diff -r e85600529ca5 -r 4794759139ea scala/crawler.scala
--- a/scala/crawler.scala	Sat Jun 15 09:11:11 2013 -0400
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,144 +0,0 @@
-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)
-      ""
-    }
-  }
-}
-
-// non-existing page -> returns the empty string
-get_page("""http://www.foobar.com""")
-
-
-// staring URL for the crawler
-val startURL = """http://www.inf.kcl.ac.uk/staff/urbanc/"""
-
-// starts with an "
-// then either http or https
-// then ://
-// then any character that is not "
-// finally "
-val http_pattern = """\"((?:http|https)://(?:[^\"])*)\"""".r
-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
-}
-
-// get all urls in startURL
-get_all_URLs(get_page(startURL))
-
-// number of all urls in startURL 
-get_all_URLs(get_page(startURL)).toList.length
-
-
-// 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)
-  }
-}
-
-crawl(startURL, 2)
-
-
-//breadth-first version without visiting 
-//pages twice
-def bf_crawl(todo: Set[String], visited: Set[String], n: Int) : Unit = {
-  if (n == 0) ()
-  else {
-    val new_todo = todo.flatMap { 
-      url => {
-        if (visited.contains(url)) Set[String]()
-        else {
-          println("Visiting: " + n + " " + url)
-          get_all_URLs(get_page(url))
-        }
-      }
-    } 
-    bf_crawl(new_todo, visited union todo, n - 1)
-  }
-}
-
-bf_crawl(Set(startURL1), Set(), 2)
-
-
-//breadth-first version without visiting 
-//pages twice and only in "my" domain
-val my_pattern = """urbanc""".r
-
-// breadth first search avoiding double searches
-def bf_crawl2(todo: Set[String], visited: Set[String], n: Int) : Unit = {
-  if (n == 0) ()
-  else {
-    val new_todo = todo.flatMap { 
-      url => {
-        if (visited.contains(url)) Set[String]()
-        else if (my_pattern.findFirstIn(url) == None) Set[String]()
-        else {
-          println("Visiting: " + n + " " + url);
-          get_all_URLs(get_page(url))
-        }
-      }
-    } 
-    bf_crawl2(new_todo, visited union todo, n - 1)
-  }
-}
-
-bf_crawl2(Set(startURL1), Set(), 5)
-
-// email harvester
-// from 
-// http://net.tutsplus.com/tutorials/other/8-regular-expressions-you-should-know/
-
-val email_pattern = """([a-z0-9_\.-]+)@([\da-z\.-]+)\.([a-z\.]{2,6})""".r
-
-def bf_crawl3(todo: Set[String], visited: Set[String], n: Int) : Unit = {
-  if (n == 0) ()
-  else {
-    val new_todo = todo.flatMap { 
-      url => {
-        if (visited.contains(url)) Set[String]()
-        else {
-          println("Visiting: " + n + " " + url);
-          val page = get_page(url)
-          println(email_pattern.findAllIn(page).mkString("\n"))
-          get_all_URLs(get_page(url))
-        }
-      }
-    } 
-    bf_crawl3(new_todo, visited union todo, n - 1)
-  }
-}
-
-bf_crawl3(Set(startURL1), Set(), 3)
-
-
-// depth-first version does not work,
-// because it might visit pages at depth 1
-// while it still wants to visit them at 
-// depth 2 
-var visited = Set("")
-
-def crawl(url: String, n: Int) : Unit = {
-  if (n == 0) ()
-  else if (visited.contains(url)) () //println("Already visited: " + n + " " + url)
-  else {
-    println("Visiting: " + n + " " + url);
-    visited += url
-    for (u <- getAllURLs(getURLpage(url))) crawl(u, n - 1);
-  }
-}