I want to be able to manage has_many caching myself.
The issue being I want to be able to archive (like soft delete, but with discardable gem) some records:
has_many :tags
def tag_list=(tag_names)
# so I do a diff
names_to_create = ...
tags_to_discard = ...
tags_to_keep = ...
to_delete.each(&:discard)
new_tags = names_to_create.each { |name| tag.create!(name: name) }
# if I just go with regular
self.tags = new_tags + tags_to_keep
# tags_to_discard will be deleted
The thing is that I don't want to just tags.reload. It's costly
I know exactly what tags should be here or not.
How I can just "force" the rails cache?
You should tread carefully with that, but I find that
has_many :tags
def tag_list=(tag_names)
# Do a diff
names_to_create = ...
tags_to_discard = ...
tags_to_keep = ...
to_delete.each(&:discard)
new_tags = names_to_create.each { |name| tag.create!(name: name) }
tags.proxy_association.target = tags_to_keep + new tags
end
To do exactly that
Though it's probably private API and not meant to be used like that.
Related
Greetings fellow developers.
I have a model candidate.rb and there are 2 columns(offer_code and candidate_type) that i want to work with.
I want the offer_code = "CHP" if the candidate_type = "chapter".
I am trying to do this with after_save but this is creating all the new candidates with candidate_type = "chapter".
I think the condition that I have used is wrong. Please guide me
In candidate.rb
After_save : chapter_offer
def chapter_offer
If self.candidate_type = "chapter"
self.offer_code = "CHP"
end
end
You are using = for comparison instead of ==
And it will be better if you did something like this
before_save :chapter_offer, if: -> { candidate_type == 'chapter' }
def chapter_offer
offer_code = 'CHP'
end
I want to pull data for each of my users. I grab their person_id from my user table, then use each person's ID to figure out how many days each person has available, and show that in my view.
I'm not sure if I am doing this correctly because I am iterating in my controller then again in my view.
def how_many_days_users_have
#my_group = User.all.pluck(:person_id)
#my_group.each do |v|
#indirect_id_v = Empaccrl.where("person_id = ? and is_active = ?", '#{v]', 'Y').pluck(:a_code).first
#v_range = Empaccrl.where("person_id = ? and is_active = ?", '#{v]', 'Y').pluck(:ac).first
#v_range_taken = Empaccrl.where("person_id = ? and is_active = ?", '#{v]', 'Y').pluck(:taken).first
#total_v_hours = #v_range.to_d - #v_range_taken.to_d
#total_v_days = #total_v_hours / 8
end
Then in my view I use this to show me this data:
%tr.trace-table
-#indirect_id_v.each do |idd|
%tr.trace-table
%td.trace-table{:style => 'border: solid black;'}= idd
-#total_v_days.each do |days|
%tr.trace-table
%td.trace-table{:style => 'border: solid black;'}= days
Okay, first things first, move some of that junk to your model, like so:
class Empaccrl < ActiveRecord::Base
def self.all_people
where(person_id: User.all.pluck(:person_id))
end
def self.active_people
all_people.where(is_active: 'Y')
end
def self.active_vacation_data
active_people.select(:person_id, :ac, :taken)
end
def total_v_hours
ac.to_d - taken.to_d
end
def total_v_days
total_v_hours / 8
end
end
Then you can use:
peoples_vacation_information = Empaccrl.active_vacation_data.all
peoples_vacation_information.map do |person|
p "person #{person.person_id} has #{person.total_v_days} vacation days"
end
Honestly, you don't even need all that, but I'm not sure why you are doing what you are doing, so I figured better be safe and add stuff. Whatever you don't need, just ignore.
First, sorry for my English, I am totally new in ruby on rails even in very basic thing, so I hope you all can help me.
I have table Role and RoleUser
table Role have has_many relationship to RoleUser with role_id as foreign key
in table RoleUser is contain user_id, so I can call it 1 role have many users
and I want is to show all record in Role with additional field in every record called total_users,
total_users is in every record have role_id and count the user_id for every role, and put it in total_users,
I know this is must use the join table, but in rails I absolutely knew nothing about that, can you all give me a simple example how to do that.
and one more, same with case above, can I do for example Role.all and then the total_users in include in that without added it in database? is that use virtual column?
anyone have a good source of link to learn of that
I have following code in model
def with_filtering(params, holding_company_id)
order = []
if params[:sort].present?
JSON.parse(params[:sort]).each do |data|
order << "#{data['property']} #{data['direction']}"
end
end
order = 'id ASC' if order.blank?
if self.column_names.include? "holding_company_id"
string_conditions = ["holding_company_id = :holding_company_id"]
placeholder_conditions = { holding_company_id: holding_company_id.id }
else
string_conditions = []
placeholder_conditions = {}
end
if params[:filter].present?
JSON.parse(params[:filter]).each do |filter|
if filter['operation'] == 'between'
string_conditions << "#{filter['property']} >= :start_#{filter['property']} AND #{filter['property']} <= :end_#{filter['property']}"
placeholder_conditions["start_#{filter['property']}".to_sym] = filter['value1']
placeholder_conditions["end_#{filter['property']}".to_sym] = filter['value2']
elsif filter['operation'] == 'like'
string_conditions << "#{filter['property']} ilike :#{filter['property']}"
placeholder_conditions["#{filter['property']}".to_sym] = "%#{filter['value1']}%"
else
string_conditions << "#{filter['property']} = :#{filter['property']}"
placeholder_conditions["#{filter['property']}".to_sym] = filter['value1']
end
end
end
conditions = [string_conditions.join(' AND '), placeholder_conditions]
total_count = where(conditions).count
if params[:limit].blank? && params[:offset].blank?
data = where(conditions).order(order)
else
data = where(conditions).limit(params[:limit].to_i).offset(params[:offset].to_i).order(order)
end
return data, total_count.to_s
end
And I have follwing code in controllers
def crud_index(model)
data, total = Role.with_filtering(params, current_holding_company)
respond_to do |format|
format.json { render json: { data: data, total_count: total }.to_json, status: 200 }
end
end
My only purpose is to add virtual field called total_users, but i want added it in model and combine it with data in method with_filtering
If you have the models like this:
Class Role < ActiveRecord::Base
has_many :role_users
end
Class RoleUser < ActiveRecord::Base
belong_to :role
end
You could use select and joins to generate summary columns, but all the Role's attributes should be include in group.
roles = Role.select("roles.*, count(role_users.id) as total_users")
.joins(:role_users)
.group("roles.id")
Type those scripts in Rails console, Rails will generate a sql like :
SELECT roles.id, count(role_users.id) as total_users
FROM roles
INNER JOIN role_users
ON roles.id = role_users.role_id
GROUP BY roles.id
Then you can use roles.to_json to see the result. The summary column total_users can be accessed in every member of roles.
And there are many other way can match your requirement. Such as this. There is a reference of counter cache.
My suggestion is after searching, you can test those method by rails console, it's a useful tool.
UPDATE
According to OP's update and comment, seems you have more works to do.
STEP1: move with_filtering class method to controller
with_filtering handle a lot of parameter things to get conditions, it should be handled in controller instead of model. So we can transfer with_filtering into conditions and orders in controller.
class RolesController < ApplicationController
def conditions(params, holding_company_id)
if self.column_names.include? "holding_company_id"
string_conditions = ["holding_company_id = :holding_company_id"]
placeholder_conditions = { holding_company_id: holding_company_id.id }
else
string_conditions = []
placeholder_conditions = {}
end
if params[:filter].present?
JSON.parse(params[:filter]).each do |filter|
if filter['operation'] == 'between'
string_conditions << "#{filter['property']} >= :start_#{filter['property']} AND #{filter['property']} <= :end_#{filter['property']}"
placeholder_conditions["start_#{filter['property']}".to_sym] = filter['value1']
placeholder_conditions["end_#{filter['property']}".to_sym] = filter['value2']
elsif filter['operation'] == 'like'
string_conditions << "#{filter['property']} ilike :#{filter['property']}"
placeholder_conditions["#{filter['property']}".to_sym] = "%#{filter['value1']}%"
else
string_conditions << "#{filter['property']} = :#{filter['property']}"
placeholder_conditions["#{filter['property']}".to_sym] = filter['value1']
end
end
end
return [string_conditions.join(' AND '), placeholder_conditions]
end
def orders(params)
ord = []
if params[:sort].present?
JSON.parse(params[:sort]).each do |data|
ord << "#{data['property']} #{data['direction']}"
end
end
ord = 'id ASC' if ord.blank?
return ord
end
end
STEP2: update action crud_index with conditions and orders to get total_count of Roles.
class AnswersController < ApplicationController
def crud_index(model)
total = Role.where(conditions(params, current_holding_company)).count
if params[:limit].blank? && params[:offset].blank?
data = Role.where(conditions(params, current_holding_company)).order(orders(params))
else
data = Role.where(conditions(params, current_holding_company)).limit(params[:limit].to_i).offset(params[:offset].to_i).order(orders(params))
end
respond_to do |format|
format.json { render json: { data: data, total_count: total }.to_json, status: 200 }
end
end
end
STEP3: update action crud_index to get total_users by every role.
Make sure the two previous steps is pass the test.
class AnswersController < ApplicationController
def crud_index(model)
total = Role.where(conditions(params, current_holding_company)).count
if params[:limit].blank? && params[:offset].blank?
data =
Role.select(Role.column_names.map{|x| "Roles.#{x}"}.join(",") + " ,count(role_users.id) as total_users")
.joins(:role_users)
.group(Role.column_names.map{|x| "Roles.#{x}"}.join(","))
.where(conditions(params, current_holding_company))
.order(orders(params))
else
data =
Role.select(Role.column_names.map{|x| "Roles.#{x}"}.join(",") + " ,count(role_users.id) as total_users")
.joins(:role_users)
.group(Role.column_names.map{|x| "Roles.#{x}"}.join(","))
.where(conditions(params, current_holding_company))
.order(orders(params))
.limit(params[:limit].to_i)
.offset(params[:offset].to_i).order(orders(params))
end
respond_to do |format|
format.json { render json: { data: data, total_count: total }.to_json, status: 200 }
end
end
end
NOTE: step3 may need you to modify conditions and orders method to generate column_name with table_name prefix to avoid column name ambiguous error
If you can make these steps through, I suggest you can try will_paginate to simplify the part of your code about total_count ,limit and offset.
With what you explained, you could do something like this:
class Role < ActiveRecord::Base
has_many :role_users
has_many :users
def total_users
self.users.count
end
end
So you just need to call the total_users method on roles object which should get you what you desire. Something like this:
Role.first.total_users
# this will give you the total users for the first role found in your database.
Hope it helps
You might want to watch this Railscast too:
#app/models/role.rb
Class Role < ActiveRecord::Base
has_many :role_users
has_many :users, -> { select "users.*", "role_users.*", "count(role_users.user_id) as total_users" }, through: :role_users
end
This will allow you to call:
#roles = Role.find params[:id]
#roles.users.each do |role|
role.total_users
end
You can see more about how this works with a question I wrote some time ago - Using Delegate With has_many In Rails?
--
It's where I learnt about Alias columns, which Ryan Bates uses to count certain values:
I have two models:
class Song < ActiveRecord::Base
attr_accessible :title, :singer, :year, :production
end
and:
class SongsCopy < ActiveRecord::Base
attr_accessible :title, :singer, :year
end
What is the most simple way to copy attributes from A(Song) to B(SongsCopy) while creating B, remembering SongsCopy has no attribute :production?
The optimal way would be to do it inside the database with a bit of SQL:
insert into songs_copies (title, singer, year)
select title, singer, year
from songs
where ...
But if you have a bunch of callbacks and such that you need to run then you could do something like this:
song = some_song_that_you_already_have
copy = SongsCopy.create(song.attributes.except('id', 'production'))
or:
copy = SongsCopy.create(song.attributes.slice('title', 'singer', 'year'))
It's not the prettiest possibility (and certainly not preferred), but the easiest would be:
class SongsCopy < ActiveRecord::Base
def initialize(args = nil)
if args.is_a? Song
super
self.title = song.title
self.singer = song.singer
self.year = song.year
else
super(args)
end
end
end
a = Song
b = SongsCopy.new(a)
I'm sure there's another way to do this, but the above should work.
I have a model, called Book, that has the fields title and filename (and other fields but they are unrelated). I'd like that the filename field was automatically created using the title, thus in my Book.rb:
class Book < ActiveRecord::Base
# ...
def title=(title)
self.filename = sanitize_filename(title)
self.title = title
end
# ...
end
Because of self.title = title it's going in a infinite recursion. How could I avoid that?
Thanks!
You can write that on before_save
def before_save
self.filename = sanitize_filename(self.title)
end
Try this way
class Book
def title=(title)
self.filename = sanitize_filename(title)
self[:title] = title
end
end
There's a section in the ActiveRecord api on 'overwriting default accessors'. The suggested solution there is:
def title=(t)
self.filename = sanitize_filename(t)
write_attribute(:title, t)
end