbinePull.isRegistered())
    140            {
    141                pullModelActive = true;
    142
    143                pullService = TurbinePull.getService();
    144
    145                log.debug("Activated Pull Tools");
    146            }
    147
    148            // Register with the template service.
    149            registerConfiguration(VelocityService.VELOCITY_EXTENSION);
    150
    151            defaultInputEncoding = getConfiguration().getString("input.encoding", DEFAULT_CHAR_SET);
    152            defaultOutputEncoding = getConfiguration().getString("output.encoding", defaultInputEncoding);
    153
    154            setInit(true);
    155        }
    156        catch (Exception e)
    157        {
    158            throw new InitializationException(
    159                "Failed to initialize TurbineVelocityService", e);
    160        }
    161    }
    162
    163    /**
    164     * Create a Context object that also contains the globalContext.
    165     *
    166     * @return A Context object.
    167     */
    168    @Override
    169    public Context getContext()
    170    {
    171        Context globalContext =
    172                pullModelActive ? pullService.getGlobalContext() : null;
    173
    174        Context ctx = new VelocityContext(globalContext);
    175        return ctx;
    176    }
    177
    178    /**
    179     * This method returns a new, empty Context object.
    180     *
    181     * @return A Context Object.
    182     */
    183    @Override
    184    public Context getNewContext()
    185    {
    186        Context ctx = new VelocityContext();
    187
    188        // Attach an Event Cartridge to it, so we get exceptions
    189        // while invoking methods from the Velocity Screens
    190        EventCartridge ec = new EventCartridge();
    191        ec.addEventHandler(this);
    192        ec.attachToContext(ctx);
    193        return ctx;
    194    }
    195
    196    /**
    197     * MethodException Event Cartridge handler
    198     * for Velocity.
    199     *
    200     * It logs an execption thrown by the velocity processing
    201     * on error level into the log file
    202     *
    203     * @param clazz The class that threw the exception
    204     * @param method The Method name that threw the exception
    205     * @param e The exception that would've been thrown
    206     * @return A valid value to be used as Return value
    207     * @throws Exception We threw the exception further up
    208     */
    209    @Override
    210    @SuppressWarnings("rawtypes") // Interface not generified
    211        public Object methodException(Class clazz, String method, Exception e)
    212            throws Exception
    213    {
    214        log.error("Class " + clazz.getName() + "." + method + " threw Exception", e);
    215
    216        if (!catchErrors)
    217        {
    218            throw e;
    219        }
    220
    221        return "[Turbine caught an Error here. Look into the turbine.log for further information]";
    222    }
    223
    224    /**
    225     * Create a Context from the PipelineData object.  Adds a pointer to
    226     * the PipelineData object to the VelocityContext so that PipelineData
    227     * is available in the templates.
    228     *
    229     * @param pipelineData The Turbine PipelineData object.
    230     * @return A clone of the WebContext needed by Velocity.
    231     */
    232    @Override
    233    public Context getContext(PipelineData pipelineData)
    234    {
    235        //Map runDataMap = (Map)pipelineData.get(RunData.class);
    236        RunData data = (RunData)pipelineData;
    237        // Attempt to get it from the data first.  If it doesn't
    238        // exist, create it and then stuff it into the data.
    239        Context context = (Context)
    240            data.getTemplateInfo().getTemplateContext(VelocityService.CONTEXT);
    241
    242        if (context == null)
    243        {
    244            context = getContext();
    245            context.put(VelocityService.RUNDATA_KEY, data);
    246            // we will add both data and pipelineData to the context.
    247            context.put(VelocityService.PIPELINEDATA_KEY, pipelineData);
    248
    249            if (pullModelActive)
    250            {
    251                // Populate the toolbox with request scope, session scope
    252                // and persistent scope tools (global tools are already in
    253                // the toolBoxContent which has been wrapped to construct
    254                // this request-specific context).
    255                pullService.populateContext(context, pipelineData);
    256            }
    257
    258            data.getTemplateInfo().setTemplateContext(
    259                VelocityService.CONTEXT, context);
    260        }
    261        return context;
    262    }
    263
    264    /**
    265     * Process the request and fill in the template with the values
    266     * you set in the Context.
    267     *
    268     * @param context  The populated context.
    269     * @param filename The file name of the template.
    270     * @return The process template as a String.
    271     *
    272     * @throws TurbineException Any exception thrown while processing will be
    273     *         wrapped into a TurbineException and rethrown.
    274     */
    275    @Override
    276    public String handleRequest(Context context, String filename)
    277        throws TurbineException
    278    {
    279        String results = null;
    280        ByteArrayOutputStream bytes = null;
    281        OutputStreamWriter writer = null;
    282        String charset = getOutputCharSet(context);
    283
    284        try
    285        {
    286            bytes = new ByteArrayOutputStream();
    287
    288            writer = new OutputStreamWriter(bytes, charset);
    289
    290            executeRequest(context, filename, writer);
    291            writer.flush();
    292            results = bytes.toString(charset);
    293        }
    294        catch (Exception e)
    295        {
    296            renderingError(filename, e);
    297        }
    298        finally
    299        {
    300            try
    301            {
    302                if (bytes != null)
    303                {
    304                    bytes.close();
    305                }
    306            }
    307            catch (IOException ignored)
    308            {
    309                // do nothing.
    310            }
    311        }
    312        return results;
    313    }
    314
    315    /**
    316     * Process the request and fill in the template with the values
    317     * you set in the Context.
    318     *
    319     * @param context A Context.
    320     * @param filename A String with the filename of the template.
    321     * @param output A OutputStream where we will write the process template as
    322     * a String.
    323     *
    324     * @throws TurbineException Any exception thrown while processing will be
    325     *         wrapped into a TurbineException and rethrown.
    326     */
    327    @Override
    328    public void handleRequest(Context context, String filename,
    329                              OutputStream output)
    330            throws TurbineException
    331    {
    332        String charset  = getOutputCharSet(context);
    333        OutputStreamWriter writer = null;
    334
    335        try
    336        {
    337            writer = new OutputStreamWriter(output, charset);
    338            executeRequest(context, filename, writer);
    339        }
    340        catch (Exception e)
    341        {
    342            renderingError(filename, e);
    343        }
    344        finally
    345        {
    346            try
    347            {
    348                if (writer != null)
    349                {
    350                    writer.flush();
    351                }
    352            }
    353            catch (Exception ignored)
    354            {
    355                // do nothing.
    356            }
    357        }
    358    }
    359
    360
    361    /**
    362     * Process the request and fill in the template with the values
    363     * you set in the Context.
    364     *
    365     * @param context A Context.
    366     * @param filename A String with the filename of the template.
    367     * @param writer A Writer where we will write the process template as
    368     * a String.
    369     *
    370     * @throws TurbineException Any exception thrown while processing will be
    371     *         wrapped into a TurbineException and rethrown.
    372     */
    373    @Override
    374    public void handleRequest(Context context, String filename, Writer writer)
    375            throws TurbineException
    376    {
    377        try
    378        {
    379            executeRequest(context, filename, writer);
    380        }
    381        catch (Exception e)
    382        {
    383            renderingError(filename, e);
    384        }
    385        finally
    386        {
    387            try
    388            {
    389                if (writer != null)
    390                {
    391                    writer.flush();
    392                }
    393            }
    394            catch (Exception ignored)
    395            {
    396                // do nothing.
    397            }
    398        }
    399    }
    400
    401
    402    /**
    403     * Process the request and fill in the template with the values
    404     * you set in the Context. Apply the character and template
    405     * encodings from RunData to the result.
    406     *
    407     * @param context A Context.
    408     * @param filename A String with the filename of the template.
    409     * @param writer A OutputStream where we will write the process template as
    410     * a String.
    411     *
    412     * @throws Exception A problem occurred.
    413     */
    414    private void executeRequest(Context context, String filename,
    415                                Writer writer)
    416            throws Exception
    417    {
    418        String encoding = getTemplateEncoding(context);
    419
    420        if (encoding == null)
    421        {
    422          encoding = defaultOutputEncoding;
    423        }
    424
    425                velocity.mergeTemplate(filename, encoding, context, writer);
    426    }
    427
    428    /**
    429     * Retrieve the required charset from the Turbine RunData in the context
    430     *
    431     * @param context A Context.
    432     * @return The character set applied to the resulting String.
    433     */
    434    private String getOutputCharSet(Context context)
    435    {
    436        String charset = null;
    437
    438        Object data = context.get(VelocityService.RUNDATA_KEY);
    439        if ((data != null) && (data instanceof RunData))
    440        {
    441            charset = ((RunData) data).getCharSet();
    442        }
    443
    444        return (StringUtils.isEmpty(charset)) ? defaultOutputEncoding : charset;
    445    }
    446
    447    /**
    448     * Retrieve the required encoding from the Turbine RunData in the context
    449     *
    450     * @param context A Context.
    451     * @return The encoding applied to the resulting String.
    452     */
    453    private String getTemplateEncoding(Context context)
    454    {
    455        String encoding = null;
    456
    457        Object data = context.get(VelocityService.RUNDATA_KEY);
    458        if ((data != null) && (data instanceof RunData))
    459        {
    460            encoding = ((RunData) data).getTemplateEncoding();
    461        }
    462
    463        return encoding != null ? encoding : defaultInputEncoding;
    464    }
    465
    466    /**
    467     * Macro to handle rendering errors.
    468     *
    469     * @param filename The file name of the unrenderable template.
    470     * @param e        The error.
    471     *
    472     * @exception TurbineException Thrown every time.  Adds additional
    473     *                             information to <code>e</code>.
    474     */
    475    private static final void renderingError(String filename, Exception e)
    476            throws TurbineException
    477    {
    478        String err = "Error rendering Velocity template: " + filename;
    479        log.error(err, e);
    480        throw new TurbineException(err, e);
    481    }
    482
    483    /**
    484     * Setup the velocity runtime by using a subset of the
    485     * Turbine configuration which relates to velocity.
    486     *
    487     * @exception Exception An Error occurred.
    488     */
    489    private synchronized void initVelocity()
    490        throws Exception
    491    {
    492        // Get the configuration for this service.
    493        Configuration conf = getConfiguration();
    494
    495        catchErrors = conf.getBoolean(CATCH_ERRORS_KEY, CATCH_ERRORS_DEFAULT);
    496
    497        conf.setProperty(RuntimeConstants.RUNTIME_LOG_LOGSYSTEM_CLASS,
    498                CommonsLogLogChute.class.getName());
    499        conf.setProperty(CommonsLogLogChute.LOGCHUTE_COMMONS_LOG_NAME,
    500                "velocity");
    501
    502        velocity = new VelocityEngine();
    503        velocity.setExtendedProperties(createVelocityProperties(conf));
    504        velocity.init();
    505    }
    506
    507
    508    /**
    509     * This method generates the Extended Properties object necessary
    510     * for the initialization of Velocity. It also converts the various
    511     * resource loader pathes into webapp relative pathes. It also
    512     *
    513     * @param conf The Velocity Service configuration
    514     *
    515     * @return An ExtendedProperties Object for Velocity
    516     *
    517     * @throws Exception If a problem occurred while converting the properties.
    518     */
    519
    520    public ExtendedProperties createVelocityProperties(Configuration conf)
    521            throws Exception
    522    {
    523        // This bugger is public, because we want to run some Unit tests
    524        // on it.
    525
    526        ExtendedProperties veloConfig = new ExtendedProperties();
    527
    528        // Fix up all the template resource loader pathes to be
    529        // webapp relative. Copy all other keys verbatim into the
    530        // veloConfiguration.
    531
    532        for (Iterator<String> i = conf.getKeys(); i.hasNext();)
    533        {
    534            String key = i.next();
    535            if (!key.endsWith(RESOURCE_LOADER_PATH))
    536            {
    537                Object value = conf.getProperty(key);
    538                if (value instanceof List<?>) {
    539                    for (Iterator<?> itr = ((List<?>)value).iterator(); itr.hasNext();)
    540                    {
    541                        veloConfig.addProperty(key, itr.next());
    542                    }
    543                }
    544                else
    545                {
    546                    veloConfig.addProperty(key, value);
    547                }
    548                continue; // for()
    549            }
    550
    551            List<Object> paths = conf.getList(key, null);
    552            if (paths == null)
    553            {
    554                // We don't copy this into VeloProperties, because
    555                // null value is unhealthy for the ExtendedProperties object...
    556                continue; // for()
    557            }
    558
    559            // Translate the supplied pathes given here.
    560            // the following three different kinds of
    561            // pathes must be translated to be webapp-relative
    562            //
    563            // jar:file://path-component!/entry-component
    564            // file://path-component
    565            // path/component
    566            for (Object p : paths)
    567            {
    568                String path = (String)p;
    569                log.debug("Translating " + path);
    570
    571                if (path.startsWith(JAR_PREFIX))
    572                {
    573                    // skip jar: -> 4 chars
    574                    if (path.substring(4).startsWith(ABSOLUTE_PREFIX))
    575                    {
    576                        // We must convert up to the jar path separator
    577                        int jarSepIndex = path.indexOf("!/");
    578
    579                        // jar:file:// -> skip 11 chars
    580                        path = (jarSepIndex < 0)
    581                            ? Turbine.getRealPath(path.substring(11))
    582                        // Add the path after the jar path separator again to the new url.
    583                            : (Turbine.getRealPath(path.substring(11, jarSepIndex)) + path.substring(jarSepIndex));
    584
    585                        log.debug("Result (absolute jar path): " + path);
    586                    }
    587                }
    588                else if(path.startsWith(ABSOLUTE_PREFIX))
    589                {
    590                    // skip file:// -> 7 chars
    591                    path = Turbine.getRealPath(path.substring(7));
    592
    593                    log.debug("Result (absolute URL Path): " + path);
    594                }
    595                // Test if this might be some sort of URL that we haven't encountered yet.
    596                else if(path.indexOf("://") < 0)
    597                {
    598                    path = Turbine.getRealPath(path);
    599
    600                    log.debug("Result (normal fs reference): " + path);
    601                }
    602
    603                log.debug("Adding " + key + " -> " + path);
    604                // Re-Add this property to the configuration object
    605                veloConfig.addProperty(key, path);
    606            }
    607        }
    608        return veloConfig;
    609    }
    610
    611    /**
    612     * Find out if a given template exists. Velocity
    613     * will do its own searching to determine whether
    614     * a template exists or not.
    615     *
    616     * @param template String template to search for
    617     * @return True if the template can be loaded by Velocity
    618     */
    619    @Override
    620    public boolean templateExists(String template)
    621    {
    622        return velocity.resourceExists(template);
    623    }
    624
    625    /**
    626     * Performs post-request actions (releases context
    627     * tools back to the object pool).
    628     *
    629     * @param context a Velocity Context
    630     */
    631    @Override
    632    public void requestFinished(Context context)
    633    {
    634        if (pullModelActive)
    635        {
    636            pullService.releaseTools(context);
    637        }
    638    }
    639}