APIProxyServlet.java

package kornell.server;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.http.Header;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.ResponseHandler;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

import kornell.core.util.StringUtils;

@SuppressWarnings("serial")
public class APIProxyServlet extends HttpServlet{
	@Override
	protected void doGet(final HttpServletRequest req, final HttpServletResponse resp)
			throws ServletException, IOException {
		String distributionURL = "http://eduvem.com";			
		String uri = req.getRequestURI(); 
		StringBuilder log = new StringBuilder();
		CloseableHttpClient httpclient = HttpClients.createDefault();
		try {
			HttpGet httpget = new HttpGet(StringUtils.mkurl(distributionURL,uri));

			log.append("Requesting " + uri);

			// Create a custom response handler
			ResponseHandler<String> responseHandler = new ResponseHandler<String>() {

				public String handleResponse(
						final HttpResponse response)
						throws ClientProtocolException, IOException {
					int status = response.getStatusLine().getStatusCode();
					if (status >= 200 && status < 300) {
						HttpEntity entity = response.getEntity();
						Header[] headers = response.getHeaders("Content-Type");
						if(headers.length > 0) {
						    String ctype = headers[0].toString();
						    //TODO: Set Correct Content Type
							resp.setHeader("Content-Type", ctype);
						} 
						return entity != null ? EntityUtils.toString(entity)
								: null;
					} else {
						throw new ClientProtocolException(
								"Unexpected response status: " + status);
					}					
				}

			};
			String responseBody = httpclient.execute(httpget, responseHandler);
			if(uri.endsWith("html")){
				resp.setContentType("text/html");
			}else if (uri.endsWith("css")){
				resp.setContentType("text/css");
			}else if (uri.endsWith("js")){
				resp.setContentType("application/javascript");
			}
			resp.setCharacterEncoding("UTF-8");
					
			System.out.println(log);
			resp.getWriter().print(responseBody);
		} finally {
			httpclient.close();
		}
	}
}