Class: DynamicActiveResource::Base

Inherits:

ActiveResource::Base

• Object
• ActiveResource::Base
• DynamicActiveResource::Base

Defined in:

lib/dynamic_active_resource/base.rb

Overview

ActiveResource makes connecting to rest resources very easy. However it has one problem and a big one at that. If you try setting the authentication credentials or the site or collection name, element name for the class for the second time it doesn’t work. E.g.

class Person < ActiveResource::Base

self.site = 'http://localhost:9090/'

end

After sometime you change it to

Person.site = ‘org-server/my_proj/’ Person.user = ‘admin’ Person.password = ‘secret’

Then you do

Person.find(:all) => It bombs

This class provides a mechanism by which you can get rid of this problem. Extend DynamicActiveResource::Base class in the actual class itself. Do not extend the extended class from ActiveResource::Base.

E.g.

class Person < DynamicActiveResource::Base end

set the credentials

Person.site = ‘localhost:8080’ Person.user = ‘foo’ Person.password = ‘bar’

Thats it. Now create some objects

asur = Person.new(:name => ‘Asur’, :job => ‘fooling around’, :status => ‘Single and ready 2 mingle’) asur.save

Now change the class attributes

Person.site = ‘org-server/mingle’ Person.collection_name = ‘boring_people’

Now instantiate an object

rakhshas = Person.new(:name => ‘Rakhshas’, :job => ‘eating people’, :status => ‘just woke up and hungry’) rakhshas.save => Voila !!!!!!! it works

CUSTOMIZATIONS

---

No amount of wrapping can provide very detailed customizations. Either you have a lot of methods that are not being used or there is hardly anything at all. To oversome this problem this module was written to provide only those methods which are common to most active resource objects. However if you want to have a little more control over your active resource objects its very easy. Here’s how you would do it normally

class Person < ActiveResource::Base

def self.count
  find(:all).size
end

def occupation
  return job if job
  'Unemployed' 
end

end

To do the same thing, here’s how you do it using this library

class Person < DynamicActiveResource::Base

module DynamicClassSingletonMethods
  def count
    find(:all).size
  end
end

module DynamicClassInstanceMethods
  def occupation
    return job if job
    'Unemployed' 
  end
end

end

The DynamicClassInstanceMethods will be available as instance methods in the objects created, DynamicClassSingletonMethods will be available as class methods in the class of the object. Also active resource associations are sometimes paginated. So even if you use find(:all), you get only the first few results. To overcome this, include in your DynamicClassSingletonMethods module a method called find_without_pagination. In that method route it to acitve resource find with proper parameters. An example of the method implementation is

module DynamicClassSingletonMethods

def find_without_pagination(*args)
  scope = args.slice!(0)
  options = args.slice!(0) || {}
  options[:params] ||= {}
  options[:params].merge!({:page => 'all'})
  # call ActiveResource::Base::find with proper options
  find(scope, options)
end

end

The class level find method will automatically pick up this method if defined as a method in the DynamicClassSingeletonMethod module else it will pass it to find.

ASSOCIATIONS

---

This gem also provides active record like associations(highly experimental). Right now it provides only two associations - 1) has_many, 2) belongs_to.

1) has_many

---

Taking the example from above the way it should be done

class Person < DynamicActiveResource::Base

has_many :cars

module DynamicClassSingletonMethods
  def count
    find(:all).size
  end
end

module DynamicClassInstanceMethods
  def occupation
    return job if job
    'Unemployed' 
  end

  def resource_identifier
   name()
 end
end

end

Next a car class has to be initialized

class Car < DynARBase (alias for DynamicActiveResource::Base, inbuilt in the gem) end

set resource options only at the top level( Person in this case)

Person.site = ‘localhost:8080/’ Person.user = ‘test’ Person.password = ‘secret’

associations take care of setting the site in the children classes automatically you will notice that an additional method resource_identifier() has been defined in the parent class. It would be discussed shortly.

The way associations work is if you do something like

person = Person.find(‘asur’).cars it will hit the url localhost:8080/people/asur/cars.xml

You would notice that its getting the cars for the person with name ‘asur’. It does so because in the Person class a method called resource_identifier has been defined which says that the id is actually name instead of the database id. If the id attribute in the xml is set appropriately (to ‘name’ in this case) then you do not need to define the method.

2) belongs_to

---

Again, referring to the example above

class Person < DynamicActiveResource::Base

has_many :cars

module DynamicClassSingletonMethods
  def count
    find(:all).size
  end
end

module DynamicClassInstanceMethods
  def occupation
    return job if job
    'Unemployed' 
  end

  def resource_identifier
   name()
 end
end

end

Next a car class has to be initialized

class Car < DynARBase (alias for DynamicActiveResource::Base)

belongs_to :person

end

Right now belongs_to supports only assocation with a single class. After defining this you automatically have a method ‘person’ available.

car = Car.find(‘WB1234I’) owner = car.person

Class Method Summary

• .inherited(subclass) ⇒ Object

Class Method Details

.inherited(subclass) ⇒ Object

# File 'lib/dynamic_active_resource/base.rb', line 202

def self.inherited(subclass)
  subclass.extend(DynamicActiveResource::CommonClassMethods)
  subclass.extend(DynamicActiveResource::Associations)
end