Class: ActiveResource::Base

Inherits:
Object
  • Object
show all
Defined in:
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 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 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 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_name value.

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, 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:[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.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 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 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 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

Constructor Details

#initialize(attributes = {}) ⇒ 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 'lib/active_resource/base.rb', line 720

def initialize(attributes = {})
  @attributes     = {}
  @prefix_options = {}
  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 'lib/active_resource/base.rb', line 1144

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

  case method_name.last
    when "="
      attributes[method_name.first(-1)] = arguments.first
    when "?"
      attributes[method_name.first(-1)]
    else
      attributes.has_key?(method_name) ? attributes[method_name] : super
  end
end

Instance Attribute Details

#attributes ⇒ Object

:nodoc:



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# File 'lib/active_resource/base.rb', line 706

def attributes
  @attributes
end

#prefix_options ⇒ Object

:nodoc:



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# File 'lib/active_resource/base.rb', line 707

def prefix_options
  @prefix_options
end

Class Method Details

.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 URL’s (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 'lib/active_resource/base.rb', line 496

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) ⇒ 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 'lib/active_resource/base.rb', line 382

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 = {}) ⇒ 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 'lib/active_resource/base.rb', line 527

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



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# File 'lib/active_resource/base.rb', line 604

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.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 'lib/active_resource/base.rb', line 470

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 = {}) ⇒ 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 'lib/active_resource/base.rb', line 615

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.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



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# File 'lib/active_resource/base.rb', line 577

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 ⇒ Object

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



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# File 'lib/active_resource/base.rb', line 335

def format
  read_inheritable_attribute(:format) || ActiveResource::Formats[:xml]
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 :xml.



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# File 'lib/active_resource/base.rb', line 326

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 ⇒ Object 



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# File 'lib/active_resource/base.rb', line 396

def headers
  @headers ||= {}
end

.password ⇒ Object

Gets the password for REST HTTP authentication.



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# File 'lib/active_resource/base.rb', line 302

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 'lib/active_resource/base.rb', line 312

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.xml) This method is regenerated at runtime based on what the prefix is set to.



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# File 'lib/active_resource/base.rb', line 409

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.xml). Default value is site.path.



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# File 'lib/active_resource/base.rb', line 426

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 = <<-end_code
    def prefix_source() "#{value}" end
    def prefix(options={}) "#{prefix_call}" end
  end_code
  silence_warnings { instance_eval code, __FILE__, __LINE__ }
rescue
  logger.error "Couldn't set prefix: #{$!}\n  #{code}"
  raise
end

.prefix_source ⇒ Object

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 'lib/active_resource/base.rb', line 419

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

.proxy ⇒ Object

Gets the proxy variable if a proxy is required



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# File 'lib/active_resource/base.rb', line 270

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 'lib/active_resource/base.rb', line 280

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

.site ⇒ Object

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 'lib/active_resource/base.rb', line 233

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 behaviour)
  #
  #   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 'lib/active_resource/base.rb', line 258

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 ⇒ Object

Returns the SSL options hash.



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# File 'lib/active_resource/base.rb', line 371

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 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 'lib/active_resource/base.rb', line 365

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

.timeout ⇒ Object

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



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# File 'lib/active_resource/base.rb', line 346

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 'lib/active_resource/base.rb', line 340

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

.user ⇒ Object

Gets the user for REST HTTP authentication.



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# File 'lib/active_resource/base.rb', line 286

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 'lib/active_resource/base.rb', line 296

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 'lib/active_resource/base.rb', line 816

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

#as_json(options = nil) ⇒ Object

Coerces to a hash for JSON encoding.

Options

The options are passed to the to_json method on each attribute, so the same options as the to_json methods 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"}



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# File 'lib/active_resource/base.rb', line 963

def as_json(options = nil)
  attributes.as_json(options)
end

#clone ⇒ Object

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 'lib/active_resource/base.rb', line 746

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 ⇒ Object

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 'lib/active_resource/base.rb', line 879

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

#dup ⇒ Object

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



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# File 'lib/active_resource/base.rb', line 843

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 'lib/active_resource/base.rb', line 970

def encode(options={})
  case self.class.format
    when ActiveResource::Formats[:xml]
      self.class.format.encode(attributes, {:root => self.class.element_name}.merge(options))
    else
      self.class.format.encode(attributes, options)
  end
end

#eql?(other) ⇒ Boolean

Tests for equality (delegates to ==).

Returns:

  • (Boolean) 


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

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 'lib/active_resource/base.rb', line 899

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

#hash ⇒ Object

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 'lib/active_resource/base.rb', line 827

def hash
  id.hash
end

#id ⇒ Object

Gets the \id attribute of the resource.



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# File 'lib/active_resource/base.rb', line 780

def id
  attributes[self.class.primary_key]
end

#id=(id) ⇒ Object

Sets the \id attribute of the resource.



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# File 'lib/active_resource/base.rb', line 785

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

#load(attributes) ⇒ 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 'lib/active_resource/base.rb', line 1015

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

#logger ⇒ Object

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



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# File 'lib/active_resource/base.rb', line 228

cattr_accessor :logger

#new? ⇒ Boolean Also known as: new_record?

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

Returns:

  • (Boolean) 


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# File 'lib/active_resource/base.rb', line 774

def new?
  id.nil?
end

#reload ⇒ Object

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 'lib/active_resource/base.rb', line 990

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 'lib/active_resource/base.rb', line 1046

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? ⇒ Object

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



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# File 'lib/active_resource/base.rb', line 1041

alias_method :respond_to_without_attributes?, :respond_to?

#save ⇒ Object

A method to save (POST) or update (PUT) a resource. It delegates to create if a new object, update if 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_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 'lib/active_resource/base.rb', line 863

def save
  new? ? create : update
end

#to_param ⇒ Object

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



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# File 'lib/active_resource/base.rb', line 790

def to_param
  id && id.to_s
end

#to_xml(options = {}) ⇒ Object

Options

The options parameter is handed off to the to_xml method on each attribute, so it has the same options as the to_xml methods 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 false by setting the module attribute ActiveSupport.dasherize_xml = false in 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 :dasherize you 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>



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# File 'lib/active_resource/base.rb', line 935

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