/*
* Copyright 2014 JBoss 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 io.apiman.manager.ui.server.servlets;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.io.IOUtils;
/**
* A proxy servlet used to get around cross-origin problems when pulling
* down content from remote sites (e.g. when pulling down a remote
* WADL file to use in API Import).
*
* @author eric.wittmann@redhat.com
*/
public class UrlFetchProxyServlet extends HttpServlet {
private static final long serialVersionUID = -4704803997251798191L;
private static Set<String> EXCLUDE_HEADERS = new HashSet<>();
static {
EXCLUDE_HEADERS.add("ETag"); //$NON-NLS-1$
EXCLUDE_HEADERS.add("Last-Modified"); //$NON-NLS-1$
EXCLUDE_HEADERS.add("Date"); //$NON-NLS-1$
EXCLUDE_HEADERS.add("Cache-control"); //$NON-NLS-1$
}
/**
* @see javax.servlet.http.HttpServlet#doGet(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
*/
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException,
IOException {
String url = req.getHeader("X-Apiman-Url"); //$NON-NLS-1$
if (url == null) {
resp.sendError(500, "No URL specified in X-Apiman-Url"); //$NON-NLS-1$
return;
}
URL remoteUrl = new URL(url);
HttpURLConnection remoteConn = (HttpURLConnection) remoteUrl.openConnection();
InputStream remoteIS = null;
OutputStream responseOS = null;
try {
remoteConn.connect();
Map<String, List<String>> headerFields = remoteConn.getHeaderFields();
for (String headerName : headerFields.keySet()) {
if (headerName == null) {
continue;
}
if (EXCLUDE_HEADERS.contains(headerName)) {
continue;
}
String headerValue = remoteConn.getHeaderField(headerName);
resp.setHeader(headerName, headerValue);
}
resp.setHeader("Cache-control", "no-cache, no-store, must-revalidate"); //$NON-NLS-1$ //$NON-NLS-2$
remoteIS = remoteConn.getInputStream();
responseOS = resp.getOutputStream();
IOUtils.copy(remoteIS, responseOS);
resp.flushBuffer();
} catch (Exception e) {
resp.sendError(500, e.getMessage());
} finally {
IOUtils.closeQuietly(responseOS);
IOUtils.closeQuietly(remoteIS);
}
}
}