diff -r 47f86885d481 -r e85600529ca5 scala/crawler1.scala --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/scala/crawler1.scala Sat Jun 15 09:11:11 2013 -0400 @@ -0,0 +1,45 @@ +import io.Source +import scala.util.matching.Regex + +// gets the first ~10K of a page +def get_page(url: String) : String = { + try { + Source.fromURL(url).take(10000).mkString + } + catch { + case e => { + println(" Problem with: " + url) + "" + } + } +} + + +// regex for URLs +val http_pattern = """\"https?://[^\"]*\"""".r + +def unquote(s: String) = s.drop(1).dropRight(1) + +def get_all_URLs(page: String) : Set[String] = { + (http_pattern.findAllIn(page)).map { unquote(_) }.toSet +} + +// naive version - seraches until a given depth +// visits pages potentially more than once +def crawl(url: String, n: Int) : Unit = { + if (n == 0) () + else { + println("Visiting: " + n + " " + url) + for (u <- get_all_URLs(get_page(url))) crawl(u, n - 1) + } +} + +// staring URL for the crawler +val startURL = """http://www.inf.kcl.ac.uk/staff/urbanc/""" +//val startURL = """http://www.inf.kcl.ac.uk/staff/mml/""" + + +// call on the command line +crawl(startURL, 2) + +crawl("""http://www.dcs.kcl.ac.uk/staff/urbanc/msc-projects-12.html""", 2)