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Java > Open Source Codes > org > apache > jetspeed > portal > portlets > ServletProxyPortlet


1 /*
2  * Copyright 2000-2001,2004 The Apache Software Foundation.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package org.apache.jetspeed.portal.portlets;
17
18 import org.apache.ecs.ConcreteElement;
19 import org.apache.ecs.StringElement;
20 import org.apache.jetspeed.portal.portlets.AbstractPortlet;
21 import org.apache.turbine.util.RunData;
22
23 import java.io.BufferedInputStream JavaDoc;
24 import java.io.ByteArrayOutputStream JavaDoc;
25 import java.io.InputStream JavaDoc;
26 import java.net.URL JavaDoc;
27 import java.net.URLConnection JavaDoc;
28
29
30 /**
31  * This portlet class is intended to be used for internal URLs that will
32  * not work properly if they are part of the same request as the Jetspeed/Turbine
33  * controller servlet--Struts-mapped URLs are an example of these.
34  * <br>
35  * ServletProxyPortlet uses an application context-relative URL as an input parameter. It uses data obtained from
36  * <code>org.apache.turbine.util.RunData</code> to construct an absolute URL and append the session id to it. Using this
37  * URL, it constructs a java.net.URL object, retrieves the content from it, and converts the content to a String. Finally,
38  * it returns an ECS StringElement created with this String for Jetspeed to render as a portlet. Content is returned as-is;
39  * no filtering is performed on the html before returning it.
40  * <br/><br/>
41  * This portlet accepts 3 parameters:<br/>
42  *
43  * URL (required) -- the web application-context relative URL (a query string may be used to pass parameters)<br/>
44  * session_token (optional) -- token key used by the web server to pass the session id on the query string<br/>
45  * protocol (optional) -- protocol to use to make the URL request
46  *
47  * @author <a HREF="mailto:joe.barefoot@motiva.com">Joe Barefoot</a>
48  */
49
50
51 public class ServletProxyPortlet extends AbstractPortlet
52 {
53     private final static int BUFFER_SIZE = 2048;
54
55     /** The name of the parameter to hold our application context-relative URL */
56     public static final String JavaDoc URL_PARAMETER_NAME = "URL";
57     /** The name of the parameter to hold the protocol to use (optional, default is http) **/
58     public static final String JavaDoc PROTOCOL_PARAMETER_NAME = "protocol";
59     /** The name of the parameter to hold the token by which the session ID is passed on the query string (optional, default is jsessionid)
60      * This is included to accomodate all web servers, as the token is usually different from one server to another.
61      */
62     public static final String JavaDoc SESSION_TOKEN_PARAMETER_NAME = "session_token";
63
64     /** The default protocol used to construct the URL -- http */
65     public static final String JavaDoc DEFAULT_PROTOCOL = "http";
66     /** The default token to use to pass the session ID on the query String -- jsessionid */
67     public static final String JavaDoc DEFAULT_SESSION_TOKEN = "jsessionid";
68
69     /** Gets content by proxy (java.net.URL) from an internal URL and returns it
70      *
71      * @param rundata The RunData object for the current request
72      * @return an ECS StringElement
73      */
74     public ConcreteElement getContent(RunData rundata)
75     {
76         String JavaDoc servletURL = processURL(rundata);
77         if(servletURL == null)
78         {
79             return new StringElement("ServletInvokerPortlet: Must specify a URL using the URL parameter");
80         }
81         String JavaDoc content;
82
83         // This is probably not robust for large content returns, but should work okay within an application context with small amounts of content.
84 try
85         {
86
87             URL JavaDoc url = new URL JavaDoc(servletURL);
88             URLConnection JavaDoc connection = url.openConnection();
89             InputStream JavaDoc stream = connection.getInputStream();
90             BufferedInputStream JavaDoc in = new BufferedInputStream JavaDoc(stream);
91             int length = 0;
92             byte[] buf = new byte[BUFFER_SIZE];
93             ByteArrayOutputStream JavaDoc out = new ByteArrayOutputStream JavaDoc();
94             while ((in != null) && ((length = in.read(buf)) != -1))
95             {
96                 // the data has already been read into buf
97 out.write(buf, 0, length);
98             }
99             content = out.toString();
100             return new StringElement(content);
101         }
102         catch (Exception JavaDoc e)
103         {
104             String JavaDoc message = "ServletInvokerPortlet: Error invoking " + servletURL + ": " + e.getMessage();
105             return new StringElement(message);
106         }
107
108     }
109
110     /** Constructs a full URL to retrieve content from. Override to append custom (default) query parameters, etc.
111      *
112      * @param rundata The RunData object for the current request
113      * @return An absolute URL with the session ID appended
114      */
115     protected String JavaDoc processURL(RunData rundata)
116     {
117         String JavaDoc servletURL = getPortletConfig().getInitParameter(URL_PARAMETER_NAME);
118         if( servletURL == null) // short-circuit
119 {
120             return null;
121         }
122         String JavaDoc protocol = getPortletConfig().getInitParameter(PROTOCOL_PARAMETER_NAME);
123         if(protocol == null)
124         {
125             protocol = DEFAULT_PROTOCOL;
126         }
127         String JavaDoc token = getPortletConfig().getInitParameter(SESSION_TOKEN_PARAMETER_NAME);
128         if(token == null)
129         {
130             token = DEFAULT_SESSION_TOKEN;
131         }
132
133
134         String JavaDoc queryString = new String JavaDoc();
135         int queryIndex = servletURL.indexOf("?");
136         if(queryIndex > 0)
137         {
138             queryString = servletURL.substring(queryIndex);
139             servletURL = servletURL.substring(0, queryIndex);
140         }
141         servletURL = protocol + "://" + rundata.getServerName() + ":" + rundata.getServerPort() + rundata.getContextPath() + servletURL + ";" + token + "=" + rundata.getSession().getId() + queryString;
142         return servletURL;
143     }
144
145 }
146
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