I have a form for creating a ticket, which needs an id of a project. This works but not when it comes to validation. If validation won't pass 'render :new' is executed and the project_id doesn't come with it.
I have tried 'redirect_to new_ticket_path(:project_id => params[:ticket][:project_id]) which renders the form again, but the error messages won't show up so it seems that I need to use 'render :new'.
How can I pass the project_id back to the form or reach project_id from the form without passing it?
def new
#ticket = Ticket.new
#id = params[:project_id]
#project = Project.find(#id)
end
def create
#ticket = Ticket.new(params[:ticket].merge(:user_id => current_user.id))
if #ticket.save
redirect_to #ticket
else
render :new <--- will render without the project_id
end
end
That will render just the view for 'new', but will not run the controller action. You'd need to set up your variables for the 'new' view in your 'create' action.
From http://guides.rubyonrails.org/layouts_and_rendering.html#using-render
Using render with :action is a frequent source of confusion for Rails
newcomers. The specified action is used to determine which view to
render, but Rails does not run any of the code for that action in the
controller. Any instance variables that you require in the view must
be set up in the current action before calling render.
The easiest way around this is to change 'new':
def new
#ticket = Ticket.new(:project_id => params[:project_id])
end
and change any references to #project in your 'new' form to #ticket.project. At that point, you shouldn't have to add anything to your 'create' action as long as your form includes a hidden field for the ticket's project id.
The easiest way to get this working (and I would do this anyway) is to nest the task resource under projects. That way you will always have project_id available in params.
# config/routes.rb
resources :projects do
resources :tasks
end
The urls will look like projects/123/tasks/new etc. Take a look at rake routes.
Write project id into a hidden field in your form and you will okay. And don't forget to initialize #id in your create action
def new
#ticket = Ticket.new
#id = params[:project_id]
#project = Project.find(#id)
end
def create
#ticket = Ticket.new(params[:ticket].merge(:user_id => current_user.id))
#id = params[:project_id] # but make sure it is under this key in params
if #ticket.save
redirect_to #ticket
else
render :new <--- will render without the project_id
end
end
and in the form add
<%= hidden_field :project_id, '', value: #id %>
Why don't you use:
flash[:alert] = #ticket.errors.inspect
redirect_to new_ticket_path(:project_id => params[:ticket][:project_id])
Related
Let's say I create a scaffold:
rails g scaffold Cat name:string age:integer
and I add a presence validation on the Cat model's age attribute:
validates :age, presence: true
When I attempt to create a cat via the form, and put in the cat's name but purposely leave out the cat's age the controller bounces me back to the form but that cat's name is still present in the name field!
How is this happening?
I would have thought the
#cat = Cat.new
would replace all of the invalid cat's attributes. Maybe if it were #cat ||= Cat.new I could understand that more.
Also, how can I make this behaviour happen in a more complex rails app? I have a simple forum where topics has_many replies. I create my new replies via a form in my topic show view:
topic#show:
#reply = Reply.new
topic/show.html.erb:
<%= form_for [#toplic, #reply] do |f| %>
<%= f.text_field :name placeholder: 'Create a new name...' %><br>
<%= f.text_area :description, placeholder: 'Create a new description...', rows: 5 %><br>
<%= f.submit 'Create Discussion' %>
<% end %>
While everything works perfectly, when I purposely leave out a reply's name, though I am redirected back to the form and an error flash shows, my form is completely empty. All of the attributes have vanished? Why is this?
The key to understanding how this works is to realize that in the case of a form failure, the controller action is not rerun, but rather the template is rendered using the existing state from the action.
In a typical Rails scaffold, your create action will look like this
def create
#cat = Cat.new(cat_params) # instance variable is initialized with the form values
if #cat.save
redirect_to #cat, notice: 'Success!'
else
# in the case of form failure, we will re-render the 'new' template
# this will NOT rerun the entire 'new' action, thus the #cat variable
# will still maintain the values from the form that we gave it above
render 'new'
# note the difference if we had instead done a redirect_to; this would
# cause the CatsController#new action to be re-run which would reinitialize
# the #cat variable according to the code within the 'new' action
# redirect_to new_cat_url
end
end
For your more complex example, you'll want to follow the same procedure, making sure you just re-render the form and don't redirect to another action (which will cause the state to be lost).
# TopicsController
def show
#topic = Topic.find(params[:id])
#reply = Reply.new
end
# RepliesController
def create
#reply = Reply.new(reply_params) # init the var with the form values
if #reply.save
redirect_to #topic, notice: 'Success!'
else
# this is the key - we need to re-render the template of the previous action
# in this case, it would be the TopicsController#show template
render 'topics/show'
# Remember - if we instead do a redirect_to #topic, then we will lose the form
# values which are currently set in the #reply variable.
end
end
In short, make sure you recognize when you are redirecting to a new action versus just re-rendering a template.
One important GOTCHA to be aware of when re-rendering a template is that you must make sure that all the instance variables which exist for the controller action are available when you render the template.
For example,
# TopicsController
def show
#topic = Topic.find(params[:id])
#reply = Reply.new
#foo = Foo.new
end
# RepliesController
before_action :set_topic
def create
#reply = Reply.new(reply_params)
if #reply.save
# ...
else
# we need to remember to set up a #foo variable here otherwise it will be undefined
# when used within the 'show' template
#foo = Foo.new
render 'topics/show'
end
protected
def set_topic
#topic = Topic.find(params[:topic_id])
end
OK, so, you go go /cat/new. Rails' route for this URL runs the method CatsController#new, which renders the new.html.erb template. You put in your data, then hit submit. The action for this form is to POST to /cats, which runs the CatsController#create method. This method does this following:
#cat = Cat.new(cat_params)
It then tries to save the Cat. If it succeeds, it redirects you to the Cat's URL. If not, it re-renders the new.html.erb template. That's where the name comes from — the CatsController#update method creates its Cat from the values you put into the original form.
For a typical scaffold create action:
# POST /products
# POST /products.json
def create
#product = Product.new(params[:product])
respond_to do |format|
if #product.save
format.html { redirect_to #product, notice: 'Product was successfully created.' }
format.json { render json: #product, status: :created, location: #product }
else
format.html { render action: "new" } #will re-submit
format.json { render json: #product.errors, status: :unprocessable_entity }
end
end
end
The magic happens in the render method! which will submit the previous POST request (won't go back to the new action while a redirect will do), this way the submited values are still there. (check this SO question for more details)
That's said, this behavior relies on following the convention, however sometimes you need to give it a hand specially with some inputs (e.g selects, checkboxes, radio) might require extra setup using selected or value options
When I initially call the new function all variables load up correctly. The params[:code] is a URL param defined in routes. However, when validation fails on create and new is rendered, the #m variable is not loaded (this causes a nomethoderror when an attribute of #m is called in the 'new' template). So, the :code parameter is not obtained after rendering new. However can the :code parameter be preserved after validation fails?
class AffiliatesController < ApplicationController
def new
#m = Merchant.find_by_code(params[:code])
#affiliate = Affiliate.new
end
def create
a = Affiliate.new(params[:affiliate])
if a.save
redirect_to 'http://' + params[:ref]
else
render 'new'
end
end
end
Another way to preserve params[:code], aside from using the session, is to add a hidden field in the form.
<%= form_for #affiliate do |f| %>
<%= hidden_field_tag :code, #m.code %>
Then change the create action to
def create
#affiliate = Affiliate.new(params[:affiliate])
if #affiliate.save
redirect_to 'http://' + params[:ref]
else
#m = Merchant.find_by_code(params[:code])
render :new
end
end
before you call render you should fill in all the variables that will be used by the view.
So in your case you need to instantiate #m = ... before you render 'new' from within the create as well.
If you need an extra parameter to accomplish this (the param[:code] in your case) I would not recomment you to configure routes and pass this information over the URI, it's complicated.
Use the session instead, it's a lot easier!
For example:
in index (or wherever you have the merchant code available) add session[:merchant_code] = the_code.
in new change #m = Merchant.find_by_code(session[:merchant_code])
Cheers,
In my Ruby on Rails application, each group has_many :expenses. I have nested my routes, so expenses are entered only as child entities of their parent groups. Here's an excerpt from routes.rb.
resources :groups do
resources :expenses
end
I cannot figure out how to render the 'new' action in the case of an expense not saving when it is submitted through /groups/:group_id/expenses/new. In my expenses_controller.rb, here is how the create action is defined:
def create
#expense = Expense.new(params[:expense])
#expense.group_id = params[:group_id]
if #expense.save
redirect_to group_expense_path(#expense.group.id, #expense.id)
else
render 'new'
end
end
Everything works fine if I satisty expense validation and #expense.save winds up working. However, when it fails and the code tries to render 'new' I get:
undefined method `expenses_path' for #<#<Class:0x007fd408b1fd58>:0x007fd408f21ca8>
So, I am assuming I have something about my nested routing wrong. How do I return the user to the new form but still display to him/her through the flash[] params the errors with the data they originally attempted to submit?
The problem is that #group is not initialized
So in your controller just do
#expense = Expense.new(params[:expense])
#group = Group.find(params[:group_id])
#expense.group_id = #group.id
Looks like you need to explicitly specify the url for form_for in your view.
Something like…
<%= form_for #expense, :url => group_expenses_path(#group.id) do |f| %>
...
<% end %>
In your <%= form_for %> you have used #group for url, because expenses belongs_to groups. But inside your create action in the controller you have not defined what is #group, so first you should define it as:
#expense = Expense.new(params[:expense])
#group = Group.find(params[:group_id])
#expense.group_id = #group.id
Also I would suggest to use respond_to in your controller:
respond_to do |format|
if #expense.save
format.html { redirect_to group_expense_path(#group.id, #expense.id), :notice => "Any msg you want" }
else
format.html { render :action => "new" }
end
end
All of these are in your create action inside the controller.
Also for different rendering methods look up: http://guides.rubyonrails.org/layouts_and_rendering.html
Hope this helps!
How do you use redirect_to when the Edit action is dependent on a parameter being passed?
I have two very simple actions edit and update. Once I click submit, following an update I'd like to redirect the user back to the edit action. How do I do this if the edit action requires a parameter?
def edit
#account = Account.find_by_user_id(#params['user_id'])
end
def update
account = Account.find(params[:account_user_id])
if account.update_attributes(params[:name])
redirect_to params[:user_id].merge!(:action => :edit)
else
render :text => 'Sorry there was an error updating.'
end
end
this code blows up
Try the following:
redirect_to edit_account_path( account.id, :user_id => params[:user_id])
I assume here you declared your routes as resources :accounts
So I'm using the excellent Ancestry gem But while the documentation seems very complete I don't understand how to pass the parameter of my element which I want to be the parent of my newly created element. Firstly, do I want to do it in the new or create action... allow me to explain. For example: (with some actions removed for brevity)
class PeopleController < ApplicationController
#...
def new
#person = Person.new
end
def create
#user = User.new(params[:user])
if #user.save
flash[:notice] = "Registration Successful."
redirect_to root_url
else
render :action => 'new'
end
end
end
So namely I don't know where to create the ancestry, the docs say:
...You can use the parent attribute to organise your records into a tree. If you have the id of the record you want to use as a parent and don’t want to fetch it, you can also use parent_id. Like any virtual model attributes, parent and parent_id can be set using parent= and parent_id= on a record or by including them in the hash passed to new, create, create!, update_attributes and update_attributes!. For example:
TreeNode.create! :name => 'Stinky', :parent => TreeNode.create!(:name => 'Squeeky')
I want to know what my controller show look like to allow me to set the parent of the #person when I create them.
So otherwise I'm stuck, I don't know what else to do here... but anyhow, I do know that this gem is similar to the more popular acts_as_tree, any help is super appreciated!
Updated
I think I almost have it but when I try this for my create action
def create
#parent = Recipe.find(params[:parent])
#recipe = Recipe.new(params[:recipe], :parent => #parent.id) do |recipe|
recipe.user_id = current_user.id
end
if #recipe.save
current_user.has_role!(:owner, #recipe)
redirect_to #recipe
else
render :action => 'new'
end
end
I get:
Couldn't find Recipe without an ID
Updated
My view has a link to the new action that looks like this <%= link_to "fork this recipe", {:controller => "recipes", :action => "new", :parent => #recipe} %>
That seems to look fine to me, also the url reads fine when you get to the form, recipes/new?parent=112, but I still get that error, there has to be a way for that parameter to be passed as the parent of the newly created object.
If it works like acts_as_tree then I'll assume that you can do something like this:
#parent.children.create(attributes)
Which will create a new child object with the parent set, regardless of what the attributes say.
According to the docs that you pasted you can do:
#...
#user = User.new(params[:user])
#user.parent_id = #parent_user.id
#user.save
#...
You can also include it in the params hash for the user -- your form submission would need to have params[:user][:parent_id]:
#user = User.create(params[:user])