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Non persistent ActiveRecord model attributes
(5 answers)
Closed 1 year ago.
I have an Agent model which gets its attributes from the underlying database table. However for one particular controller action I would like to add some 'temporary' attributes to the Agent records before passing them on to the view.
Is this possible?
Yes, you can extend your models on the fly. For example:
# GET /agents
# GET /agents.xml
def index
#agents = Agent.all
# Here we modify the particular models in the #agents array.
#agents.each do |agent|
agent.class_eval do
attr_accessor :foo
attr_accessor :bar
end
end
# And then we can then use "foo" and "bar" as extra attributes
#agents.each do |agent|
agent.foo = 4
agent.bar = Time.now
end
respond_to do |format|
format.html # index.html.erb
format.xml { render :xml => #agents}
end
end
In the view code, you can refer to foo and bar as you would with other attributes.
Related
I want to access multiple columns using Rails 3.But it gave me the following error.
Error:
ArgumentError (wrong number of arguments (2 for 1)):
app/controllers/payments_controller.rb:13:in `check_type'
Check my below code.
payment_controller.rb:
class PaymentsController < ApplicationController
def payment
#payment=Vendor.new
respond_to do |format|
format.html
format.js
end
end
def check_type
if params[:commit]=="submit"
#vendor_type=PaymentVendor.where(:v_name => params[:v_name]).pluck(:type ,:Receipt_No)
#vendor_type.each do |vendor|
end
else
#v_name=Vendor.where(:s_catagory => params[:payment][:s_catagory] ).pluck(:v_name)
end
end
end
Actually i want to retrive data like below format.
#vendor_type=["Receipt_no":"type","Receipt_no":"type",.....]
Once these data will appear,I need how to access row values according to Receipt_No.Please help me to resolve this error.
Thanks to ActiveRecord >= 4 . pluck accepts multiple arguments so in
Rails 4: Your query will work
#vendor_type=PaymentVendor.where(:v_name => params[:v_name]).pluck(:type ,:Receipt_No)
Now as you are using Rails 3 which doesn't support multiple arguments to pluck then we can extend ActiveRecord::Relation itself like this:
put your file under config/initializers
# pluck_all.rb
module ActiveRecord
class Relation
def pluck_all(*args)
args.map! do |column_name|
if column_name.is_a?(Symbol) && column_names.include?(column_name.to_s)
"#{connection.quote_table_name(table_name)}.#{connection.quote_column_name(column_name)}"
else
column_name.to_s
end
end
relation = clone
relation.select_values = args
klass.connection.select_all(relation.arel).map! do |attributes|
initialized_attributes = klass.initialize_attributes(attributes)
attributes.each do |key, attribute|
attributes[key] = klass.type_cast_attribute(key, initialized_attributes)
end
end
end
end
end
Now in your controller you can pass multiple arguments to pluck like this:
# payment_controller.rb:
#vendor_type=PaymentVendor.where(:v_name => params[:v_name]).pluck_all(:type ,:Receipt_No)
Now you can use pluck_all in whole app. Hope this helps ;)
EDIT:
Try below code if plcuk_all not worked:
#vendor_type = PaymentVendor.where(:v_name => params[:v_name]).map{|v|[v.type ,v.Receipt_No]}
Reference for more info: http://meltingice.net/2013/06/11/pluck-multiple-columns-rails/
Your pluck(:type ,:Receipt_No) looks wrong,
pluck have only one argument.
Also your type of data #vendor_type is wrong, Array don't have key, value pair.
Use map like this,
#vendor_type=PaymentVendor.where(:v_name => params[:v_name]).map { |i| [i.Receipt_No] }
In terms of making a rails 3 method that behaves the same as the Rails 4 pluck with multiple columns. This outputs a similar array (rather than a hashed key value collection). This should save a bit of pain if you ever come to upgrade and want to clean up the code.
See this tutorial which outlines a similar method that outputs a hash.
config/initializers/pluck_all.rb
module ActiveRecord
class Relation
def pluck_all(*args)
args.map! do |column_name|
if column_name.is_a?(Symbol) && column_names.include?(column_name.to_s)
"#{connection.quote_table_name(table_name)}.#{connection.quote_column_name(column_name)}"
else
column_name.to_s
end
end
relation = clone
relation.select_values = args
klass.connection.select_all(relation.arel).map! do |attributes|
initialized_attributes = klass.initialize_attributes(attributes)
attributes.map do |key, attribute|
klass.type_cast_attribute(key, initialized_attributes)
end
end
end
end
end
Standing on the shoulders of giants and all
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I made some variables that is related to models and I want to save the new variable relating to the control structure, but I can't. It said "NoMethodError - undefined method `save' for 1:Fixnum:".
What I want to make is that the function if This program get 4 people, It will show the member name for that members. 5th member will be in the next group.
Anyone can solve this?
or if you need more information, please let me know.
Thanks
This is Waitinglists_controller
class WaitinglistsController < ApplicationController
before_action :authenticate
def new
#waitinglist = current_user.created_waitinglists.build
end
def create
#waitinglist = current_user.created_waitinglists.build(waitinglist_params)
if #waitinglist.save
redirect_to waitinglist_waiting_path(#waitinglist, #owner)
else
render :new
end
end
def waiting
#group_number = Waitinglist.select(:count_number).last
#already_group_people = Waitinglist.where(count_number: #group_number).count
#current_person_group_number = current_user.created_waitinglists.select(:count_number)
#current_group_people = Waitinglist.where(count_number: #current_person_group_number).count
case #already_group_people
when 0
#current_person_group_number = 1
#current_person_group_number.save
when 1..2
#current_person_group_number = #group_number
#current_person_group_number.save
when 3
#current_person_group_number = #group_number
#current_person_group_number.save
redirect_to show_waitinglist_path
when 4
group_number += 1
#current_person_group_number = #group_number
#current_person_group_number.save
end
end
def show
#current_person_group_number = current_user.created_waitinglist.select(:count_number)
#matched_people = Waitinglist.find(count_number: #current_person_group_number)
#matched_people == 0 if #matched_people = nil
end
private
def created_by?(user)
return false unless user
owner_id == user.id
end
def waitinglist_params
params.require(:waitinglist).permit(:look_like, :id)
end
end
This is Sessions controller for User loggin
class SessionsController < ApplicationController
def create
user = User.find_or_create_from_auth_hash(request.env['omniauth.auth'])
session[:user_id] = user.id
redirect_to root_path
end
def destroy
reset_session
redirect_to root_path
end
end
Application contrtoller is this
class ApplicationController < ActionController::Base
# Prevent CSRF attacks by raising an exception.
# For APIs, you may want to use :null_session instead.
protect_from_forgery with: :exception
helper_method :current_user, :logged_in?
private
def current_user
#current_user ||= User.find(session[:user_id]) if session[:user_id]
end
def logged_in?
!!session[:user_id]
end
def authenticate
return if logged_in?
redirect_to root_path
end
end
Under codes are for models
class Waitinglist < ActiveRecord::Base
belongs_to :waiting_person, class_name: 'User'
after_initialize :init
def init
self.count_number ||= 1 #will set the default value only if it's nil
end
end
class User < ActiveRecord::Base
has_many :created_waitinglists, class_name: 'Waitinglist', foreign_key: :owner_id
def self.find_or_create_from_auth_hash(auth_hash)
provider = auth_hash[:provider]
uid = auth_hash[:uid]
name = auth_hash[:info][:name]
image_url = auth_hash[:info][:image]
User.find_or_create_by(provider: provider, uid: uid) do |user|
user.nickname = name
user.image_url = image_url
end
end
end
It's quite clear to me. You call save on #current_person_group_number, which is instance of Fixnum, so it doesn't have save method defined.
Unfortunately the code you wrote makes very little sense and it is pretty hard to understand what you're trying to do here.
Firstly, you overuse instance variables. If you're not gona use them in another methods (it is hard to say as you haven't post rest of your class)
Secondly, you overuse select method.
#group_number = Waitinglist.select(:count_number).last
All it does is changing the SELECT statement when querying the database for models, but it still returns the model, not a number or field value. So #group_number is not a number - it is a WaitingList instance. If you want a number do:
group_number = WaitingList.last.count_number
(posting now as question may be closed in a second. Will update later if that won't happen)
You can only save the ActiveRecord objects, which means you need to have it somewhere. Apparantly you want to update #current_person_group_number, however you can't reassign this variable to do the trick. You have to get the whole model, change its attribute and then save the model. It would look sth like:
current_waiting_list = current_user.created_waitinglists.last # This seems to be a collection, you need to tell here which waiting list you want to get from this collection
current_waiting_list.count_number += 1
current_waitin_list.save
My last point is - please look into act_as_list gem. Since you're creating waiting list it is a must have gem for you.
For some reason in my current controller I am getting ActiveModel::ForbiddenAttributesError even though I believe I am using strong parameters just fine. Albeit I am using permit! for the time being to permit all model attributes. See code below, what am I missing
class HeuristicsController < ApplicationController
def index
#heuristics = Heuristic.order(:name).page params[:page]
#heuristic = Heuristic.new
end
def create
#heuristic = Heuristic.new(params[:heuristic])
if #heuristic.save
redirect_to action: 'index', :flash => {:success => "New heuristic created!" }
else
render 'new'
end
end
def new
#title = "Heuristic"
#heuristic = Heuristic.new
end
private
def heuristic_params
params.require(:heuristic).permit!
end
end
i think you did not fully understand the way that strong-params work...
you have a method
def heuristic_params
params.require(:heuristic).permit!
end
and you are not using it
Heuristic.new(params[:heuristic])
I have a model, Domain, which has a text field, names.
> rails g model Domain names:text
invoke active_record
create db/migrate/20111117233221_create_domains.rb
create app/models/domain.rb
> rake db:migrate
== CreateDomains: migrating ==================================================
-- create_table(:domains)
-> 0.0015s
== CreateDomains: migrated (0.0066s) =========================================
I set this field as serialized into an array in the model.
# app/models/domain.rb
class Domain < ActiveRecord::Base
serialize :names, Array
end
Create the ActiveAdmin resource for this model
> rails g active_admin:resource Domain
create app/admin/domains.rb
then, in the app/admin/domains.rb, I setup the various blocks to handle the serialized field as such
# app/admin/domains.rb
ActiveAdmin.register Domain do
index do
id_column
column :names do |domain|
"#{domain.names.join( ", " ) unless domain.names.nil?}"
end
default_actions
end
show do |domain|
attributes_table do
row :names do
"#{domain.names.join( ", " ) unless domain.names.nil?}"
end
end
end
form do |f|
f.inputs "Domain" do
f.input :names
end
f.buttons
end
# before we save, take the param[:domain][:name] parameter,
# split and save it to our array
before_save do |domain|
domain.names = params[:domain][:names].split(",") unless params[:domain].nil? or params[:domain][:names].nil?
end
end
Nearly everything works great -- my names are displayed as comma separated in the index and show views. When I update a record with my names field set to "a,b,c", the before_save works to turn that into an array that is then saved via the ActiveRecord serialize.
What I can not solve is how to make the edit form put in a comma-separated list into the text field. I tried using a partial and using formtastic syntax directly as well as trying to make it work via the active_admin DLS syntax. Does anyone know how to make this work?
Specifically, if I have the following array saved in my domain.names field:
# array of names saved in the domain active_record
domain.names = ["a", "b", "c"]
how to change:
form do |f|
f.inputs "Domain" do
f.input :names
end
f.buttons
end
so that when the edit form is loaded, in the text field instead of seeing abc, you see a,b,c.
Here is a summary of how I handled this situation. I added an accessor to the model which can turn the Array into a string joined by a linefeed and split it back to an Array.
# app/models/domain.rb
class Domain < ActiveRecord::Base
serialize :names, Array
attr_accessor :names_raw
def names_raw
self.names.join("\n") unless self.names.nil?
end
def names_raw=(values)
self.names = []
self.names=values.split("\n")
end
end
then, in my admin resource for domain, instead of using the :names field, I used the :names_raw field. setting this value would save the names Array with the new values.
# app/admin/domains.rb
form do |f|
f.inputs "Domain" do
f.input :names_raw, :as => :text
end
f.buttons
end
Stumbled on this question looking for something to have access to a serialized Hash's YAML. I used this solution on Rails 3.2:
def target_raw
#attributes['target'].serialized_value
end
def target_raw=(new_value)
#attributes['target'].state = :serialized
#attributes['target'].value = new_value
end
This came up a bit ago ( rails model attributes without corresponding column in db ) but it looks like the Rails plugin mentioned is not maintained ( http://agilewebdevelopment.com/plugins/activerecord_base_without_table ). Is there no way to do this with ActiveRecord as is?
If not, is there any way to get ActiveRecord validation rules without using ActiveRecord?
ActiveRecord wants the table to exist, of course.
This is an approach I have used in the past:
In app/models/tableless.rb
class Tableless < ActiveRecord::Base
def self.columns
#columns ||= [];
end
def self.column(name, sql_type = nil, default = nil, null = true)
columns << ActiveRecord::ConnectionAdapters::Column.new(name.to_s, default,
sql_type.to_s, null)
end
# Override the save method to prevent exceptions.
def save(validate = true)
validate ? valid? : true
end
end
In app/models/foo.rb
class Foo < Tableless
column :bar, :string
validates_presence_of :bar
end
In script/console
Loading development environment (Rails 2.2.2)
>> foo = Foo.new
=> #<Foo bar: nil>
>> foo.valid?
=> false
>> foo.errors
=> #<ActiveRecord::Errors:0x235b270 #errors={"bar"=>["can't be blank"]}, #base=#<Foo bar: nil>>
Validations are simply a module within ActiveRecord. Have you tried mixing them into your non-ActiveRecord model?
class MyModel
include ActiveRecord::Validations
# ...
end
I figure the more answers the better since this is one of the first results in google when searching for "rails 3.1 models without tables"
I've implements the same thing without using ActiveRecord::Base while including the ActiveRecord::Validations
The main goal was to get everything working in formtastic, and below I've included a sample payment that will not get saved anywhere but still has the ability to be validated using the validations we all know and love.
class Payment
include ActiveModel::Validations
attr_accessor :cc_number, :payment_type, :exp_mm, :exp_yy, :card_security, :first_name, :last_name, :address_1, :address_2, :city, :state, :zip_code, :home_telephone, :email, :new_record
validates_presence_of :cc_number, :payment_type, :exp_mm, :exp_yy, :card_security, :first_name, :last_name, :address_1, :address_2, :city, :state
def initialize(options = {})
if options.blank?
new_record = true
else
new_record = false
end
options.each do |key, value|
method_object = self.method((key + "=").to_sym)
method_object.call(value)
end
end
def new_record?
return new_record
end
def to_key
end
def persisted?
return false
end
end
I hope this helps someone as I've spent a few hours trying to figure this out today.
UPDATE: For Rails 3 this can be done very easy. In Rails 3+ you can use the new ActiveModel module and its submodules. This should work now:
class Tableless
include ActiveModel::Validations
attr_accessor :name
validates_presence_of :name
end
For more info, you can check out the Railscast (or read about it on AsciiCasts) on the topic, as well as this blog post by Yehuda Katz.
OLD ANSWER FOLLOWS:
You may need to add this to the solution, proposed by John Topley in the previous comment:
class Tableless
class << self
def table_name
self.name.tableize
end
end
end
class Foo < Tableless; end
Foo.table_name # will return "foos"
This provides you with a "fake" table name, if you need one. Without this method, Foo::table_name will evaluate to "tablelesses".
Just an addition to the accepted answer:
Make your subclasses inherit the parent columns with:
class FakeAR < ActiveRecord::Base
def self.inherited(subclass)
subclass.instance_variable_set("#columns", columns)
super
end
def self.columns
#columns ||= []
end
def self.column(name, sql_type = nil, default = nil, null = true)
columns << ActiveRecord::ConnectionAdapters::Column.new(name.to_s, default, sql_type.to_s, null)
end
# Overrides save to prevent exceptions.
def save(validate = true)
validate ? valid? : true
end
end
This is a search form that presents an object called criteria that has a nested period object with beginning and end attributes.
The action in the controller is really simple yet it loads values from nested objects on the form and re-renders the same values with error messages if necessary.
Works on Rails 3.1.
The model:
class Criteria < ActiveRecord::Base
class << self
def column_defaults
{}
end
def column_names
[]
end
end # of class methods
attr_reader :period
def initialize values
values ||= {}
#period = Period.new values[:period] || {}
super values
end
def period_attributes
#period
end
def period_attributes= new_values
#period.attributes = new_values
end
end
In the controller:
def search
#criteria = Criteria.new params[:criteria]
end
In the helper:
def criteria_index_path ct, options = {}
url_for :action => :search
end
In the view:
<%= form_for #criteria do |form| %>
<%= form.fields_for :period do |prf| %>
<%= prf.text_field :beginning_as_text %>
<%= prf.text_field :end_as_text %>
<% end %>
<%= form.submit "Search" %>
<% end %>
Produces the HTML:
<form action="/admin/search" id="new_criteria" method="post">
<input id="criteria_period_attributes_beginning_as_text" name="criteria[period_attributes][beginning_as_text]" type="text">
<input id="criteria_period_attributes_end_as_text" name="criteria[period_attributes][end_as_text]" type="text">
Note: The action attribute provided by the helper and the nested attributes naming format that makes it so simple for the controller to load all the values at once
There is the activerecord-tableless gem. It's a gem to create tableless ActiveRecord models, so it has support for validations, associations, types. It supports Active Record 2.3, 3.0, 3.2
The recommended way to do it in Rails 3.x (using ActiveModel) has no support for associations nor types.