rails 4 activerecord更新多个属性

Question

I'm puzzled by an update I'm attempting to do with Rails 4 / Activerecord. The app I'm working on is using Stripe to handle subscriptions, and this function should deal with an updated subscription (stripe customer.subscription.updated event):

# passing in a stripe webhook event object
# event.data.object.current_period_end = 1402100302
subscription = Subscription.find_by(stripe_id: event.data.object.id)
plan = Plan.find_by(stripe_name: event.data.object.plan.id)

subscription.update(expires_at: event.data.object.current_period_end, plan_id: plan.id)

This all seems clear, and when I execute the individual lines in a rails console, I get valid data for subscription , plan , etc. However, the update doesn't work as expected. Here's what the query executed in the rails console shows for the update line:

SQL (0.7ms)  UPDATE "subscriptions" SET "expires_at" = $1, "updated_at" = $2 WHERE "subscriptions"."id" = 23  [["expires_at", nil], ["updated_at", Wed, 07 May 2014 17:09:25 UTC +00:00]]
   (15.9ms)  COMMIT
=> true

expires_at is nil , and the second value, plan.id doesn't even get passed in to the query. How should I handle this update?

Answer 1

Looks like the event.data.object.current_period_end just has to be converted to a Time like this:

subscription.update(expires_at: Time.at(event.data.object.current_period_end), plan_id: plan.id)

This is confusing since in the create_subscription event I do the update exactly the same, setting the expires_at via the webhook data, and using the same values / timestamp to set the expires_at value.

It also appears rails is smart enough to know when a value is not going to be changed by the update -- and it therefore leaves it out of the query. That was part of my confusion with the plan_id -- the expires_at date had changed, but the plan had not-- so rails was leaving that part of the update statement out of the sql.