ActiveRecord after_initialize with select

Question

With two of my Rails models when I try to call the ActiveRecord method select it just returns the error object doesn't support #inspect

These models use the after_initialize callback, so I suspect it has something to do with that.

I'm using the after_initialize callback like this:

enum state: [ :archived, :active ]

after_initialize :state_init
after_initialize :date_init

def state_init
  self.state ||= :active
end

def date_init
  self.report_date ||= self.event ? self.event.event_date : Date.current
end

and I need to use the select method to select records grouped by month using a field that has a date with Postgres

ModelName.select("date_trunc( 'month', report_date ) as month, count(*) as count").group('month')

Is there any way to work around this problem?

All depends on what your `after_initialize` does. Do you mind sharing some code? — BroiSatse, Jan 19 '16 at 02:55
Only thing that springs to mind - do you define your own initialize method in that model? — BroiSatse, Jan 19 '16 at 08:48
HI Toby, Did you get answer for your problem. I'm facing the same issue. Please let me know — pramod, Jul 12 '16 at 12:00
@Toby1Kenobi I got a solution for this. But not sure what's the error you have. Please let me know the error. — pramod, Jul 12 '16 at 12:27
@pramod the error is in the question. I didn't get any solution. I'm not using the after_initialize callback any more. — Toby 1 Kenobi, Jul 12 '16 at 12:37
@Toby1Kenobi Added a solution. Check it once. It might be helpful down the road :) — pramod, Jul 12 '16 at 12:53

score 2 · Accepted Answer · answered Jul 12 '16 at 12:51

2

Basically the problem with the after_initialize method is when you're only selecting a subset of columns for a model you will get a MissingAttributeError if your after_initialize method/block accesses a column that hasn't been included in the select clause.

One of the quick solution is just include those columns in the select clause. But as this is not the right solution. You can fix it by telling the process to initialize it when the record is not persisted only as follows:

after_initialize :state_init, unless: :persisted?
after_initialize :date_init, unless: :persisted?

def state_init
  self.state ||= :active
end

def date_init
  self.report_date ||= self.event ? self.event.event_date : Date.current
end

answered Jul 12 '16 at 12:51

pramod

2,258
1
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Thanks, that's really helpful. I was looking for a callback that would run after initialising a new object, but not when retrieving it from the database. This answer provides that. – Toby 1 Kenobi Jul 12 '16 at 13:06
It's also really nice to know why this error was occurring – Toby 1 Kenobi Jul 12 '16 at 13:12
@Toby1Kenobi Good to know that it helps – pramod Jun 04 '17 at 06:43

score 0 · Answer 2 · answered May 31 '16 at 14:33

0

I am facing the similar issue with you.

In the end, I have decided to remove the after_initialize method and set default value instead in db (migration).

Hope this helps.

answered May 31 '16 at 14:33

Yih Yang

21
3

ActiveRecord after_initialize with select

2 Answers2

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