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.atlas.web.util; import org.apache.atlas.AtlasClient; import org.apache.atlas.LocalServletRequest; import org.apache.atlas.exception.AtlasBaseException; import org.apache.atlas.utils.ParamChecker; import org.apache.commons.collections.MapUtils; import org.apache.commons.io.IOUtils; import org.apache.commons.lang3.StringEscapeUtils; import org.apache.commons.lang3.StringUtils; import org.apache.http.NameValuePair; import org.apache.http.client.utils.URLEncodedUtils; import org.codehaus.jettison.json.JSONException; import org.codehaus.jettison.json.JSONObject; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import javax.servlet.http.HttpServletRequest; import javax.ws.rs.core.MediaType; import javax.ws.rs.core.Response; import java.io.IOException; import java.io.StringWriter; import java.nio.charset.Charset; import java.util.HashMap; import java.util.List; import java.util.Map; /** * Utility functions for dealing with servlets. */ public final class Servlets { private static final Logger LOG = LoggerFactory.getLogger(Servlets.class); private Servlets() { /* singleton */ } public static final String JSON_MEDIA_TYPE = MediaType.APPLICATION_JSON + "; charset=UTF-8"; public static final String BINARY = MediaType.APPLICATION_OCTET_STREAM; /** * Returns the user of the given request. * * @param httpRequest an HTTP servlet request * @return the user */ public static String getUserFromRequest(HttpServletRequest httpRequest) { String user = httpRequest.getRemoteUser(); if (!StringUtils.isEmpty(user)) { return user; } user = httpRequest.getParameter("user.name"); // available in query-param if (!StringUtils.isEmpty(user)) { return user; } user = httpRequest.getHeader("Remote-User"); // backwards-compatibility if (!StringUtils.isEmpty(user)) { return user; } user = getDoAsUser(httpRequest); if (!StringUtils.isEmpty(user)) { return user; } return null; } private static final Charset UTF8_CHARSET = Charset.forName("UTF-8"); private static final String DO_AS = "doAs"; public static String getDoAsUser(HttpServletRequest request) { if (StringUtils.isNoneEmpty(request.getQueryString())) { List<NameValuePair> list = URLEncodedUtils.parse(request.getQueryString(), UTF8_CHARSET); if (list != null) { for (NameValuePair nv : list) { if (DO_AS.equals(nv.getName())) { return nv.getValue(); } } } } return null; } /** * Returns the URI of the given request. * * @param httpRequest an HTTP servlet request * @return the URI, including the query string */ public static String getRequestURI(HttpServletRequest httpRequest) { final StringBuilder url = new StringBuilder(100).append(httpRequest.getRequestURI()); if (httpRequest.getQueryString() != null) { url.append('?').append(httpRequest.getQueryString()); } return url.toString(); } /** * Returns the full URL of the given request. * * @param httpRequest an HTTP servlet request * @return the full URL, including the query string */ public static String getRequestURL(HttpServletRequest httpRequest) { final StringBuilder url = new StringBuilder(100).append(httpRequest.getRequestURL()); if (httpRequest.getQueryString() != null) { url.append('?').append(httpRequest.getQueryString()); } return url.toString(); } public static Response getErrorResponse(AtlasBaseException e) { String message = e.getMessage() == null ? "Failed with " + e.getClass().getName() : e.getMessage(); Response response = getErrorResponse(message, e.getAtlasErrorCode().getHttpCode()); return response; } public static Response getErrorResponse(Throwable e, Response.Status status) { String message = e.getMessage() == null ? "Failed with " + e.getClass().getName() : e.getMessage(); Response response = getErrorResponse(message, status); return response; } public static Response getErrorResponse(String message, Response.Status status) { JSONObject errorJson = new JSONObject(); Object errorEntity = escapeJsonString(message); try { errorJson.put(AtlasClient.ERROR, errorEntity); errorEntity = errorJson; } catch (JSONException jsonE) { LOG.warn("Could not construct error Json rensponse", jsonE); } return Response.status(status).entity(errorEntity).type(JSON_MEDIA_TYPE).build(); } public static String getRequestPayload(HttpServletRequest request) throws IOException { //request is an instance of LocalServletRequest for calls from LocalAtlasClient if (request instanceof LocalServletRequest) { return ((LocalServletRequest) request).getPayload(); } StringWriter writer = new StringWriter(); IOUtils.copy(request.getInputStream(), writer); return writer.toString(); } public static String getRequestId() { return Thread.currentThread().getName(); } public static String escapeJsonString(String inputStr) { ParamChecker.notNull(inputStr, "Input String cannot be null"); return StringEscapeUtils.escapeJson(inputStr); } public static String getHostName(HttpServletRequest httpServletRequest) { return httpServletRequest.getLocalName(); } public static String getUserName(HttpServletRequest httpServletRequest) throws IOException { return httpServletRequest.getRemoteUser(); } public static Map<String, Object> getParameterMap(HttpServletRequest request) { Map<String, Object> attributes = new HashMap<>(); if (MapUtils.isNotEmpty(request.getParameterMap())) { for (Map.Entry<String, String[]> e : request.getParameterMap().entrySet()) { String key = e.getKey(); if (key != null) { String[] values = e.getValue(); String value = values != null && values.length > 0 ? values[0] : null; attributes.put(key, value); } } } return attributes; } }