ActiveModel date fields with rails views

[Steven Ringo]

Hi all,

Anyone have any idea on the best way to parse a date from a rails form and coerce it into a date field in an active model object.

Rails send this in the params hash:

 "credit_card_expiry(3i)"=>"1",
 "credit_card_expiry(2i)"=>"11",
 "credit_card_expiry(1i)"=>"2012"

However the model sees these as being three separate attributes, and of course the the active model object has no way of knowing this.

I have seen techniques that manually mangle the hash like so (or introspective variants), but this feels very hacky.

params[:subscription][:credit_card_expiry] = Date.new(params[:subscription][:"credit_card_expiry(1i)"].to_i,                                                            params[:subscription][:"credit_card_expiry(2i)"].to_i, params[:subscription][:"credit_card_expiry(3i)"].to_i)

params[:subscription].delete(:"credit_card_expiry(1i)")
params[:subscription].delete(:"credit_card_expiry(2i)")
params[:subscription].delete(:"credit_card_expiry(3i)")

Thanks,

Steve

[Ivan Vanderbyl]

Hi Steve,

This is handled by ActiveRecord usually in ActiveRecord::AttributeAssignment#assign_multiparameter_attributes (https://github.com/rails/rails/blob/master/activerecord/lib/active_record/attribute_assignment.rb#L62-66)

You could experiment with either mixing in that module or pulling out the #assign_multiparameter_attributes methods into your own module and using it with ActiveModel.

AFAIK there is no equivalent for ActiveModel.

— Ivan

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[Steven Ringo]

Hi,

@Ivan, thanks :-)

Since this is a credit card field, we are going to just have separate explicit fields for month and year, as that's what the acquirer wants anyway.

I was worried about how to handle validations on the combined date, but we don't need to validate at that level. Rather we validate for all the credit card fields together.

Perhaps it might be a good idea to see multi-parameter attributes factored out of AR and into ActiveModel?

Thanks again.

Steve

[Ivan Vanderbyl]

Ah yes, I went through this same problem a few weeks ago with a CC form. Ended up doing the same thing.

[Mark Ratjens]

Another way to do this is store a date as one field on the model. It's quite easy to add methods to the model to present month and year values so that you effectively have the same model interface that you need. I'd be tempted to do this, since it relies less on less familiar AR features.

In the form, you do can something like 

f.date_select :credit_card_date, "written_on", :discard_day => true

so that the day component of the day is neither shown on the form nor sent through the params.

Mark Ratjens

Co-founder, Habanero Software

Sydney, Australia

mark.r...@habanerohq.com

@MarkRatjens

www.habanerohq.com

+61 414 159 357

[Steven Ringo]

Rails still sends them through as separate fields, in this case for month and year, and they need to be recombined manually.

[Mark Ratjens]

Refer to http://guides.rubyonrails.org/form_helpers.html#using-date-and-time-form-helpers Section 4.2

This is Rails. You should expect that it helps you with banal stuff like this, And it does!

[Steven Ringo]

This is ActiveModel. Same behaviour happens with ActiveRecord virtual attributes and date fields.

Because there is no database backing the field, rails has no idea this is a date field and therefore does not invoke the attribute combiners it would normally, as per https://github.com/rails/rails/blob/master/activerecord/lib/active_record/attribute_assignment.rb#L62-66

[Dmytrii Nagirniak]

I also did the custom CC using ActiveAttr. Quite simple and no Rails required for testing which I love :)

https://gist.github.com/4056448

Regards,

Dmytrii Nagirniak

http://ApproachE.com

On 8 November 2012 09:50, Ivan Vanderbyl <ivanva...@gmail.com> wrote: