Java tutorial
/** * 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.datanode.web.webhdfs; import io.netty.handler.codec.http.QueryStringDecoder; import org.apache.commons.io.Charsets; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.permission.FsPermission; import org.apache.hadoop.hdfs.HAUtil; import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenIdentifier; import org.apache.hadoop.hdfs.web.resources.BlockSizeParam; import org.apache.hadoop.hdfs.web.resources.BufferSizeParam; import org.apache.hadoop.hdfs.web.resources.DelegationParam; import org.apache.hadoop.hdfs.web.resources.DoAsParam; import org.apache.hadoop.hdfs.web.resources.HttpOpParam; import org.apache.hadoop.hdfs.web.resources.LengthParam; import org.apache.hadoop.hdfs.web.resources.NamenodeAddressParam; import org.apache.hadoop.hdfs.web.resources.OffsetParam; import org.apache.hadoop.hdfs.web.resources.OverwriteParam; import org.apache.hadoop.hdfs.web.resources.PermissionParam; import org.apache.hadoop.hdfs.web.resources.ReplicationParam; import org.apache.hadoop.hdfs.web.resources.UserParam; import org.apache.hadoop.security.SecurityUtil; import org.apache.hadoop.security.token.Token; import java.io.IOException; import java.net.URI; import java.nio.charset.Charset; import java.util.List; import java.util.Map; import static org.apache.hadoop.hdfs.protocol.HdfsConstants.HDFS_URI_SCHEME; import static org.apache.hadoop.hdfs.server.datanode.web.webhdfs.WebHdfsHandler.WEBHDFS_PREFIX_LENGTH; class ParameterParser { private final Configuration conf; private final String path; private final Map<String, List<String>> params; ParameterParser(QueryStringDecoder decoder, Configuration conf) { this.path = decodeComponent(decoder.path().substring(WEBHDFS_PREFIX_LENGTH), Charsets.UTF_8); this.params = decoder.parameters(); this.conf = conf; } String path() { return path; } String op() { return param(HttpOpParam.NAME); } long offset() { return new OffsetParam(param(OffsetParam.NAME)).getOffset(); } long length() { return new LengthParam(param(LengthParam.NAME)).getLength(); } String namenodeId() { return new NamenodeAddressParam(param(NamenodeAddressParam.NAME)).getValue(); } String doAsUser() { return new DoAsParam(param(DoAsParam.NAME)).getValue(); } String userName() { return new UserParam(param(UserParam.NAME)).getValue(); } int bufferSize() { return new BufferSizeParam(param(BufferSizeParam.NAME)).getValue(conf); } long blockSize() { return new BlockSizeParam(param(BlockSizeParam.NAME)).getValue(conf); } short replication() { return new ReplicationParam(param(ReplicationParam.NAME)).getValue(conf); } FsPermission permission() { return new PermissionParam(param(PermissionParam.NAME)).getFsPermission(); } boolean overwrite() { return new OverwriteParam(param(OverwriteParam.NAME)).getValue(); } Token<DelegationTokenIdentifier> delegationToken() throws IOException { String delegation = param(DelegationParam.NAME); final Token<DelegationTokenIdentifier> token = new Token<DelegationTokenIdentifier>(); token.decodeFromUrlString(delegation); URI nnUri = URI.create(HDFS_URI_SCHEME + "://" + namenodeId()); boolean isLogical = HAUtil.isLogicalUri(conf, nnUri); if (isLogical) { token.setService(HAUtil.buildTokenServiceForLogicalUri(nnUri)); } else { token.setService(SecurityUtil.buildTokenService(nnUri)); } return token; } Configuration conf() { return conf; } private String param(String key) { List<String> p = params.get(key); return p == null ? null : p.get(0); } /** * The following function behaves exactly the same as netty's * <code>QueryStringDecoder#decodeComponent</code> except that it * does not decode the '+' character as space. WebHDFS takes this scheme * to maintain the backward-compatibility for pre-2.7 releases. */ private static String decodeComponent(final String s, final Charset charset) { if (s == null) { return ""; } final int size = s.length(); boolean modified = false; for (int i = 0; i < size; i++) { final char c = s.charAt(i); if (c == '%' || c == '+') { modified = true; break; } } if (!modified) { return s; } final byte[] buf = new byte[size]; int pos = 0; // position in `buf'. for (int i = 0; i < size; i++) { char c = s.charAt(i); if (c == '%') { if (i == size - 1) { throw new IllegalArgumentException("unterminated escape sequence at" + " end of string: " + s); } c = s.charAt(++i); if (c == '%') { buf[pos++] = '%'; // "%%" -> "%" break; } if (i == size - 1) { throw new IllegalArgumentException("partial escape sequence at end " + "of string: " + s); } c = decodeHexNibble(c); final char c2 = decodeHexNibble(s.charAt(++i)); if (c == Character.MAX_VALUE || c2 == Character.MAX_VALUE) { throw new IllegalArgumentException("invalid escape sequence `%" + s.charAt(i - 1) + s.charAt(i) + "' at index " + (i - 2) + " of: " + s); } c = (char) (c * 16 + c2); // Fall through. } buf[pos++] = (byte) c; } return new String(buf, 0, pos, charset); } /** * Helper to decode half of a hexadecimal number from a string. * @param c The ASCII character of the hexadecimal number to decode. * Must be in the range {@code [0-9a-fA-F]}. * @return The hexadecimal value represented in the ASCII character * given, or {@link Character#MAX_VALUE} if the character is invalid. */ private static char decodeHexNibble(final char c) { if ('0' <= c && c <= '9') { return (char) (c - '0'); } else if ('a' <= c && c <= 'f') { return (char) (c - 'a' + 10); } else if ('A' <= c && c <= 'F') { return (char) (c - 'A' + 10); } else { return Character.MAX_VALUE; } } }