1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19
20 package org.apache.myfaces.tobago.facelets;
21
22 import org.slf4j.Logger;
23 import org.slf4j.LoggerFactory;
24
25 import javax.faces.context.ExternalContext;
26 import javax.faces.context.FacesContext;
27 import javax.servlet.ServletContext;
28 import java.io.FileNotFoundException;
29 import java.io.IOException;
30 import java.io.InputStream;
31 import java.lang.invoke.MethodHandles;
32 import java.net.MalformedURLException;
33 import java.net.URL;
34 import java.net.URLConnection;
35 import java.net.URLStreamHandler;
36
37 /*
38 * Was copied from MyFaces-Impl, because there is no JSF base class.
39 */
40 public final class Resource {
41
42 private static final Logger LOG = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
43
44 private Resource() {
45 }
46
47 /**
48 * Get an URL of an internal resource. First, {@link javax.faces.context.ExternalContext#getResource(String)} is
49 * 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
50 * for a packed war), a URL with a special URL handler is constructed, which can be used for <em>opening</em> a
51 * serlvet resource later. Internally, this special URL handler will call
52 * {@link javax.servlet.ServletContext#getResourceAsStream(String)} when an inputstream is requested.
53 * This works even on Weblogic 8.1
54 *
55 * @param ctx the faces context from which to retrieve the resource
56 * @param path an URL path
57 * @return an url representing the URL and on which getInputStream() can be called to get the resource
58 */
59 public static URL getResourceUrl(final FacesContext ctx, final String path) throws MalformedURLException {
60 final ExternalContext externalContext = ctx.getExternalContext();
61 URL url = externalContext.getResource(path);
62 if (LOG.isTraceEnabled()) {
63 LOG.trace("Resource-Url from external context: " + url);
64 }
65 if (url == null) {
66 // This might happen on Servlet container which doesnot return
67 // anything
68 // for getResource() (like weblogic 8.1 for packaged wars) we
69 // are trying
70 // to use an own URL protocol in order to use
71 // ServletContext.getResourceAsStream()
72 // when opening the url
73 if (resourceExist(externalContext, path)) {
74 url = getUrlForResourceAsStream(externalContext, path);
75 }
76 }
77 return url;
78 }
79
80 // This method could be used above to provide a 'fail fast' if a
81 // resource
82 // doesnt exist. Otherwise, the URL will fail on the first access.
83 private static boolean resourceExist(final ExternalContext externalContext, final String path) {
84 if ("/".equals(path)) {
85 // The root context exists always
86 return true;
87 }
88 final Object ctx = externalContext.getContext();
89 if (ctx instanceof ServletContext) {
90 final ServletContext servletContext = (ServletContext) ctx;
91 try (final InputStream stream = servletContext.getResourceAsStream(path)) {
92 return stream != null;
93 } catch (final IOException e) {
94 // Ignore here, since we donnot wanted to read from this
95 // resource anyway
96 }
97 }
98 return false;
99 }
100
101 // Construct URL with special URLStreamHandler for proxying
102 // ServletContext.getResourceAsStream()
103 private static URL getUrlForResourceAsStream(final ExternalContext externalContext, final String path)
104 throws MalformedURLException {
105 final URLStreamHandler handler = new URLStreamHandler() {
106 @Override
107 protected URLConnection openConnection(final URL u) throws IOException {
108 final String file = u.getFile();
109 return new URLConnection(u) {
110 @Override
111 public void connect() throws IOException {
112 }
113
114 @Override
115 public InputStream getInputStream() throws IOException {
116 if (LOG.isTraceEnabled()) {
117 LOG.trace("Opening internal url to " + file);
118 }
119 final Object ctx = externalContext.getContext();
120 // Or maybe fetch the external context afresh ?
121 // Object ctx =
122 // FacesContext.getCurrentInstance().getExternalContext().getContext();
123
124 if (ctx instanceof ServletContext) {
125 final ServletContext servletContext = (ServletContext) ctx;
126 final InputStream stream = servletContext.getResourceAsStream(file);
127 if (stream == null) {
128 throw new FileNotFoundException("Cannot open resource " + file);
129 }
130 return stream;
131 } else {
132 throw new IOException("Cannot open resource for an context of "
133 + (ctx != null ? ctx.getClass() : null));
134 }
135 }
136 };
137 }
138 };
139 return new URL("internal", null, 0, path, handler);
140 }
141 }