Package org.apache.wicket.markup.html

Source Code of org.apache.wicket.markup.html.JavascriptPackageResource$FilteringResourceStream

/*
* 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 org.apache.wicket.markup.html;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.ref.SoftReference;
import java.util.Locale;

import org.apache.wicket.Application;
import org.apache.wicket.RequestCycle;
import org.apache.wicket.ResourceReference;
import org.apache.wicket.behavior.HeaderContributor;
import org.apache.wicket.javascript.IJavascriptCompressor;
import org.apache.wicket.markup.html.resources.JavascriptResourceReference;
import org.apache.wicket.util.io.Streams;
import org.apache.wicket.util.resource.IResourceStream;
import org.apache.wicket.util.resource.ResourceStreamNotFoundException;
import org.apache.wicket.util.string.JavascriptStripper;
import org.apache.wicket.util.time.Time;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


/**
* Package resource for javascript files. It strips comments and whitespace from javascript and
* gzips the content. The stripped and gzipped version is cached.
*
* @author Matej Knopp
*/
public class JavascriptPackageResource extends CompressedPackageResource
{
  private static final long serialVersionUID = 1L;;

  private static final Logger log = LoggerFactory.getLogger(JavascriptPackageResource.class);

  /**
   * Returns a new instance of {@link HeaderContributor} with a header contributor that references
   * a java script file that lives in a package.
   *
   * @param scope
   *            The scope of the package resource (typically the class of the caller, or a class
   *            that lives in the package where the resource lives).
   * @param path
   *            The path
   * @return the new header contributor instance
   */
  public static final HeaderContributor getHeaderContribution(final Class<?> scope,
    final String path)
  {
    return new HeaderContributor(new IHeaderContributor()
    {
      private static final long serialVersionUID = 1L;

      public void renderHead(IHeaderResponse response)
      {
        response.renderJavascriptReference(new JavascriptResourceReference(scope, path));
      }
    });
  }

  /**
   * Returns a new instance of {@link HeaderContributor} with a header contributor that references
   * a java script file that lives in a package.
   *
   * @param reference
   *
   * @return the new header contributor instance
   */
  public static final HeaderContributor getHeaderContribution(final ResourceReference reference)
  {
    return new HeaderContributor(new IHeaderContributor()
    {
      private static final long serialVersionUID = 1L;

      public void renderHead(IHeaderResponse response)
      {
        response.renderJavascriptReference(reference);
      }
    });
  }

  /**
   * Returns a new instance of {@link HeaderContributor} with a header contributor referencing a
   * java script file using one of the following schemes:
   * <ul>
   * <li>Starts with http:// or https:// for an external reference.</li>
   * <li>Starts with "/" for an absolute reference that Wicket will not rewrite.</li>
   * <li>Starts with anything else, which Wicket will automatically prepend to make relative to
   * the context root of your web-app.</li>
   * </ul>
   *
   * @param location
   *            The location of the java script file.
   * @return the new header contributor instance
   */
  public static final HeaderContributor getHeaderContribution(final String location)
  {
    return new HeaderContributor(new IHeaderContributor()
    {
      private static final long serialVersionUID = 1L;

      public void renderHead(IHeaderResponse response)
      {
        response.renderJavascriptReference(returnRelativePath(location));
      }
    });
  }

  /**
   *
   * @param location
   * @return relative path
   */
  private static final String returnRelativePath(String location)
  {
    // WICKET-59 allow external URLs, WICKET-612 allow absolute URLs.
    if (location.startsWith("http://") || location.startsWith("https://") ||
      location.startsWith("/"))
    {
      return location;
    }
    else
    {
      return RequestCycle.get()
        .getProcessor()
        .getRequestCodingStrategy()
        .rewriteStaticRelativeUrl(location);
    }
  }

  /**
   * Resource Stream that caches the stripped content.
   *
   * @author Matej Knopp
   */
  protected abstract class FilteringResourceStream implements IResourceStream
  {
    private static final long serialVersionUID = 1L;

    /** Cache for compressed data */
    private SoftReference<byte[]> cache = new SoftReference<byte[]>(null);

    /** Timestamp of the cache */
    private Time timeStamp = null;

    /**
     * @see org.apache.wicket.util.resource.IResourceStream#close()
     */
    public void close() throws IOException
    {
    }

    /**
     * @see org.apache.wicket.util.resource.IResourceStream#getContentType()
     */
    public String getContentType()
    {
      return getOriginalResourceStream().getContentType();
    }

    /**
     * @see org.apache.wicket.util.resource.IResourceStream#getInputStream()
     */
    public InputStream getInputStream() throws ResourceStreamNotFoundException
    {
      return new ByteArrayInputStream(getFilteredContent());
    }

    /**
     * @see org.apache.wicket.util.resource.IResourceStream#getLocale()
     */
    public Locale getLocale()
    {
      return getOriginalResourceStream().getLocale();
    }

    /**
     * @see org.apache.wicket.util.watch.IModifiable#lastModifiedTime()
     */
    public Time lastModifiedTime()
    {
      return getOriginalResourceStream().lastModifiedTime();
    }

    /**
     * @see org.apache.wicket.util.resource.IResourceStream#length()
     */
    public long length()
    {
      return getFilteredContent().length;
    }

    /**
     * @see org.apache.wicket.util.resource.IResourceStream#setLocale(java.util.Locale)
     */
    public void setLocale(Locale locale)
    {
      getOriginalResourceStream().setLocale(locale);
    }

    /**
     * @return compressed content
     */
    private byte[] getFilteredContent()
    {
      IResourceStream stream = getOriginalResourceStream();
      try
      {
        byte ret[] = cache.get();
        if (ret != null && timeStamp != null)
        {
          if (timeStamp.equals(stream.lastModifiedTime()))
          {
            return ret;
          }
        }

        int length = (int)stream.length();
        ByteArrayOutputStream out = new ByteArrayOutputStream(length > 0 ? length : 0);
        Streams.copy(stream.getInputStream(), out);
        stream.close();
        ret = filterContent(out.toByteArray());
        timeStamp = stream.lastModifiedTime();
        cache = new SoftReference<byte[]>(ret);
        return ret;
      }
      catch (IOException e)
      {
        throw new RuntimeException(e);
      }
      catch (ResourceStreamNotFoundException e)
      {
        throw new RuntimeException(e);
      }
    }

    protected abstract byte[] filterContent(byte[] input);

    protected abstract IResourceStream getOriginalResourceStream();
  }

  /**
   * Create a new PackageResource
   *
   * @param scope
   *            This argument will be used to get the class loader for loading the package
   *            resource, and to determine what package it is in. Typically this is the class in
   *            which you call this method
   * @param path
   *            The path to the resource
   * @param locale
   *            The locale of the resource
   * @param style
   *            The style of the resource (see {@link org.apache.wicket.Session})
   * @return The resource
   */
  public static PackageResource newPackageResource(final Class<?> scope, final String path,
    final Locale locale, final String style)
  {
    return new JavascriptPackageResource(scope, path, locale, style);
  }

  /**
   * Creates a new javascript package resource.
   *
   * @param scope
   * @param path
   * @param locale
   * @param style
   */
  protected JavascriptPackageResource(Class<?> scope, String path, Locale locale, String style)
  {
    super(scope, path, locale, style);
  }

  /**
   * @see org.apache.wicket.markup.html.CompressedPackageResource#newResourceStream()
   */
  @Override
  protected IResourceStream newResourceStream()
  {
    final FilteringResourceStream filteringStream = new FilteringResourceStream()
    {
      private static final long serialVersionUID = 1L;

      @Override
      protected byte[] filterContent(byte[] input)
      {
        try
        {
          // @TODO remove in 1.5
          if (Application.get()
            .getResourceSettings()
            .getStripJavascriptCommentsAndWhitespace())
          {
            String s = new String(input, "UTF-8");
            return JavascriptStripper.stripCommentsAndWhitespace(s).getBytes("UTF-8");
          }

          IJavascriptCompressor compressor = Application.get()
            .getResourceSettings()
            .getJavascriptCompressor();
          if (compressor != null)
          {
            String s = new String(input, "UTF-8");
            return compressor.compress(s).getBytes("UTF-8");
          }

          // don't strip the comments, just return original input
          return input;
        }
        catch (Exception e)
        {
          log.error("Error while filtering content", e);
          return input;
        }
      }

      @Override
      protected IResourceStream getOriginalResourceStream()
      {
        return getPackageResourceStream();
      }
    };

    return new CompressingResourceStream()
    {
      private static final long serialVersionUID = 1L;

      @Override
      protected IResourceStream getOriginalResourceStream()
      {
        return filteringStream;
      }
    };
  }

}
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