I have a very straight-forward task to fulfil --- just to be able to write comments under posts and if the comments fail validation display error messages on the page.
My comment model uses a gem called Acts_as_commentable_with_threading, which creates a comment model after I installed.
On my post page, the logic goes like this:
Posts#show => display post and a form to enter comments => after the comment is entered, redisplay the Post#show page which has the new comment if it passes validation, otherwise display the error messages above the form.
However with my current code I can't display error messages if the comment validation fails. I think it is because when I redisplay the page it builds a new comment so the old one was erased. But I don't know how to make it work.
My codes are like this:
Comment.rb:
class Comment < ActiveRecord::Base
include Humanizer
require_human_on :create
acts_as_nested_set :scope => [:commentable_id, :commentable_type]
validates :body, :presence => true
validates :first_name, :presence => true
validates :last_name, :presence => true
# NOTE: install the acts_as_votable plugin if you
# want user to vote on the quality of comments.
#acts_as_votable
belongs_to :commentable, :polymorphic => true
# NOTE: Comments belong to a user
belongs_to :user
# Helper class method that allows you to build a comment
# by passing a commentable object, a user (could be nil), and comment text
# example in readme
def self.build_from(obj, user_id, comment, first_name, last_name)
new \
:commentable => obj,
:body => comment,
:user_id => user_id,
:first_name => first_name,
:last_name => last_name
end
end
PostController.rb:
class PostsController < ApplicationController
before_action :authenticate_user!, except: [:index, :show]
def show
#post = Post.friendly.find(params[:id])
#new_comment = Comment.build_from(#post, nil, "", "", "")
end
end
CommentsController:
class CommentsController < ApplicationController
def create
#comment = build_comment(comment_params)
respond_to do |format|
if #comment.save
make_child_comment
format.html
format.json { redirect_to(:back, :notice => 'Comment was successfully added.')}
else
format.html
format.json { redirect_to(:back, :flash => {:error => #comment.errors}) }
end
end
end
private
def comment_params
params.require(:comment).permit(:user, :first_name, :last_name, :body, :commentable_id, :commentable_type, :comment_id,
:humanizer_answer, :humanizer_question_id)
end
def commentable_type
comment_params[:commentable_type]
end
def commentable_id
comment_params[:commentable_id]
end
def comment_id
comment_params[:comment_id]
end
def body
comment_params[:body]
end
def make_child_comment
return "" if comment_id.blank?
parent_comment = Comment.find comment_id
#comment.move_to_child_of(parent_comment)
end
def build_comment(comment_params)
if current_user.nil?
user_id = nil
first_name = comment_params[:first_name]
last_name = comment_params[:last_name]
else
user_id = current_user.id
first_name = current_user.first_name
last_name = current_user.last_name
end
commentable = commentable_type.constantize.find(commentable_id)
Comment.build_from(commentable, user_id, comment_params[:body],
first_name, last_name)
end
end
comments/form: (this is on the Posts#show page)
<%= form_for #new_comment do |f| %>
<% if #new_comment.errors.any? %>
<div id="errors">
<h2><%= pluralize(#new_comment.errors.count, "error") %> encountered, please check your input.</h2>
<ul>
<% #new_comment.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
<% end %>
I would instead use nested routes to create a more restful and less tangled setup:
concerns :commentable do
resources :comments, only: [:create]
end
resources :posts, concerns: :commentable
This will give you a route POST /posts/1/comments to create a comment.
In your controller the first thing you want to do is figure out what the parent of the comment is:
class CommentsController < ApplicationController
before_action :set_commentable
private
def set_commentable
if params[:post_id]
#commentable = Post.find(params[:post_id])
end
end
end
This means that we no longer need to pass the commentable as form parameters. Its also eliminates this unsafe construct:
commentable = commentable_type.constantize.find(commentable_id)
Where a malicous user could potentially pass any class name as commentable_type and you would let them find it in the DB... Never trust user input to the point where you use it to execute any kind of code!
With that we can start building our create action:
class CommentsController < ApplicationController
before_action :set_commentable
def create
#comment = #commentable.comments.new(comment_params) do |comment|
if current_user
comment.user = current_user
comment.first_name = current_user.first_name
comment.last_name = current_user.last_name
end
end
if #comment.save
respond_to do |format|
format.json { head :created, location: #comment }
format.html { redirect_to #commentable, success: 'Comment created' }
end
else
respond_to do |format|
format.html { render :new }
format.json { render json: #comment.errors, status: 422 }
end
end
end
private
# ...
def comment_params
params.require(:comment).permit(:first_name, :last_name, :body, :humanizer_answer, :humanizer_question_id)
end
end
In Rails when the user submits a form you do not redirect the user back to the form - instead you re-render the form and send it as a response.
While you could have your CommentsController render the show view of whatever the commentable is it will be quite brittle and may not even provide a good user experience since the user will see the top of the post they where commenting. Instead we would render app/views/comments/new.html.erb which should just contain the form.
Also pay attention to how we are responding. You should generally avoid using redirect_to :back since it relies on the client sending the HTTP_REFERRER header with the request. Many clients do not send this!
Instead use redirect_to #commentable or whatever resource you are creating.
In your original code you have totally mixed up JSON and HTML responses.
When responding with JSON you do not redirect or send flash messages.
If a JSON POST request is successful you would either:
Respond with HTTP 201 - CREATED and a location header which contains the url to the newly created resource. This is preferred when using SPA's like Ember or Angular.
Respond with HTTP 200 - OK and the resource as JSON in the response body. This is often done in legacy API's.
If it fails do to validations you should respond with 422 - Unprocessable Entity - usually the errors are rendered as JSON in the response body as well.
Added.
You can scrap your Comment.build_from method as well which does you no good at all and is very idiosyncratic Ruby.
class PostsController < ApplicationController
before_action :authenticate_user!, except: [:index, :show]
def show
#post = Post.friendly.find(params[:id])
#new_comment = #post.comments.new
end
end
Don't use line contiuation (\) syntax like that - use parens.
Don't:
new \
:commentable => obj,
:body => comment,
:user_id => user_id,
:first_name => first_name,
:last_name => last_name
Do:
new(
foo: a,
bar: b
)
Added 2
When using form_for with nested resources you pass it like this:
<%= form_for([commentable, comment]) do |f| %>
<% end %>
This will create the correct url for the action attribute and bind the form to the comment object. This uses locals to make it resuable so you would render the partial like so:
I'm assuming your form_for submits a POST request which triggers the HTML format in CommentsController#create:
def create
#comment = build_comment(comment_params)
respond_to do |format|
if #comment.save
make_child_comment
format.html
format.json { redirect_to(:back, :notice => 'Comment was successfully added.')}
else
format.html
format.json { redirect_to(:back, :flash => {:error => #comment.errors}) }
end
end
end
So, if #comment.save fails, and this is an HTML request, the #create method renders create.html. I think you want to render Posts#show instead.
Keep in mind that if validations fail on an object (Either by calling save/create, or validate/valid?), the #comment object will be populated with errors. In other words calling #comment.errors returns the relevant errors if validation fails. This is how your form is able to display the errors in #new_comment.errors.
For consistency, you'll need to rename #new_comment as #comment in the posts#show action, otherwise you'll get a NoMethodError on Nil::NilClass.
TL;DR: You're not rendering your form again with your failed #comment object if creation of that comment fails. Rename to #comment in posts, and render controller: :posts, action: :show if #comment.save fails from CommentsController#create
I have figured out the answer myself with the help of others here.
The reason is that I messed up with the JSON format and html format (typical noobie error)
To be able to display the errors using the code I need to change two places ( and change #comment to #new_comment as per #Anthony's advice).
1.
routes.rb:
resources :comments, defaults: { format: 'html' } # I set it as 'json' before
2.
CommentsController.rb:
def create
#new_comment = build_comment(comment_params)
respond_to do |format|
if #new_comment.save
make_child_comment
format.html { redirect_to(:back, :notice => 'Comment was successfully added.') }
else
commentable = commentable_type.constantize.find(commentable_id)
format.html { render template: 'posts/show', locals: {:#post => commentable} }
format.json { render json: #new_comment.errors }
end
end
end
I am trying to use the acts_as_taggable_on gem. Everything works in console, I can asoicate tags with a model instance, render the tag_list and link to a results page based on the tag chosen. My issue is that my tags entered into the create form do not save in the db. I have already checked strong_params:
params.require(:contest).permit(:name, :description, :user_id, :show_name, :tag_list => [],...
I had the same problem in a Rails 4.2, ruby 2.2, and acts-as-taggable-on 3.4 app. I changed the params in the controller to update the model. Originally, I had
def update
#post = Post.find(params[:id])
if #post.update(params[:post].permit(:title, :body, :tag_list => []))
redirect_to #post
else
render 'edit'
end
end
I changed the params :tag_list => [] to just :tag_list. It works. My code now looks like the following:
def update
#post = Post.find(params[:id])
if #post.update(params[:post].permit(:title, :body, :tag_list))
redirect_to #post
else
render 'edit'
end
end
def tagged
if params[:tag].present?
#post = Post.tagged_with(params[:tag])
else
#posts = Post.postall
end
end
private
def post_params
params.require(:post).permit(:title, :body, :image, :image2, :tag_list => [])
end
Hope this helps.
I want to create an instance of "article" and the browser gives me an error
param is missing or the value is empty: article
Here my article controller
class ArticlesController < ApplicationController
def index
#article = Article.all
end
def new
#article = Article.new
end
def create
#article = Article.new(article_params)
if #article.save
redirect_to #article
else
render 'new'
end
end
def show
#article = Article.find(params[:id])
end
private
def article_params
params.require(:article).permit(:title, :body)
end
end
how fix?
This error indicates that the article parameter is missing or empty in the new form. Go into the project/views/new.html.erb and make sure that you are actually passing :article to the url: articles_path.
<%= form_for :*article*, url: articles_path do |f| %>
I had a typo in article (accidentally had typed articles) which produced exactly the same error.
This is the method that raises the error.
def article_params
params.require(:article).permit(:title, :body)
end
It means you are not passing such parameter to the controller. Make sure you have a form in the new/edit view and you are properly passing its values.
Try this code, it worked for me:
def article_params
params.require(:articles).permit(:title, :body)
end
How can you pass an error messages coming from a model --> controller to view?
= form_tag :controller => "article", :action => "create" do
/ how to retrieve error messages here?
%p
= label_tag :article, "Article"
= text_field_tag :article
= submit_tag "Submit Article"
I have this model:
class Article < ActiveRecord::Base
attr_accessible :article
validates :article, :presence => true
end
In my controller:
def create
#article = Article.new(params[:article])
if ! #article.save
# how to set errors messages?
end
end
I'm using Rails 3.0.9
The errors messages are stored in your model. You can access through the errors methods, like you can see in http://api.rubyonrails.org/classes/ActiveModel/Errors.html.
An easy way to expose the error message is including the follow line in your view:
%span= #article.errors[:article].first
But, I belive you have to change your controller to be like that:
def new
#article = Artile.new
end
def create
#article = Artile.new params[:article]
if !#article.save
render :action => :new
end
end
In the new action you don't need to try save the article, because the creation action already do that job. The new action exists, (basically) to call the new view and to provide support for validations messages.
The newmethod shouldn't save anything. create method should.
def create
#article = Article.new(params[:article])
if ! #article.save
redirect_to root_path, :error => "ops! something went wrong.."
end
end
I have a Post that has_many :comments and a Comment that belongs_to :post.
On /posts/:id (the post show method) I render a form where users can leave comments.
It all works, validations, tests and posting is just fine. Only thing missing is how to re-render the POSTed data on validation errors.
The (simplified) code for this is:
#app/controllers/posts_controller.rb
class PostsController < ApplicationController
def index
#posts = Post.all_published(params[:page])
#title = "Blog"
end
def show
#post = Post.where({:published => true}).find(params[:id])
#comment = Comment.new(:post => #post)
#title = #post.title
end
end
#app/controllers/comments_controller.rb
class CommentsController < ApplicationController
def create
#comment = Comment.new(params[:comment])
puts #comment
if #comment.save
flash[:notice] = 'Comment was successfully created.'
redirect_to(#comment.post)
else
flash[:notice] = "Error creating comment: #{#comment.errors}"
redirect_to(#comment.post)
end
end
end
#app/views/posts/show.haml
.html renders Post contents.
- form_for #comment do |f|
= f.hidden_field :post_id
= f.text_area :body
= f.text_field :name
.some more fields.
I expect the solution to be either in some magical declaration in the comments_controller.rb, part
else
flash[:notice] = "Error creating comment: #{#comment.errors}"
redirect_to(#comment.post)
end
Or in the PostsController.show where I prepare the #comment. Should I set that #comment conditional and fill it with some magic variable on errors?
Or did I make some entirely different mistake?
If you redirect, that data is usually lost, thats why in most cases in create create actions you would have noticed that in the false scenario, render not redirect_to.
So instead you could just try,
flash[:notice] = ""Error creating comment: #{#comment.errors}"
render :template => "posts/show"
#post = #comment.post
# you may need to pre-populate the instance variables used inside PostsController#show