com.clouway.friendlyserve.servlets.ServletApiSupport Maven / Gradle / Ivy

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package com.clouway.friendlyserve.servlets;

import com.clouway.friendlyserve.Cookie;
import com.clouway.friendlyserve.HttpException;
import com.clouway.friendlyserve.Response;
import com.clouway.friendlyserve.Status;
import com.clouway.friendlyserve.Take;
import com.clouway.friendlyserve.TkRequestWrap;
import com.google.common.io.ByteStreams;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * ServletApiSupport is an adapter class which adapts the Servlet API into fserve to provide seamless integration.
 *
 * Hooking it in the Servlet class:
 *  *  {@literal @}Override
 *  protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
 *     servletApiSupport.serve(req, resp);
 *  }
 *
 * 
 *
 * @author Miroslav Genov ([email protected])
 */
public final class ServletApiSupport {
  private static Logger logger = Logger.getLogger(ServletApiSupport.class.getName());

  private final Take take;

  public ServletApiSupport(Take take) {
    this.take = take;
  }

  /**
   * Serves the provided Servlet Request and writes the response back to the provided {@link HttpServletResponse}.
   *
   * @param req the servlet request which need to be served
   * @param resp the response which to be written
   * @throws IOException is thrown in case of IO error or some internal error.
   */
  public void serve(HttpServletRequest req, HttpServletResponse resp) throws IOException {
    try {
      Response response = take.ack(new TkRequestWrap(req));

      Status status = response.status();
      resp.setStatus(status.code);

      // Handle redirects
      if (status.code == HttpURLConnection.HTTP_MOVED_TEMP) {
        resp.sendRedirect(status.redirectUrl);

        return;
      }

      Map header = response.header();
      for (String key : header.keySet()) {
        resp.setHeader(key, header.get(key));
      }

      for (Cookie each : response.cookies()) {
        javax.servlet.http.Cookie cookie = new javax.servlet.http.Cookie(each.name(), each.value());
        cookie.setPath(each.path());
        cookie.setMaxAge(each.expirationTimeInSeconds());
        
        resp.addCookie(cookie);
      }

      ServletOutputStream out = resp.getOutputStream();

      try (InputStream inputStream = response.body()) {
        ByteStreams.copy(inputStream, out);
      }

      out.flush();

    } catch (HttpException e) {
      resp.setStatus(e.code());
    } catch (Exception e) { // got internal error
      logger.log(Level.SEVERE, "could not handle the request", e);
      resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
    }
    
  }
}