Helper or?

Rails
1

I have a strong handle on when to use a helper – at least I think so. A
helper may include some logic (not enough to belong in the model) and it
presents html as its output. So I have a conceptual problem about this
solution that I’ve built:

#helpers/people_helper.rb
def person_roles
(%W(assistant author collector editor foreword illustrator
interviewer introduction narrator notes translator) +
Role.group(‘name’).map(&:name)).uniq().sort
end

I use the output in a view, as part of a collection_select picker for a
string-based attribute. This picker has a JavaScript “combobox” behavior
added to it, so the editor can add new roles to the list at whim. But
the output is an array. Does this invalidate my use of a helper method?
Or am I thinking too much about the label “helper” here?

Thanks,

Walter

2

On 26 January 2012 14:26, Walter Lee D. [email protected] wrote:

I have a strong handle on when to use a helper – at least I think so. A helper
may include some logic (not enough to belong in the model) and it presents html as
its output. So I have a conceptual problem about this solution that I’ve built:

#helpers/people_helper.rb
def person_roles
(%W(assistant author collector editor foreword illustrator interviewer
introduction narrator notes translator) +
Role.group(‘name’).map(&:name)).uniq().sort
end

I use the output in a view, as part of a collection_select picker for a
string-based attribute. This picker has a JavaScript “combobox” behavior added to
it, so the editor can add new roles to the list at whim. But the output is an
array. Does this invalidate my use of a helper method? Or am I thinking too much
about the label “helper” here?

To me that looks more like something that should be called in the
controller and go into an @ variable for use in the view. The general
rule is setup data in the controller and display it in the view. The
method itself could go in the Role model or in a module in lib

Colin

–
gplus.to/clanlaw

3

On Jan 26, 2012, at 9:37 AM, Colin L. wrote:

To me that looks more like something that should be called in the
controller and go into an @ variable for use in the view. The general
rule is setup data in the controller and display it in the view. The
method itself could go in the Role model or in a module in lib

Colin

I had it in the controller, but I didn’t like the look of having to
declare an instance variable inside each method that needed this (new
and create and edit and update). The helper was there for the asking in
each view, so it seemed DRYer. Is there a way to have my cake and eat it
too?

Thanks,

Walter

4

On 26 January 2012 14:47, Walter Lee D. [email protected] wrote:

I had it in the controller, but I didn’t like the look of having to declare an
instance variable inside each method that needed this (new and create and edit and
update). The helper was there for the asking in each view, so it seemed DRYer. Is
there a way to have my cake and eat it too?

helper_method :my_controller_method

?

5

On Jan 26, 2012, at 9:51 AM, Michael P. wrote:

On 26 January 2012 14:47, Walter Lee D. [email protected] wrote:

I had it in the controller, but I didn’t like the look of having to declare an
instance variable inside each method that needed this (new and create and edit and
update). The helper was there for the asking in each view, so it seemed DRYer. Is
there a way to have my cake and eat it too?

helper_method :my_controller_method

?

If it is the same code in each action then set the variable in a
before_filter in the controller. Then it will be setup for each
action that you specify. Bone dry.

Colin

Thanks to both of you.

Walter

6

On 26 January 2012 14:47, Walter Lee D. [email protected] wrote:

I use the output in a view, as part of a collection_select picker for a
string-based attribute. This picker has a JavaScript “combobox” behavior added to
it, so the editor can add new roles to the list at whim. But the output is an
array. Does this invalidate my use of a helper method? Or am I thinking too much
about the label “helper” here?

To me that looks more like something that should be called in the
controller and go into an @ variable for use in the view. The general
rule is setup data in the controller and display it in the view. The
method itself could go in the Role model or in a module in lib

Colin

I had it in the controller, but I didn’t like the look of having to declare an
instance variable inside each method that needed this (new and create and edit and
update). The helper was there for the asking in each view, so it seemed DRYer. Is
there a way to have my cake and eat it too?

If it is the same code in each action then set the variable in a
before_filter in the controller. Then it will be setup for each
action that you specify. Bone dry.

Colin

–
gplus.to/clanlaw

7

On 26 January 2012 14:51, Michael P. [email protected] wrote:

On 26 January 2012 14:47, Walter Lee D. [email protected] wrote:

I had it in the controller, but I didn’t like the look of having to declare an
instance variable inside each method that needed this (new and create and edit and
update). The helper was there for the asking in each view, so it seemed DRYer. Is
there a way to have my cake and eat it too?

helper_method :my_controller_method

Michael: I don’t think that addresses the problem, unless I
misunderstand. The OP doesn’t need the method available in the
controller and the view, he is just not sure about which it should
be.

Colin

8

On 26 January 2012 15:03, Colin L. [email protected] wrote:

Michael: I don’t think that addresses the problem, unless I
misunderstand. The OP doesn’t need the method available in the
controller and the view, he is just not sure about which it should
be.

True… depending on where it’s wanted will affect whether it should
be a helper, helper_method or before_filter :wink:

9

On 26 January 2012 16:38, Peter V. [email protected]
wrote:

…)
User.include(:account).include(:address).include(:projects).find(params[:id])
unless we think about removing that from the controller.

I start to feel more that the controller does some “routing/decision”
logic (render, error, redirect, …), but that it should not really prepare
the data for later views. The views should “pull” their data from a
presenter.

Does this make sense? Would it address the initial question from the OP?

I think the issue there is where there may be multiple ways of
“viewing” the data. For example xml and html. In that case the
conventional MVC concept is that the controller prepares the data then
it goes off to an appropriate renderer which decides how to format it.
In your example above with user projects, if only a subset of the
projects is to be seen then it is up to the controller to make that
subset available.

Colin

Colin

10

On Jan 26, 2012, at 11:38 AM, Peter V. wrote:

Suppose that we initially show a list of all the projects of the user
A helper (in my opinion) is purely an html/decorator thing (as was

Does this make sense? Would it address the initial question from the OP?

Yes and yes. I agree with your analysis of my question, and I’d love to
see more elucidation of how a presenter pattern could work in this case.

Thanks,

Walter

11

On Thu, Jan 26, 2012 at 3:37 PM, Colin L. [email protected]
wrote:
…

To me that looks more like something that should be called in the
controller and go into an @ variable for use in the view. The general
rule is setup data in the controller and display it in the view.

TL;DR

  • controller only does “routing/decision” logic (render, error,
    redirect,
    …)
  • views get their rich data from a presenter

I feel less confident about this strategy.

I have doubts over this code in the controller that is
“pushing/pre-setting” data
into e.g. a @user instance variable

@user =
User.include(:account).include(:address).include(:projects).find(params[:id])

of which a large fraction may remain unused and the specific usage may
change over time.

Suppose that we initially show a list of all the projects of the user
in the show view, but later decide to not show that list in the first
“show” view anymore (it could e.g. be shown later with an AJAX
request when the user opens a projects tab).

Then we would be always populating the @user with too much data,
unless we think about removing that from the controller.

I would prefer a method where the view “pulls” (only) the data that it
needs, when it needs it, from … (a presenter ??).

A helper (in my opinion) is purely an html/decorator thing (as was
also the feeling of the OP, If I understood correctly).

Of course, the ActiveRecord::Relation helps to delay the actual SQL
in certain cases (e.g. in the index view). But it does not remove the
code complexity and potential inefficiency from the controller.

I start to feel more that the controller does some “routing/decision”
logic (render, error, redirect, …), but that it should not really
prepare
the data for later views. The views should “pull” their data from a
presenter.

Does this make sense? Would it address the initial question from the OP?

Peter