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Posted to slide-dev@jakarta.apache.org by cm...@apache.org on 2001/12/03 16:12:37 UTC

cvs commit: jakarta-slide/src/taglib/struts/org/apache/slide/taglib/tag/struts ContentTag.java

cmlenz      01/12/03 07:12:37

  Added:       src/taglib/common/org/apache/slide/taglib/tag
                        ContentTagSupport.java
               src/taglib/struts/org/apache/slide/taglib/tag/struts
                        ContentTag.java
  Log:
  Add an experimental 'content' tag that will reset the response buffers and
  try to stream the content of a selected node revision to the client. This
  allows the viewing of slide resources in the context of a JSP application
  without having to write a servlet, or redirect to the WebdavServlet
  (which might not even be deployed).
  This tag should also implement the usage of Content-Range for better
  performance, but for that the corresponding code in
  o.a.s.webdav.method.GetMethod should be factored out into a utility class.
  
  Revision  Changes    Path
  1.1                  jakarta-slide/src/taglib/common/org/apache/slide/taglib/tag/ContentTagSupport.java
  
  Index: ContentTagSupport.java
  ===================================================================
  /*
   * $Header: /home/cvs/jakarta-slide/src/taglib/common/org/apache/slide/taglib/tag/ContentTagSupport.java,v 1.1 2001/12/03 15:12:36 cmlenz Exp $
   * $Revision: 1.1 $
   * $Date: 2001/12/03 15:12:36 $
   *
   * ====================================================================
   *
   * The Apache Software License, Version 1.1
   *
   * Copyright (c) 1999 The Apache Software Foundation.  All rights 
   * reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer. 
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. The end-user documentation included with the redistribution, if
   *    any, must include the following acknowlegement:  
   *       "This product includes software developed by the 
   *        Apache Software Foundation (http://www.apache.org/)."
   *    Alternately, this acknowlegement may appear in the software itself,
   *    if and wherever such third-party acknowlegements normally appear.
   *
   * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
   *    Foundation" must not be used to endorse or promote products derived
   *    from this software without prior written permission. For written 
   *    permission, please contact apache@apache.org.
   *
   * 5. Products derived from this software may not be called "Apache"
   *    nor may "Apache" appear in their names without prior written
   *    permission of the Apache Group.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   * [Additional notices, if required by prior licensing conditions]
   *
   */ 
  
  package org.apache.slide.taglib.tag;
  
  import java.io.InputStream;
  import java.io.IOException;
  
  import javax.servlet.ServletOutputStream;
  import javax.servlet.http.HttpServletResponse;
  import javax.servlet.jsp.JspException;
  import javax.servlet.jsp.PageContext;
  import javax.servlet.jsp.tagext.TagSupport;
  
  import org.apache.slide.common.SlideException;
  import org.apache.slide.taglib.bean.NodeBean;
  import org.apache.slide.taglib.bean.PropertyBean;
  import org.apache.slide.taglib.bean.RevisionBean;
  
  /**
   * Very simple implementation of a tag that sends the content of a revision of 
   * a node to the client.
   * 
   * <p>The node and revision is chosen based on the tags the content tag is
   * nested in. This tag must be used before the response is commited as HTML 
   * content, because the response headers and content will be reset.</p>
   * 
   * <ul>TODO:
   *   <li>Support Content-Range</li>
   * </ul>
   * 
   * @author <a href="mailto:cmlenz@apache.org">Christopher Lenz</a>
   * @version $Revision: 1.1 $
   */
  public abstract class ContentTagSupport
      extends TagSupport {
      
      
      // ----------------------------------------------------- Instance Variables
      
      
      /**
       * The revision bean.
       */
      protected RevisionBean revision;
      
      
      // ----------------------------------------------------------- Construction
      
      
      /**
       * Initialize inherited and local state.
       */
      public ContentTagSupport() {
          super();
          
          init();
      }
      
      
      // ------------------------------------------------------------ Tag Methods
      
      
      /**
       * Called by the JSP Engine when opening this tag.
       *
       * @throws JspException If this tag isn't nested inside a NodeTag or a
       *                      NodeWrapper iteration
       */
      public int doStartTag()
          throws JspException {
          super.doStartTag();
          
          HttpServletResponse response = 
              (HttpServletResponse)pageContext.getResponse();
          if (response.isCommitted()) {
              // indicates improper use of this tag: should be used very close to
              // the beginning of a JSP, not after so much output has already 
              // been written that part of the response has already been sent.
              throw new JspException("The Slide 'content' tag has to be used " +
                                     "before the response has been committed.");
          } else {
              response.resetBuffer();
          }
          
          // revision not found
          if (revision == null) {
              try {
                  response.sendError(HttpServletResponse.SC_NOT_FOUND);
                  return SKIP_PAGE;
              } catch (IOException e) {
                  // ignore
              }
          }
          
          // set the HTTP response headers
          PropertyBean property;
          property = revision.getProperty("DAV:", "getcontenttype");
          if (property != null) {
              response.setHeader("Content-Type", property.getValue());
          }
          property = revision.getProperty("DAV:", "getcontentlength");
          if (property != null) {
              response.setHeader("Content-Length", property.getValue());
          }
          property = revision.getProperty("DAV:", "lastmodified");
          if (property != null) {
              response.setHeader("Last-Modified", property.getValue());
          }
          
          // stream the content
          ServletOutputStream os = null;
          InputStream is = null;
          try {
              os = response.getOutputStream();
              try {
                  is = revision.getInputStream();
              } catch (SlideException e) {
                  System.out.println(e.getMessage());
                  e.printStackTrace();
              }
              
              if (is != null) {
                  byte buffer[] = new byte[2048];
                  int len = buffer.length;
                  while (true) {
                      len = is.read(buffer);
                      if (len == -1)
                          break;
                      os.write(buffer, 0, len);
                  }
              }
              
          } catch (IOException e) {
              // ignore
          } finally {
              if (os != null) {
                  try {
                      os.flush();
                  } catch (Exception e) {
                      // ignore
                  }
                  try {
                      os.close();
                  } catch (Exception e) {
                      // ignore
                  }
              }
              if (is != null) {
                  try {
                      is.close();
                  } catch (Exception e) {
                      // ignore
                  }
              }
          }
          
          return SKIP_PAGE;
      }
      
      
      /**
       * Releases any resources we may have (or inherit).
       */
      public void release() {
          super.release();
          
          init();
      }
      
      
      // -------------------------------------------------------- Private Methods
      
      
      /**
       * Reset internal state.
       */
      private void init() {
          
          revision = null;
      }
      
      
  }
  
  
  
  
  
  1.1                  jakarta-slide/src/taglib/struts/org/apache/slide/taglib/tag/struts/ContentTag.java
  
  Index: ContentTag.java
  ===================================================================
  /*
   * $Header: /home/cvs/jakarta-slide/src/taglib/struts/org/apache/slide/taglib/tag/struts/ContentTag.java,v 1.1 2001/12/03 15:12:37 cmlenz Exp $
   * $Revision: 1.1 $
   * $Date: 2001/12/03 15:12:37 $
   *
   * ====================================================================
   *
   * The Apache Software License, Version 1.1
   *
   * Copyright (c) 1999 The Apache Software Foundation.  All rights 
   * reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer. 
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. The end-user documentation included with the redistribution, if
   *    any, must include the following acknowlegement:  
   *       "This product includes software developed by the 
   *        Apache Software Foundation (http://www.apache.org/)."
   *    Alternately, this acknowlegement may appear in the software itself,
   *    if and wherever such third-party acknowlegements normally appear.
   *
   * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
   *    Foundation" must not be used to endorse or promote products derived
   *    from this software without prior written permission. For written 
   *    permission, please contact apache@apache.org.
   *
   * 5. Products derived from this software may not be called "Apache"
   *    nor may "Apache" appear in their names without prior written
   *    permission of the Apache Group.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   * [Additional notices, if required by prior licensing conditions]
   *
   */ 
  
  package org.apache.slide.taglib.tag.struts;
  
  import javax.servlet.jsp.JspException;
  
  import org.apache.slide.taglib.bean.RevisionBean;
  import org.apache.slide.taglib.tag.ContentTagSupport;
  
  
  /**
   * Extends the ContentTagSupport to work in a Struts environment.
   * 
   * @author <a href="mailto:cmlenz@apache.org">Christopher Lenz</a>
   * @version $Revision: 1.1 $
   */
  public class ContentTag
      extends ContentTagSupport {
      
      
      // ------------------------------------------------------------ Tag Methods
      
      
      /**
       * Called by the JSP Engine when opening this tag.
       * 
       * @throws JspException if the 'number' attribute does not contain a 
       *         version number in a valid format
       */
      public int doStartTag()
          throws JspException {
          System.out.println("ContentTag.doStartTag()");
          
          RevisionBean revision = 
              StrutsTagUtils.findRevision(this, pageContext);
          
          return super.doStartTag();
      }
      
      
  }
  
  
  
  

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