Jobs update with Dashing and Ruby - ruby-on-rails

Question

I use Dashing for monitor trends and website statistics.
I create a jobs to check GooglesNews trends and Twitter trends .
The data is displayed well, however, they appear at first load and does put more update then. There is the code for twitter_trends.rb :
require 'nokogiri'
require 'open-uri'
url = 'http://trends24.in/france/~cloud'
data = Nokogiri::HTML(open(url))
list = data.xpath('//ol/li')
tags = list.collect do |tag|
tag.xpath('a').text
end
tags = tags.take(10)
tag_counts = Hash.new({value: 0})
SCHEDULER.every '10s' do
tag = tags.sample
tag_counts[tag] = {label: tag}
send_event('twitter_trends', {items: tag_counts.values})
end
I think I used bad "rufus-scheduler" to schedule my job jobs https://gist.github.com/pushmatrix/3978821#file-sample_job-rb
How to make the data will update correctly on a regular basis ?

Answer 1

Your scheduler looks fine, but it looks like you're making one call to the website:
data = Nokogiri::HTML(open(url))
But never calling it again. Is your intent to only check that site once along with the initial processing of it?
I assume you'd really want to wrap more of your logic into the scheduler loop - only things in there will be rerun when the schedule job hits.

Answer 2

When you covered everything in a scheduler, you are only taking one sample every 10 seconds (http://ruby-doc.org/core-2.2.0/Array.html#method-i-sample) then adding it to tag_counts. This is clearing the tag each time. Thing to remember about schedulers is it's basically a clean slate every time it runs. I'd recommend looping through tags and adding them to tag_counts that way instead of sampling. sampling is kind of unnecessary seeing as you are reducing it to 10 each time you run the scheduler.

Answer 3

If I move the SCHEDULER like this (after url on top), it works but that only one item appears randomly every 10 seconds.
require 'nokogiri'
require 'open-uri'
url = 'http://trends24.in/france/~cloud'
SCHEDULER.every '10s' do
data = Nokogiri::HTML(open(url))
list = data.xpath('//ol/li')
tags = list.collect do |tag|
tag.xpath('a').text
end
tags = tags.take(10)
tag_counts = Hash.new({value: 0})
tag = tags.sample
tag_counts[tag] = {label: tag}
send_event('twitter_trends', {items: tag_counts.values})
end
How to display a list of 10 items, which is updated regularly ?