flickr api utility

Flickr.scala

import _root_.net.liftweb.util._
import _root_.net.liftweb.json._
import _root_.net.liftweb.common._
import _root_.java.net.{HttpURLConnection, URL, URLEncoder}
import JsonAST._
import JsonDSL._
import JsonParser._
import Helpers._

//flickr uses some proprietary authentication mechanism instead of oauth
object Flickr {
    def key = Props.get("flickr.key","")
    def secret = Props.get("flickr.secret","")
    val BASE_URL:String = "http://api.flickr.com/services/rest/"
   
    def md5hex(in:String) =Helpers.hexEncode(Helpers.md5(in.getBytes("UTF-8")))
   
    def toQuery(paramMap:Map[String,String]) = "?" + (paramMap + apiKeyParam).map(p=> p._1 + "=" + p._2).mkString("&")

    def signQuery(params:Map[String,String], auth: Box[String]) = {
        val withAuthToken = auth.map(t=> params + ("auth_token" -> t)) openOr params
        toQuery(withAuthToken + ("api_sig" -> md5hex(secret + (withAuthToken + apiKeyParam).toList.map(p=>p._1+p._2).sort(_ < _).mkString)))
    }
    
    def apiKeyParam = "api_key" -> key
    
    def doRequest(params:Map[String,String], sign:Boolean, authToken:Box[String]):JValue = {
        val withJsonParams = params + ("nojsoncallback"->"1") + ("format" -> "json")
        val urlString = BASE_URL + (if (sign){
            signQuery(withJsonParams, authToken)
        } else toQuery(withJsonParams))
        
        new URL(urlString).openConnection match {
          case conn: HttpURLConnection => {
            conn.setRequestMethod("GET")
            conn.connect
            import org.apache.commons.io.IOUtils
            val str = IOUtils.toString(conn.getInputStream,"UTF-8")
            println(str)
            parse(str)
          }
        }
    }
    

    def authUrl:String = "http://flickr.com/services/auth/" + signQuery(Map("perms"->"read"),Empty)
    
    def callMethod(method:String, sign:Boolean, auth:Box[String], params:Map[String,String]):JValue = {
        doRequest(params + ("method" -> method), sign, auth)
    }
    
    case class User(nsid:String, username:String,fullname:String)
    case class Auth(token:String, user:User)

    def getToken(frob:String):Box[Auth] = {
        implicit val formats = DefaultFormats

        val json = callMethod("flickr.auth.getToken", true, Empty, Map("frob" -> frob))
        val auth = json\"auth"
        val results = for (JString(token) <- (auth\"token"\"_content");
            JString(username) <- (auth\"user"\"username");
            JString(nsid) <- (auth\"user"\"nsid");
            JString(fullname) <- (auth\"user"\"fullname")) yield Auth(token, User(nsid, username, fullname))
        
        results.firstOption

    }
}