Need help .. Rails Recipes, in_place_editor, selecting assoc

Rails
1

Hi,

I am currently reading the Rails Recipes book and like the chapter on
providing your own in_place_editor for enumerations / selects.

I understood so far, or I believe that I understood ;-), how to do
that
for a field that uses values only, like choosing from “red”, “black”,
“green”. What I fail to understand is how to chose from associated
objects?!

Consider the following example. A “Reader” has_one “Book”, the book
s/he
is currently reading. Both “Reader” and “Book” are model objects. How
would
you go about at view to make the current book selectable?

With above mentioned Rails Recipe “Making Your Own JavaScript Helper”
it
is trivial to make the IDs (book_id) selectable, but I would rather like
the
user to select from a list of book titles than from a list of book ids.

If I provide the in_place_editor with the ids and titles of the
available
book as select options it works on the surface (book titles can be
chosen,
ids are used for the update calls), but the current value displayed in
the
tag is still an id. And I believe that I have to provide the
in_place_editor
helper method with “:reader” and “:book_id”, because it uses it for the
update_url.

Providing a new parameter to the helper method for creating the
in_place_editor might work, but it seems that there is some stuff
happening
under the hood retrieving the original id when creating the instance
tag.
Would it be an option to overwrite the result? If so how to find which
attribute? tag.inspect returns pages of variables. What to look for?

Btw. What is the easiest way to open a referenced class, like
InstanceTag,
from within TextMate, when you don’t know what the source file is a
called?
Is a global search in the project the only option?

I am at loss here what to do without rewriting most of the existing
code
relevant to in_place_editors?

On the other hand though handling of associations in the view is also
absent in the generated scaffolds and I haven’t seen any support for
that in
any other view related topic. Am I doing something wrong and don’t
understand the Golden Path™? Isn’t choosing from associated objects
an
every day case?

Any help and insight is appreciated.

Thanks,
Mariano

2

I am still looking for help :wink:

Regarding the question if rails turns a blind eye on associations
handling
in the view or me on the rails doc, I came across the following in the
documentation of ActionView::Helpers::ActiveRecordHelper (
http://edgedocs.planetargon.org/classes/ActionView/Helpers/ActiveRecordHelper.html
):

[…] The most far-reaching is the form method that creates a complete
form
for all the basic content types of the record → (not associations or
aggregations, though) <–. […]

So the rails helpers don’t provide support for assocations, right? Any
idea
why that is?

Just out of curiosity. Imagine I would be capable and willing to
implement
the “missing” feature. How would I go about this and what would be the
basic
idea about doing this following the Golden Path™?

From my point of view a) an identifier/label needs to be identified in the
associated model, e.g. “name” of the associated “Book”. My first guess
is
that it belongs to the controller/view not the model of “Reader”.

Reader:
belongs_to :book

ReadersController:
in_place_edit_for :reader, :name
in_place_association_edit_for :reader, :book # <----------------

The following information should be derived:
id field = book_id (as a default, otherwise the attribute would need to
be
specified)
label field = book.name (as a default, otherwise the attribute would
need to
be specified)
I am not sure if the label field is necessary at all, because the
controller
just needs to know which field to update, right? It might only be
necessary
if the view only handles the lables. More on that below.

In the view:

in_place_select_association_editor_field :reader, :book

I believe it would be ok to make the label (book.name) unique. That
would be
convenient, because then “id” and “label/name” can be used
interchangeable,
i.e. just one, the lagel, need to be used. Otherwise all ids and
labels/names of “Book” needs to be known in the view.

The view should display a picklist with all the labels in it and
depending
on either using unique labels just have a label picked or when using ids
and
labels set the id in the view.

Cheers,
Mariano