Undefined method `update 'for nil: NilClass post scaffold
I am trying to update the post and since I added the Redcarpet gem I get an error when I try to update the post.
Here is the error: undefined method 'update' for nil:NilClass
Here is my message controller:
class PostsController < ApplicationController
before_action :set_post, only: [:show, :edit, :update, :destroy]
# GET /posts
# GET /posts.json
def index
@posts = Post.all
end
# GET /posts/1
# GET /posts/1.json
def show
@post = Post.find_by_urlid(params[:urlid])
end
# GET /posts/new
def new
@post = Post.new
end
# GET /posts/1/edit
def edite
end
# POST /posts
# POST /posts.json
def create
@post = Post.new(post_params)
@post.urlid = SecureRandom.urlsafe_base64
respond_to do |format|
if @post.save
format.html { redirect_to @post, notice: 'Your Post was successfully created!' }
format.json { render :show, status: :created, location: @post }
else
format.html { render :new }
format.json { render json: @post.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /posts/1
# PATCH/PUT /posts/1.json
def update
respond_to do |format|
if @post.update(post_params)
format.html { redirect_to @post, notice: 'Your Post was successfully updated!' }
format.json { render :show, status: :ok, location: @post }
else
format.html { render :edit }
format.json { render json: @post.errors, status: :unprocessable_entity }
end
end
end
# DELETE /posts/1
# DELETE /posts/1.json
def destroy
@post.destroy
respond_to do |format|
format.html { redirect_to posts_url, notice: 'You have successfully deleted the Post!' }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_post
@post = Post.find_by_urlid(params[:urlid])
end
# Never trust parameters from the scary internet, only allow the white list through.
def post_params
params.require(:post).permit(:urlid, :author, :title, :body, :likes, :dislikes, :tags)
end
end
I am looking at other posts and their answers are not working. Any ideas?
Edit:
Server log:
Started PATCH "/posts/sfqm5y99cbomqh4nmuxq5w" for 127.0.0.1 at 2014-10-31 13:05:07 -0700
Processing by PostsController#update as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"FRRgB2pI6GAQa6YL8KLZrUShshjjGd7+IXrLv1hTi5E=", "post"=>{"author"=>"Un3qual", "title"=>"First post", "body"=>" on new *dev* system **:D**", "likes"=>"9999", "dislikes"=>"0", "tags"=>""}, "commit"=>"Update Post", "urlid"=>"sfqm5y99cbomqh4nmuxq5w"}
Post Load (0.1ms) SELECT "posts".* FROM "posts" WHERE "posts"."urlid" = 'sfqm5y99cbomqh4nmuxq5w' LIMIT 1
Completed 500 Internal Server Error in 1ms
NoMethodError (undefined method `update' for nil:NilClass):
app/controllers/posts_controller.rb:46:in `block in update'
app/controllers/posts_controller.rb:45:in `update'
Rendered /Library/Ruby/Gems/2.0.0/gems/actionpack-4.1.4/lib/action_dispatch/middleware/templates/rescues/_source.erb (0.4ms)
Rendered /Library/Ruby/Gems/2.0.0/gems/actionpack-4.1.4/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb (0.6ms)
Rendered /Library/Ruby/Gems/2.0.0/gems/actionpack-4.1.4/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb (0.6ms)
Rendered /Library/Ruby/Gems/2.0.0/gems/actionpack-4.1.4/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout (8.9ms)
Started PATCH "/posts/sfqm5y99cbomqh4nmuxq5w" for 127.0.0.1 at 2014-10-31 15:42:18 -0700
Processing by PostsController#update as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"FRRgB2pI6GAQa6YL8KLZrUShshjjGd7+IXrLv1hTi5E=", "post"=>{"author"=>"Un3qual", "title"=>"First post", "body"=>" on new *dev* system **:D**", "likes"=>"9999", "dislikes"=>"0", "tags"=>""}, "commit"=>"Update Post", "urlid"=>"sfqm5y99cbomqh4nmuxq5w"}
Post Load (0.3ms) SELECT "posts".* FROM "posts" WHERE "posts"."urlid" = 'sfqm5y99cbomqh4nmuxq5w' LIMIT 1
Completed 500 Internal Server Error in 4ms
NoMethodError (undefined method `update' for nil:NilClass):
app/controllers/posts_controller.rb:46:in `block in update'
app/controllers/posts_controller.rb:45:in `update'
Rendered /Library/Ruby/Gems/2.0.0/gems/actionpack-4.1.4/lib/action_dispatch/middleware/templates/rescues/_source.erb (0.4ms)
Rendered /Library/Ruby/Gems/2.0.0/gems/actionpack-4.1.4/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb (0.6ms)
Rendered /Library/Ruby/Gems/2.0.0/gems/actionpack-4.1.4/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb (0.6ms)
Rendered /Library/Ruby/Gems/2.0.0/gems/actionpack-4.1.4/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout (10.2ms)
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"Post.find_by_urlid (params [: urlid])" code deprecated method find_by_. Rails 4 deprecated the "find_by_" methods. [Link]: http://edgeguides.rubyonrails.org/4_0_release_notes.html
Try using: Post.find_by (urlid: params [: urlid]). There is a typo in the "edite" method.
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Based on the comments on your question, this is because there is no entry with that urlid.
You should change the callback filter (before_action) as follows.
def set_post
@post = Post.find_by(urlid: params[:urlid])
redirect_to posts_path, flash: {error: "The post does not exists"} if @post.nil?
end
This will redirect to the error message index (you must have a div for errors flashing in your layout or your templates in order for it to appear).
If exists @post
, then it will work fine with the action.
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If you are not using any preloader that instantiates the variable @post
then this is a problem. For an action, update
you must:
def update
@post = Post.find params[:id]
respond_to do |format|
if @post.update(post_params)
format.html { redirect_to @post, notice: 'Your Post was successfully updated!' }
format.json { render :show, status: :ok, location: @post }
else
format.html { render :edit }
format.json { render json: @post.errors, status: :unprocessable_entity }
end
end
end
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