Is there an equivalent of Active Records Model.create_with to pass creation parameters separate of find parameters in Mongoid?
# Find the first user named "Scarlett" or create a new one with
# a particular last name.
User.create_with(last_name: 'Johansson').find_or_create_by(first_name: 'Scarlett')
# => #<User id: 2, first_name: "Scarlett", last_name: "Johansson">
I find myself using a clunky workaround:
user = User.find_or_initialze_by(first_name: 'Scarlett')
user.update(last_name: 'Johansson') if user.new_record?
Mongoid's find_or_create_by takes an optional block which is only used when it needs to create something. The documentation isn't exactly explicit about this behavior but if you check the code you'll see that find_or_create_by ends up as a call to this find_or method:
def find_or(method, attrs = {}, &block)
where(attrs).first || send(method, attrs, &block)
end
with method being :create and the block isn't used if the document you're looking for is found by where.
That means that you can say:
user = User.find_or_create_by(first_name: 'Scarlett') do |user|
user.last_name = 'Johansson'
end
to get the effect you're after.
Presumably this "the create half uses the block" behavior is supposed to be obvious because create takes a block to initialize the object but find doesn't.
If you're paranoid about this undocumented behavior, you can include a check for it in your specs so you'll at least know when an upgrade breaks it.
Related
I have a class called CachedObject that stores generic serialized objects indexed by a key. I want this class to implement a create_or_update method. If an object is found it will update it, otherwise it will create a new one.
Is there a way to do this in Rails or do I have to write my own method?
Rails 6
Rails 6 added an upsert and upsert_all methods that deliver this functionality.
Model.upsert(column_name: value)
[upsert] It does not instantiate any models nor does it trigger Active Record callbacks or validations.
Rails 5, 4, and 3
Not if you are looking for an "upsert" (where the database executes an update or an insert statement in the same operation) type of statement. Out of the box, Rails and ActiveRecord have no such feature. You can use the upsert gem, however.
Otherwise, you can use: find_or_initialize_by or find_or_create_by, which offer similar functionality, albeit at the cost of an additional database hit, which, in most cases, is hardly an issue at all. So unless you have serious performance concerns, I would not use the gem.
For example, if no user is found with the name "Roger", a new user instance is instantiated with its name set to "Roger".
user = User.where(name: "Roger").first_or_initialize
user.email = "email#example.com"
user.save
Alternatively, you can use find_or_initialize_by.
user = User.find_or_initialize_by(name: "Roger")
In Rails 3.
user = User.find_or_initialize_by_name("Roger")
user.email = "email#example.com"
user.save
You can use a block, but the block only runs if the record is new.
User.where(name: "Roger").first_or_initialize do |user|
# this won't run if a user with name "Roger" is found
user.save
end
User.find_or_initialize_by(name: "Roger") do |user|
# this also won't run if a user with name "Roger" is found
user.save
end
If you want to use a block regardless of the record's persistence, use tap on the result:
User.where(name: "Roger").first_or_initialize.tap do |user|
user.email = "email#example.com"
user.save
end
In Rails 4 you can add to a specific model:
def self.update_or_create(attributes)
assign_or_new(attributes).save
end
def self.assign_or_new(attributes)
obj = first || new
obj.assign_attributes(attributes)
obj
end
and use it like
User.where(email: "a#b.com").update_or_create(name: "Mr A Bbb")
Or if you'd prefer to add these methods to all models put in an initializer:
module ActiveRecordExtras
module Relation
extend ActiveSupport::Concern
module ClassMethods
def update_or_create(attributes)
assign_or_new(attributes).save
end
def update_or_create!(attributes)
assign_or_new(attributes).save!
end
def assign_or_new(attributes)
obj = first || new
obj.assign_attributes(attributes)
obj
end
end
end
end
ActiveRecord::Base.send :include, ActiveRecordExtras::Relation
The magic you have been looking for has been added in Rails 6
Now you can upsert (update or insert).
For single record use:
Model.upsert(column_name: value)
For multiple records use upsert_all :
Model.upsert_all(column_name: value, unique_by: :column_name)
Note:
Both methods do not trigger Active Record callbacks or validations
unique_by => PostgreSQL and SQLite only
Add this to your model:
def self.update_or_create_by(args, attributes)
obj = self.find_or_create_by(args)
obj.update(attributes)
return obj
end
With that, you can:
User.update_or_create_by({name: 'Joe'}, attributes)
Old question but throwing my solution into the ring for completeness.
I needed this when I needed a specific find but a different create if it doesn't exist.
def self.find_by_or_create_with(args, attributes) # READ CAREFULLY! args for finding, attributes for creating!
obj = self.find_or_initialize_by(args)
return obj if obj.persisted?
return obj if obj.update_attributes(attributes)
end
By chaining find_or_initialize_by and update, this can be achieved in a simple way which avoids the (in my experience, often) unwanted caveats of upsert, and also minimises database calls.
For example:
Class.find_or_initialize_by(
key: "foo",
...
).update(
new_attribute: "bar",
...
)
will return you newly created or updated object.
It is worth noting that if your find_or_initialize_by attributes match multiple Class instances, only the 'first' one will be selected and updated.
You can do it in one statement like this:
CachedObject.where(key: "the given key").first_or_create! do |cached|
cached.attribute1 = 'attribute value'
cached.attribute2 = 'attribute value'
end
The sequel gem adds an update_or_create method which seems to do what you're looking for.
I need to set the id parameter to a value if it is wasn't submitted with the form.
Is it ok to do something like this in Rails or does this violate any standards or cause possible issues?
if params[:cart][:cart_addresses_attributes]["0"][:id].blank?
params[:cart][:cart_addresses_attributes]["0"][:id] = 1234 #default id
end
My implementation works with this logic, but I am not sure if this is the proper way to handle the issue.
There's a chance [:record_type] is nil which will lead to an undefined method error when you attempt to call [:id] on nil. Additionally, I'd find it a bit weird to directly mutate params, even though you technically can do that. I'd consider using Strong Parameter processing methods like so (added a full action, which isn't in your sample, to give more context on how this would be used):
def create
#record_type = RecordType.new(record_type_params)
if record_type.save
redirect_to #record_type
else
render :new
end
end
def record_type_params
params.require(:record_type).permit(:id).reverse_merge(id: 1234)
end
The reverse_merge call is a way to merge the user-supplied parameters into your defaults. This accomplishes what you're after in what I would consider a more conventional way and doesn't mutate params.
def cart_params
params.require(:cart).permit(:cart_addresses_attributes => [:id]).tap do |p|
p[:cart_addresses_attributes]["0"][:id] ||= 1234
end
end
if params[:record_type][:id].nil? # or replace ".nil?" with "== nil"
params[:record_type][:id] = 1234
end
personally, this is the way I prefer to do it. Some ways are more efficient than others, but if that works for you I'd roll with it.
I want to disable all link of users at a time after deactivating users. So, for that I wrote a code like this
def link_to(*user)
if user_link_disabled?(user.id)
return nil
else
super
end
end
def user_link_disabled?(user_id)
User.where(activation: false).pluck(:name).include?(user_id)
end
But I am getting this error
undefined method `id' for #<Array:0x007efee4667d00>
Could anyone please help me on this?
I would add a column to your users model:
deactivated => type boolean
user.deactivated? #will return true or false
In your view you can then use link_to_unless
link_to_unless(user.deactivated, name, options = {}, html_options = {}, &block)
I don't know the scope because you didnt display anymore info but it could just be user_id in your if statement or try id[params[:id] instead of user.id but I'm not sure with out more context.
IN following method
def user_link_disabled?(user_id)
User.where(activation: false).pluck(:name).include?(user_id)
end
You are going to pluck name from user table records but you are checking include? for user.id, I think you should pluck id instead of name.
First of all, I am not gonna comment on your preferred code/method for overriding the the link_to helper. There is not much context available for that.
But to solve the particular error you are getting:
Your are defining method like this def link_to(*user) .
Here *user means it is expecting an Array as argument to the method and using the Ruby splat(*), it is converting it to normal arguments.
So if you call this as link_to [1,2,3], it will be same as calling a method with 3 arguments. That is link_to (1,2,3) but the argument user will be an Array.
So in here if user_link_disabled?(user.id), you are calling a id on a Array data type. That's why you are getting an error.
Depending on your use, either remove the * from method definition,
or
Use looping, if you are going to pass multiple users data to method, like:
def link_to(*user)
user.each do |u|
if user_link_disabled?(u.id)
return nil
else
super
end
end
end
As I mentioned in beginning, I don't know much about the context. So can not comment about the right way but if I may suggest, then I would suggest to use a custom helper for all user routes. like below pseudo code:
def link_to_user(user)
deactivated = user.deactivated?
if deactivated
# render some disabled link
else
# render link
end
end
I'm trying to monkey patch ActiveRecord::FinderMethods in order to use hashed ids for my models. So for example User.find(1) becomes User.find("FEW"). Sadly my overwritten method doesn't get called. Any ideas how to overwrite the find_one method?
module ActiveRecord
module FinderMethods
alias_method :orig_find_one, :find_one
def find_one(id)
if id.is_a?(String)
orig_find_one decrypt_id(id)
else
orig_find_one(id)
end
end
end
end
Here's an article that discusses how to actually do what you want by overriding the User.primary_key method like:
class User
self.primary_key = 'hashed_id'
end
Which would allow you to call User.find and pass it the "hashed_id":
http://ruby-journal.com/how-to-override-default-primary-key-id-in-rails/
So, it's possible.
That said, I would recommend against doing that, and instead using something like User.find_by_hashed_id. The only difference is that this method will return nil when a result is not found instead of throwing an ActiveRecord::RecordNotFound exception. You could throw this manually in your controller:
def show
#user = User.find_by_hashed_id(hashed_id)
raise ActiveRecord::RecordNotFound.new if #user.nil?
... continue processing ...
end
Finally, one other note to make this easier on you -- Rails also has a method you can override in your model, to_param, to tell it what property to use when generating routes. By default, of course, it users the id, but you would probably want to use the hashed_id.
class User
def to_param
self.hashed_id
end
end
Now, in your controller, params[:id] will contain the hashed_id instead of the id.
def show
#user = User.find_by_hashed_id(params[:id])
raise ActiveRecord::RecordNotFound.new if #user.nil?
... continue processing ...
end
I agree that you should be careful when doing this, but it is possible.
If you have a method decode_id that converts a hashed ID back to the original id, then the following will work:
In User.rb
# Extend AR find method to allow finding records by an encoded string id:
def self.find(*ids)
return super if ids.length > 1
# Note the short-circuiting || to fall-back to default behavior
find_by(id: decode_id(ids[0])) || super
end
Just make sure that decode_id returns nil if it's passed an invalid hash. This way you can find by Hashed ID and standard ID, so if you had a user with id 12345, then the following:
User.find(12345)
User.find("12345")
User.find(encode_id(12345))
Should all return the same user.
I have a class called CachedObject that stores generic serialized objects indexed by a key. I want this class to implement a create_or_update method. If an object is found it will update it, otherwise it will create a new one.
Is there a way to do this in Rails or do I have to write my own method?
Rails 6
Rails 6 added an upsert and upsert_all methods that deliver this functionality.
Model.upsert(column_name: value)
[upsert] It does not instantiate any models nor does it trigger Active Record callbacks or validations.
Rails 5, 4, and 3
Not if you are looking for an "upsert" (where the database executes an update or an insert statement in the same operation) type of statement. Out of the box, Rails and ActiveRecord have no such feature. You can use the upsert gem, however.
Otherwise, you can use: find_or_initialize_by or find_or_create_by, which offer similar functionality, albeit at the cost of an additional database hit, which, in most cases, is hardly an issue at all. So unless you have serious performance concerns, I would not use the gem.
For example, if no user is found with the name "Roger", a new user instance is instantiated with its name set to "Roger".
user = User.where(name: "Roger").first_or_initialize
user.email = "email#example.com"
user.save
Alternatively, you can use find_or_initialize_by.
user = User.find_or_initialize_by(name: "Roger")
In Rails 3.
user = User.find_or_initialize_by_name("Roger")
user.email = "email#example.com"
user.save
You can use a block, but the block only runs if the record is new.
User.where(name: "Roger").first_or_initialize do |user|
# this won't run if a user with name "Roger" is found
user.save
end
User.find_or_initialize_by(name: "Roger") do |user|
# this also won't run if a user with name "Roger" is found
user.save
end
If you want to use a block regardless of the record's persistence, use tap on the result:
User.where(name: "Roger").first_or_initialize.tap do |user|
user.email = "email#example.com"
user.save
end
In Rails 4 you can add to a specific model:
def self.update_or_create(attributes)
assign_or_new(attributes).save
end
def self.assign_or_new(attributes)
obj = first || new
obj.assign_attributes(attributes)
obj
end
and use it like
User.where(email: "a#b.com").update_or_create(name: "Mr A Bbb")
Or if you'd prefer to add these methods to all models put in an initializer:
module ActiveRecordExtras
module Relation
extend ActiveSupport::Concern
module ClassMethods
def update_or_create(attributes)
assign_or_new(attributes).save
end
def update_or_create!(attributes)
assign_or_new(attributes).save!
end
def assign_or_new(attributes)
obj = first || new
obj.assign_attributes(attributes)
obj
end
end
end
end
ActiveRecord::Base.send :include, ActiveRecordExtras::Relation
The magic you have been looking for has been added in Rails 6
Now you can upsert (update or insert).
For single record use:
Model.upsert(column_name: value)
For multiple records use upsert_all :
Model.upsert_all(column_name: value, unique_by: :column_name)
Note:
Both methods do not trigger Active Record callbacks or validations
unique_by => PostgreSQL and SQLite only
Add this to your model:
def self.update_or_create_by(args, attributes)
obj = self.find_or_create_by(args)
obj.update(attributes)
return obj
end
With that, you can:
User.update_or_create_by({name: 'Joe'}, attributes)
Old question but throwing my solution into the ring for completeness.
I needed this when I needed a specific find but a different create if it doesn't exist.
def self.find_by_or_create_with(args, attributes) # READ CAREFULLY! args for finding, attributes for creating!
obj = self.find_or_initialize_by(args)
return obj if obj.persisted?
return obj if obj.update_attributes(attributes)
end
By chaining find_or_initialize_by and update, this can be achieved in a simple way which avoids the (in my experience, often) unwanted caveats of upsert, and also minimises database calls.
For example:
Class.find_or_initialize_by(
key: "foo",
...
).update(
new_attribute: "bar",
...
)
will return you newly created or updated object.
It is worth noting that if your find_or_initialize_by attributes match multiple Class instances, only the 'first' one will be selected and updated.
You can do it in one statement like this:
CachedObject.where(key: "the given key").first_or_create! do |cached|
cached.attribute1 = 'attribute value'
cached.attribute2 = 'attribute value'
end
The sequel gem adds an update_or_create method which seems to do what you're looking for.