like "observe_field"

rubyonrails-talk
1

I don't see where this can be done in rails directly, but I am hoping some creative mind can see how to use dvarious rails pieces to do it.

I need an ajax request like "observe_field" that triggers an action so as to update something, but rather than a field in a form, I want to observe a file containing json data on a server, such that when the data changes, I read it, and perform an action with it to update something.

Does anyone have any idea how I might accomplish this in RoR? Thanks, Janna B

2

Janna Brossard wrote:

I don't see where this can be done in rails directly, but I am hoping some creative mind can see how to use dvarious rails pieces to do it.

I need an ajax request like "observe_field" that triggers an action so as to update something, but rather than a field in a form, I want to observe a file containing json data on a server, such that when the data changes, I read it, and perform an action with it to update something.

Does anyone have any idea how I might accomplish this in RoR? Thanks, Janna B

Hi Janna,

I could be mistaken but I don't think you can use observe_field in that way. It has to observe a DOM ID and the closest I think you could use in the DOM Location Object, but am unsure...

I know how you can read JSON data from the file though:

require 'open-uri' require 'json'

url = 'http://search.twitter.com/trends.json’

buffer = open(url, "UserAgent" => "Ruby-Wget").read

# convert JSON data into a hash result = JSON.parse(buffer)

trends = result['trends'] trends.each do |subject|   puts subject['name'] + ' ' + subject['url'] end

If I were having to automate this I would create a rake task that called a ruby file such as the one listed here that would read the json data from the file, and then update the database with the new information..

You could create a cron task to automate the rake task every 30 minutes or 1-hour depending...