I am using the cache-digests gem and following the instructions as per the Railscast, it creates and reads from a cache as you would expect, but the cache does not seem to be updating properly in relation to an associated record.
When moving a listing from one category to another, the category.live_entries count stays the same for the category I move it from, but goes up for the one I move it to.
So it sounds like I need a touch: all type method so it touches the one I am moving it from as well as the one it is moving to?
_category.html.erb
<% cache category do %>
<li>
<%= link_to category.name, category %>
<% if category.live_entries > 0 %>
(<%= category.live_entries %>)
<% end %>
- <%= category.desc %>
</li>
<% end %>
category.rb
class Category < ActiveRecord::Base
has_many :listings
def live_entries
listings.where(verified: true).count
end
end
listing.rb
class Listing < ActiveRecord::Base
belongs_to :category, touch: true
Any ideas on how to tackle this?
Guess I could create a before_update callback to touch the old category - but is there a better way?
Ok just adding this as an answer - but if anyone has a better solution please feel free to share.
I just added an after_update to touch the old category:
def touch_old_category(listing)
cat = listing.category_id_was
Category.find(cat).touch if cat
end
Related
In my rails app, I have two models, a ClientPage and a ContentSection, where ClientPage has_many :content_sections. I'm using the nested_form gem to both models to be edited with the same form. This works fine as long as the ClientPage has at least one ContentSection, but if there are no associated ClientSections, the using nested_form's link_to_add method throws the following NoMethodError:
undefined method `values_at' for nil:NilClass
The form is structured as follows:
<%= nested_form_for page, form_options do |f| %>
# ClientPage fields
# ClientSections
<%= f.link_to_add "Add new section", :content_sections %>
<% end %>
As long as there is at least one ClientSection associated with the page, this works fine. As soon as there isn't, the error is thrown. Removing the link_to_add also stops the error from being thrown. (There's actually a second nested model under ContentSection, and the same issue arises if there are no associated models.)
Not sure what I'm fairly obvious thing I'm missing, but any pointers or suggestions would be greatly appreciated.
Finally worked this out -- the error was due to the fact that I was using the gem in a slightly non-standard way. Within the form, instead of rendering all of the content sections the standard way:
<%= f.fields_for :content_sections do |section_form| %>
# section fields
<% end %>
I put it inside a loop, as I needed the index of each item (which is not stored within the model itself):
<% page.content_sections.each_with_index do |section, index| %>
<%= f.fields_for :content_sections, section do |section_form| %>
# section fields
<% end %>
<% end %>
The issue doing it this way is that the fields_for method does not get called if the association is empty, and as such the gem cannot build the blueprint for the object (which is used to add in the extra item when link_to_add is called).
The solution was to make sure fields_for got called even if the association was empty:
<% if page.content_sections.empty? %>
<%= f.fields_for :content_sections do |section_form| %>
# section fields
<% end %>
<% end %>
I have a model called Note. Each note belongs_to :call_reason. And call_reason has_many :notes.
What I want to do in a view is display a list of call_reasons and a total count of each next to it so we can see what the most popular call reasons are.
Here's what I have so far:
dashboard_controller:
def index
#notes = Note.all
end
dashboard view:
<% #notes.each do |n| %>
<%= n.call_reason.reason %>
<% end %>
This lists all notes' call_reasons.
I'm stumbling on how to list each call_reason once with a total count next to it. What I have now just lists all the call_reasons per note which is a mess. I think I could scope this out somehow or change the instance variable but I'm having a hard time getting it right.
Any thoughts?
Since you want to list call reasons, you should start with that:
def index
#call_reasons = CallReason.all
end
Then in your view you can do this:
<% #call_reasons.each do |call_reason| %>
<%= call_reason.reason %> <%= call_reason.notes.count %>
<% end %>
Note that this will perform a query for every call reason in your database. To prevent this you can use a counter cache. Check out the section on counter cache on Rails Guides too.
I am looking to get a better understanding of Active Model/Record relationships and how to call attributes dependent upon where the attributes are located (models) and where I am calling them. So for example I can access the attribute dish_name from within the recipe controller like so
def all_recipes
#recipes = Recipe.all
end
In the view
<% #recipes.each do |r| %>
<%= r.dish_name %>
<% end %>
Now say i want to access a recipe attribute from within my controller called worldrecipes and i have just written a method that returns all recipes with the same country. a country has many recipes as a relation
So my method is
def self.top_countries
joins(:recipes).
select('countries.*, count(*) AS recipes_count').
group('countries.id').
order('recipes_count DESC')
end
My controller
#worldrecipes = Country.where(:name => params[:name])
and view
<% #worldrecipes.each do |r| %>
<%= r.name %>
<% end %>
so accessing the country name attribute is easy as its in the country model and thats where my query results are being returned from (I think)...My question is how do i access the dish_name attribute from my recipe model to that links to the country name
Hope that makes sense, does anyone have a guide on how to work this out or some golden rules for this
Thank you
I think what you need is:
#country=Country.where(:name=>params[:name]).first
#worldrecipes=#country.recipes
And in the view:
<% #worldrecipes.each do |r| %>
<%= r.dish_name %>
<% end %>
This would print the dish names of the recipes of the country with name provided by params[:name]
EDIT:
Ok Let me clear this up for you :)
Your model relationship is setup such that each country has many recipes. i.e a country has many recipes.
So you have,
has_many :recipes
in country.rb and
belongs_to :country
in recipe.rb
Now when you want to access all the recipes belonging to a country, what you do is, you call country_record.recipes (country_record being the object of the country record you need).
And when you call,
Country.where(:name=>params[:name])
What you actually get is the active record object representing the COUNTRY itself and not the recipes of the country and that is why Italy was printed.
Hope this helped you.
For starters you want to make sure you have the association setup in your models:
country.rb
class Country < ActiveRecord::Base
has_many :recipes
end
recipe.rb
class Recipe < ActiveRecord::Base
belongs_to :country
end
If you haven't already done so, add a foreign_key attribute to your recipe model by running the following migration:
rails g migration add_country_id_to_recipe country_id:integer
Now that your associations are in place you can easily query for a countries respective recipes. In your controller:
#worldrecipes = Country.where(:name => params[:name])
Then in your view:
<% #worldrecipes.each do |c| %>
<% c.recipes.each do |r| %>
<%= r.dish_name %>
<% end %>
<% end %>
In regards to 'golden rules' I highly recommend you check out Association Basics. This is the go-to place for an overview of what you can do with associations.
What is the most straightforward way to check to make sure a creation of a new record includes the creation of a related record via has_and_belongs_to_many? For example, I have:
class Person < ActiveRecord::Base
has_and_belongs_to_many :groups
end
class Group < ActiveRecord::Base
has_and_belongs_to_many :people
end
I want a validation to fire on the creation of a new Person to make sure they belong to at least one group.
Also, how would I build this out in the controller? Right now I have:
def create
#person = current_user.people.new(params[:person])
end
I'd like params to include a group hash as well, to act as a sort of nested resource.
I've looked through the Rails documentation and I haven't been able to find anything on this particular case. If someone could explain this to me or point me in the right direction, I'd be very happy. Thanks!
If you want to give the user the option of creating one or more groups during the creation of a person, and then validate that those groups were created, please specify. Otherwise the remainder of this answer will be dedicated to creating a Person and validating that it is associated with at least one existing group.
If you're asking how to verify the existence of an Person-Group association on the groups_people join table, this could be done with weird sql queries and is inadvisable. Just trust that the well tested ActiveRecord works properly.
You can, however, validate the existence of one or more groups on a Person record before it is saved.
As long as you've migrated a join table called groups_people:
# db/migrate/xxxxxxxxxxxxxx_create_groups_people
class CreateGroupsPeople < ActiveRecord::Migration
def change
create_table :groups_people, :id => false do |t|
t.string :group_id, :null => false
t.string :person_id, :null => false
end
end
end
# $ rake db:migrate
, and your controller is correct:
# app/controllers/people_controller.rb
class PeopleController < ApplicationController
def new
#groups = Group.all
#person = Person.new
end
def create
#person= Person.new(params[:person])
if #person.save
# render/redirect_to and/or flash stuff
else
# render and/or flash stuff
end
end
end
, and you've all existing group options as checkboxes:
# app/views/people/new.html.erb
<%= form_for #person do |f| %>
<%= f.label :name %>
<%= f.text_field :name %>
# same for other person attributes
<% #groups.each do |g| %>
<%= check_box_tag 'person[group_ids][]', g.id, false, :id => g.group_name_attr %>
<%= label_tag g.group_name_attr %>
<% end %>
<%= f.submit 'Create!' %>
<% end %>
, then you can validate the presence of groups on your Person record:
class Person < ActiveRecord::Base
validates_presence_of :groups
has_and_belongs_to_many :groups
end
There is validates_associated helper, but wouldn't be necessary in this case, where you show Group.all as checkboxed options.
No accepts_nested_attributes_for is necessary for this. It would be if you were creating a Group for a Person while creating a Person. Again, please specify if this is the case.
Just a note: validating an incoming form that includes Group.all as options and gives the option of creating a group along with the person is possible but complicated. It would involve bypassing existing validations on the Group model, if any, which there probably is.
So I have two models & controllers. Projects and Designers.
In my designers index view, I want it to show a list of all the projects that the designer has.
However, when I do a simple query like this:
<% #projects.each do |project| %>
<tr>
<td><%= link_to 'Show', project %></td>
<td><%= link_to 'Edit', edit_project_path(project) %></td>
<td><%= link_to 'Destroy', project, :confirm => 'Are you sure?', :method => :delete %></td>
</tr>
<% end %>
From the index.html.erb in the Designers view, it gives me the following error:
NoMethodError in Designers#index
You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.each
However, when I run that EXACT code from the index.html.erb file in the projects view, it works perfectly.
So how am I able to access that controller or at least data from the view of another controller? Do I have to add a projects variable (where it queries the db) to my index object in my designers controller?
Thanks.
UPDATED TO USE A SINGLE DESIGNER RECORD
You should use associations. Add this to your models.
class Designer < ActiveRecord::Base
has_many :projects
end
class Project < ActiveRecord::Base
belongs_to :designer
end
Your view should look like this:
<% #designer.projects.each do |project| %>
<% end %>
More info on associations here:
http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html
Figured out one way to do it. All I had to do was add an instance variable in my designers controller:
#projects = Project.all
But...that's not very DRY. Does anyone have a more elegant 'DRY' solution, so if I want to access other variables in other controllers I can do that easily without having to re-create them in the current controller?
Thanks.
In your designers controller, you need to set the #projects instance variable to only those projects belonging to the signed in designer, correct?
You'll need something like this:
def index
#projects = Project.where(:user_id => where ever you've stored your userid)
end
I hope this helps.