/*
* Copyright (C) 2013 Square, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.squareup.rack.servlet;
import com.squareup.rack.RackApplication;
import com.squareup.rack.RackEnvironment;
import com.squareup.rack.RackResponse;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* <p>Hosts a {@link RackApplication}.</p>
*
* <p>Since RackServlet lacks a zero-argument constructor, you'll need to manually instantiate and
* install it in your container, rather than declaring it in a {@code web.xml} file. See our
* examples for concrete code.</p>
*/
public class RackServlet extends HttpServlet {
private final RackEnvironmentBuilder rackEnvironmentBuilder;
private final RackApplication rackApplication;
private final RackResponsePropagator rackResponsePropagator;
/**
* Creates a servlet hosting the given {@link RackApplication}.
*
* @param rackApplication the application to host.
*/
public RackServlet(RackApplication rackApplication) {
this(new RackEnvironmentBuilder(), rackApplication, new RackResponsePropagator());
}
/**
* Creates a servlet hosting the given {@link RackApplication} and that uses the given
* collaborators to translate between the Servlet and Rack environments.
*
* @param rackEnvironmentBuilder turns {@link HttpServletRequest}s into {@link RackEnvironment}s.
* @param rackApplication the application to host.
* @param rackResponsePropagator writes {@link RackResponse}s onto {@link HttpServletResponse}s.
*/
public RackServlet(RackEnvironmentBuilder rackEnvironmentBuilder,
RackApplication rackApplication,
RackResponsePropagator rackResponsePropagator) {
this.rackEnvironmentBuilder = rackEnvironmentBuilder;
this.rackApplication = rackApplication;
this.rackResponsePropagator = rackResponsePropagator;
}
@Override protected void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
RackEnvironment rackEnvironment = rackEnvironmentBuilder.build(request);
try {
RackResponse rackResponse = rackApplication.call(rackEnvironment);
rackResponsePropagator.propagate(rackResponse, response);
} finally {
rackEnvironment.closeRackInput();
}
}
}