How to handle rails enums? - ruby-on-rails

How can I handle enums in rails? I have googled this, but not finding any clean solutions. So far I have come up with including the concern below on models that use interaction_type_id. This is my foreign key to my enum table in the database. Using this approach I don't have to use ids all over my code, but when saving an object that relates to an interact_type I can say
myobject.interaction_type = :file_download
This can then persist the the database with the correct id since the concern(see concern below - included on models that use the enum) will return the correct id.
module InteractionTypeEnum
extend ActiveSupport::Concern
included do
INTERACTION_TYPE = { file_download: 1, email: 2, telesales: 3, registration: 4, enrolment: 5 }
end
def interaction_type
INTERACTION_TYPE.key(read_attribute(:interaction_type_id)).to_s.gsub('_',' ').capitalize
end
def interaction_type=(s)
write_attribute(:interaction_type_id, INTERACTION_TYPE[s])
end
end
This just feels heavy. There must be an easier/cleaner way. Now when trying to write tests for this it gets even more messy.
Most of the reasons for wanting my enums in code and database are performance (code) and reporting (database).
Any help appreciated. Thanks.

I recommend the active_enum gem.
Example from their docs, if you have an integer column called sex on the class User:
class User < ActiveRecord::Base
enumerate :sex do
value :name => 'Male'
value :name => 'Female'
end
end
Or you can define the enum in a seperate class:
class Sex < ActiveEnum::Base
value 1 => 'Male'
value 2 => 'Female'
end
class User < ActiveRecord::Base
enumerate :sex, :with => Sex
end
I like the abstraction it provides, and it saves you from having to create an entire database table just to store your enum values.

I use the following method, say I have
class PersonInfo < ActiveRecord::Base
belongs_to :person_info_type
end
and PersonInfoType is a simple domain table, containing the possible types of information.
Then I code my model as follows:
class PersonInfoType < ActiveRecord::Base
PHONE = 1
EMAIL = 2
URL = 3
end
I have a seed fills the database with the corresponding data.
And so when assigning some person-information can do something like
person.person_infos << PersonInfo.create(:info => 'http://www.some-url.com', :person_info_type_id => PersonInfoType::URL)
This code can then be further cleaned up using relations:
class PersonInfo
belongs_to :person_info_type
def self.phones
PersonInfo.where(:person_info_type_id => PersonInfoType::PHONE)
end
end
person.person_infos << PersonInfo.phones.create(:info => '555 12345')

Related

Convert an Object to hash then save it to user's column

Could not find nothing close to what I'm trying to do. I want to store an object into a user's column. That column is in the form of an array:
#postgres
def change
add_column :users, :interest, :string, array: true, default: '{}'
end
I have another model called FooBar setup for other use. Each user has unique information inside as I've added a user_id key.
Im trying to make more sense:
def interest
#user = User.find(current_user.id ) # I need the logged in user's id
#support = Support.find(params[:id]) # I need the post's id they are on
u = FooBar.new
u.user_id = #user
u.support_id = #support
u.save # This saves a new Foo object..this is what I want
#user.interest.push(FooBar.find(#user)) # This just stores the object name itself ;)
end
So when I call u1 = FooBar.find(1) I get value return in hash. I want when I say u1.interest I get the same. The reason is, I need to target those keys on the user ie: u1.interest[0].support_id
Is this possible? I've looked over my basic ruby docs and nothing works. Oh..if I passed FooBar.find(#user).inspect I get the hash but not the way I want it.
Im trying to do something similar to stripe. Look at their data key. That's a hash.
Edit for Rich' answer:
I have, literally, a model called UserInterestSent model and table:
class UserInterestSent < ActiveRecord::Base
belongs_to :user
belongs_to :support # you can call this post
end
class CreateUserInterestSents < ActiveRecord::Migration
def change
create_table :user_interest_sents do |t|
t.integer :user_id # user's unique id to associate with post (support)
t.integer :interest_sent, :default => 0 # this will manually set to 1
t.integer :support_id, :default => 0 # id of the post they're on
t.timestamps # I need the time it was sent/requested for each user
end
end
end
I call interest interest_already_sent:
supports_controller.rb:
def interest_already_sent
support = Support.find(params[:id])
u = UserInterestSent.new(
{
'interest_sent' => 1, # they can only send one per support (post)
'user_id' => current_user.id, # here I add the current user
'support_id' => support.id, # and the post id they're on
})
current_user.interest << u # somewhere this inserts twice with different timestamps
end
And the interest not interests, column:
class AddInterestToUsers < ActiveRecord::Migration
def change
add_column :users, :interest, :text
end
end
HStore
I remembered there's a PGSQL datatype called hStore:
This module implements the hstore data type for storing sets of
key/value pairs within a single PostgreSQL value. This can be useful
in various scenarios, such as rows with many attributes that are
rarely examined, or semi-structured data. Keys and values are simply
text strings.
Heroku supports it and I've seen it used on another live application I was observing.
It won't store your object in the same way as Stripe's data attribute (for that, you'll just need to use text and save the object itself), but you can store a series of key:value pairs (JSON).
I've never used it before, but I'd imagine you can send a JSON object to the column, and it will allow you to to use the attributes you need. There's a good tutorial here, and Rails documentation here:
# app/models/profile.rb
class Profile < ActiveRecord::Base
end
Profile.create(settings: { "color" => "blue", "resolution" => "800x600" })
profile = Profile.first
profile.settings # => {"color"=>"blue", "resolution"=>"800x600"}
profile.settings = {"color" => "yellow", "resolution" => "1280x1024"}
profile.save!
--
This means you should be able to just pass JSON objects to your hstore column:
#app/controllers/profiles_controller.rb
class ProfilesController < ApplicationController
def update
#profile = current_user.profile
#profile.update profile_params
end
private
def profile_params
params.require(:profile).permit(:x, :y, :z) #-> z = {"color": "blue", "weight": "heavy"}
end
end
As per your comments, it seems to me that you're trying to store "interest" in a User from another model.
My first interpretation was that you wanted to store a hash of information in your #user.interests column. Maybe you'd have {name: "interest", type: "sport"} or something.
From your comments, it seems like you're wanting to store associated objects/data in this column. If this is the case, the way you're doing it should be to use an ActiveRecord association.
If you don't know what this is, it's essentially a way to connect two or more models together through foreign keys in your DB. The way you set it up will determine what you can store & how...
#app/models/user.rb
class User < ActiveRecord::Base
has_and_belongs_to_many :interests,
class_name: "Support",
join_table: :users_supports,
foreign_key: :user_id,
association_foreign_key: :support_id
end
#app/models/support.rb
class Support < ActiveRecord::Base
has_and_belongs_to_many :users,
class_name: "Support",
join_table: :users_supports,
foreign_key: :support_id,
association_foreign_key: :user_id
end
#join table = users_supports (user_id, support_id)
by using this, you can populate the .interests or .users methods respectively:
#config/routes.rb
resources :supports do
post :interest #-> url.com/supports/:support_id/interest
end
#app/controllers/supports_controller.rb
class SupportsController < ApplicationController
def interest
#support = Support.find params[:support_id] # I need the post's id they are on
current_user.interests << #support
end
end
This will allow you to call #user.interests and bring back a collection of Support objects.
Okay, look.
What I suggested was an alternative to using interest column.
You seem to want to store a series of hashes for an associated model. This is exactly what many-to-many relationships are for.
The reason your data is being populated twice is because you're invoking it twice (u= is creating a record directly on the join model, and then you're inserting more data with <<).
I must add that in both instances, the correct behaviour is occurring; the join model is being populated, allowing you to call the associated objects.
What you're going for is something like this:
def interest_already_sent
support = Support.find params[:id]
current_user.interests << support
end
When using the method I recommended, get rid of the interest column.
You can call .interests through your join table.
When using the code above, it's telling Rails to insert the support object (IE support_id into the current_user (IE user_id) interests association (populated with the UserInterestSelf table).
This will basically then add a new record to this table with the user_id of current_user and the support_id of support.
EDIT
To store Hash into column, I suggest you to use "text" instead
def change
add_column :users, :interest, :text
end
and then set "serialize" to attribute
class User < ActiveRecord::Base
serialize :interest
end
once it's done, you can save hash object properly
def interest
#user = User.find(current_user.id ) # I need the logged in user's id
#support = Support.find(params[:id]) # I need the post's id they are on
u = FooBar.new
u.user_id = #user
u.support_id = #support
u.save # This saves a new Foo object..this is what I want
#user.interest = u.attributes # store hash
#user.save
end
To convert AR object to hash use object.attributes.
To store a custom hash in a model field you can use serialize or ActiveRecord::Store
You can also use to_json method as object.to_json
User.find(current_user.id ).to_json # gives a json string

Ruby copying between active model objects

Simply trying to work out how to copy attributes from one Active Model to another without having to do it one by one.
I have two models one is RFM (ruby to filemaker) one is mongoid both mixin active model.
gem "ginjo-rfm"
the model
require 'rfm'
class StudentAdmin < Rfm::Base
config :layout => 'STUDENT_ADMIN_LAYOUT'
attr_accessor :name_first,:name_last
end
Mongoid model
class Student
include Mongoid::Document
field :first_name, type: String
field :last_name, type: String
end
Is there a quicky copy I can do? I found a sample between active record objects e.g.
student_admin = ... #load StudentAdmin
Student.new(student_admin.attributes.slice(Student.attribute_names))
but RFM doesn't provide a attributes method.
EDIT
Sorry what I am trying to achive is a better way than this
student_admins = #get student admins from external service
students = []
student_admins.each() do |sa|
students.push(Student.create!(first_name: sa.name_first, last_name: sa.name_last))
end
This example only shows 2 attributes, but in practice there is over 50 and was wondering if there is a way to do it without having to specify every attribute e.g. if the attribute names are the same on two objects copy them automatically.
Try this:
students = student_admins.map do |sa|
attrs = sa.methods.inject({}) do |hash, m|
next unless Student.column_names.include? m.to_s
hash[m] = sa.send m
end
Student.create(attrs)
end
Student would have to be a class that inherits from ActiveRecord::Base:
class Student < ActiveRecord::Base
...
end

Mongoid: Querying from two collections and sorting by date

I currently have the following controller method in a Rails app:
def index
#entries = []
#entries << QuickPost.where(:user_id.in => current_user.followees.map(&:ff_id) << current_user.id)
#entries << Infographic.where(:user_id.in => current_user.followees.map(&:ff_id) << current_user.id)
#entries.flatten!.sort!{ |a,b| b.created_at <=> a.created_at }
#entries = Kaminari.paginate_array(#entries).page(params[:page]).per(10)
end
I realise this is terribly inefficient so I'm looking for a better way to achieve the same goal but I'm new to MongoDB and wondering what the best solution would be.
Is there a way to make a sorted limit() query or a MapReduce function in MongoDB across two collections? I'm guessing there isn't but it would certainly save a lot of effort in this case!
I'm currently thinking I have two options:
Create a master 'StreamEntry' type model and have both Infographic and QuickPost inherit from that so that both data types are stored on the same collection. The issue with this is that I have existing data and I don't know how to move it from the old collections to the new.
Create a separate Stream/ActivityStream model using something like Streama (https://github.com/christospappas/streama). The issues I can see here is that it would require a fair bit of upfront work and due to privacy settings and editing/removal of items the stream would need to be rebuilt often.
Are there options I have overlooked? Am I over-engineering with the above options? What sort of best practices are there for this type of situation?
Any info would be greatly appreciated, I'm really liking MongoDB so far and want to avoid falling into pitfalls like this in the future. Thanks.
The inherit solution is fine, but when the inherited models are close.
For example :
class Post < BasePost
field :body, type: String
end
class QuickPost < BasePost
end
class BasePost
field :title, type: String
field :created_at, type: Time
end
But when the models grows, or are too different, your second solution is better.
class Activity
include Mongoid::Document
paginates_per 20
field :occurred_at, :type => Time, :default => nil
validates_presence_of :occurred_at
belongs_to :user
belongs_to :quick_post
belongs_to :infographic
default_scope desc(:occurred_at)
end
and for example :
class QuickPost
include Mongoid::Document
has_one :activity, :dependent => :destroy
end
The dependant destroy make the activity destroyed when the QuickPost is destroyed. You can use has_many and adapt.
And to create the activities, you can create an observer :
class ActivityObserver < Mongoid::Observer
observe :quick_post, :infographic
def after_save(record)
if record.is_a? QuickPost
if record.new_record?
activity = record.build_activity
activity.user = record.user
# stuff when it is new
else
activity = record.activity
end
activity.occurred_at = record.occurred_at
# common stuff
activity.save
end
end
end

Can nested attributes be used in combination with inheritance?

I have the following classes:
Project
Person
Person > Developer
Person > Manager
In the Project model I have added the following statements:
has_and_belongs_to_many :people
accepts_nested_attributes_for :people
And of course the appropriate statements in the class Person. How can I add a Developer to a Project through the nested_attributes method? The following does not work:
#p.people_attributes = [{:name => "Epic Beard Man", :type => "Developer"}]
#p.people
=> [#<Person id: nil, name: "Epic Beard Man", type: nil>]
As you can see the type attributes is set to nil instead of "Developer".
Solution for Rails3: attributes_protected_by_default in now a class-method:
class Person < ActiveRecord::Base
private
def self.attributes_protected_by_default
super - [inheritance_column]
end
end
I encountered a similar problem few days ago. The inheritance column(i.e. type) in a STI model is a protected attribute. Do the following to override the default protection in your Person class.
Rails 2.3
class Person < ActiveRecord::Base
private
def attributes_protected_by_default
super - [self.class.inheritance_column]
end
end
Rails 3
Refer to the solution suggested by #tokland.
Caveat:
You are overriding the system protected attribute.
Reference:
SO Question on the topic
Patches above did not work for me, but this did (Rails3):
class ActiveRecord::Reflection::AssociationReflection
def build_association(*options)
if options.first.is_a?(Hash) and options.first[:type].presence
options.first[:type].to_s.constantize.new(*options)
else
klass.new(*options)
end
end
end
Foo.bars.build(:type=>'Baz').class == Baz
For those of us using Mongoid, you will need to make the _type field accessible:
class Person
include Mongoid::Document
attr_accessible :_type
end

MongoMapper has_many association

I have problem with mongomapper associations. I have one class names User and other named Model. User has many models but...
user = User.first
=> <User ...
user.models
=> []
Model.find_by_user_id(user.id.to_s)
=> <Model ...
Model.find_by_user_id(user.id.to_s).user == user
=> true
Class code (simplified):
class User
include MongoMapper::Document
# some keys definition
many :models
end
class Model
include MongoMapper::Document
# some keys definitions
belongs_to :user
end
What I am doing wrong?
It appears that MM no longer uses String format for the FK column, so
Model.find_by_user_id(user.id.to_s)
should be
Model.find_by_user_id(user.id)
Furthermore, the datatype of the Model.user_id column should be set to
key :user_id, Mongo::ObjectID
When I ran into this problem, I had to delete and recreate my collection to get it to work- in other words I used to have user_id as a String, but it would only "take" when I switched it when I rebuilt my database. Luckily I am working with test data so that was easy enough.
What kind of errors or exceptions are you getting? The code you posted looks fine.
ah, this is poorly documented in the mm docs. You need to do this here:
class User
include MongoMapper::Document
# some keys definition
many :models, :in => :model_ids
end
class Model
include MongoMapper::Document
# some keys definitions
# no belongs_to necessary here
end
You can then add models to your user via:
# use an existing object
u = User.create ...
m = Model.create ...
# and add the model to the user
u.models << m
# don't forget to save
u.save
# you can then check if it worked like so:
# u.model_ids => [ BSON::ID 'your user id']
Hope that helped.

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