Description
Easy cloning of active_record objects including associations and several operations under associations and attributes.
Amoeba alternatives and similar gems
Based on the "Abstraction" category.
Alternatively, view Amoeba alternatives based on common mentions on social networks and blogs.
-
Waterfall
A slice of functional programming to chain ruby services and blocks, thus providing a new approach to flow control. Make them flow! -
u-service
Represent use cases in a simple and powerful way while writing modular, expressive and sequentially logical code. -
Smart Init - Simple service objects in Ruby
A simple gem for eliminating Ruby initializers boilerplate code, and providing unified service objects API -
SuperModule
SuperModule allows defining class methods and method invocations the same way a super class does without using def included(base). This also succeeds ActiveSupport::Concern by offering lighter syntax -
Invokable
Objects are functions! Treat any Object or Class as a Proc (like Enumerable but for Procs). -
EasilyTypable
Ruby module that facilitates English-like type checking in an inheritance hierarchy via "type_name?" methods -
dry-rb
dry-rb is a collection of next-generation Ruby libraries, each intended to encapsulate a common task.
Scout Monitoring - Performance metrics and, now, Logs Management Monitoring with Scout Monitoring
* Code Quality Rankings and insights are calculated and provided by Lumnify.
They vary from L1 to L5 with "L5" being the highest.
Do you think we are missing an alternative of Amoeba or a related project?
Popular Comparisons
README
Amoeba
Easy cloning of active_record objects including associations and several operations under associations and attributes.
What?
The goal was to be able to easily and quickly reproduce ActiveRecord objects including their children, for example copying a blog post maintaining its associated tags or categories.
This gem is named "Amoeba" because amoebas are (small life forms that are) good at reproducing. Their children and grandchildren also reproduce themselves quickly and easily.
Technical Details
An ActiveRecord extension gem to allow the duplication of associated child record objects when duplicating an active record model.
Rails 5.2, 6.0, 6.1 compatible. For Rails 4.2 to 5.1 use version 3.x.
Features
- Supports the following association types
has_many
has_one :through
has_many :through
has_and_belongs_to_many
- A simple DSL for configuration of which fields to copy. The DSL can be applied to your rails models or used on the fly.
- Supports STI (Single Table Inheritance) children inheriting their parent amoeba settings.
- Multiple configuration styles such as inclusive, exclusive and indiscriminate (aka copy everything).
- Supports cloning of the children of Many-to-Many records or merely maintaining original associations
- Supports automatic drill-down i.e. recursive copying of child and grandchild records.
- Supports preprocessing of fields to help indicate uniqueness and ensure the integrity of your data depending on your business logic needs, e.g. prepending "Copy of " or similar text.
- Supports preprocessing of fields with custom lambda blocks so you can do basically whatever you want if, for example, you need some custom logic while making copies.
- Amoeba can perform the following preprocessing operations on fields of copied records
- set
- prepend
- append
- nullify
- customize
- regex
Usage
Installation
is hopefully as you would expect:
gem install amoeba
or just add it to your Gemfile:
gem 'amoeba'
Configure your models with one of the styles below and then just run the amoeba_dup
method on your model where you would run the dup
method normally:
p = Post.create(:title => "Hello World!", :content => "Lorum ipsum dolor")
p.comments.create(:content => "I love it!")
p.comments.create(:content => "This sucks!")
puts Comment.all.count # should be 2
my_copy = p.amoeba_dup
my_copy.save
puts Comment.all.count # should be 4
By default, when enabled, amoeba will copy any and all associated child records automatically and associate them with the new parent record.
You can configure the behavior to only include fields that you list or to only include fields that you don't exclude. Of the three, the most performant will be the indiscriminate style, followed by the inclusive style, and the exclusive style will be the slowest because of the need for an extra explicit check on each field. This performance difference is likely negligible enough that you can choose the style to use based on which is easiest to read and write, however, if your data tree is large enough and you need control over what fields get copied, inclusive style is probably a better choice than exclusive style.
Configuration
Please note that these examples are only loose approximations of real world scenarios and may not be particularly realistic, they are only for the purpose of demonstrating feature usage.
Indiscriminate Style
This is the most basic usage case and will simply enable the copying of any known associations.
If you have some models for a blog about like this:
class Post < ActiveRecord::Base
has_many :comments
end
class Comment < ActiveRecord::Base
belongs_to :post
end
simply add the amoeba configuration block to your model and call the enable method to enable the copying of child records, like this:
class Post < ActiveRecord::Base
has_many :comments
amoeba do
enable
end
end
class Comment < ActiveRecord::Base
belongs_to :post
end
Child records will be automatically copied when you run the amoeba_dup
method.
Inclusive Style
If you only want some of the associations copied but not others, you may use the inclusive style:
class Post < ActiveRecord::Base
has_many :comments
has_many :tags
has_many :authors
amoeba do
enable
include_association :tags
include_association :authors
end
end
class Comment < ActiveRecord::Base
belongs_to :post
end
Using the inclusive style within the amoeba block actually implies that you wish to enable amoeba, so there is no need to run the enable method, though it won't hurt either:
class Post < ActiveRecord::Base
has_many :comments
has_many :tags
has_many :authors
amoeba do
include_association :tags
include_association :authors
end
end
class Comment < ActiveRecord::Base
belongs_to :post
end
You may also specify fields to be copied by passing an array. If you call the include_association
with a single value, it will be appended to the list of already included fields. If you pass an array, your array will overwrite the original values.
class Post < ActiveRecord::Base
has_many :comments
has_many :tags
has_many :authors
amoeba do
include_association [:tags, :authors]
end
end
class Comment < ActiveRecord::Base
belongs_to :post
end
These examples will copy the post's tags and authors but not its comments.
The inclusive style, when used, will automatically disable any other style that was previously selected.
Exclusive Style
If you have more fields to include than to exclude, you may wish to shorten the amount of typing and reading you need to do by using the exclusive style. All fields that are not explicitly excluded will be copied:
class Post < ActiveRecord::Base
has_many :comments
has_many :tags
has_many :authors
amoeba do
exclude_association :comments
end
end
class Comment < ActiveRecord::Base
belongs_to :post
end
This example does the same thing as the inclusive style example, it will copy the post's tags and authors but not its comments. As with inclusive style, there is no need to explicitly enable amoeba when specifying fields to exclude.
The exclusive style, when used, will automatically disable any other style that was previously selected, so if you selected include fields, and then you choose some exclude fields, the exclude_association
method will disable the previously selected inclusive style and wipe out any corresponding include fields.
Conditions
Also if you need to path extra condition for include or exclude relationship you can path method name to :if
option.
class Post < ActiveRecord::Base
has_many :comments
has_many :tags
amoeba do
include_association :comments, if: :popular?
end
def popular?
likes > 15
end
end
After call Post.first.amoeba_dup
if likes
is larger 15 than all comments will be duplicated too, but in another situation - no relations will be cloned. Same behavior will be for exclude_association
.
Be aware! If you wrote:
class Post < ActiveRecord::Base
has_many :comments
has_many :tags
amoeba do
exclude_association :tags
include_association :comments, if: :popular?
end
def popular?
likes > 15
end
end
inclusion strategy will be chosen regardless of the result of popular?
method call (the same for reverse situation).
Cloning
If you are using a Many-to-Many relationship, you may tell amoeba to actually make duplicates of the original related records rather than merely maintaining association with the original records. Cloning is easy, merely tell amoeba which fields to clone in the same way you tell it which fields to include or exclude.
class Post < ActiveRecord::Base
has_and_belongs_to_many :warnings
has_many :post_widgets
has_many :widgets, :through => :post_widgets
amoeba do
enable
clone [:widgets, :warnings]
end
end
class Warning < ActiveRecord::Base
has_and_belongs_to_many :posts
end
class PostWidget < ActiveRecord::Base
belongs_to :widget
belongs_to :post
end
class Widget < ActiveRecord::Base
has_many :post_widgets
has_many :posts, :through => :post_widgets
end
This example will actually duplicate the warnings and widgets in the database. If there were originally 3 warnings in the database then, upon duplicating a post, you will end up with 6 warnings in the database. This is in contrast to the default behavior where your new post would merely be re-associated with any previously existing warnings and those warnings themselves would not be duplicated.
Limiting Association Types
By default, amoeba recognizes and attempts to copy any children of the following association types:
- has one
- has many
- has and belongs to many
You may control which association types amoeba applies itself to by using the recognize
method within the amoeba configuration block.
class Post < ActiveRecord::Base
has_one :config
has_many :comments
has_and_belongs_to_many :tags
amoeba do
recognize [:has_one, :has_and_belongs_to_many]
end
end
class Comment < ActiveRecord::Base
belongs_to :post
end
class Tag < ActiveRecord::Base
has_and_belongs_to_many :posts
end
This example will copy the post's configuration data and keep tags associated with the new post, but will not copy the post's comments because amoeba will only recognize and copy children of has_one
and has_and_belongs_to_many
associations and in this example, comments are not an has_and_belongs_to_many
association.
Field Preprocessors
Nullify
If you wish to prevent a regular (non has_*
association based) field from retaining it's value when copied, you may "zero out" or "nullify" the field, like this:
class Topic < ActiveRecord::Base
has_many :posts
end
class Post < ActiveRecord::Base
belongs_to :topic
has_many :comments
amoeba do
enable
nullify :date_published
nullify :topic_id
end
end
class Comment < ActiveRecord::Base
belongs_to :post
end
This example will copy all of a post's comments. It will also nullify the publishing date and dissociate the post from its original topic.
Unlike inclusive and exclusive styles, specifying null fields will not automatically enable amoeba to copy all child records. As with any active record object, the default field value will be used instead of nil
if a default value exists on the migration.
Set
If you wish to just set a field to an arbitrary value on all duplicated objects you may use the set
directive. For example, if you wanted to copy an object that has some kind of approval process associated with it, you likely may wish to set the new object's state to be open or "in progress" again.
class Post < ActiveRecord::Base
amoeba do
set :state_tracker => "open_for_editing"
end
end
In this example, when a post is duplicated, it's state_tracker
field will always be given a value of open_for_editing
to start.
Prepend
You may add a string to the beginning of a copied object's field during the copy phase:
class Post < ActiveRecord::Base
amoeba do
enable
prepend :title => "Copy of "
end
end
Append
You may add a string to the end of a copied object's field during the copy phase:
class Post < ActiveRecord::Base
amoeba do
enable
append :title => "Copy of "
end
end
Regex
You may run a search and replace query on a copied object's field during the copy phase:
class Post < ActiveRecord::Base
amoeba do
enable
regex :contents => {:replace => /dog/, :with => 'cat'}
end
end
Custom Methods
Customize
You may run a custom method or methods to do basically anything you like, simply pass a lambda block, or an array of lambda blocks to the customize
directive. Each block must have the same form, meaning that each block must accept two parameters, the original object and the newly copied object. You may then do whatever you wish, like this:
class Post < ActiveRecord::Base
amoeba do
prepend :title => "Hello world! "
customize(lambda { |original_post,new_post|
if original_post.foo == "bar"
new_post.baz = "qux"
end
})
append :comments => "... know what I'm sayin?"
end
end
or this, using an array:
class Post < ActiveRecord::Base
has_and_belongs_to_many :tags
amoeba do
include_association :tags
customize([
lambda do |orig_obj,copy_of_obj|
# good stuff goes here
end,
lambda do |orig_obj,copy_of_obj|
# more good stuff goes here
end
])
end
end
Override
Lambda blocks passed to customize run, by default, after all copying and field pre-processing. If you wish to run a method before any customization or field pre-processing, you may use override
the cousin of customize
. Usage is the same as above.
class Post < ActiveRecord::Base
amoeba do
prepend :title => "Hello world! "
override(lambda { |original_post,new_post|
if original_post.foo == "bar"
new_post.baz = "qux"
end
})
append :comments => "... know what I'm sayin?"
end
end
Chaining
You may apply a single preprocessor to multiple fields at once.
class Post < ActiveRecord::Base
amoeba do
enable
prepend :title => "Copy of ", :contents => "Copied contents: "
end
end
Stacking
You may apply multiple preprocessing directives to a single model at once.
class Post < ActiveRecord::Base
amoeba do
prepend :title => "Copy of ", :contents => "Original contents: "
append :contents => " (copied version)"
regex :contents => {:replace => /dog/, :with => 'cat'}
end
end
This example should result in something like this:
post = Post.create(
:title => "Hello world",
:contents => "I like dogs, dogs are awesome."
)
new_post = post.amoeba_dup
new_post.title # "Copy of Hello world"
new_post.contents # "Original contents: I like cats, cats are awesome. (copied version)"
Like nullify
, the preprocessing directives do not automatically enable the copying of associated child records. If only preprocessing directives are used and you do want to copy child records and no include_association
or exclude_association
list is provided, you must still explicitly enable the copying of child records by calling the enable method from within the amoeba block on your model.
Precedence
You may use a combination of configuration methods within each model's amoeba block. Recognized association types take precedence over inclusion or exclusion lists. Inclusive style takes precedence over exclusive style, and these two explicit styles take precedence over the indiscriminate style. In other words, if you list fields to copy, amoeba will only copy the fields you list, or only copy the fields you don't exclude as the case may be. Additionally, if a field type is not recognized it will not be copied, regardless of whether it appears in an inclusion list. If you want amoeba to automatically copy all of your child records, do not list any fields using either include_association
or exclude_association
.
The following example syntax is perfectly valid, and will result in the usage of inclusive style. The order in which you call the configuration methods within the amoeba block does not matter:
class Topic < ActiveRecord::Base
has_many :posts
end
class Post < ActiveRecord::Base
belongs_to :topic
has_many :comments
has_many :tags
has_many :authors
amoeba do
exclude_association :authors
include_association :tags
nullify :date_published
prepend :title => "Copy of "
append :contents => " (copied version)"
regex :contents => {:replace => /dog/, :with => 'cat'}
include_association :authors
enable
nullify :topic_id
end
end
class Comment < ActiveRecord::Base
belongs_to :post
end
This example will copy all of a post's tags and authors, but not its comments. It will also nullify the publishing date and dissociate the post from its original topic. It will also preprocess the post's fields as in the previous preprocessing example.
Note that, because of precedence, inclusive style is used and the list of exclude fields is never consulted. Additionally, the enable
method is redundant because amoeba is automatically enabled when using include_association
.
The preprocessing directives are run after child records are copied and are run in this order.
- Null fields
- Prepends
- Appends
- Search and Replace
Preprocessing directives do not affect inclusion and exclusion lists.
Recursing
You may cause amoeba to keep copying down the chain as far as you like, simply add amoeba blocks to each model you wish to have copy its children. Amoeba will automatically recurse into any enabled grandchildren and copy them as well.
class Post < ActiveRecord::Base
has_many :comments
amoeba do
enable
end
end
class Comment < ActiveRecord::Base
belongs_to :post
has_many :ratings
amoeba do
enable
end
end
class Rating < ActiveRecord::Base
belongs_to :comment
end
In this example, when a post is copied, amoeba will copy each all of a post's comments and will also copy each comment's ratings.
Has One Through
Using the has_one :through
association is simple, just be sure to enable amoeba on the each model with a has_one
association and amoeba will automatically and recursively drill down, like so:
class Supplier < ActiveRecord::Base
has_one :account
has_one :history, :through => :account
amoeba do
enable
end
end
class Account < ActiveRecord::Base
belongs_to :supplier
has_one :history
amoeba do
enable
end
end
class History < ActiveRecord::Base
belongs_to :account
end
Has Many Through
Copying of has_many :through
associations works automatically. They perform the copy in the same way as the has_and_belongs_to_many
association, meaning the actual child records are not copied, but rather the associations are simply maintained. You can add some field preprocessors to the middle model if you like but this is not strictly necessary:
class Assembly < ActiveRecord::Base
has_many :manifests
has_many :parts, :through => :manifests
amoeba do
enable
end
end
class Manifest < ActiveRecord::Base
belongs_to :assembly
belongs_to :part
amoeba do
prepend :notes => "Copy of "
end
end
class Part < ActiveRecord::Base
has_many :manifests
has_many :assemblies, :through => :manifests
amoeba do
enable
end
end
On The Fly Configuration
You may control how amoeba copies your object, on the fly, by passing a configuration block to the model's amoeba method. The configuration method is static but the configuration is applied on a per instance basis.
class Post < ActiveRecord::Base
has_many :comments
amoeba do
enable
prepend :title => "Copy of "
end
end
class Comment < ActiveRecord::Base
belongs_to :post
end
class PostsController < ActionController
def duplicate_a_post
old_post = Post.create(
:title => "Hello world",
:contents => "Lorum ipsum"
)
old_post.class.amoeba do
prepend :contents => "Here's a copy: "
end
new_post = old_post.amoeba_dup
new_post.title # should be "Copy of Hello world"
new_post.contents # should be "Here's a copy: Lorum ipsum"
new_post.save
end
end
Inheritance
If you are using the Single Table Inheritance provided by ActiveRecord, you may cause amoeba to automatically process child classes in the same way as their parents. All you need to do is call the propagate
method within the amoeba block of the parent class and all child classes should copy in a similar manner.
create_table :products, :force => true do |t|
t.string :type # this is the STI column
# these belong to all products
t.string :title
t.decimal :price
# these are for shirts only
t.decimal :sleeve_length
t.decimal :collar_size
# these are for computers only
t.integer :ram_size
t.integer :hard_drive_size
end
class Product < ActiveRecord::Base
has_many :images
has_and_belongs_to_many :categories
amoeba do
enable
propagate
end
end
class Shirt < Product
end
class Computer < Product
end
class ProductsController
def some_method
my_shirt = Shirt.find(1)
my_shirt.amoeba_dup
my_shirt.save
# this shirt should now:
# - have its own copy of all parent images
# - be in the same categories as the parent
end
end
This example should duplicate all the images and sections associated with this Shirt, which is a child of Product
Parenting Style
By default, propagation uses submissive parenting, meaning the config settings on the parent will be applied, but any child settings, if present, will either add to or overwrite the parent settings depending on how you call the DSL methods.
You may change this behavior, the so called "parenting style", to give preference to the parent settings or to ignore any and all child settings.
Relaxed Parenting
The :relaxed
parenting style will prefer parent settings.
class Product < ActiveRecord::Base
has_many :images
has_and_belongs_to_many :sections
amoeba do
exclude_association :images
propagate :relaxed
end
end
class Shirt < Product
include_association :images
include_association :sections
prepend :title => "Copy of "
end
In this example, the conflicting include_association
settings on the child will be ignored and the parent exclude_association
setting will be used, while the prepend
setting on the child will be honored because it doesn't conflict with the parent.
Strict Parenting
The :strict
style will ignore child settings altogether and inherit any parent settings.
class Product < ActiveRecord::Base
has_many :images
has_and_belongs_to_many :sections
amoeba do
exclude_association :images
propagate :strict
end
end
class Shirt < Product
include_association :images
include_association :sections
prepend :title => "Copy of "
end
In this example, the only processing that will happen when a Shirt is duplicated is whatever processing is allowed by the parent. So in this case the parent's exclude_association
directive takes precedence over the child's include_association
settings, and not only that, but none of the other settings for the child are used either. The prepend
setting of the child is completely ignored.
Parenting and Precedence
Because of the two general forms of DSL config parameter usage, you may wish to make yourself mindful of how your coding style will affect the outcome of duplicating an object.
Just remember that:
- If you pass an array you will wipe all previous settings
- If you pass single values, you will add to currently existing settings
This means that, for example:
- When using the submissive parenting style, you can child take full precedence on a per field basis by passing an array of config values. This will cause the setting from the parent to be overridden instead of added to.
- When using the relaxed parenting style, you can still let the parent take precedence on a per field basis by passing an array of config values. This will cause the setting for that child to be overridden instead of added to.
A Submissive Override Example
This version will use both the parent and child settings, so both the images and sections will be copied.
class Product < ActiveRecord::Base
has_many :images
has_and_belongs_to_many :sections
amoeba do
include_association :images
propagate
end
end
class Shirt < Product
include_association :sections
end
The next version will use only the child settings because passing an array will override any previous settings rather than adding to them and the child config takes precedence in the submissive
parenting style. So in this case only the sections will be copied.
class Product < ActiveRecord::Base
has_many :images
has_and_belongs_to_many :sections
amoeba do
include_association :images
propagate
end
end
class Shirt < Product
include_association [:sections]
end
A Relaxed Override Example
This version will use both the parent and child settings, so both the images and sections will be copied.
class Product < ActiveRecord::Base
has_many :images
has_and_belongs_to_many :sections
amoeba do
include_association :images
propagate :relaxed
end
end
class Shirt < Product
include_association :sections
end
The next version will use only the parent settings because passing an array will override any previous settings rather than adding to them and the parent config takes precedence in the relaxed
parenting style. So in this case only the images will be copied.
class Product < ActiveRecord::Base
has_many :images
has_and_belongs_to_many :sections
amoeba do
include_association [:images]
propagate
end
end
class Shirt < Product
include_association :sections
end
Validating Nested Attributes
If you end up with some validation issues when trying to validate the presence of a child's belongs_to
association, just be sure to include the :inverse_of
declaration on your relationships and all should be well.
For example this will throw a validation error saying that your posts are invalid:
class Author < ActiveRecord::Base
has_many :posts
amoeba do
enable
end
end
class Post < ActiveRecord::Base
belongs_to :author
validates_presence_of :author
amoeba do
enable
end
end
author = Author.find(1)
author.amoeba_dup
author.save # this will fail validation
Where this will work fine:
class Author < ActiveRecord::Base
has_many :posts, :inverse_of => :author
amoeba do
enable
end
end
class Post < ActiveRecord::Base
belongs_to :author, :inverse_of => :posts
validates_presence_of :author
amoeba do
enable
end
end
author = Author.find(1)
author.amoeba_dup
author.save # this will pass validation
This issue is not amoeba specific and also occurs when creating new objects using accepts_nested_attributes_for
, like this:
class Author < ActiveRecord::Base
has_many :posts
accepts_nested_attributes_for :posts
end
class Post < ActiveRecord::Base
belongs_to :author
validates_presence_of :author
end
# this will fail validation
author = Author.create({:name => "Jim Smith", :posts => [{:title => "Hello World", :contents => "Lorum ipsum dolor}]})
This issue with accepts_nested_attributes_for
can also be solved by using :inverse_of
, like this:
class Author < ActiveRecord::Base
has_many :posts, :inverse_of => :author
accepts_nested_attributes_for :posts
end
class Post < ActiveRecord::Base
belongs_to :author, :inverse_of => :posts
validates_presence_of :author
end
# this will pass validation
author = Author.create({:name => "Jim Smith", :posts => [{:title => "Hello World", :contents => "Lorum ipsum dolor}]})
The crux of the issue is that upon duplication, the new Author
instance does not yet have an ID because it has not yet been persisted, so the :posts
do not yet have an :author_id
either, and thus no :author
and thus they will fail validation. This issue may likely affect amoeba usage so if you get some validation failures, be sure to add :inverse_of
to your models.
Cloning using custom method
If you need to clone model with custom method you can use through
:
class ChildPrototype < ActiveRecord::Base
amoeba do
through :become_child
end
def become_child
self.dup.becomes(Child)
end
end
class Child < ChildPrototype
end
After cloning we will get instance of Child
instead of ChildPrototype
Remapping associations
If you will need to do complex cloning with remapping associations name you can user remapper
:
class ObjectPrototype < ActiveRecord::Base
has_many :child_prototypes
amoeba do
method :become_real
remapper :remap_associations
end
def become_real
self.dup().becomes( RealObject )
end
def remap_associations( name )
:childs if name == :child_prototypes
end
end
class RealObject < ObjectPrototype
has_many :childs
end
class ChildPrototype < ActiveRecord::Base
amoeba do
method :become_child
end
def become_child
self.dup().becomes( Child )
end
end
class Child < ChildPrototype
end
In result we will get next:
prototype = ObjectPrototype.new
prototype.child_prototypes << ChildPrototype.new
object = prototype.amoeba_dup
object.class # => RealObject
object.childs.first.class #=> Child
Configuration Reference
Here is a static reference to the available configuration methods, usable within the amoeba block on your rails models.
through
Set method what we will use for cloning model instead of dup
.
for example:
amoeba do
through :supper_pupper_dup
end
def supper_pupper_dup
puts "multiplied by budding"
self.dup
end
Controlling Associations
enable
Enables amoeba in the default style of copying all known associated child records. Using the enable method is only required if you wish to enable amoeba but you are not using either the include_association
or exclude_association
directives. If you use either inclusive or exclusive style, amoeba is automatically enabled for you, so calling enable
would be redundant, though it won't hurt.
include_association
Adds a field to the list of fields which should be copied. All associations not in this list will not be copied. This method may be called multiple times, once per desired field, or you may pass an array of field names. Passing a single symbol will add to the list of included fields. Passing an array will empty the list and replace it with the array you pass.
exclude_association
Adds a field to the list of fields which should not be copied. Only the associations that are not in this list will be copied. This method may be called multiple times, once per desired field, or you may pass an array of field names. Passing a single symbol will add to the list of excluded fields. Passing an array will empty the list and replace it with the array you pass.
clone
Adds a field to the list of associations which should have their associated children actually cloned. This means for example, that instead of just maintaining original associations with previously existing tags, a copy will be made of each tag, and the new record will be associated with these new tag copies rather than the old tag copies. This method may be called multiple times, once per desired field, or you may pass an array of field names. Passing a single symbol will add to the list of excluded fields. Passing an array will empty the list and replace it with the array you pass.
propagate
This causes any inherited child models to take the same config settings when copied. This method may take up to one argument to control the so called "parenting style". The argument should be one of strict
, relaxed
or submissive
.
The default "parenting style" is submissive
for example
amoeba do
propagate :strict
end
will choose the strict parenting style of inherited settings.
raised
This causes any child to behave with a (potentially) different "parenting style" than its actual parent. This method takes up to a single parameter for which there are three options, strict
, relaxed
and submissive
.
The default "parenting style" is submissive
for example:
amoeba do
raised :relaxed
end
will choose the relaxed parenting style of inherited settings for this child. A parenting style set via the raised
method takes precedence over the parenting style set using the propagate
method.
remapper
Set the method what will be used for remapping of association name. Method will have one argument - association name as Symbol. If method will return nil then association will not be remapped.
for example:
amoeba do
remapper :childs_to_parents
end
def childs_to_parents(association_name)
:parents if association_name == :childs
end
Pre-Processing Fields
nullify
Adds a field to the list of non-association based fields which should be set to nil during copy. All fields in this list will be set to nil
- note that any nullified field will be given its default value if a default value exists on this model's migration. This method may be called multiple times, once per desired field, or you may pass an array of field names. Passing a single symbol will add to the list of null fields. Passing an array will empty the list and replace it with the array you pass.
prepend
Prefix a field with some text. This only works for string fields. Accepts a hash of fields to prepend. The keys are the field names and the values are the prefix strings. An example scenario would be to add a string such as "Copy of " to your title field. Don't forget to include extra space to the right if you want it. Passing a hash will add each key value pair to the list of prepend directives. If you wish to empty the list of directives, you may pass the hash inside of an array like this [{:title => "Copy of "}]
.
append
Append some text to a field. This only works for string fields. Accepts a hash of fields to prepend. The keys are the field names and the values are the prefix strings. An example would be to add " (copied version)" to your description field. Don't forget to add a leading space if you want it. Passing a hash will add each key value pair to the list of append directives. If you wish to empty the list of directives, you may pass the hash inside of an array like this [{:contents => " (copied version)"}]
.
set
Set a field to a given value. This should work for almost any type of field. Accepts a hash of fields and the values you want them set to.. The keys are the field names and the values are the prefix strings. An example would be to add " (copied version)" to your description field. Don't forget to add a leading space if you want it. Passing a hash will add each key value pair to the list of append directives. If you wish to empty the list of directives, you may pass the hash inside of an array like this [{:approval_state => "open_for_editing"}]
.
regex
Globally search and replace the field for a given pattern. Accepts a hash of fields to run search and replace upon. The keys are the field names and the values are each a hash with information about what to find and what to replace it with. in the form of . An example would be to replace all occurrences of the word "dog" with the word "cat", the parameter hash would look like this :contents => {:replace => /dog/, :with => "cat"}
. Passing a hash will add each key value pair to the list of regex directives. If you wish to empty the list of directives, you may pass the hash inside of an array like this [{:contents => {:replace => /dog/, :with => "cat"}]
.
override
Runs a custom method so you can do basically whatever you want. All you need to do is pass a lambda block or an array of lambda blocks that take two parameters, the original object and the new object copy. These blocks will run before any other duplication or field processing.
This method may be called multiple times, once per desired customizer block, or you may pass an array of lambdas. Passing a single lambda will add to the list of processing directives. Passing an array will empty the list and replace it with the array you pass.
customize
Runs a custom method so you can do basically whatever you want. All you need to do is pass a lambda block or an array of lambda blocks that take two parameters, the original object and the new object copy. These blocks will run after all copying and field processing.
This method may be called multiple times, once per desired customizer block, or you may pass an array of lambdas. Passing a single lambda will add to the list of processing directives. Passing an array will empty the list and replace it with the array you pass.
Known Limitations and Issues
The regular expression preprocessor uses case-sensitive String#gsub
. Given the performance decreases inherrent in using regular expressions already, the fact that character classes can essentially account for case-insensitive searches, the desire to keep the DSL simple and the general use cases for this gem, I don't see a good reason to add yet more decision based conditional syntax to accommodate using case-insensitive searches or singular replacements with String#sub
. If you find yourself wanting either of these features, by all means fork the code base and if you like your changes, submit a pull request.
The behavior when copying nested hierarchical models is undefined. Copying a category model which has a parent_id
field pointing to the parent category, for example, is currently undefined.
The behavior when copying polymorphic has_many
associations is also undefined. Support for these types of associations is planned for a future release.
For Developers
You may run the rspec tests like this:
bundle exec rspec spec
TODO
- add ability to cancel further processing from within an override block
- write some spec for the override method