How can I pass an object via params in rails? - ruby-on-rails-3

I'm sure there is a better way to do this, but in my inexperience, I'm having trouble sorting that better way out. I have a link that needs to send and object to controller for processing. It isn't working properly:
views/home/index.html.erb
<% search_term = "pizza" %>
<% #tag = Tag.find(:all, :conditions => ["name = ?", search_term ]).first %>
<li> <%= link_to(search_term, {:controller => "restaurants", :action => "index", :search_item => #tag}) %> </li>
controllers/restaurants.rb
def index
search_tag = params[:search_item]
#restaurants = Restaurant.search_by_tag(search_tag)
models/restaurant.rb
Class Restauarant < ActiveRecord::Base
def self.search_by_tag(search_tag)
search_condition = search_tag.name
#tags = Tag.find(:all, :conditions => [" name = ?", search_condition ])
#tag = #tags.first
#Restaurants = #tag.restaurants
end
end
This causes a NoMethodError in ResataurantsController#index
parameters:
{"searchitem" => "15"}
For some reason, the tag object isn't being passed properly from the home/index.html.erb and is only passing along the Tag-object :id to the restaurants controller. Isn't possible to pass a full object this way. what am I doing wrong?

You can't submit an object through get params like that. Typically, you'll just pass the object's id (which you are already doing), and then do a lookup in the controller:
#tag = Tag.find(params[:search_item])
It would make more sense to rename the "search_item" param to "tag_id".

Related

Why isn't my search method working in Ruby on Rails?

In my Ruby on Rails application, I have a cinema system and am trying to return the screen a showing is in when a user searches for the showing.
To display the search drop down I am using this code in my _application.html.erb:
<%= render( :partial => '/screen_lookup', :locals => {:showings => #showings = Showing.all, :my_path => '/screens/display_screens_by_showing' })%>
Which renders the search from the _screen_lookup.html.erb:
<%= form_tag my_path, :method=>'post', :multipart => true do %>
<%= select_tag ('showings_id'),
options_from_collection_for_select(#showings, :id, :showing_times, 0 ),
:prompt => "Showings" %>
<%= submit_tag 'Search' %>
<% end %>
And uses the display_screens_by_showing in the screens_controller:
def display_screens_by_showing
#screens = Screen.showing_search(params[:showing_id])
if #screens.empty?
# assign a warning message to the flash hash to be displayed in
# the div "feedback-top"
flash.now[:alert] = "There are no films of that genre."
# return all products, in alphabetical order
#screens = Screen.all
end
render :action => "index"
end
And this searches using the method in the screen.rb model:
def self.showing_search(showing_id)
screen = Showing.where("id = ?", showing_id).screen_id
self.where("id = ?", screen)
end
Now, the problem I am having is that because a showing belongs_to a screen, and a screen has_many showings, I need to be able to search for the showing, and store that showing's screen_id in a variable to search for the screen that showing is in with, which I have tried doing in the model:
screen = Showing.where("id = ?", showing_id).screen_id
self.where("id = ?", screen)
But the error I am getting is:
NoMethodError in ScreensController#display_screens_by_showing
undefined method `screen_id' for #<ActiveRecord::Relation []>
These are the model relationships:
showing.rb:
class Showing < ActiveRecord::Base
belongs_to :screen
end
screen.rb:
class Screen < ActiveRecord::Base
has_many :showings
end
What code will get my search working?
The problem is that where doesn't return a record, it returns a relation that can be enumerated or chained, instead you want to use find or find_by to return a single record, which is kind equivalent to where + first
screen = Showing.find(showing_id).screen_id
which is sort of like doing
screen = Showing.where(id: showing_id).first.screen_id
If you want to pass a hash you can use find_by which will be like this
screen = Showing.find_by(id: showing_id).screen_id
PS:
I'm not sure what you're doing exactly, but i think those two lines can be merged into a single query ( not sure what it should be returning, but I'm assuming a screen )
def self.showing_search(showing_id)
Showing.find(showing_id).screen
end

Rails sorting associations with Ransack

first time poster. I am trying to sort a table of users using the Ransack gem and Kaminari for pagination. When I use name, id, etc. sorting works but when I try an association with posts_count, sorting breaks and won't work. Note: in the view, 'u.posts.count' work correctly. I have tried custom scopes in the users model, and creating custom objects for the search params but nothing seems to work. I think I am having trouble either in the default scope or the #search object not having the data. Need help!
Here are some relevant snippets:
models/user.rb
has_many :posts, :dependent => :destroy
models/post.rb
belongs_to :user
default_scope :order => 'post.created_at DESC'
controllers/users_controller.rb
def index
#title = "User Index"
#search = User.search(params[:q]) # Ransack
#total_users = User.all.count
# .per(10) is the per page for pagination (Kaminari).
#users = #search.result.order("updated_at DESC").page(params[:page]).per(10) #This displays the users that are in the search criteria, paginated.
end
views/users/index.html.erb
..
<%= sort_link #search, :posts_count, "No. of Posts" %> #Sort links at column headers
..
<% #users.each do |u| %> #Display everything in the table
<%= u.posts.count %>
<% end %>
You can add a scope to your User model:
def self.with_posts
joins(:posts).group('posts.id').select('users.*, count(posts.id) as posts_count')
end
and use it like this:
#search = User.with_posts.search(params[:q]) # Ransack
then, you can treat posts_count like any other attribute.
I found a solution:
Controller:
def index
sql = "users.*, (select count(posts.id) from posts\
where posts.user_id = users.id) as count"
#search = User.select(sql).search(params[:q])
if params[:q] && params[:q][:s].include?('count')
#users = #search.result.order(params[:q][:s])
else
#users = #search.result
end
.......
end
View:
<th><%= sort_link #search, :count, "posts count" %></th>

rails OR query based on multiple checkbox selections

This seems like it should be a common problem but I'm having trouble finding an answer. Basically I want to have a form with 10 or so checkboxes which I'm creating with check_box_tag. When the form is submitted I want to generate a query that return all records that match ANY of the checked selections. So, the number of checked selections will vary.
So, for example, if I have
class Book < ActiveRecord::Base
belongs_to :author
end
I want to generate something like
Book.where("author_id = ? or author_id = ?", params[authors[0]], params[authors[1]]) if there are two boxes checked, etc.
Thanks for any insight.
Will this work for you?
Book.where(author_id: [array_of_author_ids])
You need to collect author_ids from params first
I recently had to do something similar, this is how I achieved this. It's pretty clever (at least I think so. :))
I created a query model that serializes the query column (text field) in JSON. I use a form to get the query data from the user with selection fields.
class BookQuery < ActiveRecord::Base
has_many :books
# loop through each foreign key of the Book table and create a hash with empty selection
def self.empty_query
q = {}
Book.column_names.each do |column_name|
next unless column_name.ends_with?("_id")
q.merge column_name => []
end
end
end
I'm using Author as an example below:
<%= form_for #book_query do |f| %>
<% for author in Author.all %>
<%= check_box_tag "book_query[query][author_ids][]", author.id, false%>
<%= author.name %>
<% end %>
<%= f.submit "Save Query" %>
<% end %>
When this form is submitted you ended up with parameters like this:
When the form is submitted it generates this parameter:
Parameters: {"utf8"=>"✓", "authenticity_token"=>"XXXXXXXXXXX", "book_query"=>{"query"=>{"author_ids"=>["2", "3"]}}, "commit"=>"Save Query"}
Now in the BookQuery controller's create action you can just do what create function always does:
def create
#book_query = BookQuery.build(params[:book_query])
if #book_query.save
flash[:success] = "Book query successfully saved."
redirect_to ...
else
flash[:error] = "Failed to save book query."
render :new
end
end
But by default rails serializes the data in hash type:
1.9.3p194 :015 > pp BookQuery.find(9).query
BookQuery Load (0.7ms) SELECT "book_queries".* FROM "book_queries" WHERE "book_queries"."id" = $1 LIMIT 1 [["id", 9]]
"--- !ruby/hash:ActiveSupport::HashWithIndifferentAccess\nauthor_ids:\n- '2'\n- '3'\n"
=> "--- !ruby/hash:ActiveSupport::HashWithIndifferentAccess\nauthor_ids:\n- '2'\n- '3'\n"
In BookQuery model, add the following:
serialize :query, JSON
But rail would change the IDs to string:
1.9.3p194 :018 > query = JSON.parse(BookQuery.find(10).query)
BookQuery Load (0.5ms) SELECT "book_queries".* FROM "book_queries" WHERE "book_queries"."id" = $1 LIMIT 1 [["id", 10]]
=> {"author_ids"=>["2", "3"]}
1.9.3p194 :019 > query["author_ids"]
=> ["2", "3"]
What I did then is override the attribute accessors in BookQuery model:
The below has to be done because the hash returns strings, not ids in integer.
def query=(query)
query.each_pair do |k, v|
if query[k].first.present?
query[k].map!(&:to_i)
else
query.except!(k)
end
end
write_attribute(:query, query)
end
# just want to avoid getting nil query's
def query
read_attribute(:query) || {}
end
To find book with this query, you can simply add this function to your Book model:
def self.find_by_book_query(book_query, options = {})
options[:conditions] = book_query.query
find(:all, options)
end
Now you get a customizable query string based on the model definition Book and everything works like the Rails way. :)

form_for non-AR model - fields_for Array attribute doesn't iterate

I'm having trouble getting fields_for to work on an Array attribute of a non-ActiveRecord model.
Distilled down, I have to following:
models/parent.rb
class Parent
extend ActiveModel::Naming
include ActiveModel::Conversion
include ActiveModel::Validations
extend ActiveModel::Translation
attr_accessor :bars
end
controllers/parent_controller.rb
def new_parent
#parent = Parent.new
#parent.bars = ["hello", "world"]
render 'new_parent'
end
views/new_parent.html.haml
= form_for #parent, :url => new_parent_path do |f|
= f.fields_for :bars, #parent.bars do |r|
= r.object.inspect
With the code as above, my page contains ["hello", "world"] - that is, the result of inspect called on the Array assigned to bars. (With #parent.bars omitted from the fields_for line, I just get nil displayed).
How can I make fields_for behave as for an AR association - that is, perform the code in the block once for each member of my bars array?
I think the correct technique is:
= form_for #parent, :url => new_parent_path do |f|
- #parent.bars.each do |bar|
= f.fields_for "bars[]", bar do |r|
= r.object.inspect
Quite why it can't be made to Just Work I'm not sure, but this seems to do the trick.
I think that it can be done without the need of each:
= form_for #parent, :url => new_parent_path do |f|
= f.fields_for :bars do |r|
= r.object.inspect
You need to set some methods that are expected in the parent class to identify the collection.
class Parent
def bars_attributes= attributes
end
end
And you also will need to make sure that the objects in the array respond to persisted (so you cannot use strings) :(
I ditched the fields_for and added multiple: true
= form_for #parent, :url => new_parent_path do |f|
- #parent.bars.each_with_index do |bar, i|
= f.text_field :bars, value: bar, multiple: true, id: "bar#{i}"

Rails filtering with acts_as_taggable gem

I am working the acts-as-taggable-on gem and have a question about how to filter down search results based on tags users select. Here's an abridged look at my controller:
class PhotosController < ApplicationController
def index
#photos = Photo.where(["created_at > ? AND is_approved = ?", 1.months.ago, true])
#tags = ["Animals", "Architecture", "Cars", "Flowers", "Food/Drink", "General", "Landscape", "Mountains", "Nature"]
end
def search_by_tag(tag)
#photos = Photo.where('tagged_with LIKE ?', tag)
end
end
Photos/index
<% #tags.each do |tag| %>
<%= link_to tag, {:search_by_tag => tag}, :class => "tag" %>
<% end %>
This lists out all of the tags from the hash #tags defined in index, but clicking them doesn't actually filter anything down. Here's a look at what clicking one of those links produces in the log:
Started GET "/photos?search_by_tag=Animals" for 127.0.0.1 at Sun Oct 09 17:11:09 -0400 2011
Processing by PhotosController#index as HTML
Parameters: {"search_by_tag"=>"Animals"}
SQL (0.5ms) SELECT name FROM sqlite_master WHERE type = 'table' AND NOT name = 'sqlite_sequence'
The result I want is for the page to display only Photos that are tagged_with whichever tag was clicked on. I can't quite figure out how to accomplish this.
(Side-question: I can't seem to find a way to list out all of the tags from the tags table that acts-as-taggable-on generated. Doing something like Photo.tagged_with or Photo.tags doesn't work. I am able to see the "tags" table the gem created, and the entries inside of it; I'm just not really clear how to handle that using this gem)
Any thoughts greatly appreciated.
UPDATE
I've updated my code and am a bit closer.
class PhotosController < ApplicationController
def search_by_tag
#photos = Photo.tagged_with(params[:tag_name])
end
photos/index
<% Photo.tag_counts_on(:tags).map(&:name).each do |tag| %>
<%= link_to tag, {:action => 'search_by_tag', :tag_name => tag}, :class => "tag" %>
<% end %>
I believe this is closer, but still working through this...
You have a number of errors in your code:
Your link_to call is actually calling the index action.
Your search_by_tag method is expecting an argument, where it should be using the params hash to access the parameters passed to it in the web request.
tagged_with is a class method added by acts_as_taggable_on, not a field in your table - therefore you can't use it in the where method like you have done.
Finally, to get all the tag names: Photo.tag_counts_on(:tags_or_whatever_you_tagged_on).map(&:name)
Take a look at the acts_as_taggable_on documentation and you'll see examples of how to use tag_counts_on and tagged_with.
As for the Rails things: http://guides.rubyonrails.org/ http://railsforzombies.org/ and/or http://railscasts.com/