HelloSinatra.scala

package chestnut

import java.io.{File, IOException}
import java.util.{ArrayList, List}

import javax.servlet.{ServletConfig, ServletException}
import javax.servlet.annotation.WebServlet
import javax.servlet.http.{HttpServlet, HttpServletRequest => HSReq, HttpServletResponse => HSResp}

import org.jruby.embed.{LocalContextScope, ScriptingContainer => Container}

import scala.collection.JavaConversions._
import scala.collection.mutable.ListBuffer


class HelloSinatra extends HttpServlet() {
	private val gemPaths = new ListBuffer[String]
    private var config: ServletConfig = _
    private val container = new Container(LocalContextScope.THREADSAFE)
    private var config_ru_path: String = _
           
    def addGemPaths(gem_path: String) {
        val gem_dir = new File(gem_path)
        val gems = gem_dir.listFiles
        for (gem <- gems) {
            val path = gem + "/lib"
            gemPaths += path
        }
    }
    
    override def init(c: ServletConfig) {
        config = c
        val path = config.getServletContext().getRealPath("/WEB-INF/lib/vendor/jruby/1.8/gems")
        addGemPaths(path)
        gemPaths += config.getServletContext().getRealPath("/WEB-INF/lib/app")
        config_ru_path = config.getServletContext().getRealPath("/WEB-INF/lib/app/config.ru")
    }

	override def doGet(request: HSReq, response: HSResp) = processHttpRequest(request, response)

	override def doPost(request: HSReq, response: HSResp) = processHttpRequest(request, response)
	
	private def processHttpRequest(request: HSReq, response: HSResp) {
        container.setLoadPaths(gemPaths)
        container.runScriptlet("require 'rubygems'")
        container.put("config_ru_path", config_ru_path);
        container.put("request", request);
        container.put("config", config);
        val script = 
            """require 'rack'
            rack_app, options = Rack::Builder.parse_file config_ru_path
            require 'jruby-rack'
            require 'rack/handler/servlet'
            handler = Rack::Handler::Servlet.new rack_app
            request.instance_variable_set(:@context, config.getServletContext)
            class << request
              def to_io
                self.getInputStream.to_io
              end
              def getScriptName
                self.getPathTranslated
              end
              def context
                @context
              end
            end
            handler.call(request)"""
        var rack_response = container.runScriptlet(script);
        var body : String = container.callMethod(rack_response, "getBody").asInstanceOf[String]
        body += "\n\n\nand Hello from Scala Servlet!!"
        response.getWriter().print(body);
        container.clear();
    }

}