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diff --git a/guides/source/active_model_basics.md b/guides/source/active_model_basics.md index bfb088ed03..0019d08328 100644 --- a/guides/source/active_model_basics.md +++ b/guides/source/active_model_basics.md @@ -1,20 +1,20 @@ Active Model Basics =================== -This guide should provide you with all you need to get started using model classes. Active Model allows for Action Pack helpers to interact with non-ActiveRecord models. Active Model also helps building custom ORMs for use outside of the Rails framework. +This guide should provide you with all you need to get started using model classes. Active Model allows for Action Pack helpers to interact with non-Active Record models. Active Model also helps building custom ORMs for use outside of the Rails framework. --------------------------------------------------------------------------------- +After reading this guide, you will know: -WARNING. This guide is based on Rails 3.0. Some of the code shown here will not work in earlier versions of Rails. +-------------------------------------------------------------------------------- Introduction ------------ -Active Model is a library containing various modules used in developing frameworks that need to interact with the Rails Action Pack library. Active Model provides a known set of interfaces for usage in classes. Some of modules are explained below. +Active Model is a library containing various modules used in developing frameworks that need to interact with the Rails Action Pack library. Active Model provides a known set of interfaces for usage in classes. Some of modules are explained below. ### AttributeMethods -The AttributeMethods module can add custom prefixes and suffixes on methods of a class. It is used by defining the prefixes and suffixes, which methods on the object will use them. +The AttributeMethods module can add custom prefixes and suffixes on methods of a class. It is used by defining the prefixes and suffixes and which methods on the object will use them. ```ruby class Person @@ -26,28 +26,26 @@ class Person attr_accessor :age -private - def reset_attribute(attribute) - send("#{attribute}=", 0) - end + private + def reset_attribute(attribute) + send("#{attribute}=", 0) + end - def attribute_highest?(attribute) - send(attribute) > 100 ? true : false - end - + def attribute_highest?(attribute) + send(attribute) > 100 + end end person = Person.new person.age = 110 person.age_highest? # true person.reset_age # 0 -person.age_highest? # false - +person.age_highest? # false ``` ### Callbacks -Callbacks gives Active Record style callbacks. This provides the ability to define the callbacks and those will run at appropriate time. After defining a callbacks you can wrap with before, after and around custom methods. +Callbacks gives Active Record style callbacks. This provides an ability to define callbacks which run at appropriate times. After defining callbacks, you can wrap them with before, after and around custom methods. ```ruby class Person @@ -59,19 +57,19 @@ class Person def update run_callbacks(:update) do - # This will call when we are trying to call update on object. + # This method is called when update is called on an object. end end def reset_me - # This method will call when you are calling update on object as a before_update callback as defined. + # This method is called when update is called on an object as a before_update callback is defined. end end ``` ### Conversion -If a class defines `persisted?` and `id` methods then you can include `Conversion` module in that class and you can able to call Rails conversion methods to objects of that class. +If a class defines `persisted?` and `id` methods, then you can include the `Conversion` module in that class and call the Rails conversion methods on objects of that class. ```ruby class Person @@ -87,14 +85,14 @@ class Person end person = Person.new -person.to_model == person #=> true -person.to_key #=> nil -person.to_param #=> nil +person.to_model == person # => true +person.to_key # => nil +person.to_param # => nil ``` ### Dirty -An object becomes dirty when it has gone through one or more changes to its attributes and has not been saved. This gives the ability to check whether an object has been changed or not. It also has attribute based accessor methods. Let's consider a Person class with attributes first_name and last_name +An object becomes dirty when it has gone through one or more changes to its attributes and has not been saved. This gives the ability to check whether an object has been changed or not. It also has attribute based accessor methods. Let's consider a Person class with attributes `first_name` and `last_name`: ```ruby require 'active_model' @@ -122,9 +120,9 @@ class Person end def save - @previously_changed = changes + # do save work... + changes_applied end - end ``` @@ -132,21 +130,22 @@ end ```ruby person = Person.new -person.first_name = "First Name" +person.changed? # => false -person.first_name #=> "First Name" -person.first_name = "First Name Changed" +person.first_name = "First Name" +person.first_name # => "First Name" -person.changed? #=> true +# returns if any attribute has changed. +person.changed? # => true -#returns an list of fields arry which all has been changed before saved. -person.changed #=> ["first_name"] +# returns a list of attributes that have changed before saving. +person.changed # => ["first_name"] -#returns a hash of the fields that have changed with their original values. -person.changed_attributes #=> {"first_name" => "First Name Changed"} +# returns a hash of the attributes that have changed with their original values. +person.changed_attributes # => {"first_name"=>nil} -#returns a hash of changes, with the attribute names as the keys, and the values will be an array of the old and new value for that field. -person.changes #=> {"first_name" => ["First Name","First Name Changed"]} +# returns a hash of changes, with the attribute names as the keys, and the values will be an array of the old and new value for that field. +person.changes # => {"first_name"=>[nil, "First Name"]} ``` #### Attribute based accessor methods @@ -154,28 +153,24 @@ person.changes #=> {"first_name" => ["First Name","First Name Changed"]} Track whether the particular attribute has been changed or not. ```ruby -#attr_name_changed? -person.first_name #=> "First Name" - -#assign some other value to first_name attribute -person.first_name = "First Name 1" - -person.first_name_changed? #=> true +# attr_name_changed? +person.first_name # => "First Name" +person.first_name_changed? # => true ``` Track what was the previous value of the attribute. ```ruby -#attr_name_was accessor -person.first_name_was #=> "First Name" +# attr_name_was accessor +person.first_name_was # => "First Name" ``` Track both previous and current value of the changed attribute. Returns an array if changed, else returns nil. ```ruby -#attr_name_change -person.first_name_change #=> ["First Name", "First Name 1"] -person.last_name_change #=> nil +# attr_name_change +person.first_name_change # => [nil, "First Name"] +person.last_name_change # => nil ``` ### Validations @@ -187,20 +182,19 @@ class Person include ActiveModel::Validations attr_accessor :name, :email, :token - - validates :name, :presence => true - validates_format_of :email, :with => /\A([^\s]+)((?:[-a-z0-9]\.)[a-z]{2,})\z/i - validates! :token, :presence => true - + + validates :name, presence: true + validates_format_of :email, with: /\A([^\s]+)((?:[-a-z0-9]\.)[a-z]{2,})\z/i + validates! :token, presence: true end -person = Person.new(:token => "2b1f325") -person.valid? #=> false -person.name = 'vishnu' -person.email = 'me' -person.valid? #=> false +person = Person.new(token: "2b1f325") +person.valid? # => false +person.name = 'vishnu' +person.email = 'me' +person.valid? # => false person.email = 'me@vishnuatrai.com' -person.valid? #=> true +person.valid? # => true person.token = nil -person.valid? #=> raises ActiveModel::StrictValidationFailed +person.valid? # => raises ActiveModel::StrictValidationFailed ``` |