I created a model for a thing called a Lesson that has :content and a :user_id. For early builds of this app, I want the content to be changing, based on my entry, and for the user_id to always = 1 so that it's clean in the DB and there's not a nil value.
How do I go about this?
In my lessons_controller.rb I have this:
def create
#lesson = Lesson.new(params[:lesson])
if #lesson.save
... do something
else
... do something else
I'm guessing this would be the best place to define that the user_id = 1 but how should I go about that?
You can just set #lesson.user_id = 1 in the line after you create it with new, and before you save it.
Another way to do it would be to set a hook in the lesson model -
before_validation :on => :create do |lesson|
lesson.user_id = 1
end
Related
I created a class method that is called when a new object is created and copied from an old existing object. However, I only want to copy some of the values. Is there some sort of Ruby shorthand I can use to clean this up? It's not entirely necessary, just curious to know if something like this exists?
Here is the method I want to DRY up:
def set_message_settings_from_existing existing
self.can_message = existing.can_message
self.current_format = existing.current_format
self.send_initial_message = existing.send_initial_message
self.send_alert = existing.send_alert
self.location = existing.location
end
Obviously this works perfectly fine, but to me looks a little ugly. Is there any way to clean this up? If I wanted to copy over every value that would be easy enough, but because I only want to copy these 5 (out of 20 something) values, I decided to do it this way.
def set_message_settings_from_existing(existing)
[:can_message, :current_format, :send_initial_message, :send_alert, :location].each do |attribute|
self.send("#{attribute}=", existing.send(attribute))
end
end
Or
def set_message_settings_from_existing(existing)
self.attributes = existing.attributes.slice('can_message', 'current_format', 'send_initial_message', 'send_alert', 'location')
end
a hash might be cleaner:
def set_message_settings_from_existing existing
fields = {
can_message: existing.can_message,
current_format: existing.current_format,
send_initial_message: existing.send_initial_message,
send_alert: existing.send_alert,
location: existing.location
}
self.attributes = fields
end
you can take this further by only selecting the attributes you want:
def set_message_settings_from_existing existing
fields = existing.attributes.slice(
:can_message,
:current_format,
:send_initial_message,
:send_alert,
:location
)
self.attributes = fields
end
at this point you could also have these fields defined somewhere, eg:
SUB_SET_OF_FIELDS = [:can_message, :current_format, :send_initial_message, :send_alert, :location]
and use that for your filter instance.attributes.slice(SUB_SET_OF_FIELDS)
I have two models with the [fields]:
Order [:date]
Delivery Slot [:day]
Order belongs_to :delivery_slot
When an order is created, I want a delivery slot to be created with the :day set to the order :date.
So far I have created a new method create_delivery_slots in the Order controller that creates a Delivery Slot when the Order is created, but where I am stumped is, how do I get the Order :date in the Delivery Slot :day field?
#Create delivery slots if they dont already exist
def create_delivery_slots
existingslots = []
existingslots = DeliverySlot.all.select {|slot| slot.day == #order.date}
if existingslots.empty?
slot = DeliverySlot.new(:day => #order.date)
slot.save!
end
I have tried multiple approaches, but no luck. My gut tells me its something to do with strong parameters but I can't figure it out...
I'm not sure exactly of how you're set up but you'll probably want something like this:
class Order < ActiveRecord::Base
has_a :delivery_slot
after_create => :create_delivery_slots
.
#other code stuffs
.
.
private
def create_delivery_slots
existingslots = []
existingslots = DeliverySlot.all.select {|slot| slot.day == self.date}
if existingslots.empty?
slot = DeliverySlot.new(:day => self.date)
slot.save!
end
end
end
That's untested but it should be basically what you need.
I have an array of values, like:
- #colors.each do |color|
= check_box_tag 'colors[]', color.id
Every time, when I update the values from those checkbox in the DB table, I am doing that by this way:
UserColor.delete_all(['user_id = ?'], current_user.id) #delete all user's rows
unless params[:colors].nil?
params[:colors].each do |color|
UserColor.create(:user_id => current_user.id, :color_id => color)
end
end
It's the working solution, but I don't like it very much. That's why I would like to ask you, how do you solve this problem and if doesn't exist any some better way to do it.
Thanks
class User
has_many :colors, through: :user_colors
end
in controller
if params[:colors]
user = current_user
user.color_ids = params[:colors]
user.save
end
or u can try
current_user.update_attribute(:color_ids, params[:colors]) if params[:colors]
I would define a method in the User model
def update_colors!(new_color_ids)
# get an array of the current color ids
old_color_ids = user_colors.map(&:color_id)
# destroy colors that appear in the old list but not in the new
user_colors.where(color_id: old_color_ids - new_color_ids).destroy_all
# add colors that appear in the new list but not in the old
(new_color_ids - old_color_ids).each do |add_color_id|
user_colors.create!(color_id: add_color_id)
end
end
From the controller, just call
current_user.update_colors!(params[:colors])
.
I have a create statement for some models, but it’s creating a record within a join table regardless of whether the record already exists.
Here is what my code looks like:
#user = User.find(current_user)
#event = Event.find(params[:id])
for interest in #event.interests
#user.choices.create(:interest => interest, :score => 4)
end
The problem is that it creates records no matter what. I would like it to create a record only if no record already exists; if a record does exist, I would like it to take the attribute of the found record and add or subtract 1.
I’ve been looking around have seen something called find_or_create_by. What does this do when it finds a record? I would like it to take the current :score attribute and add 1.
Is it possible to find or create by id? I’m not sure what attribute I would find by, since the model I’m looking at is a join model which only has id foreign keys and the score attribute.
I tried
#user.choices.find_or_create_by_user(:user => #user.id, :interest => interest, :score => 4)
but got
undefined method find_by_user
What should I do?
my_class = ClassName.find_or_initialize_by_name(name)
my_class.update_attributes({
:street_address => self.street_address,
:city_name => self.city_name,
:zip_code => self.zip_code
})
Assuming that the Choice model has a user_id (to associate with a user) and an interest_id (to associate with an interest), something like this should do the trick:
#user = User.find(current_user)
#event = Event.find(params[:id])
#event.interests.each do |interest|
choice = #user.choices.find_or_initialize_by_interest_id(interest.id) do |c|
c.score = 0 # Or whatever you want the initial value to be - 1
end
choice.score += 1
choice.save!
end
Some notes:
You don't need to include the user_id column in the find_or_*_by_*, as you've already instructed Rails to only fetch choices belonging to #user.
I'm using find_or_initialize_by_*, which is essentially the same as find_or_create_by_*, with the one key difference being that initialize doesn't actually create the record. This would be similar to Model.new as opposed to Model.create.
The block that sets c.score = 0 is only executed if the record does not exist.
choice.score += 1 will update the score value for the record, regardless if it exists or not. Hence, the default score c.score = 0 should be the initial value minus one.
Finally, choice.save! will either update the record (if it already existed) or create the initiated record (if it didn't).
find_or_create_by_user_id sounds better
Also, in Rails 3 you can do:
#user.choices.where(:user => #user.id, :interest => interest, :score => 4).first_or_create
If you're using rails 4 I don't think it creates the finder methods like it used to, so find_or_create_by_user isn't created for you. Instead you'd do it like this:
#user = User.find(current_user)
#event = Event.find(params[:id])
for interest in #event.interests
#user.choices.find_or_create_by(:interest => interest) do |c|
c.score ||= 0
c.score += 1
end
end
In Rails 4
You can use find_or_create_by to get an object(if not exist,it will create), then use update to save or update the record, the update method will persist record if it is not exist, otherwise update record.
For example
#edu = current_user.member_edu_basics.find_or_create_by(params.require(:member).permit(:school))
if #edu.update(params.require(:member).permit(:school, :majoy, :started, :ended))
Here is my one model..
CardSignup.rb
def credit_status_on_create
Organization.find(self.organization_id).update_credits
end
And here's my other model. As you can see what I wrote here is an incorrect way to pass the var
def update_credits
#organization = Organization.find(params[:id])
credit_count = #organization.card_signups.select { |c| c.credit_status == true}.count
end
If it can't be done by (params[:id]), what can it be done by?
Thanks!
Ideally the data accessible to the controller should be passed as parameter to model methods. So I advise you to see if it is possible to rewrite your code. But here are two possible solutions to your problem. I prefer the later approach as it is generic.
Approach 1: Declare a virtual attribute
class CardSignup
attr_accessor call_context
def call_context
#call_context || {}
end
end
In your controller code:
def create
cs = CardSignup.new(...)
cs.call_context = params
if cs.save
# success
else
# error
end
end
In your CardSignup model:
def credit_status_on_create
Organization.find(self.organization_id).update_credits(call_context)
end
Update the Organization model. Note the change to your count logic.
def update_credits
#organization = Organization.find(call_context[:id])
credit_count = #organization.card_signups.count(:conditions =>
{:credit_status => true})
end
Approach 2: Declare a thread local variable accessible to all models
Your controller code:
def create
Thread.local[:call_context] = params
cs = CardSignup.new(...)
if cs.save
# success
else
# error
end
end
Update the Organization model. Note the change to your count logic.
def update_credits
#organization = Organization.find((Thread.local[:call_context] ||{})[:id])
credit_count = #organization.card_signups.count(:conditions =>
{:credit_status => true})
end
Use an attr_accessor.
E.g.,
class << self
#myvar = "something for all instances of model"
attr_accessor :myvar
end
#myothervar = "something for initialized instances"
attr_accessor :myothervar
then you can access them as ModelName.myvar and ModelName.new.myvar respectively.
You don't say whether you're using Rails 2 or 3 but let's assume Rails 2 for this purpose (Rails 3 provides the a new DSL for constructing queries).
You could consider creating a named scope for in your Organization model as follows:
named_scope :update_credits,
lambda { |id| { :include => :card_signup, :conditions => [ "id = ? AND card_signups.credit_status = TRUE", id ] } }
And then use it as follows:
def credit_status_on_create
Organization.update_credits(self.organization_id)
end
Admittedly I don't quite understand the role of the counter in your logic but I'm sure you could craft that back into this suggestion if you adopt it.