// Copyright 2006, 2007, 2008, 2009, 2010, 2011 The Apache Software Foundation
//
// Licensed 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.tapestry5.internal.services;
import org.apache.tapestry5.SymbolConstants;
import org.apache.tapestry5.internal.IOOperation;
import org.apache.tapestry5.internal.InternalConstants;
import org.apache.tapestry5.internal.TapestryInternalUtils;
import org.apache.tapestry5.internal.services.assets.ResourceChangeTracker;
import org.apache.tapestry5.ioc.OperationTracker;
import org.apache.tapestry5.ioc.Resource;
import org.apache.tapestry5.ioc.annotations.Symbol;
import org.apache.tapestry5.services.Request;
import org.apache.tapestry5.services.Response;
import org.apache.tapestry5.services.ResponseCompressionAnalyzer;
import org.apache.tapestry5.services.assets.CompressionStatus;
import org.apache.tapestry5.services.assets.StreamableResource;
import org.apache.tapestry5.services.assets.StreamableResourceProcessing;
import org.apache.tapestry5.services.assets.StreamableResourceSource;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.OutputStream;
public class ResourceStreamerImpl implements ResourceStreamer
{
static final String IF_MODIFIED_SINCE_HEADER = "If-Modified-Since";
private final Request request;
private final Response response;
private final StreamableResourceSource streamableResourceSource;
private final ResponseCompressionAnalyzer analyzer;
private final boolean productionMode;
private final OperationTracker tracker;
private final ResourceChangeTracker resourceChangeTracker;
public ResourceStreamerImpl(Request request,
Response response,
StreamableResourceSource streamableResourceSource,
ResponseCompressionAnalyzer analyzer,
OperationTracker tracker,
@Symbol(SymbolConstants.PRODUCTION_MODE)
boolean productionMode, ResourceChangeTracker resourceChangeTracker)
{
this.request = request;
this.response = response;
this.streamableResourceSource = streamableResourceSource;
this.analyzer = analyzer;
this.tracker = tracker;
this.productionMode = productionMode;
this.resourceChangeTracker = resourceChangeTracker;
}
public void streamResource(final Resource resource) throws IOException
{
if (!resource.exists())
{
response.sendError(HttpServletResponse.SC_NOT_FOUND, String.format("Unable to locate asset '%s' (the file does not exist).", resource));
return;
}
TapestryInternalUtils.performIO(tracker, String.format("Streaming %s", resource), new IOOperation()
{
public void perform() throws IOException
{
StreamableResourceProcessing processing = analyzer.isGZipSupported() ? StreamableResourceProcessing.COMPRESSION_ENABLED
: StreamableResourceProcessing.COMPRESSION_DISABLED;
StreamableResource streamable = streamableResourceSource.getStreamableResource(resource, processing, resourceChangeTracker);
streamResource(streamable);
}
});
}
public void streamResource(StreamableResource streamable) throws IOException
{
long lastModified = streamable.getLastModified();
long ifModifiedSince = 0;
try
{
ifModifiedSince = request.getDateHeader(IF_MODIFIED_SINCE_HEADER);
} catch (IllegalArgumentException ex)
{
// Simulate the header being missing if it is poorly formatted.
ifModifiedSince = -1;
}
if (ifModifiedSince > 0)
{
if (ifModifiedSince >= lastModified)
{
response.sendError(HttpServletResponse.SC_NOT_MODIFIED, "");
return;
}
}
// Prevent the upstream code from compressing when we don't want to.
response.disableCompression();
response.setDateHeader("Last-Modified", lastModified);
if (productionMode)
{
response.setDateHeader("Expires", lastModified + InternalConstants.TEN_YEARS);
}
response.setContentLength(streamable.getSize());
if (streamable.getCompression() == CompressionStatus.COMPRESSED)
{
response.setHeader(InternalConstants.CONTENT_ENCODING_HEADER, InternalConstants.GZIP_CONTENT_ENCODING);
}
OutputStream os = response.getOutputStream(streamable.getContentType());
streamable.streamTo(os);
os.close();
}
}