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 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:password@proxy.people.com: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.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 site variable. 

     class Person < ActiveResource::Base
   self.site = "http://ryan:password@api.people.com: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.xml
  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 exception (other than 301, 302)

  • 301, 302 - 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

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.xml
  # 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.

Instance Attribute Summary (collapse)

Class Method Summary (collapse)

Instance Method Summary (collapse)

Methods included from ActiveModel::Naming

model_name, plural, singular, 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, #encode_json, #from_json

Methods included from ActiveModel::Conversion

#to_key, #to_model, #to_param

Methods included from Validations

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

Methods included from ActiveModel::Validations

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

Methods included from ActiveSupport::Callbacks

#callback, #run_callbacks

Constructor Details

- (Base) initialize(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


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# File 'activeresource/lib/active_resource/base.rb', line 962

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

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

- (Object) method_missing(method_symbol, *arguments) (private)

:nodoc: 



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# File 'activeresource/lib/active_resource/base.rb', line 1387

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

Instance Attribute Details

- (Object) attributes

:nodoc: 



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# File 'activeresource/lib/active_resource/base.rb', line 933

def attributes
  @attributes
end

- (Object) prefix_options

:nodoc: 



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# File 'activeresource/lib/active_resource/base.rb', line 934

def prefix_options
  @prefix_options
end

Class Method Details

+ (Object) all(*args)

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 802

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

+ (Object) auth_type 



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# File 'activeresource/lib/active_resource/base.rb', line 459

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

+ (Object) auth_type=(auth_type) 



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# File 'activeresource/lib/active_resource/base.rb', line 465

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

+ (Object) build(attributes = {})

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 680

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

+ (Object) collection_path(prefix_options = {}, query_options = nil)

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.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


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# File 'activeresource/lib/active_resource/base.rb', line 665

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

+ (Object) 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). 



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# File 'activeresource/lib/active_resource/base.rb', line 535

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

+ (Object) 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. # => 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


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# File 'activeresource/lib/active_resource/base.rb', line 709

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

+ (Object) delete(id, options = {})

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.xml
  Event.delete(params[:id]) # sends DELETE /events/5


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# File 'activeresource/lib/active_resource/base.rb', line 821

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

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

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.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


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# File 'activeresource/lib/active_resource/base.rb', line 623

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}/#{URI.escape id.to_s}.#{format.extension}#{query_string(query_options)}"
end

+ (Boolean) exists?(id, options = {})

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 832

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

+ (Object) find(*arguments)

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.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

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 772

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

+ (Object) first(*args)

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 789

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

+ (Object) format

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



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# File 'activeresource/lib/active_resource/base.rb', line 488

def format
  read_inheritable_attribute(:format) || ActiveResource::Formats::XmlFormat
end

+ (Object) 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. 



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# File 'activeresource/lib/active_resource/base.rb', line 479

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

+ (Object) headers 



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# File 'activeresource/lib/active_resource/base.rb', line 550

def headers
  @headers ||= {}
end

+ (Object) known_attributes

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 MethodNotFound); 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 369

def known_attributes
  @known_attributes ||= []
end

+ (Object) last(*args)

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 796

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

+ (Object) new_element_path(prefix_options = {})

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.xml).

Examples

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

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


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# File 'activeresource/lib/active_resource/base.rb', line 640

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

+ (Object) password

Gets the \password for REST HTTP authentication. 



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# File 'activeresource/lib/active_resource/base.rb', line 444

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

+ (Object) password=(password)

Sets the \password for REST HTTP authentication. 



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# File 'activeresource/lib/active_resource/base.rb', line 454

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

+ (Object) 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. 



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# File 'activeresource/lib/active_resource/base.rb', line 561

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

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

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



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# File 'activeresource/lib/active_resource/base.rb', line 578

def prefix=(value = '/')
  # Replace :placeholders with '#{embedded options[:lookups]}'
  prefix_call = value.gsub(/:\w+/) { |key| "\#{URI.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      def prefix_source() "#{value}" end
      def prefix(options={}) "#{prefix_call}, __FILE__, __LINE__ + 1
" end
    RUBY_EVAL
  end
rescue
  logger.error "Couldn't set prefix: #{$!}\n  #{code}" if logger
  raise
end

+ (Object) 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. 



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# File 'activeresource/lib/active_resource/base.rb', line 571

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

+ (Object) proxy

Gets the \proxy variable if a proxy is required 



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

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

+ (Object) proxy=(proxy)

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 422

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

+ (Object) schema(&block)

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_colour', 'hair_colour'
    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’) # John343 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 308

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

+ (Object) schema=(the_schema)

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 347

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

+ (Object) 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. 



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# File 'activeresource/lib/active_resource/base.rb', line 375

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

+ (Object) site=(site)

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 400

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

+ (Object) ssl_options

Returns the SSL options hash. 



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# File 'activeresource/lib/active_resource/base.rb', line 524

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

+ (Object) 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. 



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# File 'activeresource/lib/active_resource/base.rb', line 518

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

+ (Object) timeout

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 499

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

+ (Object) timeout=(timeout)

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 493

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

+ (Object) user

Gets the \user for REST HTTP authentication. 



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# File 'activeresource/lib/active_resource/base.rb', line 428

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

+ (Object) user=(user)

Sets the \user for REST HTTP authentication. 



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# File 'activeresource/lib/active_resource/base.rb', line 438

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

Instance Method Details

- (Object) ==(other)

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 1069

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

- (Object) clone

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 988

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

- (Object) 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)


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# File 'activeresource/lib/active_resource/base.rb', line 1149

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

- (Object) dup

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 1096

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

- (Object) encode(options = {})

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 1176

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

- (Boolean) eql?(other)

Tests for equality (delegates to ==).

Returns:

  • (Boolean) 


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# File 'activeresource/lib/active_resource/base.rb', line 1074

def eql?(other)
  self == other
end

- (Boolean) exists?

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 1169

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

- (Object) 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)]


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# File 'activeresource/lib/active_resource/base.rb', line 1080

def hash
  id.hash
end

- (Object) id

Gets the \id attribute of the resource. 



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# File 'activeresource/lib/active_resource/base.rb', line 1038

def id
  attributes[self.class.primary_key]
end

- (Object) id=(id)

Sets the \id attribute of the resource. 



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# File 'activeresource/lib/active_resource/base.rb', line 1043

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

- (Object) known_attributes

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 946

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

- (Object) load(attributes)

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 1216

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?(Hash)
              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.dup rescue value
      end
  end
  self
end

- (Boolean) new? 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 1016

def new?
  id.nil?
end

- (Boolean) persisted?

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 1033

def persisted?
  !new?
end

- (Object) 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"


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# File 'activeresource/lib/active_resource/base.rb', line 1191

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

- (Boolean) respond_to?(method, include_priv = false) Also known as: respond_to_without_attributes?

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 1277

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

- (Object) save

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 XML 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 1116

def save
  new? ? create : update
end

- (Object) save!

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 1133

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

- (Object) schema

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 939

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

- (Object) to_json(options = {}) 



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# File 'activeresource/lib/active_resource/base.rb', line 1292

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

- (Object) to_xml(options = {}) 



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# File 'activeresource/lib/active_resource/base.rb', line 1296

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

- (Object) update_attribute(name, value)

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 1252

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

- (Object) update_attributes(attributes)

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 1267

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