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 files/vendor/rails/activeresource/README.html.

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 sitevalue, 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 lifecycles 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_namevalue.

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

Lifecycle 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 lifecycle methods for database records. You can read more about each of these methods in their respective documentation.

Custom REST methods

Since simple CRUD/lifecycle 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, putand \deletemethods where you can specify a custom REST method name to invoke.

# POST to the custom 'register' REST method, i.e. POST /people/new/register.xml.
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.xml?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.xml.
Person.get(:positions)
# => [{:name => 'Manager'}, {:name => 'Clerk'}]
# DELETE to 'fire' a person, i.e. DELETE /people/1/fire.xml.
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 sitevariable.

    class Person < ActiveResource::Base
      self.site = "http://ryan:password@api.people.com:3000/"
    end
    
  • defining userand/or passwordvariables

    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.xml
ryan = Person.find(999) # 404, raises ActiveResource::ResourceNotFound

404is 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:

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

Validation errors

Active Resource supports validations on resources and will return errors if any 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 422and 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.xml
# or
# PUT http://api.people.com:3000/people/1.json
# is requested with invalid values, the response is:
#
# Response (422):
# <errors type="array"><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 timeoutto 5 seconds. You can adjust the timeoutto 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 timeoutsets the read_timeoutof the internal Net::HTTP instance to the same value. The default read_timeoutis 60 seconds on most Ruby implementations.

Methods
#
A
C
D
E
F
H
I
L
N
P
R
S
T
U
Class Public methods
collection_path(prefix_options = {}, query_options = nil)

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

Options

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

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

Examples

Post.collection_path
# => /posts.xml
Comment.collection_path(:post_id => 5)
# => /posts/5/comments.xml
Comment.collection_path(:post_id => 5, :active => 1)
# => /posts/5/comments.xml?active=1
Comment.collection_path({:post_id => 5}, {:active => 1})
# => /posts/5/comments.xml?active=1
# File activeresource/lib/active_resource/base.rb, line 499
def collection_path(prefix_options = {}, query_options = nil)
  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)

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).

# File activeresource/lib/active_resource/base.rb, line 385
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.timeout = timeout if timeout
    @connection.ssl_options = ssl_options if ssl_options
    @connection
  else
    superclass.connection
  end
end
create(attributes = {})

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 => 'myname@nospam.com', :enabled => true)
my_person = Person.find(:first)
my_person.email # => myname@nospam.com
dhh = Person.create(:name => 'David', :email => 'dhh@nospam.com', :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 => 'thatguy@nospam.com', :enabled => true)
that_guy.valid? # => false
that_guy.new?   # => true
# File activeresource/lib/active_resource/base.rb, line 530
def create(attributes = {})
  self.new(attributes).tap { |resource| resource.save }
end
delete(id, options = {})

Deletes the resources with the ID in the idparameter.

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.xml
Event.delete(params[:id]) # sends DELETE /events/5
# File activeresource/lib/active_resource/base.rb, line 607
def delete(id, options = {})
  connection.delete(element_path(id, options))
end
element_path(id, prefix_options = {}, query_options = nil)

Gets the element path for the given ID in id. If the query_optionsparameter 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.xml</tt>).

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

Examples

Post.element_path(1)
# => /posts/1.xml
Comment.element_path(1, :post_id => 5)
# => /posts/5/comments/1.xml
Comment.element_path(1, :post_id => 5, :active => 1)
# => /posts/5/comments/1.xml?active=1
Comment.element_path(1, {:post_id => 5}, {:active => 1})
# => /posts/5/comments/1.xml?active=1
# File activeresource/lib/active_resource/base.rb, line 473
def element_path(id, prefix_options = {}, query_options = nil)
  prefix_options, query_options = split_options(prefix_options) if query_options.nil?
  "#{prefix(prefix_options)}#{collection_name}/#{id}.#{format.extension}#{query_string(query_options)}"
end
exists?(id, options = {})

Asserts the existence of a resource, returning trueif the resource is found.

Examples

Note.create(:title => 'Hello, world.', :body => 'Nothing more for now...')
Note.exists?(1) # => true
Note.exists(1349) # => false
# File activeresource/lib/active_resource/base.rb, line 618
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)

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

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.xml
Person.find(:all)
# => GET /people.xml
Person.find(:all, :params => { :title => "CEO" })
# => GET /people.xml?title=CEO
Person.find(:first, :from => :managers)
# => GET /people/managers.xml
Person.find(:last, :from => :managers)
# => GET /people/managers.xml
Person.find(:all, :from => "/companies/1/people.xml")
# => GET /companies/1/people.xml
Person.find(:one, :from => :leader)
# => GET /people/leader.xml
Person.find(:all, :from => :developers, :params => { :language => 'ruby' })
# => GET /people/developers.xml?language=ruby
Person.find(:one, :from => "/companies/1/manager.xml")
# => GET /companies/1/manager.xml
StreetAddress.find(1, :params => { :person_id => 1 })
# => GET /people/1/street_addresses/1.xml
# File activeresource/lib/active_resource/base.rb, line 580
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
format()

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

# File activeresource/lib/active_resource/base.rb, line 338
def format
  read_inheritable_attribute(:format) || ActiveResource::Formats[:xml]
end
format=(mime_type_reference_or_format)

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 :xml.

# File activeresource/lib/active_resource/base.rb, line 329
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
  write_inheritable_attribute(:format, format)
  connection.format = format if site
end
headers()
# File activeresource/lib/active_resource/base.rb, line 399
def headers
  @headers ||= {}
end
logger

The logger for diagnosing and tracing Active Resource calls.

# File activeresource/lib/active_resource/base.rb, line 228
cattr_accessor :logger
new(attributes = {})

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
# File activeresource/lib/active_resource/base.rb, line 723
def initialize(attributes = {})
  @attributes     = {}
  @prefix_options = {}
  load(attributes)
end
password()

Gets the password for REST HTTP authentication.

# File activeresource/lib/active_resource/base.rb, line 305
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)

Sets the password for REST HTTP authentication.

# File activeresource/lib/active_resource/base.rb, line 315
def password=(password)
  @connection = nil
  @password = password
end
prefix(options={})

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

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

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

Also aliased as: set_prefix
# File activeresource/lib/active_resource/base.rb, line 429
      def prefix=(value = '/')
        # Replace :placeholders with '#{embedded options[:lookups]}'
        prefix_call = value.gsub(/:\w+/) { |key| "\#{options[#{key}]}" }
        # Clear prefix parameters in case they have been cached
        @prefix_parameters = nil
        # Redefine the new methods.
        code, line = "          def prefix_source() "#{value}" end
          def prefix(options={}) "#{prefix_call}" end
", __LINE__ + 1
        silence_warnings { instance_eval code, __FILE__, line }
      rescue
        logger.error "Couldn't set prefix: #{$!}\n  #{code}"
        raise
      end
prefix_source()

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.

# File activeresource/lib/active_resource/base.rb, line 422
def prefix_source
  prefix # generate #prefix and #prefix_source methods first
  prefix_source
end
proxy()

Gets the proxy variable if a proxy is required

# File activeresource/lib/active_resource/base.rb, line 273
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)

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

# File activeresource/lib/active_resource/base.rb, line 283
def proxy=(proxy)
  @connection = nil
  @proxy = proxy.nil? ? nil : create_proxy_uri_from(proxy)
end
set_prefix(value = '/')
site()

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

# File activeresource/lib/active_resource/base.rb, line 236
def site
  # Not using superclass_delegating_reader because don't want subclasses to modify superclass instance
  #
  # With superclass_delegating_reader
  #
  #   Parent.site = 'http://anonymous@test.com'
  #   Subclass.site # => 'http://anonymous@test.com'
  #   Subclass.site.user = 'david'
  #   Parent.site # => 'http://david@test.com'
  #
  # Without superclass_delegating_reader (expected behaviour)
  #
  #   Parent.site = 'http://anonymous@test.com'
  #   Subclass.site # => 'http://anonymous@test.com'
  #   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)

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

# File activeresource/lib/active_resource/base.rb, line 261
def site=(site)
  @connection = nil
  if site.nil?
    @site = nil
  else
    @site = create_site_uri_from(site)
    @user = URI.decode(@site.user) if @site.user
    @password = URI.decode(@site.password) if @site.password
  end
end
ssl_options()

Returns the SSL options hash.

# File activeresource/lib/active_resource/base.rb, line 374
def ssl_options
  if defined?(@ssl_options)
    @ssl_options
  elsif superclass != Object && superclass.ssl_options
    superclass.ssl_options
  end
end
ssl_options=(opts={})

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 contrain 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 begining 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.

# File activeresource/lib/active_resource/base.rb, line 368
def ssl_options=(opts={})
  @connection   = nil
  @ssl_options  = opts
end
timeout()

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

# File activeresource/lib/active_resource/base.rb, line 349
def timeout
  if defined?(@timeout)
    @timeout
  elsif superclass != Object && superclass.timeout
    superclass.timeout
  end
end
timeout=(timeout)

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

# File activeresource/lib/active_resource/base.rb, line 343
def timeout=(timeout)
  @connection = nil
  @timeout = timeout
end
user()

Gets the user for REST HTTP authentication.

# File activeresource/lib/active_resource/base.rb, line 289
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)

Sets the user for REST HTTP authentication.

# File activeresource/lib/active_resource/base.rb, line 299
def user=(user)
  @connection = nil
  @user = user
end
Instance Public methods
==(other)

Test for equality. Resource are equal if and only if otheris 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
# File activeresource/lib/active_resource/base.rb, line 819
def ==(other)
  other.equal?(self) || (other.instance_of?(self.class) && other.id == id && other.prefix_options == prefix_options)
end
as_json(options = nil)

Coerces to a hash for JSON encoding.

Options

The optionsare passed to the to_jsonmethod on each attribute, so the same options as the to_jsonmethods in Active Support.

  • :only- Only include the specified attribute or list of attributes in the serialized output. Attribute names must be specified as strings.

  • :except- Do not include the specified attribute or list of attributes in the serialized output. Attribute names must be specified as strings.

Examples

person = Person.new(:first_name => "Jim", :last_name => "Smith")
person.to_json
# => {"first_name": "Jim", "last_name": "Smith"}
person.to_json(:only => ["first_name"])
# => {"first_name": "Jim"}
person.to_json(:except => ["first_name"])
# => {"last_name": "Smith"}
# File activeresource/lib/active_resource/base.rb, line 966
def as_json(options = nil)
  attributes.as_json(options)
end
clone()

Returns a clone of the resource that hasn't been assigned an idyet 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_optionsthat 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"}
# File activeresource/lib/active_resource/base.rb, line 749
def clone
  # Clone all attributes except the pk and any nested ARes
  cloned = attributes.reject {|k,v| k == self.class.primary_key || v.is_a?(ActiveResource::Base)}.inject({}) do |attrs, (k, v)|
    attrs[k] = v.clone
    attrs
  end
  # 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
destroy()

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)
# File activeresource/lib/active_resource/base.rb, line 882
def destroy
  connection.delete(element_path, self.class.headers)
end
dup()

Duplicate 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
# File activeresource/lib/active_resource/base.rb, line 846
def dup
  self.class.new.tap do |resource|
    resource.attributes     = @attributes
    resource.prefix_options = @prefix_options
  end
end
encode(options={})

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

# File activeresource/lib/active_resource/base.rb, line 973
def encode(options={})
  case self.class.format
    when ActiveResource::Formats[:xml]
      self.class.format.encode(attributes, {:root => self.class.element_name}.merge(options))
    when ActiveResource::Formats::JsonFormat
      if ActiveResource::Base.include_root_in_json
        self.class.format.encode({self.class.element_name => attributes}, options)
      else
        self.class.format.encode(attributes, options)
      end
    else
      self.class.format.encode(attributes, options)
  end
end
eql?(other)

Tests for equality (delegates to ==).

# File activeresource/lib/active_resource/base.rb, line 824
def eql?(other)
  self == other
end
exists?()

Evaluates to trueif 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
# File activeresource/lib/active_resource/base.rb, line 902
def exists?
  !new? && self.class.exists?(to_param, :params => prefix_options)
end
hash()

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

[Person.find(1), Person.find(2)] & [Person.find(1), Person.find(4)] # => [Person.find(1)]
# File activeresource/lib/active_resource/base.rb, line 830
def hash
  id.hash
end
id()

Gets the \idattribute of the resource.

# File activeresource/lib/active_resource/base.rb, line 783
def id
  attributes[self.class.primary_key]
end
id=(id)

Sets the \idattribute of the resource.

# File activeresource/lib/active_resource/base.rb, line 788
def id=(id)
  attributes[self.class.primary_key] = id
end
load(attributes)

A method to manually load attributes from a hash. Recursively loads collections of resources. This method is called in initialize and createwhen 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
# File activeresource/lib/active_resource/base.rb, line 1024
def load(attributes)
  raise ArgumentError, "expected an attributes Hash, got #{attributes.inspect}" unless attributes.is_a?(Hash)
  @prefix_options, attributes = split_options(attributes)
  attributes.each do |key, value|
    @attributes[key.to_s] =
      case value
        when Array
          resource = find_or_create_resource_for_collection(key)
          value.map do |attrs|
            if attrs.is_a?(String) || attrs.is_a?(Numeric)
              attrs.duplicable? ? attrs.dup : attrs
            else
              resource.new(attrs)
            end
          end
        when Hash
          resource = find_or_create_resource_for(key)
          resource.new(value)
        else
          value.dup rescue value
      end
  end
  self
end
new?()

A method to determine if the resource a new object (i.e., it has not been POSTed to the remote service yet).

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
Also aliased as: new_record?
# File activeresource/lib/active_resource/base.rb, line 777
def new?
  id.nil?
end
new_record?()
reload()

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"
# File activeresource/lib/active_resource/base.rb, line 999
def reload
  self.load(self.class.find(to_param, :params => @prefix_options).attributes)
end
respond_to?(method, include_priv = false)

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 trueto my_person.respond_to?(:name), my_person.respond_to?(:name=), and my_person.respond_to?(:name?).

# File activeresource/lib/active_resource/base.rb, line 1055
def respond_to?(method, include_priv = false)
  method_name = method.to_s
  if attributes.nil?
    return super
  elsif attributes.has_key?(method_name)
    return true
  elsif ['?','='].include?(method_name.last) && attributes.has_key?(method_name.first(-1))
    return true
  end
  # 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
respond_to_without_attributes?(method, include_priv = false)

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

save()

A method to save ( POST) or update ( PUT) a resource. It delegates to createif a new object, updateif it is existing. If the response to the save includes a body, it will be assumed that this body is XML for the final object as it looked after the save (which would include attributes like created_atthat 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)
# File activeresource/lib/active_resource/base.rb, line 866
def save
  new? ? create : update
end
to_param()

Allows Active Resource objects to be used as parameters in Action Pack URL generation.

# File activeresource/lib/active_resource/base.rb, line 793
def to_param
  id && id.to_s
end
to_xml(options={})

Converts the resource to an XML string representation.

Options

The optionsparameter is handed off to the to_xml method on each attribute, so it has the same options as the to_xmlmethods in Active Support.

  • :indent- Set the indent level for the XML output (default is 2).

  • :dasherize- Boolean option to determine whether or not element names should replace underscores with dashes. Default is true. The default can be set to falseby setting the module attribute ActiveSupport.dasherize_xml = falsein an initializer. Because save uses this method, and there are no options on save, then you will have to set the default if you don't want underscores in element names to become dashes when the resource is saved. This is important when integrating with non-Rails applications.

  • :camelize- Boolean option to determine whether or not element names should be converted to camel case, e.g some_name to SomeName. Default is false. Like :dasherizeyou can change the default by setting the module attribute ActiveSupport.camelise_xml = true in an initializer.

  • :skip_instruct- Toggle skipping the instruct! call on the XML builder that generates the XML declaration (default is false).

Examples

my_group = SubsidiaryGroup.find(:first)
my_group.to_xml
# => <?xml version="1.0" encoding="UTF-8"?>
#    <subsidiary_group> [...] </subsidiary_group>
my_group.to_xml(:dasherize => true)
# => <?xml version="1.0" encoding="UTF-8"?>
#    <subsidiary-group> [...] </subsidiary-group>
my_group.to_xml(:skip_instruct => true)
# => <subsidiary_group> [...] </subsidiary_group>
# File activeresource/lib/active_resource/base.rb, line 938
def to_xml(options={})
  attributes.to_xml({:root => self.class.element_name}.merge(options))
end
Instance Protected methods
collection_path(options = nil)
# File activeresource/lib/active_resource/base.rb, line 1105
def collection_path(options = nil)
  self.class.collection_path(options || prefix_options)
end
connection(refresh = false)
# File activeresource/lib/active_resource/base.rb, line 1071
def connection(refresh = false)
  self.class.connection(refresh)
end
create()

Create (i.e., save to the remote service) the new resource.

# File activeresource/lib/active_resource/base.rb, line 1083
def create
  connection.post(collection_path, encode, self.class.headers).tap do |response|
    self.id = id_from_response(response)
    load_attributes_from_response(response)
  end
end
element_path(options = nil)
# File activeresource/lib/active_resource/base.rb, line 1101
def element_path(options = nil)
  self.class.element_path(to_param, options || prefix_options)
end
id_from_response(response)

Takes a response from a typical create post and pulls the ID out

# File activeresource/lib/active_resource/base.rb, line 1097
def id_from_response(response)
  response['Location'][/\/([^\/]*?)(\.\w+)?$/, 1] if response['Location']
end
load_attributes_from_response(response)
# File activeresource/lib/active_resource/base.rb, line 1090
def load_attributes_from_response(response)
  if response['Content-Length'] != "0" && response.body.strip.size > 0
    load(self.class.format.decode(response.body))
  end
end
update()

Update the resource on the remote service.

# File activeresource/lib/active_resource/base.rb, line 1076
def update
  connection.put(element_path(prefix_options), encode, self.class.headers).tap do |response|
    load_attributes_from_response(response)
  end
end