LinkCheckerpublic class LinkChecker extends JFrame | 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.
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. |
| Fields Summary |
|---|
| protected boolean | doneThe "global" activation flag: set false to halt. | | protected JTextField | textFldURLThe textfield for the starting URL.
Should have a Properties file and a JComboBox instead. | | protected JButton | checkButton | | protected JButton | saveButton | | protected JButton | killButton | | protected JTextArea | textWindow | | protected int | indent |
| Constructors Summary |
|---|
public LinkChecker()Construct a 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;
checkButton.setEnabled(false);
killButton.setEnabled(true);
Thread t = new Thread() {
public void run() {
textWindow.setText("Checking...");
checkOut(textFldURL.getText());
textWindow.append("-- All done --");
}
};
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;
checkButton.setEnabled(true);
killButton.setEnabled(false);
}
});
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";
com.darwinsys.util.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("North", p);
textWindow = new JTextArea(80, 40);
cp.add("Center", new JScrollPane(textWindow));
com.darwinsys.util.UtilGUI.maximize(this);
|
| Methods Summary |
|---|
| public java.lang.String | checkLink(java.net.URL linkURL)Check one link, given its DocumentBase and the tag
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";
}
| | public void | checkOut(java.lang.String rootURLString)Start checking, given a URL by name.
Calls checkLink to check each link.
URL rootURL = null;
GetURLs urlGetter = null;
if (done)
return;
if (rootURLString == null) {
textWindow.append("checkOut(null) isn't very useful");
return;
}
// 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();
com.darwinsys.util.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.startsWith("mailto:")) {
textWindow.append(href + " -- not checking");
continue;
}
if (href.startsWith("..") || href.startsWith("#")) {
textWindow.append(href + " -- not checking");
// 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");
textWindow.append("\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 +")");
}
| | public java.lang.String | extractHREF(java.lang.String tag)Extract the URL from
We presume that the HREF is correctly quoted!!!!!
TODO: Handle Applets.
String caseTag = tag.toLowerCase(), attrib;
int p1, p2, p3, p4;
if (caseTag.startsWith("<a "))
attrib = "href"; // A
else
attrib = "src"; // image, frame
p1 = caseTag.indexOf(attrib);
if (p1 < 0) {
throw new MalformedURLException("Can't find " + attrib + " in " + tag);
}
p2 = tag.indexOf ("=", p1);
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;
| | public static void | main(java.lang.String[] args)
LinkChecker lc = new LinkChecker();
if (args.length == 0)
return;
lc.textFldURL.setText(args[0]);
lc.setVisible(true);
| | public java.lang.String | readTag(java.io.BufferedReader is)Read one tag. Adapted from code by Elliott Rusty Harold
StringBuffer theTag = new StringBuffer("<");
int i = '<";
try {
while (i != '>" && (i = is.read()) != -1)
theTag.append((char)i);
}
catch (IOException e) {
System.err.println("IO Error: " + e);
}
catch (Exception e) {
System.err.println(e);
}
return theTag.toString();
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