/*
* 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.myfaces.tobago.facelets;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;
import javax.servlet.ServletContext;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLStreamHandler;
/*
* Was copied from MyFaces-Impl, because there is no JSF base class.
*/
public class Resource {
private static final Logger LOG = LoggerFactory.getLogger(Resource.class);
/**
* Get an URL of an internal resource. First, {@link javax.faces.context.ExternalContext#getResource(String)} is
* checked for an non-null URL return value. In the case of a null return value (as it is the case for Weblogic 8.1
* for a packed war), a URL with a special URL handler is constructed, which can be used for <em>opening</em> a
* serlvet resource later. Internally, this special URL handler will call
* {@link javax.servlet.ServletContext#getResourceAsStream(String)} when an inputstream is requested.
* This works even on Weblogic 8.1
*
* @param ctx the faces context from which to retrieve the resource
* @param path an URL path
* @return an url representing the URL and on which getInputStream() can be called to get the resource
* @throws java.net.MalformedURLException
*/
public static URL getResourceUrl(FacesContext ctx, String path) throws MalformedURLException {
final ExternalContext externalContext = ctx.getExternalContext();
URL url = externalContext.getResource(path);
if (LOG.isTraceEnabled()) {
LOG.trace("Resource-Url from external context: " + url);
}
if (url == null) {
// This might happen on Servlet container which doesnot return
// anything
// for getResource() (like weblogic 8.1 for packaged wars) we
// are trying
// to use an own URL protocol in order to use
// ServletContext.getResourceAsStream()
// when opening the url
if (resourceExist(externalContext, path)) {
url = getUrlForResourceAsStream(externalContext, path);
}
}
return url;
}
// This method could be used above to provide a 'fail fast' if a
// resource
// doesnt exist. Otherwise, the URL will fail on the first access.
private static boolean resourceExist(ExternalContext externalContext, String path) {
if ("/".equals(path)) {
// The root context exists always
return true;
}
Object ctx = externalContext.getContext();
if (ctx instanceof ServletContext) {
ServletContext servletContext = (ServletContext) ctx;
InputStream stream = servletContext.getResourceAsStream(path);
if (stream != null) {
try {
stream.close();
} catch (IOException e) {
// Ignore here, since we donnot wanted to read from this
// resource anyway
}
return true;
}
}
return false;
}
// Construct URL with special URLStreamHandler for proxying
// ServletContext.getResourceAsStream()
private static URL getUrlForResourceAsStream(final ExternalContext externalContext, String path)
throws MalformedURLException {
URLStreamHandler handler = new URLStreamHandler() {
protected URLConnection openConnection(URL u) throws IOException {
final String file = u.getFile();
return new URLConnection(u) {
public void connect() throws IOException {
}
public InputStream getInputStream() throws IOException {
if (LOG.isTraceEnabled()) {
LOG.trace("Opening internal url to " + file);
}
Object ctx = externalContext.getContext();
// Or maybe fetch the external context afresh ?
// Object ctx =
// FacesContext.getCurrentInstance().getExternalContext().getContext();
if (ctx instanceof ServletContext) {
ServletContext servletContext = (ServletContext) ctx;
InputStream stream = servletContext.getResourceAsStream(file);
if (stream == null) {
throw new FileNotFoundException("Cannot open resource " + file);
}
return stream;
} else {
throw new IOException("Cannot open resource for an context of "
+ (ctx != null ? ctx.getClass() : null));
}
}
};
}
};
return new URL("internal", null, 0, path, handler);
}
}