Rails 4, Argument Error Unknown Key, Update Controller

Question

I receive an error when trying to edit a post:

posts#edit controller:

def edit
 @post = Post.find params[:id]
end

posts#update controller:

def update
 @post = Post.find params[:post]

 if @post.update_attributes params[:post]
  redirect_to posts_path
 else
  render 'edit'
 end
end

edit view:

h1 Edit Post
= form_for @post do |f|
 p
  = f.label :title
  = f.text_field :title
 p
  br
 p
  = f.label :content
  = f.text_area :content
 p
  br
 p
  = f.submit 'Update Post'
 p
  br

This is when I get the ArgumentError in PostsController#update, Unknown Key: title error. I am still wrapping my head around the strong parameter concept in Rails 4 so it might have something to do with this...any ideas?

have you tested the controller actions in the rails console? Does `Post.find(id: )` return what you expect? — Nikola, Oct 15 '13 at 00:01
Yes Nikola, Post.find(13) inside of the console returns what is expected... — Ryan Waits, Oct 15 '13 at 02:21

score 2 · Accepted Answer · answered Oct 15 '13 at 07:49

2

Try the following i hope it will help you.

def update
  @post = Post.find(params[:id])
  if @post.update(post_params)
    redirect_to @post
  else
    render 'edit'
  end
end

answered Oct 15 '13 at 07:49

Amit Sharma

3,427
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score 0 · Answer 2 · answered Oct 15 '13 at 14:30

I updated the posts#update controller to

params[:id]

rather than

params[:post]

this fix brought me the ForbiddenAttributesError caused by

if @post.update_attributes params[:post]

this is due to the strong parameters concept introduced with Rails 4...I fixed this by substituting the

params[:post]

with a strong parameter

post_params

from the private method post_params

 private
  def post_params
   params.require(:post).permit(:title, :content)
 end

eventually solving the unknown key error of :title

Rails 4, Argument Error Unknown Key, Update Controller

2 Answers2