import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.io.*;
import java.util.*;
import com.darwinsys.io.FileIO;
import com.darwinsys.swingui.UtilGUI;
import com.darwinsys.util.Debug;
/** A simple HTML Link Checker.
* Need a Properties file to set depth, URLs to check. etc.
* Responses not adequate; need to check at least for 404-type errors!
* When all that is (said and) done, display in a Tree instead of a TextArea.
* Then use Color coding to indicate errors.
* <p>
* Further, it needs to use Swing and Threads properly (see
* Java Swing, section on "MultiThreading Issues with Swing".
* As it stands, the GUI thread is locked up until the complete
* checking is completed, which could take a long time.
* <p>
* TODO: parse using an XML parser, though this would fail for most web
* sites today (and how much longer do you think we must maintain
* so much ad-hoc code for parsing the almost-regular kludge known as HTML?)
*
* @author Ian Darwin, Darwin Open Systems, www.darwinsys.com.
* @version $Id: LinkChecker.java,v 1.21 2004/06/21 01:36:53 ian Exp $
*/
public class LinkChecker extends JFrame {
/** The "global" activation flag: set true to halt. */
protected boolean done = false;
/** The textfield for the starting URL.
* Should have a Properties file and a JComboBox instead.
*/
protected JTextField textFldURL;
protected JButton checkButton;
protected JButton saveButton;
protected JButton killButton;
protected JTextArea textWindow;
protected int indent = 0;
protected Map hash = new HashMap();
public static void main(String[] args) {
LinkChecker lc = new LinkChecker();
if (args.length >= 1)
lc.textFldURL.setText(args[0]);
lc.setVisible(true);
}
void setGUIStartable(boolean startable ) {
checkButton.setEnabled(startable);
killButton.setEnabled(!startable);
}
/** Construct a LinkChecker */
public LinkChecker() {
super("LinkChecker");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container cp = getContentPane();
cp.setLayout(new BorderLayout());
JPanel p = new JPanel();
p.setLayout(new FlowLayout());
p.add(new JLabel("URL"));
p.add(textFldURL = new JTextField(30));
p.add(checkButton = new JButton("Check URL"));
// Make a single action listener for both the text field (when
// you hit return) and the explicit "Check URL" button.
ActionListener starter = new ActionListener() {
public void actionPerformed(ActionEvent e) {
done = false;
setGUIStartable(true);
Thread t = new Thread() {
public void run() {
textWindow.setText("Checking...");
setGUIStartable(false);
checkOut(textFldURL.getText());
textWindow.append("-- All done --");
setGUIStartable(true);
}
};
t.start();
}
};
textFldURL.addActionListener(starter);
checkButton.addActionListener(starter);
p.add(killButton = new JButton("Stop"));
killButton.setEnabled(false); // until startChecking is called.
killButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
done = true;
}
});
p.add(saveButton = new JButton("Save Log"));
saveButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try {
String log = textWindow.getText();
String fileName = "linkchecker.log";
FileIO.stringToFile(log, fileName);
JOptionPane.showMessageDialog(LinkChecker.this,
"File saved as " + fileName, "Done",
JOptionPane.INFORMATION_MESSAGE);
} catch (IOException ex) {
JOptionPane.showMessageDialog(LinkChecker.this,
"IOError",
ex.toString(),
JOptionPane.ERROR_MESSAGE);
}
}
});
// Now lay out the main GUI - URL & buttons on top, text larger
cp.add(p, BorderLayout.NORTH);
textWindow = new JTextArea(80, 40);
cp.add(new JScrollPane(textWindow), BorderLayout.CENTER);
UtilGUI.maximize(this);
}
/** Start checking, given a URL by name.
* Calls checkLink to check each link.
*/
public void checkOut(String rootURLString) {
URL rootURL = null;
GetURLs urlGetter = null;
if (done)
return;
if (rootURLString == null) {
textWindow.append("checkOut(null) isn't very useful");
return;
}
if (hash.get(rootURLString) != null) {
return; // already visited
}
hash.put(rootURLString, Boolean.TRUE);
// Open the root URL for reading. May be a filename or a real URL.
try {
try {
rootURL = new URL(rootURLString);
} catch (MalformedURLException e) {
// Neat Trick: if not a valid URL, try again as a file.
rootURL = new File(rootURLString).toURL();
}
// Either way, now try to open it.
urlGetter = new GetURLs(rootURL);
} catch (FileNotFoundException e) {
textWindow.append("Can't open file " + rootURLString + "\n");
return;
} catch (IOException e) {
textWindow.append("openStream " + rootURLString + " " + e + "\n");
return;
}
// If we're still here, the root URL given is OK.
// Next we make up a "directory" URL from it.
String rootURLdirString;
if (rootURLString.endsWith("/") ||
rootURLString.endsWith("\\"))
rootURLdirString = rootURLString;
else {
rootURLdirString = rootURLString.substring(0,
rootURLString.lastIndexOf('/')); // XXX or \
}
try {
ArrayList urlTags = urlGetter.getURLs();
Iterator urlIterator = urlTags.iterator();
while (urlIterator.hasNext()) {
if (done)
return;
String tag = (String)urlIterator.next();
Debug.println("TAG", tag);
String href = extractHREF(tag);
for (int j=0; j<indent; j++)
textWindow.append("\t");
textWindow.append(href + " -- ");
// Can't really validate these!
if (href == null) {
textWindow.append(" null? !!\n");
continue;
}
if (href.startsWith("mailto:")) {
textWindow.append(href + " -- not checking\n");
continue;
}
if (href.startsWith("..") || href.startsWith("#")) {
textWindow.append(href + " -- not checking\n");
// nothing doing!
continue;
}
URL hrefURL = new URL(rootURL, href);
// TRY THE URL.
// (don't combine previous textWindow.append with this one,
// since this one can throw an exception)
textWindow.append(checkLink(hrefURL));
// There should be an option to control whether to
// "try the url" first and then see if off-site, or
// vice versa, for the case when checking a site you're
// working on on your notebook on a train in the Rockies
// with no web access available.
// Now see if the URL is off-site.
if (!hrefURL.getHost().equals(rootURL.getHost())) {
textWindow.append("-- OFFSITE -- not following\n");
continue;
}
textWindow.append("\n");
// If HTML, check it recursively. No point checking
// PHP, CGI, JSP, etc., since these usually need forms input.
// If a directory, assume HTML or something under it will work.
if (href.endsWith(".htm") ||
href.endsWith(".html") ||
href.endsWith("/")) {
++indent;
if (href.indexOf(':') != -1)
checkOut(href); // RECURSE
else {
String newRef =
rootURLdirString + '/' + href;
checkOut(newRef); // RECURSE
}
--indent;
}
}
urlGetter.close();
} catch (IOException e) {
System.err.println("Error: (" + e +")");
}
}
/** Check one link, given its DocumentBase and the tag */
public String checkLink(URL linkURL) {
try {
// Open it; if the open fails we'll likely throw an exception
URLConnection luf = linkURL.openConnection();
if (linkURL.getProtocol().equals("http")) {
HttpURLConnection huf = (HttpURLConnection)luf;
String s = huf.getResponseCode() + " " + huf.getResponseMessage();
if (huf.getResponseCode() == -1)
return "Server error: bad HTTP response";
return s;
} else if (linkURL.getProtocol().equals("file")) {
InputStream is = luf.getInputStream();
is.close();
// If that didn't throw an exception, the file is probably OK
return "(File)";
} else
return "(non-HTTP)";
}
catch (SocketException e) {
return "DEAD: " + e.toString();
}
catch (IOException e) {
return "DEAD";
}
}
/** Extract the URL from <sometag attrs HREF="http://foo/bar" attrs ...>
* We presume that the HREF is correctly quoted!!!!!
* TODO: Handle Applets.
*/
public String extractHREF(String tag) throws MalformedURLException {
String caseTag = tag.toLowerCase(), attrib;
int p1, p2, p3, p4;
if (caseTag.startsWith("<a") &&
Character.isWhitespace(caseTag.charAt(2))) {
attrib = "href"; // A
} else if (caseTag.startsWith("<applet ")){
attrib = "code";
} else
attrib = "src"; // image, frame
// XXX refactor to use 1.5 enum here
if (attrib.equals("href") && caseTag.indexOf("name") != -1) {
return null; // silently ignore <a name=...>
}
p1 = caseTag.indexOf(attrib);
if (p1 < 0) {
throw new MalformedURLException("Can't find " + attrib + " in " + tag);
}
p2 = tag.indexOf ("=", p1);
// This fails to handle unquoted href, which some dinosaurs insist
// on using, saying the parser can sort it out. Phhhhhhhht!!!!
// XXX should handle single-quoted hrefs here
p3 = tag.indexOf("\"", p2);
p4 = tag.indexOf("\"", p3+1);
if (p3 < 0 || p4 < 0) {
throw new MalformedURLException("Invalid " + attrib + " in " + tag);
}
String href = tag.substring(p3+1, p4);
return href;
}
}
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