/**
* 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 javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.net.*;
import java.util.List;
import org.apache.hadoop.hdfs.DFSClient;
import org.apache.hadoop.hdfs.DFSInputStream;
import org.apache.hadoop.hdfs.HftpFileSystem;
import org.apache.hadoop.hdfs.protocol.DatanodeID;
import org.apache.hadoop.hdfs.server.datanode.DataNode;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.security.UnixUserGroupInformation;
import org.apache.hadoop.conf.*;
public class StreamFile extends DfsServlet {
private static final Configuration masterConf = new Configuration();
/** getting a client for connecting to dfs */
protected DFSClient getDFSClient(HttpServletRequest request)
throws IOException, InterruptedException {
Configuration conf = new Configuration(masterConf);
UnixUserGroupInformation.saveToConf(conf,
UnixUserGroupInformation.UGI_PROPERTY_NAME, getUGI(request));
return JspHelper.getDFSClient(request, conf);
}
/** Get the datanode candidates from the request */
private DatanodeID[] getDatanodes(HttpServletRequest request)
throws IOException {
final String datanodes = request.getParameter("candidates");
if (datanodes == null) {
return null;
}
final String[] datanodeStrs = datanodes.split(" ");
if (datanodeStrs.length == 0) {
return null;
}
final DatanodeID[] dnIDs = new DatanodeID[datanodeStrs.length];
for (int i=0; i<dnIDs.length; i++) {
String hostName = datanodeStrs[i];
int colon = datanodeStrs[i].indexOf(":");
if (colon < 0) {
throw new IOException("Invalid datanode name " +
datanodeStrs[i] + ", expecting name:port pair");
}
hostName = datanodeStrs[i].substring(0, colon);
int infoPort;
try {
infoPort = Integer.parseInt(datanodeStrs[i].substring(colon+1));
} catch (NumberFormatException ne) {
throw new IOException("Invalid datanode name " +
datanodeStrs[i] + ", expecting name:port pair", ne);
}
dnIDs[i] = new DatanodeID(hostName, null, infoPort, -1);
}
return dnIDs;
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
final String filename = request.getParameter("filename") != null ?
request.getParameter("filename") :
request.getPathInfo();
String posStr = request.getParameter("seek");
Long pos = posStr == null ? null : Long.valueOf(posStr);
if (filename == null || filename.length() == 0) {
DataNode.LOG.info("Invalid input");
response.setContentType("text/plain");
PrintWriter out = response.getWriter();
out.print("Invalid input");
return;
}
DFSClient dfs = null;
DFSInputStream in = null;
OutputStream os = null;
try {
dfs = getDFSClient(request);
} catch (IOException e) {
// Can not connect to NN; redirect to a different datanode
List<DatanodeID> candidates = JspHelper.bestNode(
getDatanodes(request), false);
try {
response.sendRedirect(
createUri(filename,
candidates.toArray(new DatanodeID[candidates.size()]),
getUGI(request),
request).toURL().toString());
return;
} catch (URISyntaxException ue) {
throw new ServletException(ue);
}
} catch (InterruptedException e) {
response.sendError(400, e.getMessage());
return;
}
in = dfs.open(filename);
long contentLength = in.getFileLength();
if (pos != null) {
contentLength -= pos;
in.seek(pos);
}
os = response.getOutputStream();
response.setHeader("Content-Disposition", "attachment; filename=\"" +
filename + "\"");
response.setHeader("isUnderConstruction",
in.isUnderConstruction() ? "true" : "false");
response.setContentType("application/octet-stream");
response.setHeader(
HftpFileSystem.CONTENT_LENGTH_FIELD,
String.valueOf(contentLength)
);
byte buf[] = new byte[4096];
try {
int bytesRead;
while ((bytesRead = in.read(buf)) != -1) {
os.write(buf, 0, bytesRead);
}
} catch (IOException ioe) {
DataNode.LOG.warn("Failed to server request: " + request, ioe);
} finally {
IOUtils.closeStream(in);
IOUtils.closeStream(os);
if(dfs!=null) dfs.close();
}
}
}