Withings Create Notification Always response 342

I have to try Subscribe notification to withings use this doc
http://oauth.withings.com/api/doc#api-Notification-notify_subscribe i am
using rails

I am call OauthUtil from controller

oauth = OauthUtil.new
oauth.consumer_key = WITHINGS_API_KEY
oauth.consumer_secret = WITHINGS_API_SECRET
oauth.token = profile.oauth_token # Token from step 3
oauth.token_secret = profile.token_secret # Token secret from step 3
oauth.userid = profile.uid
In OauthUtil.rb i am create function to call url

def register_webhook
    parsed_url = URI.parse( WITHINGS_URL + '/notify' )

    Net::HTTP.start( parsed_url.host ) { | http |
      req = Net::HTTP::Get.new "#{ parsed_url.path }?#{
self.hook_url(parsed_url).query_string }"
      response = http.request(req)
      response.read_body
    }
  end
Add function hook_url to organize param and build signature

def hook_url( parsed_url )

    @params = {
      'action' => 'subscribe',
      'callbackurl' => @callback_url,
      'comment' => @comment,
      'oauth_consumer_key' => @consumer_key,
      'oauth_nonce' => nonce,
      'oauth_signature_method' => @sig_method,
      'oauth_timestamp' => Time.now.to_i.to_s,
      'oauth_token' => @token,
      'oauth_version' => @oauth_version,
      'userid' => @userid
    }

    # if url has query, merge key/values into params obj overwriting
defaults
    if parsed_url.query
      @params.merge! CGI.parse( parsed_url.query )
    end

    # @ref http://oauth.net/core/1.0/#rfc.section.9.1.2
    @req_url = parsed_url.scheme + '://' + parsed_url.host +
parsed_url.path

    # create base str. make it an object attr for ez debugging
    # ref http://oauth.net/core/1.0/#anchor14
    @base_str = [
      @req_method,
      percent_encode( req_url ),

      # normalization is just x-www-form-urlencoded
      percent_encode( query_string )

    ].join( '&' )

    # add signature
    @params[ 'oauth_signature' ] = signature
    return self
  end
Then function signature to create oauth signature

  def signature
    key = percent_encode( @consumer_secret ) + '&' + percent_encode(
@token_secret )

    # ref:
http://blog.nathanielbibler.com/post/63031273/openssl-hmac-vs-ruby-hmac-benchmarks
    digest = OpenSSL::Digest.new( 'sha1' )
    hmac = OpenSSL::HMAC.digest( digest, key, @base_str )

    # ref
http://groups.google.com/group/oauth-ruby/browse_thread/thread/9110ed8c8f3cae81
    Base64.encode64( hmac ).chomp.gsub( /\n/, '' )
  end
But always response 342 : The signature (using Oauth) is invalid
reference https://gist.github.com/erikeldridge/383159 i think the
problem on hook_url function or signature function. Thank's

Update i'm change params to base_string to

@params = {
      'action' => 'subscribe',
      'oauth_consumer_key' => @consumer_key,
      'oauth_nonce' => nonce,
      'oauth_timestamp' => Time.now.to_i.to_s,
      'oauth_token' => @token,
      'oauth_signature_method' => @sig_method,
      'oauth_version' => @oauth_version,
      'userid' => @userid
    }
Update base string example

GET&https%3A%2F%2Fwbsapi.withings.net%2Fnotify&action%3Dsubscribe%26callbackurl%3Dhttp%253A%252F%252Fstaging.medic-trust.com%252Fwearables%252Fwebhooks%252Fwithings%26comment%3DMedicTrust%26oauth_consumer_key%3D40b7c20955f4193d4ce51248f5c0921281f99483fdd5c6857b0d2974cd2340%26oauth_nonce%3Dc2e7423a12%26oauth_signature_method%3DHMAC-SHA1%26oauth_timestamp%3D1426142430%26oauth_token%3Df9c32509ef7b690e88b2f17e1ddcfb0ed957e420ee02be2328f6f252329d%26oauth_version%3D1.0%26userid%3D6689931
But still response 342