/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.hadoop.hdfs.server.namenode;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.InetSocketAddress;
import java.security.PrivilegedExceptionAction;
import java.util.Enumeration;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSInputStream;
import org.apache.hadoop.hdfs.DFSClient;
import org.apache.hadoop.hdfs.server.common.JspHelper;
import org.apache.hadoop.hdfs.server.datanode.DataNode;
import org.apache.hadoop.security.UserGroupInformation;
import org.mortbay.jetty.InclusiveByteRange;
@InterfaceAudience.Private
public class StreamFile extends DfsServlet {
/** for java.io.Serializable */
private static final long serialVersionUID = 1L;
static InetSocketAddress nameNodeAddr;
static DataNode datanode = null;
static {
if ((datanode = DataNode.getDataNode()) != null) {
nameNodeAddr = datanode.getNameNodeAddr();
}
}
/** getting a client for connecting to dfs */
protected DFSClient getDFSClient(HttpServletRequest request)
throws IOException, InterruptedException {
final Configuration conf =
(Configuration) getServletContext().getAttribute("name.conf");
UserGroupInformation ugi = getUGI(request, conf);
DFSClient client = ugi.doAs(new PrivilegedExceptionAction<DFSClient>() {
@Override
public DFSClient run() throws IOException {
return new DFSClient(nameNodeAddr, conf);
}
});
return client;
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
final String filename = JspHelper.validatePath(
request.getParameter("filename"));
if (filename == null) {
response.setContentType("text/plain");
PrintWriter out = response.getWriter();
out.print("Invalid input");
return;
}
Enumeration reqRanges = request.getHeaders("Range");
if (reqRanges != null && !reqRanges.hasMoreElements())
reqRanges = null;
DFSClient dfs;
try {
dfs = getDFSClient(request);
} catch (InterruptedException e) {
response.sendError(400, e.getMessage());
return;
}
long fileLen = dfs.getFileInfo(filename).getLen();
FSInputStream in = dfs.open(filename);
OutputStream os = response.getOutputStream();
try {
if (reqRanges != null) {
List ranges = InclusiveByteRange.satisfiableRanges(reqRanges,
fileLen);
StreamFile.sendPartialData(in, os, response, fileLen, ranges);
} else {
// No ranges, so send entire file
response.setHeader("Content-Disposition", "attachment; filename=\"" +
filename + "\"");
response.setContentType("application/octet-stream");
StreamFile.writeTo(in, os, 0L, fileLen);
}
} finally {
in.close();
os.close();
dfs.close();
}
}
static void sendPartialData(FSInputStream in,
OutputStream os,
HttpServletResponse response,
long contentLength,
List ranges)
throws IOException {
if (ranges == null || ranges.size() != 1) {
// if there are no satisfiable ranges, or if multiple ranges are
// requested (we don't support multiple range requests), send 416 response
response.setContentLength(0);
int status = HttpServletResponse.SC_REQUESTED_RANGE_NOT_SATISFIABLE;
response.setStatus(status);
response.setHeader("Content-Range",
InclusiveByteRange.to416HeaderRangeString(contentLength));
} else {
// if there is only a single valid range (must be satisfiable
// since were here now), send that range with a 206 response
InclusiveByteRange singleSatisfiableRange =
(InclusiveByteRange)ranges.get(0);
long singleLength = singleSatisfiableRange.getSize(contentLength);
response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT);
response.setHeader("Content-Range",
singleSatisfiableRange.toHeaderRangeString(contentLength));
System.out.println("first: "+singleSatisfiableRange.getFirst(contentLength));
System.out.println("singleLength: "+singleLength);
StreamFile.writeTo(in,
os,
singleSatisfiableRange.getFirst(contentLength),
singleLength);
}
}
static void writeTo(FSInputStream in,
OutputStream os,
long start,
long count)
throws IOException {
byte buf[] = new byte[4096];
long bytesRemaining = count;
int bytesRead;
int bytesToRead;
in.seek(start);
while (true) {
// number of bytes to read this iteration
bytesToRead = (int)(bytesRemaining<buf.length ?
bytesRemaining:
buf.length);
// number of bytes actually read this iteration
bytesRead = in.read(buf, 0, bytesToRead);
// if we can't read anymore, break
if (bytesRead == -1) {
break;
}
os.write(buf, 0, bytesRead);
bytesRemaining -= bytesRead;
// if we don't need to read anymore, break
if (bytesRemaining <= 0) {
break;
}
}
}
}