Rails newbie here, trying to get a new controller working.
When I try to show ann existing instance, I get an undefined method error on a helper method.
Code follows.
Any idea why getRecipes would be undefined?!
Controller:
def show
id = params[:id]
recipe_ids = ConcreteMenu.getRecipes(id)
respond_to do |format|
format.html
end
end
Model
require 'json/objects'
class ConcreteMenu < ActiveRecord::Base
has_many :menu_recipes
has_many :recipes, :through => :menu_recipes
belongs_to :menu
def self.getRecipes(id)
recipes = MenuRecipe.find(:all, :conditions => {:concrete_menu_id => id}, :select => 'id')
end
end
It would help if you pasted the error text, because your explanation leaves a lot of possibilities for what could be wrong. BUT, there is an easier way to get what you want. The value of defining "has_many" relationships is that instead of calling a class method and passing the id of a concrete menu to get its associated recipes, you can just do this:
def show
#concrete_menu = ConcreteMenu.find(params[:id], :include => :recipes)
end
Now you'll have the menu object, and #concrete_menu.recipes returns an array of recipes you need. This feature is already built in, no need to reinvent the wheel.
Also, I noticed you were attempting to collect id's in the controller instead of the objects themselves. This suggests that you're going back and actually retrieving the records in the view itself. This is less efficient, and more difficult to troubleshoot when things go wrong. My example above will do what you need in a better (and more rails-accepted) way.
As you have it defined there, it should be available. Is there a chance you have something else called ConcreteMenu defined, but in a different context?
To be sure you're calling the correct one, where there may be ambiguity, you can refer to the top-level class:
recipe_ids = ::ConcreteMenu.getRecipes(id)
The other way to check that the method is defined correctly via script/console:
ConcreteMenu.methods.grep(/getRecipe/)
# => ["getRecipes"]
This is presuming, of course, you're having trouble with the getRecipes method. There's a possibility you're mistaking how controller variables are passed to the view:
def show
#id = params[:id]
#recipe_ids = ConcreteMenu.getRecipes(#id)
respond_to do |format|
format.html
end
end
Any instance variables defined (#...) will be available within the context of the view, but any local variables will no longer be defined as they are out of scope.
Related
Scenario: I have a has_many association (Post has many Authors), and I have a nested Post form to accept attributes for Authors.
What I found is that when I call post.update_attributes(params[:post]) where params[:post] is a hash with post and all author attributes to add, there doesn't seem to be a way to ask Rails to only create Authors if certain criteria is met, e.g. the username for the Author already exists. What Rails would do is just failing and rollback update_attributes routine if username has uniqueness validation in the model. If not, then Rails would add a new record Author if one that does not have an id is in the hash.
Now my code for the update action in the Post controller becomes this:
def update
#post = Post.find(params[:id])
# custom code to work around by inspecting the author attributes
# and pre-inserting the association of existing authors into the testrun's author
# collection
params[:post][:authors_attributes].values.each do |author_attribute|
if author_attribute[:id].nil? and author_attribute[:username].present?
existing_author = Author.find_by_username(author_attribute[:username])
if existing_author.present?
author_attribute[:id] = existing_author.id
#testrun.authors << existing_author
end
end
end
if #post.update_attributes(params[:post])
flash[:success] = 'great!'
else
flash[:error] = 'Urgg!'
end
redirect_to ...
end
Are there better ways to handle this that I missed?
EDIT: Thanks for #Robd'Apice who lead me to look into overriding the default authors_attributes= function that accepts_nested_attributes_for inserts into the model on my behalf, I was able to come up with something that is better:
def authors_attributes=(authors_attributes)
authors_attributes.values.each do |author_attributes|
if author_attributes[:id].nil? and author_attributes[:username].present?
author = Radar.find_by_username(radar_attributes[:username])
if author.present?
author_attributes[:id] = author.id
self.authors << author
end
end
end
assign_nested_attributes_for_collection_association(:authors, authors_attributes, mass_assignment_options)
end
But I'm not completely satisfied with it, for one, I'm still mucking the attribute hashes from the caller directly which requires understanding of how the logic works for these hashes (:id set or not set, for instance), and two, I'm calling a function that is not trivial to fit here. It would be nice if there are ways to tell 'accepts_nested_attributes_for' to only create new record when certain condition is not met. The one-to-one association has a :update_only flag that does something similar but this is lacking for one-to-many relationship.
Are there better solutions out there?
This kind of logic probably belongs in your model, not your controller. I'd consider re-writing the author_attributes= method that is created by default for your association.
def authors_attributes=(authors_attributes)
authors_attributes.values.each do |author_attributes|
author_to_update = Author.find_by_id(author_attributes[:id]) || Author.find_by_username(author_attributes[:username]) || self.authors.build
author_to_update.update_attributes(author_attributes)
end
end
I haven't tested that code, but I think that should work.
EDIT: To retain the other functionality of accepts_nested_Attributes_for, you could use super:
def authors_attributes=(authors_attributes)
authors_attributes.each do |key, author_attributes|
authors_attributes[key][:id] = Author.find_by_username(author_attributes[:username]).id if author_attributes[:username] && !author_attributes[:username].present?
end
super(authors_attributes)
end
If that implementation with super doesn't work, you probably have two options: continue with the 'processing' of the attributes hash in the controller (but turn it into a private method of your controller to clean it up a bit), or continue with my first solution by adding in the functionality you've lost from :destroy => true and reject_if with your own code (which wouldn't be too hard to do). I'd probably go with the first option.
I'd suggest using a form object instead of trying to get accepts_nested_attributes to work. I find that form object are often much cleaner and much more flexible. Check out this railscast
I am building a Ruby on Rails app with the usual assortment of models, views and controllers.
The 'create' action in one of my controllers is supposed to create an instance of two different models. Here's my code:
def create
#league = League.new(params[:league])
#user = #league.users.build(params[:user])
... .save conditions appended ...
end
So, when you call 'create' through the LeaguesController via a POST request to /leagues, you get a new instance of League and a new instance of User. I also want the new User instance to inherit the ID of the new League instance, so it can be used as the foreign key to link the instances together. This is accomplished with:
def create
#league = League.new(params[:league])
#user = #league.users.build(params[:user])
#league_id = #league.id
#user.update_attribute('league_id', #league_id)
... .save conditions appended ...
end
The User model already belongs_to the League model, which has_many users.
The above code works just fine and dandy, verified via manual testing. However, I can't for the life of me figure out how to automate these tests with Rspec. I'm trying to be a good boy and use test-driven design, but this has me stumped.
The issue is that I can't figure out how to access the attributes of the newly created instances of League and User in my tests. I am attempting to do so using the following code:
describe LeaguesController do
describe 'new league and user' do
it 'should create a new user with a league_id equal to the new leagues id'
#league_attr = { :name => "myleague", :confirmation_code => "mycode", :id => 5}
#user_attr = { :username => "myname", :password => "mypass"}
post :create, :user => #user_attr, :league => #league_attr
assigns(:league_id).should eql(5)
end
end
end
But the test returns nil for the value of :league_id
I'm new to both programming in general and Rspec in particular, so I really appreciate any help someone might offer!
You cannot assign :id with new. Try this:
def create
#league = League.new(params[:league])
#league.id = params[:league][:id] if params[:league][:id]
#user = #league.users.build(params[:user])
#league_id = #league.id
#user.update_attribute('league_id', #league_id)
... .save conditions appended ...
end
That said, I wonder how come it works in the browser.
Also, you better off using FactoryGirl or Fixtures to assign data to models when testing.
Have you tried pry?
Whenever I discover something like this I find it very handy to be able to insert a brakepoint via Pry (or Ruby-Debug) so I can inspect the variables and their behavior.
I suspect putting in a binding.pry between #league_id = #league.id and #user.update_attribute('league_id', #league_id) may very well shed some light on the issue.
Also note that user will automatically inherit the #league_id when you persist it via the #league.save call. (that's the idea behind #league.users.build(..) - it will set the required relationships correctly upon persistance.
I am aware of the basic dirty indicator methods for rails, which work if direct attributes of an object have changed, I'm wondering how to determine if my children were updated..
I have a form for a collection of files, we'll call it a folder. A folder accepts_nested_attributes_for :files. What I need to determine (within the controller action) is whether or not the files that are within the params hash are different from the ones that are in the db.. So, did the user delete one of the files, did they add a new file, or both (delete one file, and add another)
I need to determine this because I need to redirect the user to a different action if they deleted a file, versus adding a new file, versus just updated attributes of the folder.
def update
#folder = Folder.find(params[:id])
#folder.attributes = params[:folder]
add_new_file = false
delete_file = false
#folder.files.each do |file|
add_new_file = true if file.new_record?
delete_file = true if file.marked_for_destruction?
end
both = add_new_file && delete_file
if both
redirect_to "both_action"
elsif add_new_file
redirect_to "add_new_file_action"
elsif delete_file
redirect_to "delete_file_action"
else
redirect_to "folder_not_changed_action"
end
end
Sometimes you want to know that folder is changed without determining how. In that case you can use autosave mode in your association:
class Folder < ActiveRecord::Base
has_many :files, :autosave => true
accepts_nested_attributes_for :files
attr_accessible :files_attributes
end
Then in controller you can use #folder.changed_for_autosave? which returns whether or not this record has been changed in any way (new_record?, marked_for_destruction?, changed?), including whether any of its nested autosave associations are likewise changed.
Updated.
You can move model specific logic from controller to a method in folder model, e.q. #folder.how_changed?, which can return one of :add_new_file, :delete_file and etc. symbols (I agree with you that it's a better practice, I'd just tried to keep things simple). Then in controller you can keep logic pretty simple.
case #folder.how_changed?
when :both
redirect_to "both_action"
when :add_new_file
redirect_to "add_new_file_action"
when :delete_file
redirect_to "delete_file_action"
else
redirect_to "folder_not_changed_action"
end
This solution uses 2 methods: new_record? and marked_for_destruction? on each child model, because Rails in-box method changed_for_autosave? can tell only that children were changed without how. This is just the way how to use this indicators to achieve your goal.
I have been trying to get my head around render_to but I haven't had much success.
Essentially I have controller methods:
def first
#I want to get the value of VAR1 here
end
def second
VAR1 = ["Hello", "Goodbye"]
render_to ??
end
What I can't figure out is how to accomplish that. Originally I just wanted to render the first.html.erb file but that didn't seem to work either.
Thanks
Edit: I appreciate the answers I have received, however all of them tend to avoid using the render method or redirect_to. Is it basically the case then that a you cannot pass variables from controller to controller? I have to think that there is some way but I can't seem to find it.
It is not a good idea to assign the object to a constant. True this is in a global space, but it is global for everyone so any other user going to this request will get this object. There are a few solutions to this.
I am assuming you have a multi-step form you are going through. In that case you can pass the set attributes as hidden fields.
<%= f.hidden_field :name %>
If there are a lot of fields this can be tedious so you may want to loop through the params[...] hash or column_names method to determine which attributes to pass.
Alternatively you can store attributes in the session.
def first
#item = Item.new(params[:item])
session[:item_attributes] = #item.attributes
end
def second
#item = Item.new(session[:item_attributes])
#item.attributes = params[:item]
end
Thirdly, as Paul Keeble mentioned you can save the model to the database but mark it as incomplete. You may want to use a state machine for this.
Finally, you may want to take a look at the Acts As Wizard plugin.
I usually don't have my controllers calling each other's actions. If you have an identifier that starts with a capital letter, in Ruby that is a constant. If you want to an instance level variable, have it start with #.
#var1 = ["Hello", "Goodbye"]
Can you explain what your goal is?
Have you considered using the flash hash? A lot of people use it solely for error messages and the like, it's explicitly for the sort of transient data passing you might be interested in.
Basically, the flash method returns a hash. Any value you assign to a key in the hash will be available to the next action, but then it's gone. So:
def first
flash[:var] = ["hello", "goodbye"]
redirect_to :action => :second
end
def second
#hello = flash[:var].first
end
way 1
Global variable
(fail during concurrent requests)
way 2
class variable
(fail during concurrent requests)
way 3
Stash the object on the server between requests. The typical way is to save it in the session, since it automatically serializes/deserializes the object for you.
Serialize the object and include it in the form somewhere, and
deserialize it from the parameters in the next request. so you can store attributes in the session.
def first
#item = Item.new(params[:item])
session[:item_attributes] = #item.attributes
end
def second
#item = Item.new(session[:item_attributes])
#item.attributes = params[:item]
end
way 4
The flash provides a way to pass temporary objects between actions. Anything you place in the flash will be exposed to the very next action and then cleared out.
def new
#test_suite_run = TestSuiteRun.new
#tests = Test.find(:all, :conditions => { :test_suite_id => params[:number] })
flash[:someval] = params[:number]
end
def create
#test_suite_run = TestSuiteRun.new(params[:test_suite_run])
#tests = Test.find(:all, :conditions => { :test_suite_id => flash[:someval] })
end
way 5
you can use rails cache.
Rails.cache.write("list",[1,2,3])
Rails.cache.read("list")
But what happens when different sessions have different values?
Unless you ensure the uniqueness of the list name across the session this solution will fail during concurrent requests
way 6
In one action store the value in db table based on the session id and other action can retrieve it from db based on session id.
way 7
class BarsController < UsersController
before_filter :init_foo_list
def method1
render :method2
end
def method2
#foo_list.each do | item|
# do something
end
end
def init_foo_list
#foo_list ||= ['Money', 'Animals', 'Ummagumma']
end
end
way 8
From action sent to view and again from view sent to other actions in controller.
How do I get the to_param method to deliver keyword slugs all the time? I have trouble getting it to work with this route:
map.pike '/auction/:auction_id/item/:id', :controller => 'items', :action => 'show'
Earlier the overridden to_param was working for
'items/1-cashmere-scarf'
but fails with 'auction/123/item/1'
Update:
I'm not sure if the syntax is correct[(edit: it's correct: it works :-)], or even efficient.... but using haml, I found that the following code works to generate the desired link ('auction/:auction_id/item/:id')
- for auction in #auctions.sort{|a, b| a.scheduled_start <=> b.scheduled_start}
-for item in #items
- unless auction.current_auction
... pike_path(auction.auction_id, item)
I'm not sure whether I understand your question. (it's 3:41 AM here)
From what I see, you directly access auction_id method, instead of using pike_path(auction, item) that'd use #to_param.
Also, it might fail for auction/123/item/1 because you haven't changed your controller.
I think it'd be helpful to describe how to get working slugs.
Broadly speaking, if you override #to_param, IDs no longer works. It means, that if you go with slugs, every time polymorpic URL is generated (eg, link_to object, object), it passes to_param's value. It is worth noting that you must change your controller as well.
Personally I think that the best way to generate slugs easily is to use techno-weenie's permalink_fu, adding has_permalink to your model, and then, override to_param. For example
class Auction < ActiveRecord::Base
has_permalink :title, :slug
end
assuming that you have slug, a string field, and want to slugize your title.
You also need to adjust your controller:
class AuctionsController < ApplicationController
def show
#auction = Auction.find_by_slug(params[:id]) || raise(ActiveRecord::RecordNotFound)
respond_to do |format|
format.html # show.html.erb
end
end
Then, you can generate routes, in the views, this way:
link_to #action, #action
By the way, you should NOT sort your actions in the view. The best way is to use named_scope.