Rails Time to String - either ignores function or acts randomly

Question

In Ruby on Rails 3 I'm trying to modify my Model dataset's dates to only show hours and minutes, which I then return as an AJAX string.

My code is the following:

 list_of_time_fields = [:a, :list, :of, :symbols]
 result = Model.where(conditions).take(100)
 result.each { |row|
        list_of_time_fields.each { |field|
            row[field] = row[field].strftime("%H:%M") unless row[field].nil?
        }
    }
 return result

For some fields I get the whole time string (something like yyyy-mm-ddTHH:MM:ssZ) and for others I get nulleven if the field is not null. The difference is that the ones that return strings are TIME fields in MySQL, whereas the others are DATETIME.

I've checked the types to which Rails maps these columns and everything is class Time.

If you can point which things I should look at It'd be great.

Are you returning the data as JSON? – Stefan Nov 28 '13 at 11:27 — Stefan, Nov 28 '13 at 11:27
Yes, with a `render json: result`. – Pedro Montoto García Nov 28 '13 at 12:17 — Pedro Montoto García, Nov 28 '13 at 12:17

score 1 · Accepted Answer · answered Nov 28 '13 at 12:49

1

When assigning the time string to the attribute:

row[field] = row[field].strftime("%H:%M")

Rails parses the string and creates a new datetime (actually a ActiveSupport::TimeWithZone) object instead:

user = User.new
user.created_at = "01:00"
#=> "01:00"
user.created_at
#=> Thu, 28 Nov 2013 01:00:00 CET +01:00

Using a custom hash would work. Something like:

result = Model.where(conditions).take(100).map { |model|
  {
    id: model.id,
    time_field: model.time_field.try(:strftime, "%H:%M")
  }
}
render json: result

JBuilder might be another option.

answered Nov 28 '13 at 12:49

Stefan

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Thanks, also just found it's the same case as http://stackoverflow.com/questions/2937740/rails-dates-with-json – Pedro Montoto García Nov 28 '13 at 12:50
Just a question, does using `model_return = model.attributes` break your solution? – Pedro Montoto García Nov 28 '13 at 12:59

Rails Time to String - either ignores function or acts randomly

1 Answers1