How to propagate http response code from back-end to client
- by Manoj Neelapu
Oracle service bus can be used as for pass through casses. Some use
cases require propagating the http-response code back to the caller.
http://forums.oracle.com/forums/thread.jspa?messageID=4326052�
is one such example we will try to accomplish in this tutorial.We
will try to demonstrate this feature using Oracle
Service Bus (11.1.1.3.0. We will also use commons-logging-1.1.1,
httpcomponents-client-4.0.1, httpcomponents-core-4.0.1 for writing the
client to demonstrate.First we create a simple JSP which will
always set response code to 304.The JSP snippet will look like <%@
page language="java" contentType="text/xml;
charset=UTF-8" pageEncoding="UTF-8" %><%
System.out.println("Servlet setting Responsecode=304");
response.setStatus(304); response.flushBuffer();%>We
will now deploy this JSP on weblogic server with
URI=http://localhost:7021/reponsecode/For this JSP we will create a
simple Any XML BS We will also create proxy service as shown below
Once the proxy is created we configure pipeline for the proxy to use route node, which invokes the BS(JSPCaller) created in the first place.
So now we will create a error handler for route node and will add a stage.
When a HTTP BS sends a request, the JSP sends the response back. If the response code is not 200, then the http BS will consider that as error and the above configured error handler is invoked. We will print $outbound to show the response code sent by the JSP.
The next actions. To test this I had create a simple clientimport org.apache.http.Header;import org.apache.http.HttpEntity;import org.apache.http.HttpHost;import org.apache.http.HttpResponse;import org.apache.http.HttpVersion;import org.apache.http.client.methods.HttpGet;import org.apache.http.conn.ClientConnectionManager;import org.apache.http.conn.scheme.PlainSocketFactory;import org.apache.http.conn.scheme.Scheme;import org.apache.http.conn.scheme.SchemeRegistry;import org.apache.http.impl.client.DefaultHttpClient;import org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager;import org.apache.http.params.BasicHttpParams;import org.apache.http.params.HttpParams;import org.apache.http.params.HttpProtocolParams;import org.apache.http.util.EntityUtils;/** * @author MNEELAPU * */public class TestProxy304{ public static void main(String arg[]) throws Exception{ HttpHost target = new HttpHost("localhost", 7021, "http"); // general setup SchemeRegistry supportedSchemes = new SchemeRegistry(); // Register the "http" protocol scheme, it is required // by the default operator to look up socket factories. supportedSchemes.register(new Scheme("http", PlainSocketFactory.getSocketFactory(), 7021)); // prepare parameters HttpParams params = new BasicHttpParams(); HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1); HttpProtocolParams.setContentCharset(params, "UTF-8"); HttpProtocolParams.setUseExpectContinue(params, true); ClientConnectionManager connMgr = new ThreadSafeClientConnManager(params, supportedSchemes); DefaultHttpClient httpclient = new DefaultHttpClient(connMgr, params); HttpGet req = new HttpGet("/HttpResponseCode/ProxyExposed"); System.out.println("executing request to " + target); HttpResponse rsp = httpclient.execute(target, req); HttpEntity entity = rsp.getEntity(); System.out.println("----------------------------------------"); System.out.println(rsp.getStatusLine()); Header[] headers = rsp.getAllHeaders(); for (int i = 0; i < headers.length; i++) { System.out.println(headers[i]); } System.out.println("----------------------------------------"); if (entity != null) { System.out.println(EntityUtils.toString(entity)); } // When HttpClient instance is no longer needed, // shut down the connection manager to ensure // immediate deallocation of all system resources httpclient.getConnectionManager().shutdown(); }}On compiling and executing this we see the below output in STDOUT which clearly indicates the response code was propagated from Business Service to Proxy serviceexecuting request to http://localhost:7021----------------------------------------HTTP/1.1 304 Not ModifiedDate: Tue, 08 Jun 2010 16:13:42 GMTContent-Type: text/xml; charset=UTF-8X-Powered-By: Servlet/2.5 JSP/2.1----------------------------------------
