| /** |
| * 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.util; |
| |
| import java.io.IOException; |
| import java.io.PrintWriter; |
| import java.io.UnsupportedEncodingException; |
| import java.net.URI; |
| import java.net.URISyntaxException; |
| import java.net.URLEncoder; |
| import java.util.Calendar; |
| |
| import javax.servlet.*; |
| import javax.servlet.http.HttpServletRequest; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| |
| import com.google.common.base.Preconditions; |
| import org.apache.http.client.utils.URIBuilder; |
| |
| @InterfaceAudience.Private |
| @InterfaceStability.Unstable |
| public class ServletUtil { |
| /** |
| * Initial HTML header |
| */ |
| public static PrintWriter initHTML(ServletResponse response, String title |
| ) throws IOException { |
| response.setContentType("text/html"); |
| PrintWriter out = response.getWriter(); |
| out.println("<html>\n" |
| + "<link rel='stylesheet' type='text/css' href='/static/hadoop.css'>\n" |
| + "<title>" + title + "</title>\n" |
| + "<body>\n" |
| + "<h1>" + title + "</h1>\n"); |
| return out; |
| } |
| |
| /** |
| * Get a parameter from a ServletRequest. |
| * Return null if the parameter contains only white spaces. |
| */ |
| public static String getParameter(ServletRequest request, String name) { |
| String s = request.getParameter(name); |
| if (s == null) { |
| return null; |
| } |
| s = s.trim(); |
| return s.length() == 0? null: s; |
| } |
| |
| /** |
| * @return a long value as passed in the given parameter, throwing |
| * an exception if it is not present or if it is not a valid number. |
| */ |
| public static long parseLongParam(ServletRequest request, String param) |
| throws IOException { |
| String paramStr = request.getParameter(param); |
| if (paramStr == null) { |
| throw new IOException("Invalid request has no " + param + " parameter"); |
| } |
| |
| return Long.parseLong(paramStr); |
| } |
| |
| public static final String HTML_TAIL = "<hr />\n" |
| + "<a href='http://hadoop.apache.org/core'>Hadoop</a>, " |
| + Calendar.getInstance().get(Calendar.YEAR) + ".\n" |
| + "</body></html>"; |
| |
| /** |
| * HTML footer to be added in the jsps. |
| * @return the HTML footer. |
| */ |
| public static String htmlFooter() { |
| return HTML_TAIL; |
| } |
| /** |
| * Escape and encode a string regarded as within the query component of an URI. |
| * @param value the value to encode |
| * @return encoded query, null if the default charset is not supported |
| */ |
| public static String encodeQueryValue(final String value) { |
| try { |
| return URLEncoder.encode(value, "UTF-8"); |
| } catch (UnsupportedEncodingException e) { |
| throw new AssertionError("Failed to encode query value in UTF-8: " + |
| value); |
| } |
| } |
| |
| /** |
| * Escape and encode a string regarded as the path component of an URI. |
| * @param path the path component to encode |
| * @return encoded path, null if UTF-8 is not supported |
| */ |
| public static String encodePath(final String path) { |
| return new URIBuilder().setPath(path).toString(); |
| } |
| |
| /** |
| * Decode a string regarded as the path component of an URI. |
| * |
| * @param path the path component to decode |
| * @return decoded path, null if UTF-8 is not supported |
| * @throws URISyntaxException |
| */ |
| public static String decodePath(final String path) { |
| try { |
| return new URI(path).getPath(); |
| } catch (URISyntaxException e) { |
| throw new AssertionError("Failed to decode URI: " + path); |
| } |
| } |
| |
| /** |
| * Parse and decode the path component from the given request. |
| * @param request Http request to parse |
| * @param servletName the name of servlet that precedes the path |
| * @return decoded path component, null if UTF-8 is not supported |
| */ |
| public static String getDecodedPath(final HttpServletRequest request, |
| String servletName) { |
| String requestURI = request.getRequestURI(); |
| String uriPath = getRawPath(request, servletName); |
| try { |
| return new URI(uriPath).getPath(); |
| } catch (URISyntaxException e) { |
| throw new AssertionError("Failed to decode URI: " + requestURI); |
| } |
| } |
| |
| /** |
| * Parse the path component from the given request and return w/o decoding. |
| * @param request Http request to parse |
| * @param servletName the name of servlet that precedes the path |
| * @return path component, null if the default charset is not supported |
| */ |
| public static String getRawPath(final HttpServletRequest request, String servletName) { |
| Preconditions.checkArgument(request.getRequestURI().startsWith(servletName+"/")); |
| return request.getRequestURI().substring(servletName.length()); |
| } |
| } |