so4nu.scala

#!/usr/bin/env sbt -Dsbt.version=0.13.9 -Dsbt.main.class=sbt.ScriptMain --error

// This script uses the Stack Exchange API to retrieve the most recent
// Stack Overflow questions tagged with "netlogo" and print their
// titles and URLs.  The output is suitable for posting to the
// netlogo-users group on Yahoo, in messages such as
//   http://netlogo-users.18673.x6.nabble.com/NetLogo-Q-A-on-Stack-Overflow-Mar-14-19-tp5004602.html

/***
scalaVersion := "2.11.7"

onLoadMessage := ""

scalacOptions ++= Seq(
 "-deprecation", "-unchecked", "-feature", "-Xfatal-warnings")

libraryDependencies ++= Seq(
  "net.databinder.dispatch" %% "dispatch-core" % "0.11.2",
  "org.json4s" %% "json4s-native" % "3.2.11",
  "org.slf4j" % "slf4j-nop" % "1.7.10",
  "org.apache.commons" % "commons-lang3" % "3.3.2"
)
*/

import dispatch._, Defaults._
import org.json4s.JsonAST._
import org.json4s.native.JsonParser
import java.util.zip.GZIPInputStream
import org.apache.commons.lang3.StringEscapeUtils.{ unescapeHtml4 => unescape }

case class Question(name: String, url: String)
object Question {
  def fromJson(j: JValue): Question = {
    val JString(title) = j \ "title"
    val JString(link) = j \ "share_link"
    Question(unescape(title), link)
  }
}

//
// Notes on our use of Dispatch:
//
// - By policy, Stack Exchange always responds with compressed data,
//   so it isn't strictly necessary for us to set Accept-Encoding in our
//   request, but at http://api.stackexchange.com/docs/compression
//   they recommend doing it anyway.
//
// - The support for gzip-encoded responses that existed in Dispatch
//   0.8 seems not to exist in 0.9 and subsequent versions, so we
//   bypass Dispatch's json4s integration, and bypass Dispatch's
//   Future-based APIs, too and, drop down to dealing with InputStream
//   directly.  At least, that's the only way forward I was able to
//   find.  See https://github.com/dispatch/reboot/issues/52
//
// Notes on our use of the Stack Exchange API:
//
// - We want the "share" URL not the regular URL of the questions
//   (it's no big deal, but IMO the regular ones are too long),
//   but the share_link field isn't included in the default filter.
//   So I made a new filter with the [edit] link near the bottom of
//   http://api.stackexchange.com/docs/questions, checking the
//   share_link box.  When you make an edit like this the page shows
//   a string you can use to refer to the filter you just made; so
//   that's where "!9WgJf_3fM" came from.
//

val host = :/("api.stackexchange.com").secure <:<
  Map("Accept-Encoding" -> "gzip")
val base = host / "2.2" / "questions"

def getQuestions(): List[Question] = {
  val req = base <<? Map("site" -> "stackoverflow",
                         "tagged" -> "netlogo",
                         "sort" -> "creation",
                         "order" -> "desc",
                         "filter" -> "!9WgJf_3fM")
  // println(req.toRequest.getRawUrl)  // useful for debugging
  val stream = Http(req OK as.Response(_.getResponseBodyAsStream)).apply
  val result =
    JsonParser.parse(
      new java.io.InputStreamReader(
        new GZIPInputStream(stream)))
  val JArray(items) = result \ "items"
  for (item <- items)
  yield Question.fromJson(item)
}

println(
  """|Stack Overflow is a popular Q&A site for getting help with coding
     |in all languages, including NetLogo.  NetLogo questions are at: 
     |http://stackoverflow.com/questions/tagged/netlogo
     |
     |Here are some recent questions and answers.
     |
     |""".stripMargin)

for(Question(title, link) <- getQuestions()) {
  println(title)
  println(link)
  println()
}

Http.shutdown()