res.setContentType("text/html");
PrintWriter out = res.getWriter();
// We accept the URL to process as extra path info
// http://localhost:8080/servlet/Links/http://www.servlets.com/
String url = req.getPathInfo();
if (url == null || url.length() == 0) {
res.sendError(res.SC_BAD_REQUEST,
"Please pass a URL to read from as extra path info");
return;
}
url = url.substring(1); // cut off leading '/'
String page = null;
try {
// Request the page
HttpMessage msg = new HttpMessage(new URL(url));
BufferedReader in =
new BufferedReader(new InputStreamReader(msg.sendGetMessage()));
// Read the entire response into a String
StringBuffer buf = new StringBuffer(10240);
char[] chars = new char[10240];
int charsRead = 0;
while ((charsRead = in.read(chars, 0, chars.length)) != -1) {
buf.append(chars, 0, charsRead);
}
page = buf.toString();
}
catch (IOException e) {
res.sendError(res.SC_NOT_FOUND,
"Link Extractor could not read from " + url + ":<BR>" +
ServletUtils.getStackTraceAsString(e));
return;
}
out.println("<HTML><HEAD><TITLE>Link Extractor</TITLE>");
try {
// We need to specify a <BASE> so relative links work correctly
// If the page already has one, we can use that
RE re = new RE("<base[^>]*>", RE.MATCH_CASEINDEPENDENT);
boolean hasBase = re.match(page);
if (hasBase) {
// Use the existing <BASE>
out.println(re.getParen(0));
}
else {
// Calculate the base from the URL, use everything up to last '/'
re = new RE("http://.*/", RE.MATCH_CASEINDEPENDENT);
boolean extractedBase = re.match(url);
if (extractedBase) {
// Success, print the calculated base
out.println("<BASE HREF=\"" + re.getParen(0) + "\">");
}
else {
// No trailing slash, add one ourselves
out.println("<BASE HREF=\"" + url + "/" + "\">");
}
}
out.println("</HEAD><BODY>");
out.println("The links on <A HREF=\"" + url + "\">" + url + "</A>" +
" are: <BR>");
out.println("<UL>");
String search = "<a\\s+[^<]*</a\\s*>";
re = new RE(search, RE.MATCH_CASEINDEPENDENT);
int index = 0;
while (re.match(page, index)) {
String match = re.getParen(0);
index = re.getParenEnd(0);
out.println("<LI>" + match + "<BR>");
}
out.println("</UL>");
out.println("</BODY></HTML>");
}
catch (RESyntaxException e) {
// Should never happen as the search strings are hard coded
e.printStackTrace(out);
}
