001// Licensed under the Apache License, Version 2.0 (the "License");
002// you may not use this file except in compliance with the License.
003// You may obtain a copy of the License at
005// http://www.apache.org/licenses/LICENSE-2.0
007// Unless required by applicable law or agreed to in writing, software
008// distributed under the License is distributed on an "AS IS" BASIS,
009// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
010// See the License for the specific language governing permissions and
011// limitations under the License.
013package org.apache.tapestry5.services;
015import org.apache.tapestry5.internal.services.assets.ClasspathAssetRequestHandler;
016import org.apache.tapestry5.ioc.Resource;
017import org.apache.tapestry5.ioc.annotations.IncompatibleChange;
018import org.apache.tapestry5.ioc.annotations.UsesMappedConfiguration;
020import java.util.Map;
023 * Used as part of the support for classpath {@link org.apache.tapestry5.Asset}s, to convert the Asset's
024 * {@link org.apache.tapestry5.ioc.Resource} to a URL that can be accessed by the client. The asset path, within the
025 * classpath, is converted into a shorter virtual path. The term "alias" here is generally referred to as
026 * "virtual folder" elsewhere.
027 *
028 * Service configuration is a map from folder aliases (short names) to complete paths. Names should not start or end end
029 * with a slash. Generally, an alias should be a single name (not contain a slash). Paths should also not start or end
030 * with a slash. An example mapping would be <code>mylib</code> to <code>com/example/mylib</code>.
031 *
032 * As originally envisioned, this service would simply <em>optimize</em> classpath assets, allowing the URL path for
033 * such assets to be shortened (and have a version number added, important for caching); thus the word "alias" makes
034 * sense ... it was responsible for creating an "alias" URL shorter than the default "classpath" URL.
035 *
036 * Starting in Tapestry 5.2, this changed; all classpath assets <strong>must</strong> be "aliased" to a shorter URL
037 * path. Any URL that can not be shortened is now rejected. This simplifies creating new libraries, but also helps with
038 * security concerns, as it limits which portions of the classpath can <em>ever</em> be exposed to the user agent.
039 *
040 * Tapestry automatically contributes a number of mappings: for the application root package itself (as alias "app") and
041 * for each library (via {@link ComponentClassResolver#getFolderToPackageMapping()});
042 *
043 * @deprecated Deprecated in 5.4, with no replacement. This will no longer be used in Tapestry 5.5, as all classpath assets
044 *             will need to be under the {@code META-INF/assets} folder (but may be maintained for compatibility reasons until 5.6).
045 */
047public interface ClasspathAssetAliasManager
049    /**
050     * Takes a classpath resource and determines the proper alias for it based on the mappings contributed to the service.
051     *
052     * @param resource
053     *         classpath resource
054     * @return URL ready to send to the client
055     */
056    @IncompatibleChange(release = "5.4", details = "parameter changed from String to Resource, renamed from toClientURL() to better identify purpose")
057    AssetAlias extractAssetAlias(Resource resource);
059    /**
060     * Returns the mappings used by the service: the keys are the folder aliases (i.e, "corelib")
061     * and the values are the corresponding paths (i.e., "org/apache/tapestry5/corelib"). This
062     * exists primarily so that {@link ClasspathAssetRequestHandler}s can be created automatically
063     * for each mapping.
064     *
065     * @since 5.2.0
066     */
067    Map<String, String> getMappings();