// Copyright 2006-2013 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.ioc.annotations.Marker;
import org.apache.tapestry5.ioc.annotations.Symbol;
import org.apache.tapestry5.ioc.annotations.UsesMappedConfiguration;
import org.apache.tapestry5.ioc.internal.util.CollectionFactory;
import org.apache.tapestry5.services.*;
import org.apache.tapestry5.services.assets.AssetRequestHandler;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
/**
* Recognizes requests where the path begins with "/asset/" (actually, as defined by the
* {@link SymbolConstants#ASSET_PATH_PREFIX} symbol), and delivers the content therein as a bytestream. Also
* handles requests that are simply polling for a change to the file (including checking the ETag in the
* request against {@linkplain org.apache.tapestry5.services.assets.StreamableResource#getChecksum() the asset's checksum}.
*
* @see ResourceStreamer
* @see ClasspathAssetAliasManager
* @see AssetRequestHandler
*/
@UsesMappedConfiguration(AssetRequestHandler.class)
@Marker(AssetRequestDispatcher.class)
public class AssetDispatcher implements Dispatcher
{
/**
* Keyed on extended path name, which includes the pathPrefix first and a trailing slash.
*/
private final Map<String, AssetRequestHandler> pathToHandler = CollectionFactory.newMap();
/**
* List of path prefixes in the pathToHandler, sorted be descending length.
*/
private final List<String> assetPaths = CollectionFactory.newList();
private final String requestPathPrefix;
public AssetDispatcher(Map<String, AssetRequestHandler> configuration,
PathConstructor pathConstructor,
@Symbol(SymbolConstants.ASSET_PATH_PREFIX)
String assetPathPrefix)
{
requestPathPrefix = pathConstructor.constructDispatchPath(assetPathPrefix, "");
for (String path : configuration.keySet())
{
AssetRequestHandler handler = configuration.get(path);
addPath(requestPathPrefix, path, handler);
}
// Sort by descending length
Collections.sort(assetPaths, new Comparator<String>()
{
public int compare(String o1, String o2)
{
return o2.length() - o1.length();
}
});
}
private void addPath(String prefix, String path, AssetRequestHandler handler)
{
String extendedPath = buildPath(prefix, path);
pathToHandler.put(extendedPath, handler);
assetPaths.add(extendedPath);
}
private String buildPath(String prefix, String path)
{
// TODO: Not sure when path would be length 0!
return path.length() == 0
? prefix
: prefix + path + "/";
}
public boolean dispatch(Request request, Response response) throws IOException
{
String path = request.getPath();
// Remember that the request path does not include the context path, so we can simply start
// looking for the asset path prefix right off the bat.
if (!path.startsWith(requestPathPrefix))
{
return false;
}
for (String extendedPath : assetPaths)
{
if (path.startsWith(extendedPath))
{
AssetRequestHandler handler = pathToHandler.get(extendedPath);
String extraPath = path.substring(extendedPath.length());
boolean handled = handler.handleAssetRequest(request, response, extraPath);
if (handled)
{
return true;
}
}
}
response.sendError(HttpServletResponse.SC_NOT_FOUND, path);
return true;
}
}