Rails state machine is not working - ruby-on-rails

Question

I am creating a blog application in which User can post and can view his own post only.There is only one admin who can view everyone post and has feature to accept or decline users post..For example when user will share his post then admin will approve or decline that post.If he approves the post will be there if admin decline the post will be deleted .I am using state machines for that but I am having some problem .I have taken two buttons approve and decline but they are not working.
i just want that when i click on approve button so there is a column in my posts table which is given by default a value "pending" so it will change to approve or decline whichever button i click ....and if decline so the post should be deleted
when clicking approve button undefined method `permit' for "state_event=approve":String
[post.rb]
class Post < ActiveRecord::Base
require 'rubygems'
require 'state_machine'
has_many :documents
has_many :comments, dependent: :destroy
belongs_to :user
validates :title, presence: true, length: {in: 5..10}
validates :body, presence: true,length: {in: 5..200}
#:status is the column in posts table
state_machine :status, :initial => :pending do
#button name which is approve
event :approve do
transition :pending => :approve
end
event :decline do
transition :pending => :decline
end
end
def self.user_post(id)
role = User.find_role(id)
if role == 'admin'
Post.all
elsif role == 'user'
Post.where(user_id: id)
elsif role == 'developer'
Post.where(user_id: id)
end
end
def self.icon(extension)
case extension
when 'pdf'
EXTENSION[1]['pdf']
when 'png' || 'jpg' || 'jpeg'
EXTENSION[0]['png']
when 'doc' || 'odt'
EXTENSION[2]['doc']
end
end
####limit to upload files not more than ######
def self.upload(files,post_id)
files.each do |file|
#file_extension=file.content_type.split('/')[1]
doc = Document.new(document: file,post_id: post_id )
#save is a method which will save the content in the database
doc.save!
end
end
end
[post_controller]
class PostsController < ApplicationController
before_action :authenticate_user!
def index
#posts = Post.user_post(current_user).order('created_at DESC').paginate(:page => params[:page], :per_page => 5)
end
def new
#post = Post.new
end
def show
#post=find_params
end
def create
#post = Post.new(post_params)
#post.user = current_user
if #post.save
Post.upload(params[:post][:files],#post.id)
redirect_to #post
else
render 'new'
end
end
def edit
#post = find_params
end
def update
#post = find_params
if #post.update(post_params)
redirect_to #post
else
render 'edit'
end
end
def destroy
#post = find_params
#post.destroy
redirect_to posts_path
end
private
def post_params
p = params.require(:post)
if current_user.roles=='admin' # or however you check if the user is authorized
p.permit(:title, :body, :state_event)
else
p.permit(:title, :body)
end
end
def find_params
Post.find(params[:id])
end
end
[posts/_form.html.erb]
<%= form_for #post,html: { multipart: true } do |f| %>
<% if #post.errors.any? %>
<div id="errors">
<h2><%= pluralize(#post.errors.count, "error") %> prevented this post from saving:</h2>
<ul>
<% #post.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
<%= f.label :title %><br>
<%= f.text_field :title %><br>
<br>
<%= f.label :body %><br>
<%= f.text_field :body %><br>
<br>
<!-- if you want to upload multiple files at a time -->
<%= f.label :files %><br>
<%= f.file_field :files,:multiple => true %><br>
<br>
<%= f.submit %>
<br>
<% end %>
<br>
[posts/edit.html.erb]
<div id="page_wrapper">
<h1>Edit Post</h1>
<%= render 'form' %>
<br>
<%= form_for #post do %>
<%= button_to 'Approve', #post,
params: { post: { state_event: 'approve' } } ,
method: :patch
%>
<%= button_to 'Decline', #post,
params: { post: { state_event: 'decline' } } ,
method: :patch
%>
<% end %>
</div>

Answer 1

If you want to change the state of your model you need to set the state_event property.
<%= button_to 'Approve', #post,
params: { post: { state_event: 'approve' } }
method: :patch
%>
<%= button_to 'Decline', #post,
params: { post: { state_event: 'decline' } }
method: :patch
%>
You also need to add the parameter in the strong parameters list:
def post_params
p = params.require(:post)
if current_user.is_admin? # or however you check if the user is authorized
p.permit(:title, :body, :state_event)
else
p.permit(:title, :body)
end
end
Just using f.submit "approve" just changes the submit key in the params hash.

Answer 2

First of all: both your buttons approve and decline will trigger the same behaviour: they will just send your form build with form_for #posts.
I guess when you press one of those you will send POST message to your application to the post_path(#post).
My advice for you is first of all split this buttons behaviour. Try to add value to your buttons like this:
<%= f.button :submit , name: "subaction",value: "approve"%>
And in your action you should be see params[:subaction] == "approve".