Update collection passed to form_tag


#1

Hi everyone,

I’m trying to update attributes in a collection passed to form_tag.
However my syntax for extracting values from the params hash results
in this exception:

undefined method `keys’ for [“Vanilla”, “Rose”, “Cranberry”]:Array

So it appears I am trying to call keys on an array of “flavor”
attribute values, rather than extracting “Candle” object id keys from
the params hash. I have included the code from the view and controller
below.

Thanks for taking the time to read this. I appreciate any specific
suggestions, as well as any resources that explain the intricacies of
params.

Thank You!
Supraja


edit_all.html.erb:
<% form_tag(:action => “update_candle_line”) do %>
<% for @candle in @candles %>
<%= text_field_tag(“candle[]”, @candle.flavor) %>
<% end %>

<%= submit_tag “Update” %>
<% end %>


edit_all_controller.rb:
def update_candle_line
Candle.update(params[:candle].keys, params[:candle].values)
redirect_to_index(“Flavors updated!”) # private method of
controller
end


#2

On 19 Nov 2008, at 16:25, Supraja wrote:

attribute values, rather than extracting “Candle” object id keys from
the params hash. I have included the code from the view and controller
below.

If you call your parameters candle[] then you will indeed get back a
single array parameter

if you wanted a hash keyed by id then you’d need parameters of the
form candle[some_id][flavor]. fields_for etc… may be able to help
you create those parameter names rather than having to bash them in by
hand.

Fred


#3

Hi Fred,

I appreciate your quick reply.

Here’s an example of an HTML tag after I used fields_for() (code
pasted below*):

How can I change edit_all.html.erb code to get:

id=“candle[id][flavor]” name=“candle[id][flavor]”

Thanks,
Supraja


  • edit_all.html.erb
    <% form_tag(:action => “update_candle_line”) do %>

    <% for @candle in @candles %>

    <% fields_for @candle do |can| %> <%= can.text_field(:flavor) %> <% end %>

    <% end %>

    <%= submit_tag "Update" %>

<% end %>

On Nov 19, 11:07 am, Frederick C. removed_email_address@domain.invalid


#4

Hi everyone,

Thanks to Fred for an excellent explanation of params in his blog
post: http://www.spacevatican.org/2008/7/18/parametrised-to-the-max.
Anyone who is interested in params could probably learn a lot from
reading this interactive post.

Based on the post, I was able to update_attributes() to a collection
of candles.

Thank You!
Supraja

edit_all.html.erb

<% form_tag(:action => “update_candle_line”) do %>

<% for @candle in @candles %>


<% fields_for @candle do |can| %>
<%= can.text_field(:flavor, “index” => @candle.id) %>
<% end %>


<% end %>

<%= submit_tag "Update" %>

<% end %>

edit_all_controller.rb

def update_candle_line
params[:candle].each do |id, new_attributes|
Candle.find(id).update_attributes new_attributes
end
redirect_to_index(“Flavors updated!”)
end