build_duby.rb

dubyc = "~/tmp/src_clones/duby/bin/dubyc"
javac = "javac"
classpath = [
  "~/tmp/appengine-java-sdk-1.3.2/lib/shared/geronimo-servlet_2.5_spec-1.2.jar",
  "~/tmp/appengine-java-sdk-1.3.2/lib/impl/appengine-api.jar",
  "~/tmp/appengine-java-sdk-1.3.2/lib/impl/appengine-api-stubs.jar"
].join(":")

Dir.chdir 'dubysrc'
#system "CLASSPATH=#{classpath} #{dubyc} fwspin/HelloDubyServlet.duby"
#system "CLASSPATH=#{classpath} #{dubyc} fwspin/HelloDubyFilter.duby"

case ARGV[0]
when "duby"
  system("rm fwspin/*.class")
  system "CLASSPATH=#{classpath} #{dubyc}       fwspin/ForwardSpinupFilter.duby"
when "java"
  system "CLASSPATH=#{classpath} #{dubyc} -java fwspin/ForwardSpinupFilter.duby"
  s = File.read("fwspin/ForwardSpinupFilter.java")
  s.sub!("FetchOptions$Builder", "FetchOptions.Builder")
  s.sub!("package fwspin;", "package fwspin;\nimport com.google.appengine.api.urlfetch.FetchOptions;")
  s.sub!("public static void main(java.lang.String[] argv) {", "")
  File.open("fwspin/ForwardSpinupFilter.java", "w"){|f| f.write(s) }
when "javac"
  system("rm fwspin/*.class")
  system "CLASSPATH=#{classpath} #{javac} -Xlint:unchecked fwspin/ForwardSpinupFilter.java"
when "jar"
  system "LANG=C jar -cvf ../WEB-INF/lib/fwspin.jar fwspin/*.class"
else
  raise "ruby build_duby.rb duby|java|javac|jar"
end
Dir.chdir '..'

ForwardSpinupFilter.duby

import javax.servlet.http.HttpServletRequest
import javax.servlet.http.HttpServletResponse
import javax.servlet.Filter
import java.util.Date
import java.util.ArrayList
import java.net.URL
import java.net.MalformedURLException
import java.io.IOException
import com.google.appengine.api.urlfetch.URLFetchService
import com.google.appengine.api.urlfetch.FetchOptions
import "FetchOptionsBuilder", "com.google.appengine.api.urlfetch.FetchOptions$Builder"
import com.google.appengine.api.urlfetch.HTTPHeader
import com.google.appengine.api.urlfetch.HTTPRequest
import com.google.appengine.api.urlfetch.HTTPResponse
import com.google.appengine.api.urlfetch.URLFetchServiceFactory
import com.google.appengine.api.urlfetch.HTTPMethod

class ForwardSpinupFilter; implements Filter
  def initialize
  end
  def init(conf)
    {:return=>void}
    @counter = 0
    @load_counter = 0
    @jruby_loaded = false
    @spinup_path = "/spinup"
    log("ForwardSpinupFilter:init")
  end

  def doFilter(_request, _response, chain)
    {data=>byte[], :return=>void}

    request  = HttpServletRequest(_request)
    response = HttpServletResponse(_response)

    @counter += 1
    log("#{@counter} : "+request.getRequestURL.toString)
    if 2<=@load_counter || is_spinup_url(request)
      # @load_counter == 0 => load jruby
      # @load_counter == 1 => load rails
      # @load_counter == 2 => load app and run!
      chain.doFilter(request, response)
      # if success
        @load_counter += 1
      # else
      #  timeout etc. instance is bloken?
      # end
      nil
    else
      kick_spinup_url(request)

      # forward request to active instance
      fetched = url_fetch(request)
      # Thread.sleep(2000) rescue nil

      # copy headers
      fetched.getHeaders.each do |_header|
        header = HTTPHeader(_header)
        response.setHeader(header.getName, header.getValue)
      end

      # copy body
      os = response.getOutputStream
      os.write(fetched.getContent)
      os.flush
      nil
    end
  end

  def destroy
    {:return=>void}
    log("destroy")
  end

  # http://code.google.com/intl/en/appengine/docs/java/javadoc/com/google/appengine/api/urlfetch/package-summary.html
  def url_fetch(request:HttpServletRequest)
    throws MalformedURLException, IOException

    url = request.getRequestURL
    q = request.getQueryString
    if q
      url.append("?").append(q)
    end
    data = "".getBytes # TODO post
    

    fs = URLFetchServiceFactory.getURLFetchService
    opt = FetchOptionsBuilder.disallowTruncate.doNotFollowRedirects.setDeadline(double(5.0))
    req = HTTPRequest.new(URL.new(url.toString), HTTPMethod.valueOf(request.getMethod), opt)
#    each_header(request) do |name,value|
#      #addHeader(header)
#      puts key, value
#    end
#todo setPayload(data)
    fs.fetch(req) # HTTPResponse
  end

  def is_spinup_url(request:HttpServletRequest)
#    log "@spinup_path: #{@spinup_path}"
#    log "PathInfo    : #{request.getPathInfo    || '(null)'}"
#    log "ContextPath : #{request.getContextPath || '(null)'}"
    log "is_spinup_url:ServletPath=#{request.getServletPath || '(null)'}"
    return @spinup_path.equals(request.getServletPath)
  end

  def kick_spinup_url(request:HttpServletRequest)
    throws MalformedURLException
    fs = URLFetchServiceFactory.getURLFetchService
    url = "http://"+request.getServerName
    url += ":#{request.getServerPort}" if 80 != request.getServerPort
    url += @spinup_path
    log "kick_spinup_url: #{url}"
    fs.fetchAsync(URL.new(url))
  end

##  * Can I use yield?
##  * Can I use each for java.util.Enumeration
#  def each_header(request:HttpServletRequest)
#    headers = ArrayList.new
#    names = request.getHeaderNames
#    while(names.hasMoreElements) do
#      name = String(names.nextElement)
#      values = request.getHeaders(name)
#      while(values.hasMoreElements) do
#        value = String(values.nextElement)
#        yield(name)
#      end
#    end
#  end

  def log(s:String)
    {:return=>void}
    puts(Date.new.toString + " : " + s)
  end
end

QUESTIONS.txt

I am using self-build duby.
Source code(bitescript, jruby, duby) is from github, yesterday.

1. imcomplete main method:
   "public static void main(java.lang.String[] argv) {"
   I removed it in build_duby.rb.
     s.sub!("public static void main(java.lang.String[] argv) {", "")

2. How to use inner class
   I want to use http://code.google.com/intl/en/appengine/docs/java/javadoc/com/google/appengine/api/urlfetch/FetchOptions.Builder.html this class.

   Now, I write duby like:
     import "FetchOptionsBuilder", "com.google.appengine.api.urlfetch.FetchOptions$Builder"
   And compile to java and patch:
     s.sub!("FetchOptions$Builder", "FetchOptions.Builder")
     s.sub!("package fwspin;", "package fwspin;\nimport com.google.appengine.api.urlfetch.FetchOptions;")

   Can I use better way?

3. VerifyError with dubyc
   "duby -> class" directly compiled class is not work.
   "duby -> java -> patch -> javac" is work well.
 
4. No main found
in examples:
% duby fib.duby                       
No main found

VerifyError

# VerifyError with "dubyc"

Apr 4, 2010 12:02:57 AM com.google.apphosting.utils.jetty.JettyLogger warn
WARNING: failed ForwardSpinupFilter: java.lang.VerifyError: (class: fwspin/ForwardSpinupFilter, method: url_fetch signature: (Ljavax/servlet/http/HttpServletRequest;)Lcom/google/appengine/api/urlfetch/HTTPResponse;) Expecting to find object/array on stack
Apr 4, 2010 12:02:57 AM com.google.apphosting.utils.jetty.JettyLogger warn
WARNING: failed com.google.apphosting.utils.jetty.DevAppEngineWebAppContext@1142196{/,/Users/takeru/..../versions/fwspin}: java.lang.VerifyError: (class: fwspin/ForwardSpinupFilter, method: url_fetch signature: (Ljavax/servlet/http/HttpServletRequest;)Lcom/google/appengine/api/urlfetch/HTTPResponse;) Expecting to find object/array on stack
Apr 4, 2010 12:02:57 AM com.google.apphosting.utils.jetty.JettyLogger warn
WARNING: failed JettyContainerService$ApiProxyHandler@13ada: java.lang.VerifyError: (class: fwspin/ForwardSpinupFilter, method: url_fetch signature: (Ljavax/servlet/http/HttpServletRequest;)Lcom/google/appengine/api/urlfetch/HTTPResponse;) Expecting to find object/array on stack
Apr 4, 2010 12:02:57 AM com.google.apphosting.utils.jetty.JettyLogger warn
WARNING: Error starting handlers
java.lang.VerifyError: (class: fwspin/ForwardSpinupFilter, method: url_fetch signature: (Ljavax/servlet/http/HttpServletRequest;)Lcom/google/appengine/api/urlfetch/HTTPResponse;) Expecting to find object/array on stack
        at java.lang.Class.getDeclaredConstructors0(Native Method)
        at java.lang.Class.privateGetDeclaredConstructors(Class.java:2389)
        at java.lang.Class.getConstructor0(Class.java:2699)
        at java.lang.Class.newInstance0(Class.java:326)
        at java.lang.Class.newInstance(Class.java:308)
        at org.mortbay.jetty.servlet.Holder.newInstance(Holder.java:153)
        at org.mortbay.jetty.servlet.FilterHolder.doStart(FilterHolder.java:92)
        at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
        at org.mortbay.jetty.servlet.ServletHandler.initialize(ServletHandler.java:662)
        at org.mortbay.jetty.servlet.Context.startContext(Context.java:140)
        at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1250)
        at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:517)
        at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:467)
        at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
        at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)
        at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
        at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)
        at org.mortbay.jetty.Server.doStart(Server.java:224)
        at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
        at com.google.appengine.tools.development.JettyContainerService.startContainer(JettyContainerService.java:185)
        at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:146)
        at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:219)
        at com.google.appengine.tools.development.DevAppServerMain$StartAction.apply(DevAppServerMain.java:162)
        at com.google.appengine.tools.util.Parser$ParseResult.applyArgs(Parser.java:48)
        at com.google.appengine.tools.development.DevAppServerMain.<init>(DevAppServerMain.java:113)
        at com.google.appengine.tools.development.DevAppServerMain.main(DevAppServerMain.java:89)