Withings API: The callback URL is either unknown or invalid - ruby-on-rails

Question

I'm trying to set a notification in the withings API (with the withings-simplificator gem). I always get this error, no matter what URL I enter or if I encode it or not:
irb(main):013:0> user.subscribe_notification('http://foo.bar.com', 'test subscription')
Withings::ApiError: The callback URL 'http://foo.bar.com' is either unknown or invalid - Status code: 293
from /app/vendor/bundle/ruby/2.2.0/gems/simplificator-withings-0.7.0/lib/withings/connection.rb:80:in `verify_response!'
from /app/vendor/bundle/ruby/2.2.0/gems/simplificator-withings-0.7.0/lib/withings/connection.rb:22:in `get_request'
from /app/vendor/bundle/ruby/2.2.0/gems/simplificator-withings-0.7.0/lib/withings/connection.rb:27:in `get_request'
from /app/vendor/bundle/ruby/2.2.0/gems/simplificator-withings-0.7.0/lib/withings/user.rb:26:in `subscribe_notification'
from (irb):13
from /app/vendor/bundle/ruby/2.2.0/gems/railties-4.2.4/lib/rails/commands/console.rb:110:in `start'
from /app/vendor/bundle/ruby/2.2.0/gems/railties-4.2.4/lib/rails/commands/console.rb:9:in `start'
from /app/vendor/bundle/ruby/2.2.0/gems/railties-4.2.4/lib/rails/commands/commands_tasks.rb:68:in `console'
from /app/vendor/bundle/ruby/2.2.0/gems/railties-4.2.4/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
from /app/vendor/bundle/ruby/2.2.0/gems/railties-4.2.4/lib/rails/commands.rb:17:in `<top (required)>'
from bin/rails:8:in `require'
from bin/rails:8:in `<main>'
Has anyone encountered this and has a solution?
Update 1:
So I tried without the withings simplificator gem:
API_KEY = '123'
API_SECRET = '456'
USER_ID = '789'
USER_KEY = 'abc'
USER_SECRET = 'def'
CONFIGURATION = { site: 'https://oauth.withings.com',
request_token_path: '/account/request_token',
access_token_path: '/account/access_token',
authorize_path: '/account/authorize',
http_method: :get,
scheme: :query_string
}
#consumer = OAuth::Consumer.new API_KEY, API_SECRET, CONFIGURATION
#access_token = OAuth::AccessToken.new #consumer, USER_KEY, USER_SECRET
url = ERB::Util.url_encode("www.foo.bar/trigger")
comment = ERB::Util.url_encode("Trigger")
response = #access_token.get("https://wbsapi.withings.net/notify?action=subscribe&userid=#{USER_ID}&callbackurl=#{url}&comment=#{comment}")
JSON.parse(response.body)
And same error:
irb(main):051:0> JSON.parse(response.body)
=> {"status"=>293}
What am I doing wrong?

Answer 1

You have to make sure during setup
your "trigger url" exists
it responds with "ok" to a POST
it is fast ... I couldn't figure this out exactly how fast, but I think the response time should be < 1 second
With an environment like this, my code above works.

Answer 2

Your notification endpoint going to do two operations:
it is going to respond test request response (while you register it will check your URL is exist or not). You will receive call with empty body object. If it is not have userid, it is not a data notification, so you have to respond status as 200 with empty body;
after successful registration you will receive data alert. This time you can handle by your business logic.