import java.io.*;
import java.net.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import com.oreilly.servlet.*;
import org.apache.regexp.*;
public class Links extends HttpServlet {
public void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
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 + ":
" +
ServletUtils.getStackTraceAsString(e));
return;
}
out.println("Link Extractor");
try {
// We need to specify a so relative links work correctly
// If the page already has one, we can use that
RE re = new RE("]*>", RE.MATCH_CASEINDEPENDENT);
boolean hasBase = re.match(page);
if (hasBase) {
// Use the existing
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("");
}
else {
// No trailing slash, add one ourselves
out.println("");
}
}
out.println("");
out.println("The links on " + url + "" +
" are:
");
out.println("");
String search = "";
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("- " + match + "
");
}
out.println("
");
out.println("");
}
catch (RESyntaxException e) {
// Should never happen as the search strings are hard coded
e.printStackTrace(out);
}
}
}