import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* This is a transparent HTTP proxy written in Java that is similar to the proxy in
* the OpenLayers examples, which is written in Python. These proxies are used
* to circumvent browser restrictions on cross-domain requests with java script.
*
*
* To use the proxy you need to 1) configure the proxy servlet in your web.xml
* and 2) use OpenLayers.setProxyHost to set the url-path to the proxy. If the
* proxy is configured to listen to the url-pattern '/gwtOpenLayersProxy/*' then
* the proxy host should be set to 'gwtOpenLayersProxy targetURL='.
*
* Initial code for this proxy is based upon * "the">http://trac.openlayers.org/changeset/8099/sandbox format=diff&new=8099">the
* following code
* see also * "http://java.sun.com/docs/books/tutorial/networking/urls/readingWriting.html"
* title="this networking tutorial">this networking tutorial
*
*/
@SuppressWarnings("serial")
public class GwtOpenLayersProxyServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
processRequest(request,response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
processRequest(request, response);
}
private void processRequest(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
HttpURLConnection connection = null;
InputStream istream = null; //input to proxy
OutputStream ostream = null; //output from proxy
InputStream connectionIstream = null; //output for the target is input for the connection
OutputStream connectionOstream = null; //input for the target is output for the connection
String remoteHost = request.getRemoteHost(); // get host address of client - for checking allowedHosts
boolean allowedHost = isAllowedHost(remoteHost); //The allowedHosts are the hosts that are allowed to use the Open Proxy.
try {
// easy way to ignore case of param
if(request.getParameter("targetURL") != null && request.getParameter("targetURL") != "" && allowedHost) {
// HTTPUrlConnection looks at http.proxyHost and http.proxyPort system properties.
// Make sure these properties are set these if you are behind a proxy.
//step 1: initialize
String requestMethod = request.getMethod();
URL targetURL = new URL(request.getParameter("targetURL"));
connection = (HttpURLConnection) targetURL.openConnection();
connection.setRequestMethod(requestMethod);
transferHTTPRequestHeaders(connection, request);
//step 2: proxy requests
if (requestMethod.equals("GET")){
//default for setDoInput is true
connectionIstream = connection.getInputStream();
};