/*
* Copyright 2013 Netflix, Inc.
*
* 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 netflix.adminresources.resources;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Maps;
import com.sun.jersey.api.NotFoundException;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.UriInfo;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.concurrent.ConcurrentMap;
/**
* Karyon admin resources infrastructure expects modules in the form of .jar files. These
* .jar files contain Jersey REST resource java classes and also resources for
* rendering like *.js, *.jpg, *.css files. The REST classes are discovered by
* the Jersey container scanning the classpath. To get the other resources, we
* will use this class to scan the classpath (and hence the module .jar files)
* and return the bytes corresponding to the contents of the resources files
* (i.e. the *.js, *.jpg, *.css files)
*
* @author pkamath
* @author Nitesh Kant
*
*/
@Path("/adminres")
public class EmbeddedContentResource {
private static final Logger logger = LoggerFactory.getLogger(EmbeddedContentResource.class);
private static final ImmutableMap<String, String> EXT_TO_MEDIATYPE = new ImmutableMap.Builder<String, String>()
.put("js", "text/javascript").put("png", "image/png")
.put("gif", "image/gif").put("css", "text/css")
.put("jpg", "image/jpeg").put("jpeg", "image/jpeg")
.put("html", "text/html").build();
private ConcurrentMap<String, byte[]> resourceCache = Maps.newConcurrentMap();
@Context
private UriInfo uriInfo;
/**
* The karyon admin resources can exist in the form of .jar files.
* These .jar files contain Jersey REST resource java classes and also
* resources for rendering like *.js, *.jpg, *.css files. The REST classes
* are discovered by the Jersey container scanning the classpath. To get the
* other resources, we will use this method to scan the classpath (and hence
* the module .jar files) and return the bytes corresponding to the contents
* of the resources files (i.e. the *.js, *.jpg, *.css files)
*/
// For URIs of the form /adminres/<something>
@GET
@Path("{subResources:.*}")
public Response get() {
// get the part after /adminres
String path = uriInfo.getPath().substring("adminres".length());
String ext = StringUtils.substringAfterLast(path, ".");
String mediaType = EXT_TO_MEDIATYPE.get(ext);
byte[] contentAsBytes = null;
if (mediaType != null) {
if (resourceCache.containsKey(path)) {
contentAsBytes = resourceCache.get(path);
} else {
InputStream is = getClass().getResourceAsStream(path);
if (is != null) {
try {
ByteArrayOutputStream baos = new ByteArrayOutputStream(4096);
byte[] chunk = new byte[4096];
int bytesRead;
while ((bytesRead = is.read(chunk)) > 0) {
baos.write(chunk, 0, bytesRead);
}
// This is a rather costly operation as we are throwing away all content loaded in memory, but
// this is only the case when the same resource is requested concurrently.
contentAsBytes = baos.toByteArray();
byte[] existing = resourceCache.putIfAbsent(path, contentAsBytes);
if (null != existing) {
contentAsBytes = existing;
}
} catch (IOException e) {
logger.error("Error loading resource with path: " + uriInfo.getPath(), e);
} finally {
try {
is.close();
} catch (IOException e) {
logger.info("Could not close the resource stream for loading admin resource, ignoring.", e);
}
}
}
}
}
if (contentAsBytes == null) {
logger.info("Could not find resource: " + uriInfo.getPath());
throw new NotFoundException();
} else {
return Response.ok(contentAsBytes, mediaType).build();
}
}
}