wso2bpel-ext/wso2bpel-core/BPEL4RESTLight/src/main/java/org/opentosca/bpel4restlight/rest/LowLevelRestApi.java

   1 /*******************************************************************************
   2  * Copyright (c) 2012-2013 University of Stuttgart.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Eclipse Public License v1.0
   5  * and the Apache License 2.0 which both accompany this distribution,
   6  * and are available at http://www.eclipse.org/legal/epl-v10.html
   7  * and http://www.apache.org/licenses/LICENSE-2.0
   8  *******************************************************************************/
   9 /*
  10  * Modifications Copyright 2016-2017 ZTE Corporation.
  11  */
  12  /**
  13  * This static-class eases HTTP-method execution by self-managed fault-handling
  14  * and automated Response-information processing
  15  */
  16 package org.opentosca.bpel4restlight.rest;
  17
  18 import java.io.IOException;
  19 import java.util.Map;
  20 import java.util.Set;
  21
  22 import org.apache.commons.httpclient.Header;
  23 import org.apache.commons.httpclient.HttpClient;
  24 import org.apache.commons.httpclient.HttpMethod;
  25 import org.apache.commons.logging.Log;
  26 import org.apache.commons.logging.LogFactory;
  27 import org.json.simple.JSONArray;
  28 import org.json.simple.JSONObject;
  29 import org.json.simple.parser.JSONParser;
  30 import org.json.simple.parser.ParseException;
  31
  32
  33 public class LowLevelRestApi {
  34
  35   protected static final Log log = LogFactory.getLog(LowLevelRestApi.class);
  36         // Local HttpClient used for every communication (Singleton implementation)
  37 //      private static HttpClient httpClient = new HttpClient();
  38
  39         /**
  40          * Executes a passed HttpMethod (Method type is either PUT, POST, GET or
  41          * DELETE) and returns a HttpResponseMessage
  42          *
  43          * @param method Method to execute
  44          * @return HttpResponseMessage which contains all information about the
  45          *         execution
  46          */
  47         public static HttpResponseMessage executeHttpMethod(HttpMethod method) {
  48
  49                 HttpResponseMessage responseMessage = null;
  50
  51                 try {
  52                         log.debug("Method invocation on URI: \n");
  53                         log.debug(method.getURI().toString());
  54
  55                         // Execute Request
  56                         HttpClient httpClient = new HttpClient();
  57                         httpClient.executeMethod(method);
  58                         responseMessage = LowLevelRestApi.extractResponseInformation(method);
  59
  60                 } catch (Exception e) {
  61                   log.error("call rest error:", e);
  62                 } finally {
  63                         // Release Connection anyway
  64                         method.releaseConnection();
  65                 }
  66
  67                 // Extract response information and return
  68                 return responseMessage;
  69         }
  70
  71         /**
  72          * Extracts the response information from an executed HttpMethod
  73          *
  74          * @param method Executed Method
  75          * @return Packaged response information
  76          */
  77         private static HttpResponseMessage extractResponseInformation(HttpMethod method) {
  78                 // Create and return HttpResponseMethod
  79                 HttpResponseMessage responseMessage = new HttpResponseMessage();
  80                 responseMessage.setStatusCode(method.getStatusCode());
  81                 try {
  82                         responseMessage.setResponseBody(getResponseBody(method));
  83                 } catch (Exception e) {
  84                     log.error(e);
  85                 }
  86                 return responseMessage;
  87
  88         }
  89
  90         /**
  91          * getResponseBody
  92          *
  93          * get response body info, if response body is a json object, then translate json object to xml
  94          * if the rest request failed, i.e. the response body is a 404 error page, then response the body with header <root>
  95          * @param method
  96          * @return
  97          * @throws ParseException
  98          */
  99         private static String getResponseBody(HttpMethod method) throws ParseException
 100         {
 101           String result = null;
 102           try {
 103             result = method.getResponseBodyAsString();
 104                 log.debug("result:");
 105                 log.debug(result);
 106           } catch (IOException e) {
 107             log.error(e);
 108           }
 109
 110           Header header = method.getRequestHeader("Accept");
 111           if ("application/json".equals(header.getValue())) {
 112             StringBuilder sb = new StringBuilder();
 113             sb.append("<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>");
 114             sb.append("<root>");
 115             if(result != null && !"".equals(result)) {
 116               /**
 117                   if(result.startsWith("<html>")) {
 118                 sb.append("<![CDATA[");
 119                 sb.append(result);
 120                 sb.append("]]>");
 121               } else {
 122                 Object json = new JSONParser().parse(result);
 123                 json2Xml(sb, "obj", json);
 124               }
 125                   */
 126
 127                   try {
 128                         Object json = new JSONParser().parse(result);
 129                 json2Xml(sb, "obj", json);
 130                   } catch (Exception e) {
 131                         log.error(e);
 132                         sb.append("<![CDATA[");
 133                 sb.append(result);
 134                 sb.append("]]>");
 135                   }
 136             }
 137             sb.append("</root>");
 138
 139                 log.debug("responseBody:");
 140                 log.debug(sb.toString());
 141             return sb.toString();
 142           }
 143           return result;
 144         }
 145
 146
 147         @SuppressWarnings("unchecked")
 148         public static void json2Xml(StringBuilder sb, String key,  Object jsonObject) {
 149           if(jsonObject == null) {
 150             sb.append("<error>empty</error>");
 151             return;
 152           }
 153
 154           if(jsonObject instanceof JSONArray) {
 155             JSONArray array = (JSONArray) jsonObject;
 156             sb.append("<").append(key).append("s").append(">");
 157             for(int i=0, len=array.size(); i<len; i++) {
 158               json2Xml(sb, key, array.get(i));
 159             }
 160             sb.append("</").append(key).append("s").append(">");
 161
 162             return;
 163           } else if(jsonObject instanceof JSONObject) {
 164             sb.append("<").append(key).append(">");
 165             JSONObject json = (JSONObject) jsonObject;
 166             for(Map.Entry<String, Object> entry : (Set<Map.Entry<String, Object>>)json.entrySet()) {
 167               json2Xml(sb, entry.getKey(), entry.getValue());
 168             }
 169             sb.append("</").append(key).append(">");
 170             return;
 171           } else {
 172             sb.append("<").append(key).append(">");
 173             sb.append("<![CDATA[");
 174             sb.append(jsonObject.toString());
 175             sb.append("]]>");
 176             sb.append("</").append(key).append(">");
 177
 178             return;
 179           }
 180         }
 181
 182 }