My Tasks belongs to different models but are always assigned to a company and/or a user. I am trying to narrow what gets displayed by grouping them by there due_at date without doing to many queries.
Have a application helper
def current_tasks
if user_signed_in? && !current_company.blank?
#tasks = Task.where("assigned_company = ? OR assigned_to = ?", current_company, current_user)
#current_tasks = #tasks
else
#current_tasks = nil
end
end
Then in my Main view I have
<%= render :partial => "common/tasks_show", :locals => { :tasks => current_tasks }%>
My problem is that in my task class I have what you see below. I have the same as a scope just named due_today. when I try current_tasks.due_today it works if I try current_tasks.select_due_today I get a undefined method "select_due_tomorrow" for #<ActiveRecord::Relation:0x66a7ee8>
def select_due_today
self.to_a.select{|task|task.due_at < Time.now.midnight || !task.due_at.blank?}
end
If you want to call current_tasks.select_due_today then it'll have to be a class method, something like this (translating your Ruby into SQL):
def self.select_due_today
select( 'due_at < ? OR due_at IS NOT NULL', Time.now.midnight )
end
Or, you could have pretty much the same thing as a scope - but put it in a lambda so that Time.now.midnight is called when you call the scope, not when you define it.
[edited to switch IS NULL to IS NOT NULL - this mirrors the Ruby in the question, but makes no sense because it will negate the left of the ORs meaning]
Related
I want to create a class method for a class inherits ActiveRecord:Base.
What the method need to do is add where clauses based on the options and it works well.
class Article < ActiveRecord::Base
def self.list_by_params(params={})
articles = self
articles = articles.where(author_id: params[:author_id]) unless params[:author_id].blank?
articles = articles.where(category_id: params[:category_id]) unless params[:category_id].blank?
articles = articles.where("created_at > ?", params[:created_at].to_date) unless params[:created_at].blank?
articles
end
end
This code works fine in case of the call such as:
articles = Article.list_by_params({author_id: 700})
#=> Works fine as I expected.
articles = Article.joins(:authors).list_by_params({author_id: 700})
#=> Works fine as I expected.
However, the problem is that, if I want to call the list_by_params without filtering params, then it lose its former relations. For example:
articles = Article.joins(:authors).list_by_params({})
#=> articles is just a `Article` (not an ActiveRecord_Relation) class itself without joining :authors.
Is there any chance that I made a mistake?
Thanks in advance.
What you are looking for is a scope.
I would do something like this
scope :for_author, lambda { |author| where(author_id: author) unless author.blank? }
scope :in_category, lambda { |category| where(category_id: category) unless category.blank? }
scope :created_after, lambda { |date| where('created_at > ?', date.to_date) unless date.blank? }
scope :list_by_params, lambda do |params|
for_author(params[:author_id])
.in_category(params[:category_id])
.created_after(params[:created_at])
end
Now you can reuse the components of your query. Everything has a names and it gets easier to read the code.
For the self explanation, I've solved the problems by using where(nil).
Actually, Model.scoped returned anonymous scope but the method has been deprecated since Rails version 4. Now, where(nil) can replace the functionality.
class Article < ActiveRecord::Base
def self.list_by_params(params={})
articles = where(nil) # <-- HERE IS THE PART THAT I CHANGED.
articles = articles.where(author_id: params[:author_id]) unless params[:author_id].blank?
articles = articles.where(category_id: params[:category_id]) unless params[:category_id].blank?
articles = articles.where("created_at > ?", params[:created_at].to_date) unless params[:created_at].blank?
articles
end
end
What I'm trying to do: I have a model "Recipe" in which I defined a method "search" that takes an array of strings from checkboxes (I call them tags), and a single string. The idea is to search the db for recipes that has anything in it's 'name' or 'instructions' that contains the string, AND also has any of the tags matching it's 'tags' property.
Problem: The search method return all the recipes in my db, and doesn't seem to work at all at finding by the specific parameters.
The action method in the controller:
def index
#recipes = Recipe.search(params[:search], params[:tag])
if !#recipes
#recipes = Recipe.all
end
respond_to do |format|
format.html
format.json { render json: #recipe }
end
end
The search method in my model:
def self.search(search, tags)
conditions = ""
search.present? do
# Condition 1: recipe.name OR instruction same as search?
conditions = "name LIKE ? OR instructions LIKE ?, '%#{search[0].strip}%', '%#{search[0].strip}%'"
# Condition 2: if tags included, any matching?
if !tags.empty?
tags.each do |tag|
conditions += "'AND tags LIKE ?', '%#{tag}%'"
end
end
end
# Hämtar och returnerar alla recipes där codition 1 och/eller 2 stämmer.
Recipe.find(:all, :conditions => [conditions]) unless conditions.length < 1
end
Any ideas why it return all records?
if you are using rails 3, then it is easy to chain find conditions
def self.search(string, tags)
klass = scoped
if string.present?
klass = klass.where('name LIKE ? OR instructions LIKE ?', "%#{string}%", "%#{string}%")
end
if tags.present?
tags.each do |tag|
klass = klass.where('tags LIKE ?', "%#{tag}%")
end
end
klass
end
When you do
search.present? do
...
end
The contents of that block are ignored - it's perfectly legal to pass a block to a function that doesn't expect one, however the block won't get called unless the functions decides to. As a result, none of your condition building code is executed. You probably meant
if search.present?
...
end
As jvnill points out, it is in general much nicer (and safer) to manipulate scopes than to build up SQL fragments by hand
I'm a novice in ruby-on-rails.
I have an applications counting distance between metro station and a ATM.
There's two models with many-to-many relation: Station, Cashpoint. And there's a controller SHOW, that should get the station and show ATMs in order there's proximity to the station.
class StationsController < ApplicationController
def show
#station = Station.find(params[:id])
#cashpoints = #station.cashpoints.find(:all)
respond_to do |format|
format.html
end
end
end
Also there's a helper that counts distance using Google Directions API.
module StationsHelper
def count_distance(origin,destination)
...
return {:text => ... # 1 min
, :value => ... # 60 (seconds)
}
end
end
All this works properly.
But I'm wondering how to order ATMs by :value returned by StationsHelper?
I tried to write something in controller similar to:
#cashpoints = #station.cashpoints.find(:all,
:order => count_distance(#station.address, cashpoint.address)[:value])
But it's evidently doesn't work 'cause I have know idea how to link single cashpoint object
to count_distance method parameter.
May be you can help me, it appears that my project structure is wrong to do this.
Try this:
#cashpoints = #station.cashpoints.find(:all).sort_by { |c| count_distance(c.address, #station.address) }
On my Question model I have some scopes
scope :recent, order("created_at DESC")
scope :approved, where("status = ?", "approved")
scope :answered, approved.recent.where("answers_count > ?", 0)
On my question controller I'm retrieving questions using the scopes
example 1:
#questions = Question.approved.recent
example 2:
#questions = User.find(session[:user_id]).topics.map { |t| t.questions.approved.recent }.flatten.uniq
I'm trying to put will_paginate on my model to make things easier on the controller but the 2nd example is very tricky as it is using mapping to retrieve questions according to preferences.
I've tried to add this on my model
def self.pagination(page = 1)
self.paginate(:page => page, :per_page => 5)
end
and then on my controller I have
#questions = Question.approved.recent.pagination.(params[:page])
That works fine for the 1st example but I Dont know how to implement that on the 2nd example
Any hints?
This looks like Rails 3. Be sure to use the ~> 3.0.pre2 version of the will_paginate gem.
You can use the paginate method at the end of your chain of scopes. For example, your "example 1" would be:
#questions = Question.approved.recent.paginate(:page => params[:page], :per_page => 20)
I see you created a custom method (pagination) to wrap this pattern, but it's best that you keep this syntax in original form for now, especially since you're dealing with scopes and Relation objects in Rails 3 and will_paginate doesn't have proper support for this yet (but it's coming).
In your "example 2" it seems you only need to fetch the first few recent questions from each topic and that you won't perform a full-blown pagination here (like, going to page 2 and forward). You don't have to use the paginate method here; you can simply use ActiveRecord's limit:
current_user = User.find(session[:user_id])
#questions = current_user.topics.map { |topic|
topic.questions.approved.recent.limit(5).to_a
}.flatten.uniq
So I have some posts, and would like to show n..m most recent entries in the sidebar (these numbers being set in a config)
I can get the latest n records easily enough
class Post < ActiveRecord::Base
default_scope :order => "created_at DESC"
scope :published, lambda { where("blog_entries.created_at <= ?", Time.zone.now) }
scope :latest, lambda { |n| published.limit(n) }
end
#posts = Post.latest(6)
But what I'd like is
#posts = Post.published.limit(6, 12)
but this gives wrong number of arguments, so is there any way in AR? Right now I'm playing with will_paginate, but it seems hacky to use it for this.
Ok, so the answer is, I think:
#posts = Post.published.limit(6).offset(5)
It will retrieve 6 posts, starting from the sixth.
edit2: About the limit([6, 12]), I find that strange:
attr_accessor :limit_value
def limit(value)
relation = clone
relation.limit_value = value
relation
end
def build_arel
...
arel.take(connection.sanitize_limit(#limit_value)) if #limit_value
...
end
def sanitize_limit(limit)
if limit.is_a?(Integer) || limit.is_a?(Arel::Nodes::SqlLiteral)
limit
elsif limit.to_s =~ /,/
Arel.sql limit.to_s.split(',').map{ |i| Integer(i) }.join(',')
else
Integer(limit)
end
end
So I don't really see how it works with an array. But I obviously missed something. Do you see what?
For rails 5 (not sure for rails 4). offset(x).limit(y) works correctly. limit(y).offset(x) still behaves as described in other answers.