Update_attriubtes meets "Can't mass-assign protected attributes" problem

Rails
1

hi all:
I have met the "Can’t mass-assign protected attributes: " problem.
I have two models. one is province

class Province < ActiveRecord::Base
attr_accessible :name
has_many :cities
accepts_nested_attributes_for :cities
end

and another is city
class City < ActiveRecord::Base
attr_accessible :name,:province_id
belongs_to :province
has_many :districts
end

when I created the city instant by @city=City.new(params[:city]). It
works
but when I updated it using:
@city=City.find(params[:id])
flash[:notice]=“error cannot update information of the city” if
@city.update_attributes(params[:city])

I got “Can’t mass-assign protected attributes: province_id”

I really added province_id to attrib_accessible and massAssignment works
fine when I new an object. I have googled a lot but I cannot find
answer.
does anybody have idea?

thanks

kang

2

Is it possible you haven’t migrated your database?

Although, it’s not supposed to complain when you update_attributes and
the params hash has things OTHER than the allowed attribs, so that’s
interesting.

Julian

3

On 6 April 2013 06:48, [email protected] wrote:

and another is city
@city.update_attributes(params[:city])

I got “Can’t mass-assign protected attributes: province_id”

I image that the reason new works is that you are not assigning
provice_id using update_attributes.
Is the code for class City that you posted above copied and pasted
from the source or did you re-type it?
Can you copy/paste the full error message please and also the bit from
development.log for the failing action.
Also the code for that action from the controller.

Also check that you have not accidentally left any files in the model
folder that should not be there - a copy of an old version of city.rb
for example.

Colin

4

following is my code copied from my codes:
cities_controller and it is in app/controller/admin folder:

#–encoding: UTF-8
class Admin::CitiesController < ApplicationController
respond_to :html, :json
def index
@provinces=Province.all
respond_with [:admin,@provinces]
end

def new
@city=City.new
respond_with [:admin,@city]
end

def edit
@city=City.find(params[:id])
respond_with [:admin,@city]
end

def update
@city=Province.find(params[:id])
flash[:notice]=‘已更新’ if @city.update_attributes(params[:city])
respond_with([:admin,@city])
end

def create
@city=City.new(params[:city])
flash[:notice]=‘已保存’ if @city.save
respond_with [:admin,@city]
end

def destroy
@city=City.find(params[:id])
@city.destroy
flash[:notice]=‘已删除’
respond_with [:admin,@city]
end

def show
redirect_to :action=> ‘index’
end
end

the models:

class City < ActiveRecord::Base
attr_accessible :name,:province_id
belongs_to :province
has_many :districts
end

class Province < ActiveRecord::Base
attr_accessible :name
has_many :cities
accepts_nested_attributes_for :cities
end

and the error message:
Started PUT “/admin/cities/3” for 10.0.2.2 at 2013-04-07 09:05:38 +0800
Processing by Admin::CitiesController#update as HTML
Parameters: {“utf8”=>“✓”,
“authenticity_token”=>“K+tQCFj1wM04nN9ZophjVUd3B6k3sQr0immjMJNWb/o=”,
“city”=>{“province_id”=>“3”, “name”=>“石家庄”}, “commit”=>“提交”, “id”=>“3”}
Province Load (0.3ms) SELECT “provinces”.* FROM “provinces” WHERE
“provinces”.“id” = ? LIMIT 1 [[“id”, “3”]]
(0.2ms) begin transaction
(0.1ms) rollback transaction
Completed 500 Internal Server Error in 5ms

ActiveModel::MassAssignmentSecurity::Error (Can’t mass-assign protected
attributes: province_id):
app/controllers/admin/cities_controller.rb:23:in `update’

and I have double checked the models folder, there is no useless file. I
have used sunspot and sunspot_solr for the other model. does it have
some
thing with this problem?

actually this problem is not big problem for me since the city only has
two
attributes. but I want to know what make it since I cannot google a
problem
as same as this one.
thanks colin
kang

5

Shouldn’t you have attr_accessible AFTER the has_many association DSL
message call?

Julian

6

I find the problem that I made mistake in controller since I just copied
codes from province_controller and replace every province with city. but
in
update method, I miss replacing the Province with City. thus the problem
happens. the error message led me to wrong direction.
thanks you all