webservices/compbio/stat/servlet/HttpCodeResponseServiceStatus.java

   1 package compbio.stat.servlet;\r
   2 \r
   3 import java.io.IOException;\r
   4 import java.io.PrintWriter;\r
   5 import java.io.StringWriter;\r
   6 import java.util.Arrays;\r
   7 \r
   8 import javax.servlet.ServletException;\r
   9 import javax.servlet.http.HttpServlet;\r
  10 import javax.servlet.http.HttpServletRequest;\r
  11 import javax.servlet.http.HttpServletResponse;\r
  12 \r
  13 import org.apache.log4j.Logger;\r
  14 \r
  15 import compbio.util.Util;\r
  16 import compbio.ws.client.Services;\r
  17 import compbio.ws.client.WSTester;\r
  18 \r
  19 /**\r
  20  * This servlet checks the webservice coming as pathinfo and returns http code\r
  21  * as a reply. If the web service functions correctly then OK (200) is returned.\r
  22  * otherwise Service unavailable (503). When the webservice is not recognised\r
  23  * unknown service error (400) is sent as a response.\r
  24  * \r
  25  * If no pathinfo is specified all web services are checked and OK is returned\r
  26  * only if all webservices are functioning.\r
  27  * \r
  28  * @author pvtroshin\r
  29  * \r
  30  */\r
  31 public class HttpCodeResponseServiceStatus extends HttpServlet {\r
  32 \r
  33         private final static Logger log = Logger\r
  34                         .getLogger(HttpCodeResponseServiceStatus.class);\r
  35 \r
  36         @Override\r
  37         protected void doHead(HttpServletRequest req, HttpServletResponse resp)\r
  38                         throws ServletException, IOException {\r
  39                 doGet(req, resp);\r
  40         }\r
  41 \r
  42         @Override\r
  43         protected void doGet(HttpServletRequest req, HttpServletResponse resp)\r
  44                         throws ServletException, IOException {\r
  45 \r
  46                 Services[] servicesToTest = null;\r
  47                 String path = req.getPathInfo();\r
  48                 if (!Util.isEmpty(path)) {\r
  49                         // test a particular service\r
  50                         // e.g. /DisEMBLWS\r
  51                         path = path.trim().substring(1);\r
  52                         Services service = Services.getService(path);\r
  53                         if (service == null) {\r
  54                                 resp.sendError(\r
  55                                                 HttpServletResponse.SC_BAD_REQUEST,\r
  56                                                 "Unknown service name: " + path\r
  57                                                                 + "\n Known services are: "\r
  58                                                                 + Arrays.toString(Services.values())); // bad\r
  59                                 // request\r
  60                                 return;\r
  61                         }\r
  62                         servicesToTest = new Services[]{service};\r
  63                 } else {\r
  64                         // assume all services require testing\r
  65                         servicesToTest = Services.values();\r
  66                 }\r
  67 \r
  68                 // find out the application path to give it to the tester\r
  69                 // e.g.\r
  70                 // http://localhost:8080/jabaws/HttpCodeResponseServiceStatus/DisEMBLWS\r
  71                 // convert it to http://localhost:8080/jabaws\r
  72                 StringBuffer jabawspath = req.getRequestURL();\r
  73                 jabawspath = jabawspath.delete(\r
  74                                 jabawspath.indexOf("/"\r
  75                                                 + HttpCodeResponseServiceStatus.class.getSimpleName()),\r
  76                                 jabawspath.length());\r
  77                 boolean operating = false;\r
  78                 // save for the future use\r
  79                 Services failedService = null;\r
  80                 String failMessage = "";\r
  81                 for (Services serv : servicesToTest) {\r
  82                         String serverPath = jabawspath.toString();\r
  83                         StringWriter testres = new StringWriter();\r
  84                         PrintWriter writer = new PrintWriter(testres, true);\r
  85                         // test\r
  86                         try {\r
  87                                 WSTester tester = new WSTester(serverPath, writer);\r
  88                                 operating = tester.checkService(serv);\r
  89                         } catch (Exception e) {\r
  90                                 log.info(e, e.getCause());\r
  91                                 writer.println("Fails to connect to a web service: " + serv\r
  92                                                 + " With " + e.getLocalizedMessage() + "\nDetails: ");\r
  93                                 // if one service fails, everything fails\r
  94                                 operating = false;\r
  95                         } finally {\r
  96                                 writer.close();\r
  97                         }\r
  98                         if (!operating) {\r
  99                                 failedService = serv;\r
 100                                 failMessage = testres.toString();\r
 101                                 break;\r
 102                         }\r
 103                 }\r
 104 \r
 105                 if (operating) {\r
 106                         resp.setStatus(HttpServletResponse.SC_OK); // OK\r
 107                 } else {\r
 108                         // Internal server error - Service Unavailable\r
 109                         resp.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE,\r
 110                                         "Service: " + failedService\r
 111                                                         + "\n is not available! Error message:\n "\r
 112                                                         + failMessage);\r
 113 \r
 114                 }\r
 115 \r
 116         }\r
 117 }\r