/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.shindig.gadgets.servlet;
import org.apache.shindig.common.servlet.HttpUtil;
import org.apache.shindig.common.servlet.InjectedServlet;
import org.apache.shindig.common.uri.UriBuilder;
import org.apache.shindig.gadgets.GadgetContext;
import org.apache.shindig.gadgets.http.HttpRequest;
import org.apache.shindig.gadgets.render.Renderer;
import org.apache.shindig.gadgets.render.RenderingResults;
import org.apache.shindig.gadgets.uri.IframeUriManager;
import org.apache.shindig.gadgets.uri.UriStatus;
import org.apache.shindig.gadgets.uri.UriCommon.Param;
import com.google.inject.Inject;
import org.apache.commons.lang.StringEscapeUtils;
import org.apache.commons.lang.StringUtils;
import java.io.IOException;
import java.util.logging.Logger;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet for rendering Gadgets.
*/
public class GadgetRenderingServlet extends InjectedServlet {
private static final long serialVersionUID = -5634040113214794888L;
static final int DEFAULT_CACHE_TTL = 60 * 5;
private static final Logger LOG = Logger.getLogger(GadgetRenderingServlet.class.getName());
private transient Renderer renderer;
private transient IframeUriManager iframeUriManager;
@Inject
public void setRenderer(Renderer renderer) {
checkInitialized();
this.renderer = renderer;
}
@Inject
public void setIframeUriManager(IframeUriManager iframeUriManager) {
checkInitialized();
this.iframeUriManager = iframeUriManager;
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
// If an If-Modified-Since header is ever provided, we always say
// not modified. This is because when there actually is a change,
// cache busting should occur.
UriStatus urlStatus = getUrlStatus(req);
if (req.getHeader("If-Modified-Since") != null &&
!"1".equals(req.getParameter("nocache")) &&
urlStatus == UriStatus.VALID_VERSIONED) {
resp.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
return;
}
render(req, resp, urlStatus);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
render(req, resp, getUrlStatus(req));
}
private void render(HttpServletRequest req, HttpServletResponse resp, UriStatus urlstatus)
throws IOException {
if (req.getHeader(HttpRequest.DOS_PREVENTION_HEADER) != null) {
// Refuse to render for any request that came from us.
// TODO: Is this necessary for any other type of request? Rendering seems to be the only one
// that can potentially result in an infinite loop.
resp.sendError(HttpServletResponse.SC_FORBIDDEN);
return;
}
resp.setContentType("text/html");
resp.setCharacterEncoding("UTF-8");
GadgetContext context = new HttpGadgetContext(req);
RenderingResults results = renderer.render(context);
// process the rendering results
postGadgetRendering(new PostGadgetRenderingParams(req, resp, urlstatus, context, results));
}
/**
* Implementations that extend this class are strongly discouraged from overriding this method.
* To customize the behavior please override the hook methods for each of the
* RenderingResults.Status enum values instead.
*/
protected void postGadgetRendering(PostGadgetRenderingParams params) throws IOException {
switch (params.getResults().getStatus()) {
case OK:
onOkRenderingResultsStatus(params);
break;
case ERROR:
onErrorRenderingResultsStatus(params);
break;
case MUST_REDIRECT:
onMustRedirectRenderingResultsStatus(params);
break;
}
}
protected void onOkRenderingResultsStatus(PostGadgetRenderingParams params)
throws IOException {
UriStatus urlStatus = params.getUrlStatus();
HttpServletResponse resp = params.getResponse();
if (params.getContext().getIgnoreCache() ||
urlStatus == UriStatus.INVALID_VERSION) {
HttpUtil.setCachingHeaders(resp, 0);
} else if (urlStatus == UriStatus.VALID_VERSIONED) {
// Versioned files get cached indefinitely
HttpUtil.setCachingHeaders(resp, true);
} else {
// Unversioned files get cached for 5 minutes by default, but this can be overridden
// with a query parameter.
int ttl = DEFAULT_CACHE_TTL;
String ttlStr = params.getRequest().getParameter(Param.REFRESH.getKey());
if (!StringUtils.isEmpty(ttlStr)) {
try {
ttl = Integer.parseInt(ttlStr);
} catch (NumberFormatException e) {
// Ignore malformed TTL value
LOG.info("Bad TTL value '" + ttlStr + "' was ignored");
}
}
HttpUtil.setCachingHeaders(resp, ttl, true);
}
resp.getWriter().print(params.getResults().getContent());
}
protected void onErrorRenderingResultsStatus(PostGadgetRenderingParams params)
throws IOException {
HttpServletResponse resp = params.getResponse();
resp.setStatus(params.getResults().getHttpStatusCode());
resp.getWriter().print(StringEscapeUtils.escapeHtml(params.getResults().getErrorMessage()));
}
protected void onMustRedirectRenderingResultsStatus(PostGadgetRenderingParams params)
throws IOException {
params.getResponse().sendRedirect(params.getResults().getRedirect().toString());
}
private UriStatus getUrlStatus(HttpServletRequest req) {
return iframeUriManager.validateRenderingUri(new UriBuilder(req).toUri());
}
/**
* Contains the input parameters for post rendering methods.
*/
protected static class PostGadgetRenderingParams {
private HttpServletRequest req;
private HttpServletResponse resp;
private UriStatus urlStatus;
private GadgetContext context;
private RenderingResults results;
public PostGadgetRenderingParams (HttpServletRequest req, HttpServletResponse resp,
UriStatus urlStatus, GadgetContext context, RenderingResults results) {
this.req = req;
this.resp = resp;
this.urlStatus = urlStatus;
this.context = context;
this.results = results;
}
public HttpServletRequest getRequest() {
return req;
}
public HttpServletResponse getResponse() {
return resp;
}
public UriStatus getUrlStatus() {
return urlStatus;
}
public GadgetContext getContext() {
return context;
}
public RenderingResults getResults() {
return results;
}
}
}