I have an Image model that is supported by a Binary model. The latter
contains metadata about a physical file and performs all operations
related to the physical file (I will eventually have other models for
different file types). I have a binary.upload method working, but I''d
like to move its call from my ImagesController into the
image.before_create callback. The binary.upload method returns the
binary object. Since my Image model belongs_to my Binary model, I need
the binary.id value to save the Image. How can I access that?
In my ImagesController, I currently have:
def create
@image = Image.new( params[:image] )
# @binary = Binary.new
# if @binary.upload( params[:image][:upload] )
# @image.binary_id = @binary.id
if @image.save
flash[:notice] = "Successfully created image."
redirect_to @image
else
render :action => ''new''
end
end
end
I''ve commented the code that I''d like to move into the Image
model
callback, but I''m not sure how the mechanics would work. Can someone
point me in the right direction?
Any help would be much appreciated. I''m still learning how to access
and manipulate objects in Ruby, as you can see.
On Aug 11, 10:10 pm, Rob Wilkerson <r...-p3XgzcAqCW0fM4Z9iGYqvQ@public.gmane.org> wrote:> I have an Image model that is supported by a Binary model. The latter > contains metadata about a physical file and performs all operations > related to the physical file (I will eventually have other models for > different file types). I have a binary.upload method working, but I''d > like to move its call from my ImagesController into the > image.before_create callback. The binary.upload method returns the > binary object. Since my Image model belongs_to my Binary model, I need > the binary.id value to save the Image. How can I access that? >why not do the assignment from the before_create callback ? I''m not entirely sure why you''re trying to do this . Fred> In my ImagesController, I currently have: > > def create > @image = Image.new( params[:image] ) > # @binary = Binary.new > > # if @binary.upload( params[:image][:upload] ) > # -x/gRBBXwDXh7HUbzM/PHvg@public.gmane.org_id = @binary.id > > if @image.save > flash[:notice] = "Successfully created image." > redirect_to @image > else > render :action => ''new'' > end > end > end > > I''ve commented the code that I''d like to move into the Image model > callback, but I''m not sure how the mechanics would work. Can someone > point me in the right direction? > > Any help would be much appreciated. I''m still learning how to access > and manipulate objects in Ruby, as you can see.
On Aug 11, 5:53 pm, Frederick Cheung <frederick.che...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> why not do the assignment from the before_create callback ? I''m not > entirely sure why you''re trying to do this .I guess what I''m saying is that I''m not sure how to do this. Here''s what I''m thinking that I''d like to do in terms of order of operations: ImagesController::create - accepts the form input. This includes the uploaded file since the Image model has an accessor attribute (:upload). - instantiates a new image with the passed params. - calls the Image model''s save method Image - calls the Binary model to upload the physical file and set/store its properties - sets its own binary_id property based on the return value from the call to Binary::upload - saves itself Maybe there''s a more efficient way to do this than how I''m thinking? If not, I guess what I''m not sure about is how to make that all work together most efficiently. There are several different callback mechanisms in Rails and I don''t have a good enough feel for which is most appropriate in this scenario. I''m thinking of something like this in the Image model: class Image < ActiveRecord::Base belongs_to :binary validates_presence_of( :upload ) before_create :upload_physical_file attr_accessor :upload protected def upload_physical_file @binary = self.binary.upload( :upload ) self.binary_id = @binary.id end end I have an unexpected nil object that I''ll debug, but I don''t have a good feel that I''m doing this the best way. Being completely new to Ruby and Rails, I don''t have a good feel for how to access related models or what objects are available at which times. For example, I don''t know whether I have to explicitly instantiate a Binary object in my Image model or, since they''re related, I can assume one is instantiated and access it as self.binary. At this point, I''m fighting the learning curve and may not even be asking the right questions. Any advice you can offer based on either the scenario or the posted code would be much appreciated. Thanks again.
On Aug 11, 11:43 pm, Rob Wilkerson <r...-p3XgzcAqCW0fM4Z9iGYqvQ@public.gmane.org> wrote:> I have an unexpected nil object that I''ll debug, but I don''t have a > good feel that I''m doing this the best way. Being completely new to > Ruby and Rails, I don''t have a good feel for how to access related > models or what objects are available at which times. For example, I > don''t know whether I have to explicitly instantiate a Binary object in > my Image model or, since they''re related, I can assume one is > instantiated and access it as self.binary.You would have to create an instance of Binary. associations just add a bunch of methods that make manipulation objects easier. if you do build_binary that will both create an instance of binary and associate it with the image (ie you don''t have have to set self.binary_id). You may want to read the guide about associations at guides.rubyonrails.org Fred> > At this point, I''m fighting the learning curve and may not even be > asking the right questions. Any advice you can offer based on either > the scenario or the posted code would be much appreciated. > > Thanks again.