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Java > Open Source Codes > org > archive > net > DownloadURLConnection


1 /* $Id: DownloadURLConnection.java,v 1.1 2006/08/18 16:13:31 stack-sf Exp $
2  *
3  * Created August 11th, 2006
4  *
5  * Copyright (C) 2006 Internet Archive.
6  *
7  * This file is part of the Heritrix web crawler (crawler.archive.org).
8  *
9  * Heritrix is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU Lesser Public License as published by
11  * the Free Software Foundation; either version 2.1 of the License, or
12  * any later version.
13  *
14  * Heritrix is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17  * GNU Lesser Public License for more details.
18  *
19  * You should have received a copy of the GNU Lesser Public License
20  * along with Heritrix; if not, write to the Free Software
21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22  */
23 package org.archive.net;
24
25 import java.io.BufferedInputStream JavaDoc;
26 import java.io.File JavaDoc;
27 import java.io.FileInputStream JavaDoc;
28 import java.io.IOException JavaDoc;
29 import java.io.InputStream JavaDoc;
30 import java.net.URL JavaDoc;
31 import java.net.URLConnection JavaDoc;
32 import java.util.logging.Level JavaDoc;
33 import java.util.logging.Logger JavaDoc;
34
35 import org.archive.util.ProcessUtils;
36 import org.archive.util.ProcessUtils.ProcessResult;
37
38 /**
39  * An URL Connection that pre-downloads URL reference before passing back a
40  * Stream reference. When closed, it removes the local download file.
41  * @author stack
42  * @version $Date: 2006/08/18 16:13:31 $, $Revision: 1.1 $
43  */
44 public abstract class DownloadURLConnection extends URLConnection JavaDoc {
45     private final String JavaDoc CLASSNAME = DownloadURLConnection.class.getName();
46     private final Logger JavaDoc LOGGER = Logger.getLogger(CLASSNAME);
47     private static final File JavaDoc TMPDIR =
48         new File JavaDoc(System.getProperty("java.io.tmpdir", "/tmp"));
49     private File JavaDoc downloadFile = null;
50
51     protected DownloadURLConnection(URL JavaDoc u) {
52         super(u);
53     }
54     
55     protected String JavaDoc getScript() {
56         return System.getProperty(this.getClass().getName() + ".path",
57             "UNDEFINED");
58     }
59     
60     protected String JavaDoc [] getCommand(final URL JavaDoc thisUrl,
61             final File JavaDoc downloadFile) {
62         return new String JavaDoc[] {getScript(), thisUrl.getPath(),
63             downloadFile.getAbsolutePath()};
64     }
65
66     /**
67      * Do script copy to local file.
68      * File is available via {@link #getFile()}.
69      * @throws IOException
70      */
71     public void connect() throws IOException JavaDoc {
72         if (this.connected) {
73             return;
74         }
75         
76         this.downloadFile = File.createTempFile(CLASSNAME, null, TMPDIR);
77         try {
78             String JavaDoc [] cmd = getCommand(this.url, this.downloadFile);
79             if (LOGGER.isLoggable(Level.FINE)) {
80                 StringBuffer JavaDoc buffer = new StringBuffer JavaDoc();
81                 for (int i = 0; i < cmd.length; i++) {
82                     if (i > 0) {
83                         buffer.append(" ");
84                     }
85                     buffer.append(cmd[i]);
86                 }
87                 LOGGER.fine("Command: " + buffer.toString());
88             }
89             ProcessResult pr = ProcessUtils.exec(cmd);
90             if (pr.getResult() != 0) {
91                 LOGGER.info(cmd + " returned non-null " + pr.getResult());
92             }
93             // Assume download went smoothly.
94 this.connected = true;
95         } catch (IOException JavaDoc ioe) {
96             // Clean up my tmp file.
97 this.downloadFile.delete();
98             this.downloadFile = null;
99             // Rethrow.
100 throw ioe;
101         }
102     }
103     
104     public File JavaDoc getFile() {
105         return this.downloadFile;
106     }
107     
108     protected void setFile(final File JavaDoc f) {
109         this.downloadFile = f;
110     }
111
112     public InputStream JavaDoc getInputStream() throws IOException JavaDoc {
113         if (!this.connected) {
114             connect();
115         }
116         
117         // Return BufferedInputStream so 'delegation' is done for me, so
118 // I don't have to implement all IS methods and pass to my
119 // 'delegate' instance.
120 final DownloadURLConnection connection = this;
121         return new BufferedInputStream JavaDoc(new FileInputStream JavaDoc(this.downloadFile)) {
122             private DownloadURLConnection ruc = connection;
123
124             public void close() throws IOException JavaDoc {
125                 super.close();
126                 if (this.ruc != null && this.ruc.getFile()!= null &&
127                     this.ruc.getFile().exists()) {
128                     this.ruc.getFile().delete();
129                     this.ruc.setFile(null);
130                 }
131             }
132         };
133     }
134 }
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