org.getobjects.ofs.OFSResourceFileRenderer.java Source code

Introduction

Here is the source code for org.getobjects.ofs.OFSResourceFileRenderer.java

Source

/*
  Copyright (C) 2007-2009 Helge Hess
    
  This file is part of Go.
    
  Go is free software; you can redistribute it and/or modify it under
  the terms of the GNU Lesser General Public License as published by the
  Free Software Foundation; either version 2, or (at your option) any
  later version.
    
  Go is distributed in the hope that it will be useful, but WITHOUT ANY
  WARRANTY; without even the implied warranty of MERCHANTABILITY or
  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  License for more details.
    
  You should have received a copy of the GNU Lesser General Public
  License along with Go; see the file COPYING.  If not, write to the
  Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  02111-1307, USA.
*/
package org.getobjects.ofs;

import java.io.IOException;
import java.io.InputStream;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.getobjects.appserver.core.WOContext;
import org.getobjects.appserver.core.WOMessage;
import org.getobjects.appserver.core.WOResponse;
import org.getobjects.appserver.publisher.IGoObjectRenderer;
import org.getobjects.appserver.publisher.GoInternalErrorException;
import org.getobjects.foundation.NSObject;

/**
 * OFSResourceFileRenderer
 * <p>
 * This renderer directly streams the content of an OFSResourceFile object to
 * the WOResponse.
 */
public class OFSResourceFileRenderer extends NSObject implements IGoObjectRenderer {
    protected static final Log log = LogFactory.getLog("GoOFS");

    public OFSResourceFileRenderer() {
        super();
    }

    /* control rendering */

    public boolean canRenderObjectInContext(Object _object, WOContext _ctx) {
        return _object instanceof OFSResourceFile;
    }

    /* rendering */

    /**
     * Stream the given OFSResourceFile object to the response.
     */
    public Exception renderObjectInContext(Object _object, final WOContext _ctx) {
        if (_object == null)
            return new GoInternalErrorException("got no object to render");

        /* retrieve basic info */

        final OFSResourceFile doc = (OFSResourceFile) _object;

        final String mimeType = doc.defaultDeliveryMimeType();

        /* start response */

        final WOResponse r = _ctx.response();
        r.setStatus(WOMessage.HTTP_STATUS_OK);
        r.setHeaderForKey(mimeType, "content-type");

        /* setup caching headers */

        final Date now = new Date();
        final GregorianCalendar cal = new GregorianCalendar();

        cal.setTime(doc.lastModified());
        r.setHeaderForKey(WOMessage.httpFormatDate(cal), "last-modified");

        cal.setTime(now);
        r.setHeaderForKey(WOMessage.httpFormatDate(cal), "date");

        // TBD: document
        if (mimeType.startsWith("image/"))
            cal.add(Calendar.HOUR, 1);
        else if (mimeType.startsWith("text/css"))
            cal.add(Calendar.MINUTE, 10);
        else
            cal.add(Calendar.SECOND, 5);
        r.setHeaderForKey(WOMessage.httpFormatDate(cal), "expires");

        /* transfer content */

        r.setHeaderForKey("" + doc.size(), "content-length");

        /* remember that no headers can be set after streaming got activated */
        // TODO: this should be ensured by WOResponse
        if (!r.enableStreaming())
            log.warn("could not enable streaming for doc: " + doc);

        final InputStream is = doc.openStream();
        if (is == null)
            return new GoInternalErrorException("could not open resource stream");

        r.resetLastException();
        try {
            byte[] buffer = new byte[0xFFFF];
            for (int len; (len = is.read(buffer)) != -1;)
                r.appendContentData(buffer, len);
        } catch (IOException e) {
            return new GoInternalErrorException("failed to read from resource stream");
        } finally {
            try {
                if (is != null)
                    is.close();
            } catch (IOException e) {
                log.warn("could not close input stream");
            }
        }

        return r.lastException(); /* WOResponse might have caught an issue */
    }
}