Class: ActiveResource::Base

Inherits:
Object show all
Extended by:
ActiveModel::Naming
Includes:
ActiveModel::Conversion, ActiveModel::Serializers::JSON, ActiveModel::Serializers::Xml, CustomMethods, Observing, Validations
Defined in:
activeresource/lib/active_resource/base.rb,
activeresource/lib/active_resource/base.rb

Overview

ActiveResource::Base is the main class for mapping RESTful resources as models in a Rails application.

For an outline of what Active Resource is capable of, see its README.

Automated mapping

Active Resource objects represent your RESTful resources as manipulatable Ruby objects. To map resources to Ruby objects, Active Resource only needs a class name that corresponds to the resource name (e.g., the class Person maps to the resources people, very similarly to Active Record) and a site value, which holds the URI of the resources.

class Person < ActiveResource::Base
  self.site = "http://api.people.com:3000/"
end

Now the Person class is mapped to RESTful resources located at http://api.people.com:3000/people/, and you can now use Active Resource's life cycle methods to manipulate resources. In the case where you already have an existing model with the same name as the desired RESTful resource you can set the element_name value.

class PersonResource < ActiveResource::Base
  self.site = "http://api.people.com:3000/"
  self.element_name = "person"
end

If your Active Resource object is required to use an HTTP proxy you can set the proxy value which holds a URI.

class PersonResource < ActiveResource::Base
  self.site = "http://api.people.com:3000/"
  self.proxy = "http://user:[email protected]:8080"
end

Life cycle methods

Active Resource exposes methods for creating, finding, updating, and deleting resources from REST web services.

ryan = Person.new(:first => 'Ryan', :last => 'Daigle')
ryan.save                # => true
ryan.id                  # => 2
Person.exists?(ryan.id)  # => true
ryan.exists?             # => true

ryan = Person.find(1)
# Resource holding our newly created Person object

ryan.first = 'Rizzle'
ryan.save                # => true

ryan.destroy             # => true

As you can see, these are very similar to Active Record's life cycle methods for database records. You can read more about each of these methods in their respective documentation.

Custom REST methods

Since simple CRUD/life cycle methods can't accomplish every task, Active Resource also supports defining your own custom REST methods. To invoke them, Active Resource provides the get, post, put and \delete methods where you can specify a custom REST method name to invoke.

# POST to the custom 'register' REST method, i.e. POST /people/new/register.json.
Person.new(:name => 'Ryan').post(:register)
# => { :id => 1, :name => 'Ryan', :position => 'Clerk' }

# PUT an update by invoking the 'promote' REST method, i.e. PUT /people/1/promote.json?position=Manager.
Person.find(1).put(:promote, :position => 'Manager')
# => { :id => 1, :name => 'Ryan', :position => 'Manager' }

# GET all the positions available, i.e. GET /people/positions.json.
Person.get(:positions)
# => [{:name => 'Manager'}, {:name => 'Clerk'}]

# DELETE to 'fire' a person, i.e. DELETE /people/1/fire.json.
Person.find(1).delete(:fire)

For more information on using custom REST methods, see the ActiveResource::CustomMethods documentation.

Validations

You can validate resources client side by overriding validation methods in the base class.

class Person < ActiveResource::Base
   self.site = "http://api.people.com:3000/"
   protected
     def validate
       errors.add("last", "has invalid characters") unless last =~ /[a-zA-Z]*/
     end
end

See the ActiveResource::Validations documentation for more information.

Authentication

Many REST APIs will require authentication, usually in the form of basic HTTP authentication. Authentication can be specified by:

HTTP Basic Authentication

  • putting the credentials in the URL for the site variable.

    class Person < ActiveResource::Base
      self.site = "http://ryan:[email protected]:3000/"
    end
    
  • defining user and/or password variables

    class Person < ActiveResource::Base
      self.site = "http://api.people.com:3000/"
      self.user = "ryan"
      self.password = "password"
    end
    

For obvious security reasons, it is probably best if such services are available over HTTPS.

Note: Some values cannot be provided in the URL passed to site. e.g. email addresses as usernames. In those situations you should use the separate user and password option.

Certificate Authentication

  • End point uses an X509 certificate for authentication. See ssl_options= for all options.

    class Person < ActiveResource::Base
      self.site = "https://secure.api.people.com/"
      self.ssl_options = {:cert         => OpenSSL::X509::Certificate.new(File.open(pem_file))
                          :key          => OpenSSL::PKey::RSA.new(File.open(pem_file)),
                          :ca_path      => "/path/to/OpenSSL/formatted/CA_Certs",
                          :verify_mode  => OpenSSL::SSL::VERIFY_PEER}
    end
    

Errors & Validation

Error handling and validation is handled in much the same manner as you're used to seeing in Active Record. Both the response code in the HTTP response and the body of the response are used to indicate that an error occurred.

Resource errors

When a GET is requested for a resource that does not exist, the HTTP 404 (Resource Not Found) response code will be returned from the server which will raise an ActiveResource::ResourceNotFound exception.

# GET http://api.people.com:3000/people/999.json
ryan = Person.find(999) # 404, raises ActiveResource::ResourceNotFound

404 is just one of the HTTP error response codes that Active Resource will handle with its own exception. The following HTTP response codes will also result in these exceptions:

  • 200..399 - Valid response. No exceptions, other than these redirects:

  • 301, 302, 303, 307 - ActiveResource::Redirection

  • 400 - ActiveResource::BadRequest

  • 401 - ActiveResource::UnauthorizedAccess

  • 403 - ActiveResource::ForbiddenAccess

  • 404 - ActiveResource::ResourceNotFound

  • 405 - ActiveResource::MethodNotAllowed

  • 409 - ActiveResource::ResourceConflict

  • 410 - ActiveResource::ResourceGone

  • 422 - ActiveResource::ResourceInvalid (rescued by save as validation errors)

  • 401..499 - ActiveResource::ClientError

  • 500..599 - ActiveResource::ServerError

  • Other - ActiveResource::ConnectionError

These custom exceptions allow you to deal with resource errors more naturally and with more precision rather than returning a general HTTP error. For example:

begin
  ryan = Person.find(my_id)
rescue ActiveResource::ResourceNotFound
  redirect_to :action => 'not_found'
rescue ActiveResource::ResourceConflict, ActiveResource::ResourceInvalid
  redirect_to :action => 'new'
end

When a GET is requested for a nested resource and you don't provide the prefix_param an ActiveResource::MissingPrefixParam will be raised.

class Comment < ActiveResource::Base
  self.site = "http://someip.com/posts/:post_id/"
end

Comment.find(1)
# => ActiveResource::MissingPrefixParam: post_id prefix_option is missing

Validation errors

Active Resource supports validations on resources and will return errors if any of these validations fail (e.g., “First name can not be blank” and so on). These types of errors are denoted in the response by a response code of 422 and an XML or JSON representation of the validation errors. The save operation will then fail (with a false return value) and the validation errors can be accessed on the resource in question.

ryan = Person.find(1)
ryan.first # => ''
ryan.save  # => false

# When
# PUT http://api.people.com:3000/people/1.json
# or
# PUT http://api.people.com:3000/people/1.json
# is requested with invalid values, the response is:
#
# Response (422):
# <errors><error>First cannot be empty</error></errors>
# or
# {"errors":["First cannot be empty"]}
#

ryan.errors.invalid?(:first)  # => true
ryan.errors.full_messages     # => ['First cannot be empty']

Learn more about Active Resource's validation features in the ActiveResource::Validations documentation.

Timeouts

Active Resource relies on HTTP to access RESTful APIs and as such is inherently susceptible to slow or unresponsive servers. In such cases, your Active Resource method calls could timeout. You can control the amount of time before Active Resource times out with the timeout variable.

class Person < ActiveResource::Base
  self.site = "http://api.people.com:3000/"
  self.timeout = 5
end

This sets the timeout to 5 seconds. You can adjust the timeout to a value suitable for the RESTful API you are accessing. It is recommended to set this to a reasonably low value to allow your Active Resource clients (especially if you are using Active Resource in a Rails application) to fail-fast (see en.wikipedia.org/wiki/Fail-fast) rather than cause cascading failures that could incapacitate your server.

When a timeout occurs, an ActiveResource::TimeoutError is raised. You should rescue from ActiveResource::TimeoutError in your Active Resource method calls.

Internally, Active Resource relies on Ruby's Net::HTTP library to make HTTP requests. Setting timeout sets the read_timeout of the internal Net::HTTP instance to the same value. The default read_timeout is 60 seconds on most Ruby implementations.

Class Attribute Summary collapse

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from ActiveModel::Naming

model_name, param_key, plural, route_key, singular, singular_route_key, uncountable?

Methods included from ActiveModel::Serializers::Xml

#from_xml

Methods included from ActiveSupport::Concern

#append_features, extended, #included

Methods included from ActiveModel::Serialization

#serializable_hash

Methods included from ActiveModel::Serializers::JSON

#as_json, #from_json

Methods included from ActiveModel::Conversion

#to_key, #to_model, #to_param, #to_partial_path

Methods included from CustomMethods

#delete, #get, #post, #put

Methods included from Validations

#errors, #load_remote_errors, #save_with_validation, #valid?

Methods included from ActiveModel::Validations

#errors, #initialize_dup, #invalid?, #valid?, #validates_with

Methods included from ActiveSupport::Callbacks

#run_callbacks

Constructor Details

#initialize(attributes = {}, persisted = false) ⇒ Base

Constructor method for new resources; the optional attributes parameter takes a hash of attributes for the new resource.

Examples

my_course = Course.new
my_course.name = "Western Civilization"
my_course.lecturer = "Don Trotter"
my_course.save

my_other_course = Course.new(:name => "Philosophy: Reason and Being", :lecturer => "Ralph Cling")
my_other_course.save

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# File 'activeresource/lib/active_resource/base.rb', line 1002

def initialize(attributes = {}, persisted = false)
  @attributes     = {}.with_indifferent_access
  @prefix_options = {}
  @persisted = persisted
  load(attributes)
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method_symbol, *arguments) ⇒ Object (private)

:nodoc:


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# File 'activeresource/lib/active_resource/base.rb', line 1456

def method_missing(method_symbol, *arguments) #:nodoc:
  method_name = method_symbol.to_s

  if method_name =~ /(=|\?)$/
    case $1
    when "="
      attributes[$`] = arguments.first
    when "?"
      attributes[$`]
    end
  else
    return attributes[method_name] if attributes.include?(method_name)
    # not set right now but we know about it
    return nil if known_attributes.include?(method_name)
    super
  end
end

Class Attribute Details

.collection_nameObject


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# File 'activeresource/lib/active_resource/base.rb', line 574

def collection_name
  @collection_name ||= ActiveSupport::Inflector.pluralize(element_name)
end

.element_nameObject


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# File 'activeresource/lib/active_resource/base.rb', line 568

def element_name
  @element_name ||= model_name.element
end

.primary_keyObject


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# File 'activeresource/lib/active_resource/base.rb', line 580

def primary_key
  @primary_key ||= 'id'
end

Instance Attribute Details

#attributesObject

:nodoc:


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# File 'activeresource/lib/active_resource/base.rb', line 973

def attributes
  @attributes
end

#prefix_optionsObject

:nodoc:


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# File 'activeresource/lib/active_resource/base.rb', line 974

def prefix_options
  @prefix_options
end

Class Method Details

.all(*args) ⇒ Object

This is an alias for find(:all). You can pass in all the same arguments to this method as you can to find(:all)


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# File 'activeresource/lib/active_resource/base.rb', line 838

def all(*args)
  find(:all, *args)
end

.auth_typeObject


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# File 'activeresource/lib/active_resource/base.rb', line 471

def auth_type
  if defined?(@auth_type)
    @auth_type
  end
end

.auth_type=(auth_type) ⇒ Object


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# File 'activeresource/lib/active_resource/base.rb', line 477

def auth_type=(auth_type)
  @connection = nil
  @auth_type = auth_type
end

.build(attributes = {}) ⇒ Object

Builds a new, unsaved record using the default values from the remote server so that it can be used with RESTful forms.

Options

  • attributes - A hash that overrides the default values from the server.

Returns the new resource instance.


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# File 'activeresource/lib/active_resource/base.rb', line 716

def build(attributes = {})
  attrs = self.format.decode(connection.get("#{new_element_path}").body).merge(attributes)
  self.new(attrs)
end

.collection_path(prefix_options = {}, query_options = nil) ⇒ Object

Gets the collection path for the REST resources. If the query_options parameter is omitted, Rails will split from the prefix_options.

Options

  • prefix_options - A hash to add a prefix to the request for nested URLs (e.g., :account_id => 19 would yield a URL like /accounts/19/purchases.json).

  • query_options - A hash to add items to the query string for the request.

Examples

Post.collection_path
# => /posts.json

Comment.collection_path(:post_id => 5)
# => /posts/5/comments.json

Comment.collection_path(:post_id => 5, :active => 1)
# => /posts/5/comments.json?active=1

Comment.collection_path({:post_id => 5}, {:active => 1})
# => /posts/5/comments.json?active=1

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# File 'activeresource/lib/active_resource/base.rb', line 700

def collection_path(prefix_options = {}, query_options = nil)
  check_prefix_options(prefix_options)
  prefix_options, query_options = split_options(prefix_options) if query_options.nil?
  "#{prefix(prefix_options)}#{collection_name}.#{format.extension}#{query_string(query_options)}"
end

.connection(refresh = false) ⇒ Object

An instance of ActiveResource::Connection that is the base connection to the remote service. The refresh parameter toggles whether or not the connection is refreshed at every request or not (defaults to false).


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# File 'activeresource/lib/active_resource/base.rb', line 547

def connection(refresh = false)
  if defined?(@connection) || superclass == Object
    @connection = Connection.new(site, format) if refresh || @connection.nil?
    @connection.proxy = proxy if proxy
    @connection.user = user if user
    @connection.password = password if password
    @connection.auth_type = auth_type if auth_type
    @connection.timeout = timeout if timeout
    @connection.ssl_options = ssl_options if ssl_options
    @connection
  else
    superclass.connection
  end
end

.create(attributes = {}) ⇒ Object

Creates a new resource instance and makes a request to the remote service that it be saved, making it equivalent to the following simultaneous calls:

ryan = Person.new(:first => 'ryan')
ryan.save

Returns the newly created resource. If a failure has occurred an exception will be raised (see save). If the resource is invalid and has not been saved then valid? will return false, while new? will still return true.

Examples

Person.create(:name => 'Jeremy', :email => '[email protected]', :enabled => true)
my_person = Person.find(:first)
my_person.email # => [email protected]

dhh = Person.create(:name => 'David', :email => '[email protected]', :enabled => true)
dhh.valid? # => true
dhh.new?   # => false

# We'll assume that there's a validation that requires the name attribute
that_guy = Person.create(:name => '', :email => '[email protected]', :enabled => true)
that_guy.valid? # => false
that_guy.new?   # => true

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# File 'activeresource/lib/active_resource/base.rb', line 745

def create(attributes = {})
  self.new(attributes).tap { |resource| resource.save }
end

.delete(id, options = {}) ⇒ Object

Deletes the resources with the ID in the id parameter.

Options

All options specify prefix and query parameters.

Examples

Event.delete(2) # sends DELETE /events/2

Event.create(:name => 'Free Concert', :location => 'Community Center')
my_event = Event.find(:first) # let's assume this is event with ID 7
Event.delete(my_event.id) # sends DELETE /events/7

# Let's assume a request to events/5/cancel.json
Event.delete(params[:id]) # sends DELETE /events/5

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# File 'activeresource/lib/active_resource/base.rb', line 857

def delete(id, options = {})
  connection.delete(element_path(id, options))
end

.element_path(id, prefix_options = {}, query_options = nil) ⇒ Object

Gets the element path for the given ID in id. If the query_options parameter is omitted, Rails will split from the prefix options.

Options

prefix_options - A hash to add a prefix to the request for nested URLs (e.g., :account_id => 19

would yield a URL like <tt>/accounts/19/purchases.json</tt>).

query_options - A hash to add items to the query string for the request.

Examples

Post.element_path(1)
# => /posts/1.json

class Comment < ActiveResource::Base
  self.site = "http://37s.sunrise.i/posts/:post_id/"
end

Comment.element_path(1, :post_id => 5)
# => /posts/5/comments/1.json

Comment.element_path(1, :post_id => 5, :active => 1)
# => /posts/5/comments/1.json?active=1

Comment.element_path(1, {:post_id => 5}, {:active => 1})
# => /posts/5/comments/1.json?active=1

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# File 'activeresource/lib/active_resource/base.rb', line 652

def element_path(id, prefix_options = {}, query_options = nil)
  check_prefix_options(prefix_options)

  prefix_options, query_options = split_options(prefix_options) if query_options.nil?
  "#{prefix(prefix_options)}#{collection_name}/#{URI.parser.escape id.to_s}.#{format.extension}#{query_string(query_options)}"
end

.exists?(id, options = {}) ⇒ Boolean

Asserts the existence of a resource, returning true if the resource is found.

Examples

Note.create(:title => 'Hello, world.', :body => 'Nothing more for now...')
Note.exists?(1) # => true

Note.exists(1349) # => false

Returns:

  • (Boolean)

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# File 'activeresource/lib/active_resource/base.rb', line 868

def exists?(id, options = {})
  if id
    prefix_options, query_options = split_options(options[:params])
    path = element_path(id, prefix_options, query_options)
    response = connection.head(path, headers)
    response.code.to_i == 200
  end
  # id && !find_single(id, options).nil?
rescue ActiveResource::ResourceNotFound, ActiveResource::ResourceGone
  false
end

.find(*arguments) ⇒ Object

Core method for finding resources. Used similarly to Active Record's find method.

Arguments

The first argument is considered to be the scope of the query. That is, how many resources are returned from the request. It can be one of the following.

  • :one - Returns a single resource.

  • :first - Returns the first resource found.

  • :last - Returns the last resource found.

  • :all - Returns every resource that matches the request.

Options

  • :from - Sets the path or custom method that resources will be fetched from.

  • :params - Sets query and prefix (nested URL) parameters.

Examples

Person.find(1)
# => GET /people/1.json

Person.find(:all)
# => GET /people.json

Person.find(:all, :params => { :title => "CEO" })
# => GET /people.json?title=CEO

Person.find(:first, :from => :managers)
# => GET /people/managers.json

Person.find(:last, :from => :managers)
# => GET /people/managers.json

Person.find(:all, :from => "/companies/1/people.json")
# => GET /companies/1/people.json

Person.find(:one, :from => :leader)
# => GET /people/leader.json

Person.find(:all, :from => :developers, :params => { :language => 'ruby' })
# => GET /people/developers.json?language=ruby

Person.find(:one, :from => "/companies/1/manager.json")
# => GET /companies/1/manager.json

StreetAddress.find(1, :params => { :person_id => 1 })
# => GET /people/1/street_addresses/1.json

Failure or missing data

A failure to find the requested object raises a ResourceNotFound
exception if the find was called with an id.
With any other scope, find returns nil when no data is returned.

Person.find(1)
# => raises ResourceNotFound

Person.find(:all)
Person.find(:first)
Person.find(:last)
# => nil

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# File 'activeresource/lib/active_resource/base.rb', line 808

def find(*arguments)
  scope   = arguments.slice!(0)
  options = arguments.slice!(0) || {}

  case scope
    when :all   then find_every(options)
    when :first then find_every(options).first
    when :last  then find_every(options).last
    when :one   then find_one(options)
    else             find_single(scope, options)
  end
end

.first(*args) ⇒ Object

A convenience wrapper for find(:first, *args). You can pass in all the same arguments to this method as you can to find(:first).


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# File 'activeresource/lib/active_resource/base.rb', line 825

def first(*args)
  find(:first, *args)
end

.formatObject

Returns the current format, default is ActiveResource::Formats::JsonFormat.


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# File 'activeresource/lib/active_resource/base.rb', line 500

def format
  self._format || ActiveResource::Formats::JsonFormat
end

.format=(mime_type_reference_or_format) ⇒ Object

Sets the format that attributes are sent and received in from a mime type reference:

Person.format = :json
Person.find(1) # => GET /people/1.json

Person.format = ActiveResource::Formats::XmlFormat
Person.find(1) # => GET /people/1.xml

Default format is :json.


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# File 'activeresource/lib/active_resource/base.rb', line 491

def format=(mime_type_reference_or_format)
  format = mime_type_reference_or_format.is_a?(Symbol) ?
    ActiveResource::Formats[mime_type_reference_or_format] : mime_type_reference_or_format

  self._format = format
  connection.format = format if site
end

.headersObject


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# File 'activeresource/lib/active_resource/base.rb', line 562

def headers
  @headers ||= {}
end

.known_attributesObject

Returns the list of known attributes for this resource, gathered from the provided schema Attributes that are known will cause your resource to return 'true' when respond_to? is called on them. A known attribute will return nil if not set (rather than <t>MethodNotFound</tt>); thus known attributes can be used with validates_presence_of without a getter-method.


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# File 'activeresource/lib/active_resource/base.rb', line 381

def known_attributes
  @known_attributes ||= []
end

.last(*args) ⇒ Object

A convenience wrapper for find(:last, *args). You can pass in all the same arguments to this method as you can to find(:last).


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# File 'activeresource/lib/active_resource/base.rb', line 832

def last(*args)
  find(:last, *args)
end

.new_element_path(prefix_options = {}) ⇒ Object

Gets the new element path for REST resources.

Options

  • prefix_options - A hash to add a prefix to the request for nested URLs (e.g., :account_id => 19 would yield a URL like /accounts/19/purchases/new.json).

Examples

Post.new_element_path
# => /posts/new.json

class Comment < ActiveResource::Base
  self.site = "http://37s.sunrise.i/posts/:post_id/"
end

Comment.collection_path(:post_id => 5)
# => /posts/5/comments/new.json

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# File 'activeresource/lib/active_resource/base.rb', line 675

def new_element_path(prefix_options = {})
  "#{prefix(prefix_options)}#{collection_name}/new.#{format.extension}"
end

.passwordObject

Gets the password for REST HTTP authentication.


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# File 'activeresource/lib/active_resource/base.rb', line 456

def password
  # Not using superclass_delegating_reader. See +site+ for explanation
  if defined?(@password)
    @password
  elsif superclass != Object && superclass.password
    superclass.password.dup.freeze
  end
end

.password=(password) ⇒ Object

Sets the password for REST HTTP authentication.


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# File 'activeresource/lib/active_resource/base.rb', line 466

def password=(password)
  @connection = nil
  @password = password
end

.prefix(options = {}) ⇒ Object

Gets the prefix for a resource's nested URL (e.g., prefix/collectionname/1.json) This method is regenerated at runtime based on what the prefix is set to.


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# File 'activeresource/lib/active_resource/base.rb', line 586

def prefix(options={})
  default = site.path
  default << '/' unless default[-1..-1] == '/'
  # generate the actual method based on the current site path
  self.prefix = default
  prefix(options)
end

.prefix=(value = '/') ⇒ Object Also known as: set_prefix

Sets the prefix for a resource's nested URL (e.g., prefix/collectionname/1.json). Default value is site.path.


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# File 'activeresource/lib/active_resource/base.rb', line 603

def prefix=(value = '/')
  # Replace :placeholders with '#{embedded options[:lookups]}'
  prefix_call = value.gsub(/:\w+/) { |key| "\#{URI.parser.escape options[#{key}].to_s}" }

  # Clear prefix parameters in case they have been cached
  @prefix_parameters = nil

  silence_warnings do
    # Redefine the new methods.
    instance_eval <<-RUBY_EVAL, __FILE__, __LINE__ + 1
      def prefix_source() "#{value}" end
      def prefix(options={}) "#{prefix_call}" end
    RUBY_EVAL
  end
rescue Exception => e
  logger.error "Couldn't set prefix: #{e}\n  #{code}" if logger
  raise
end

.prefix_sourceObject

An attribute reader for the source string for the resource path prefix. This method is regenerated at runtime based on what the prefix is set to.


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# File 'activeresource/lib/active_resource/base.rb', line 596

def prefix_source
  prefix # generate #prefix and #prefix_source methods first
  prefix_source
end

.proxyObject

Gets the proxy variable if a proxy is required


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# File 'activeresource/lib/active_resource/base.rb', line 424

def proxy
  # Not using superclass_delegating_reader. See +site+ for explanation
  if defined?(@proxy)
    @proxy
  elsif superclass != Object && superclass.proxy
    superclass.proxy.dup.freeze
  end
end

.proxy=(proxy) ⇒ Object

Sets the URI of the http proxy to the value in the proxy argument.


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# File 'activeresource/lib/active_resource/base.rb', line 434

def proxy=(proxy)
  @connection = nil
  @proxy = proxy.nil? ? nil : create_proxy_uri_from(proxy)
end

.schema(&block) ⇒ Object

Creates a schema for this resource - setting the attributes that are known prior to fetching an instance from the remote system.

The schema helps define the set of known_attributes of the current resource.

There is no need to specify a schema for your Active Resource. If you do not, the known_attributes will be guessed from the instance attributes returned when an instance is fetched from the remote system.

example: class Person < ActiveResource::Base

schema do
  # define each attribute separately
  attribute 'name', :string

  # or use the convenience methods and pass >=1 attribute names
  string  'eye_color', 'hair_color'
  integer 'age'
  float   'height', 'weight'

  # unsupported types should be left as strings
  # overload the accessor methods if you need to convert them
  attribute 'created_at', 'string'
end

end

p = Person.new p.respond_to? :name # => true p.respond_to? :age # => true p.name # => nil p.age # => nil

j = Person.find_by_name('John') # <person><name>John</name><age>34</age><num_children>3</num_children></person> j.respond_to? :name # => true j.respond_to? :age # => true j.name # => 'John' j.age # => '34' # note this is a string! j.num_children # => '3' # note this is a string!

p.num_children # => NoMethodError

Attribute-types must be one of:

string, integer, float

Note: at present the attribute-type doesn't do anything, but stay tuned… Shortly it will also cast the value of the returned attribute. ie: j.age # => 34 # cast to an integer j.weight # => '65' # still a string!


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# File 'activeresource/lib/active_resource/base.rb', line 320

def schema(&block)
  if block_given?
    schema_definition = Schema.new
    schema_definition.instance_eval(&block)

    # skip out if we didn't define anything
    return unless schema_definition.attrs.present?

    @schema ||= {}.with_indifferent_access
    @known_attributes ||= []

    schema_definition.attrs.each do |k,v|
      @schema[k] = v
      @known_attributes << k
    end

    schema
  else
    @schema ||= nil
  end
end

.schema=(the_schema) ⇒ Object

Alternative, direct way to specify a schema for this Resource. schema is more flexible, but this is quick for a very simple schema.

Pass the schema as a hash with the keys being the attribute-names and the value being one of the accepted attribute types (as defined in schema)

example:

class Person < ActiveResource::Base

schema = {'name' => :string, 'age' => :integer }

end

The keys/values can be strings or symbols. They will be converted to strings.

Raises:

  • (ArgumentError)

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# File 'activeresource/lib/active_resource/base.rb', line 359

def schema=(the_schema)
  unless the_schema.present?
    # purposefully nulling out the schema
    @schema = nil
    @known_attributes = []
    return
  end

  raise ArgumentError, "Expected a hash" unless the_schema.kind_of? Hash

  schema do
    the_schema.each {|k,v| attribute(k,v) }
  end
end

.siteObject

Gets the URI of the REST resources to map for this class. The site variable is required for Active Resource's mapping to work.


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# File 'activeresource/lib/active_resource/base.rb', line 387

def site
  # Not using superclass_delegating_reader because don't want subclasses to modify superclass instance
  #
  # With superclass_delegating_reader
  #
  #   Parent.site = 'http://[email protected]'
  #   Subclass.site # => 'http://[email protected]'
  #   Subclass.site.user = 'david'
  #   Parent.site # => 'http://[email protected]'
  #
  # Without superclass_delegating_reader (expected behavior)
  #
  #   Parent.site = 'http://[email protected]'
  #   Subclass.site # => 'http://[email protected]'
  #   Subclass.site.user = 'david' # => TypeError: can't modify frozen object
  #
  if defined?(@site)
    @site
  elsif superclass != Object && superclass.site
    superclass.site.dup.freeze
  end
end

.site=(site) ⇒ Object

Sets the URI of the REST resources to map for this class to the value in the site argument. The site variable is required for Active Resource's mapping to work.


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# File 'activeresource/lib/active_resource/base.rb', line 412

def site=(site)
  @connection = nil
  if site.nil?
    @site = nil
  else
    @site = create_site_uri_from(site)
    @user = URI.parser.unescape(@site.user) if @site.user
    @password = URI.parser.unescape(@site.password) if @site.password
  end
end

.ssl_optionsObject

Returns the SSL options hash.


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# File 'activeresource/lib/active_resource/base.rb', line 536

def ssl_options
  if defined?(@ssl_options)
    @ssl_options
  elsif superclass != Object && superclass.ssl_options
    superclass.ssl_options
  end
end

.ssl_options=(opts = {}) ⇒ Object

Options that will get applied to an SSL connection.

  • :key - An OpenSSL::PKey::RSA or OpenSSL::PKey::DSA object.

  • :cert - An OpenSSL::X509::Certificate object as client certificate

  • :ca_file - Path to a CA certification file in PEM format. The file can contain several CA certificates.

  • :ca_path - Path of a CA certification directory containing certifications in PEM format.

  • :verify_mode - Flags for server the certification verification at beginning of SSL/TLS session. (OpenSSL::SSL::VERIFY_NONE or OpenSSL::SSL::VERIFY_PEER is acceptable)

  • :verify_callback - The verify callback for the server certification verification.

  • :verify_depth - The maximum depth for the certificate chain verification.

  • :cert_store - OpenSSL::X509::Store to verify peer certificate.

  • :ssl_timeout -The SSL timeout in seconds.


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# File 'activeresource/lib/active_resource/base.rb', line 530

def ssl_options=(opts={})
  @connection   = nil
  @ssl_options  = opts
end

.timeoutObject

Gets the number of seconds after which requests to the REST API should time out.


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# File 'activeresource/lib/active_resource/base.rb', line 511

def timeout
  if defined?(@timeout)
    @timeout
  elsif superclass != Object && superclass.timeout
    superclass.timeout
  end
end

.timeout=(timeout) ⇒ Object

Sets the number of seconds after which requests to the REST API should time out.


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# File 'activeresource/lib/active_resource/base.rb', line 505

def timeout=(timeout)
  @connection = nil
  @timeout = timeout
end

.userObject

Gets the user for REST HTTP authentication.


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# File 'activeresource/lib/active_resource/base.rb', line 440

def user
  # Not using superclass_delegating_reader. See +site+ for explanation
  if defined?(@user)
    @user
  elsif superclass != Object && superclass.user
    superclass.user.dup.freeze
  end
end

.user=(user) ⇒ Object

Sets the user for REST HTTP authentication.


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# File 'activeresource/lib/active_resource/base.rb', line 450

def user=(user)
  @connection = nil
  @user = user
end

Instance Method Details

#==(other) ⇒ Object

Test for equality. Resource are equal if and only if other is the same object or is an instance of the same class, is not new?, and has the same id.

Examples

ryan = Person.create(:name => 'Ryan')
jamie = Person.create(:name => 'Jamie')

ryan == jamie
# => false (Different name attribute and id)

ryan_again = Person.new(:name => 'Ryan')
ryan == ryan_again
# => false (ryan_again is new?)

ryans_clone = Person.create(:name => 'Ryan')
ryan == ryans_clone
# => false (Different id attributes)

ryans_twin = Person.find(ryan.id)
ryan == ryans_twin
# => true

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# File 'activeresource/lib/active_resource/base.rb', line 1107

def ==(other)
  other.equal?(self) || (other.instance_of?(self.class) && other.id == id && other.prefix_options == prefix_options)
end

#cloneObject

Returns a clone of the resource that hasn't been assigned an id yet and is treated as a new resource.

ryan = Person.find(1)
not_ryan = ryan.clone
not_ryan.new?  # => true

Any active resource member attributes will NOT be cloned, though all other attributes are. This is to prevent the conflict between any prefix_options that refer to the original parent resource and the newly cloned parent resource that does not exist.

ryan = Person.find(1)
ryan.address = StreetAddress.find(1, :person_id => ryan.id)
ryan.hash = {:not => "an ARes instance"}

not_ryan = ryan.clone
not_ryan.new?            # => true
not_ryan.address         # => NoMethodError
not_ryan.hash            # => {:not => "an ARes instance"}

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# File 'activeresource/lib/active_resource/base.rb', line 1029

def clone
  # Clone all attributes except the pk and any nested ARes
  cloned = Hash[attributes.reject {|k,v| k == self.class.primary_key || v.is_a?(ActiveResource::Base)}.map { |k, v| [k, v.clone] }]
  # Form the new resource - bypass initialize of resource with 'new' as that will call 'load' which
  # attempts to convert hashes into member objects and arrays into collections of objects.  We want
  # the raw objects to be cloned so we bypass load by directly setting the attributes hash.
  resource = self.class.new({})
  resource.prefix_options = self.prefix_options
  resource.send :instance_variable_set, '@attributes', cloned
  resource
end

#destroyObject

Deletes the resource from the remote service.

Examples

my_id = 3
my_person = Person.find(my_id)
my_person.destroy
Person.find(my_id) # 404 (Resource Not Found)

new_person = Person.create(:name => 'James')
new_id = new_person.id # => 7
new_person.destroy
Person.find(new_id) # 404 (Resource Not Found)

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# File 'activeresource/lib/active_resource/base.rb', line 1187

def destroy
  connection.delete(element_path, self.class.headers)
end

#dupObject

Duplicates the current resource without saving it.

Examples

my_invoice = Invoice.create(:customer => 'That Company')
next_invoice = my_invoice.dup
next_invoice.new? # => true

next_invoice.save
next_invoice == my_invoice # => false (different id attributes)

my_invoice.customer   # => That Company
next_invoice.customer # => That Company

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# File 'activeresource/lib/active_resource/base.rb', line 1134

def dup
  self.class.new.tap do |resource|
    resource.attributes     = @attributes
    resource.prefix_options = @prefix_options
  end
end

#encode(options = {}) ⇒ Object

Returns the serialized string representation of the resource in the configured serialization format specified in ActiveResource::Base.format. The options applicable depend on the configured encoding format.


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# File 'activeresource/lib/active_resource/base.rb', line 1214

def encode(options={})
  send("to_#{self.class.format.extension}", options)
end

#eql?(other) ⇒ Boolean

Tests for equality (delegates to ==).

Returns:

  • (Boolean)

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# File 'activeresource/lib/active_resource/base.rb', line 1112

def eql?(other)
  self == other
end

#exists?Boolean

Evaluates to true if this resource is not new? and is found on the remote service. Using this method, you can check for resources that may have been deleted between the object's instantiation and actions on it.

Examples

Person.create(:name => 'Theodore Roosevelt')
that_guy = Person.find(:first)
that_guy.exists? # => true

that_lady = Person.new(:name => 'Paul Bean')
that_lady.exists? # => false

guys_id = that_guy.id
Person.delete(guys_id)
that_guy.exists? # => false

Returns:

  • (Boolean)

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# File 'activeresource/lib/active_resource/base.rb', line 1207

def exists?
  !new? && self.class.exists?(to_param, :params => prefix_options)
end

#hashObject

Delegates to id in order to allow two resources of the same type and id to work with something like:

[(a = Person.find 1), (b = Person.find 2)] & [(c = Person.find 1), (d = Person.find 4)] # => [a]

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# File 'activeresource/lib/active_resource/base.rb', line 1118

def hash
  id.hash
end

#idObject

Gets the \id attribute of the resource.


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# File 'activeresource/lib/active_resource/base.rb', line 1076

def id
  attributes[self.class.primary_key]
end

#id=(id) ⇒ Object

Sets the \id attribute of the resource.


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# File 'activeresource/lib/active_resource/base.rb', line 1081

def id=(id)
  attributes[self.class.primary_key] = id
end

#known_attributesObject

This is a list of known attributes for this resource. Either gathered from the provided schema, or from the attributes set on this instance after it has been fetched from the remote system.


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# File 'activeresource/lib/active_resource/base.rb', line 986

def known_attributes
  self.class.known_attributes + self.attributes.keys.map(&:to_s)
end

#load(attributes, remove_root = false) ⇒ Object

A method to manually load attributes from a hash. Recursively loads collections of resources. This method is called in initialize and create when a hash of attributes is provided.

Examples

my_attrs = {:name => 'J&J Textiles', :industry => 'Cloth and textiles'}
my_attrs = {:name => 'Marty', :colors => ["red", "green", "blue"]}

the_supplier = Supplier.find(:first)
the_supplier.name # => 'J&M Textiles'
the_supplier.load(my_attrs)
the_supplier.name('J&J Textiles')

# These two calls are the same as Supplier.new(my_attrs)
my_supplier = Supplier.new
my_supplier.load(my_attrs)

# These three calls are the same as Supplier.create(my_attrs)
your_supplier = Supplier.new
your_supplier.load(my_attrs)
your_supplier.save

Raises:

  • (ArgumentError)

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# File 'activeresource/lib/active_resource/base.rb', line 1254

def load(attributes, remove_root = false)
  raise ArgumentError, "expected an attributes Hash, got #{attributes.inspect}" unless attributes.is_a?(Hash)
  @prefix_options, attributes = split_options(attributes)

  if attributes.keys.size == 1
    remove_root = self.class.element_name == attributes.keys.first.to_s
  end

  attributes = Formats.remove_root(attributes) if remove_root

  attributes.each do |key, value|
    @attributes[key.to_s] =
      case value
        when Array
          resource = nil
          value.map do |attrs|
            if attrs.is_a?(Hash)
              resource ||= find_or_create_resource_for_collection(key)
              resource.new(attrs)
            else
              attrs.duplicable? ? attrs.dup : attrs
            end
          end
        when Hash
          resource = find_or_create_resource_for(key)
          resource.new(value)
        else
          value.duplicable? ? value.dup : value
      end
  end
  self
end

#loggerObject

:singleton-method: The logger for diagnosing and tracing Active Resource calls.


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# File 'activeresource/lib/active_resource/base.rb', line 262

cattr_accessor :logger

#new?Boolean Also known as: new_record?

Returns true if this object hasn't yet been saved, otherwise, returns false.

Examples

not_new = Computer.create(:brand => 'Apple', :make => 'MacBook', :vendor => 'MacMall')
not_new.new? # => false

is_new = Computer.new(:brand => 'IBM', :make => 'Thinkpad', :vendor => 'IBM')
is_new.new? # => true

is_new.save
is_new.new? # => false

Returns:

  • (Boolean)

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# File 'activeresource/lib/active_resource/base.rb', line 1054

def new?
  !persisted?
end

#persisted?Boolean

Returns true if this object has been saved, otherwise returns false.

Examples

persisted = Computer.create(:brand => 'Apple', :make => 'MacBook', :vendor => 'MacMall')
persisted.persisted? # => true

not_persisted = Computer.new(:brand => 'IBM', :make => 'Thinkpad', :vendor => 'IBM')
not_persisted.persisted? # => false

not_persisted.save
not_persisted.persisted? # => true

Returns:

  • (Boolean)

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# File 'activeresource/lib/active_resource/base.rb', line 1071

def persisted?
  @persisted
end

#reloadObject

A method to reload the attributes of this object from the remote web service.

Examples

my_branch = Branch.find(:first)
my_branch.name # => "Wislon Raod"

# Another client fixes the typo...

my_branch.name # => "Wislon Raod"
my_branch.reload
my_branch.name # => "Wilson Road"

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# File 'activeresource/lib/active_resource/base.rb', line 1229

def reload
  self.load(self.class.find(to_param, :params => @prefix_options).attributes)
end

#respond_to?(method, include_priv = false) ⇒ Boolean

A method to determine if an object responds to a message (e.g., a method call). In Active Resource, a Person object with a name attribute can answer true to my_person.respond_to?(:name), my_person.respond_to?(:name=), and my_person.respond_to?(:name?).

Returns:

  • (Boolean)

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# File 'activeresource/lib/active_resource/base.rb', line 1323

def respond_to?(method, include_priv = false)
  method_name = method.to_s
  if attributes.nil?
    super
  elsif known_attributes.include?(method_name)
    true
  elsif method_name =~ /(?:=|\?)$/ && attributes.include?($`)
    true
  else
    # super must be called at the end of the method, because the inherited respond_to?
    # would return true for generated readers, even if the attribute wasn't present
    super
  end
end

#respond_to_without_attributes?Object

For checking respond_to? without searching the attributes (which is faster).


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# File 'activeresource/lib/active_resource/base.rb', line 1318

alias_method :respond_to_without_attributes?, :respond_to?

#saveObject

Saves (POST) or updates (PUT) a resource. Delegates to create if the object is new, update if it exists. If the response to the save includes a body, it will be assumed that this body is Json for the final object as it looked after the save (which would include attributes like created_at that weren't part of the original submit).

Examples

my_company = Company.new(:name => 'RoleModel Software', :owner => 'Ken Auer', :size => 2)
my_company.new? # => true
my_company.save # sends POST /companies/ (create)

my_company.new? # => false
my_company.size = 10
my_company.save # sends PUT /companies/1 (update)

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# File 'activeresource/lib/active_resource/base.rb', line 1154

def save
  new? ? create : update
end

#save!Object

Saves the resource.

If the resource is new, it is created via POST, otherwise the existing resource is updated via PUT.

With save! validations always run. If any of them fail ActiveResource::ResourceInvalid gets raised, and nothing is POSTed to the remote system. See ActiveResource::Validations for more information.

There's a series of callbacks associated with save!. If any of the before_* callbacks return false the action is cancelled and save! raises ActiveResource::ResourceInvalid.


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# File 'activeresource/lib/active_resource/base.rb', line 1171

def save!
  save || raise(ResourceInvalid.new(self))
end

#schemaObject

If no schema has been defined for the class (see ActiveResource::schema=), the default automatic schema is generated from the current instance's attributes


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# File 'activeresource/lib/active_resource/base.rb', line 979

def schema
  self.class.schema || self.attributes
end

#to_json(options = {}) ⇒ Object


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# File 'activeresource/lib/active_resource/base.rb', line 1338

def to_json(options={})
  super({ :root => self.class.element_name }.merge(options))
end

#to_xml(options = {}) ⇒ Object


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# File 'activeresource/lib/active_resource/base.rb', line 1342

def to_xml(options={})
  super({ :root => self.class.element_name }.merge(options))
end

#update_attribute(name, value) ⇒ Object

Updates a single attribute and then saves the object.

Note: Unlike ActiveRecord::Base.update_attribute, this method is subject to normal validation routines as an update sends the whole body of the resource in the request. (See Validations).

As such, this method is equivalent to calling update_attributes with a single attribute/value pair.

If the saving fails because of a connection or remote service error, an exception will be raised. If saving fails because the resource is invalid then false will be returned.


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# File 'activeresource/lib/active_resource/base.rb', line 1298

def update_attribute(name, value)
  self.send("#{name}=".to_sym, value)
  self.save
end

#update_attributes(attributes) ⇒ Object

Updates this resource with all the attributes from the passed-in Hash and requests that the record be saved.

If the saving fails because of a connection or remote service error, an exception will be raised. If saving fails because the resource is invalid then false will be returned.

Note: Though this request can be made with a partial set of the resource's attributes, the full body of the request will still be sent in the save request to the remote service.


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# File 'activeresource/lib/active_resource/base.rb', line 1313

def update_attributes(attributes)
  load(attributes, false) && save
end