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rails--rails/activeresource/lib/active_resource/base.rb
Joshua Peek 22752ec27c All ARes modules are safe to defer
2009-12-22 17:36:29 -06:00

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require 'active_support'
require 'active_support/core_ext/class/attribute_accessors'
require 'active_support/core_ext/class/inheritable_attributes'
require 'active_support/core_ext/hash/indifferent_access'
require 'active_support/core_ext/kernel/reporting'
require 'active_support/core_ext/module/attr_accessor_with_default'
require 'active_support/core_ext/module/delegation'
require 'active_support/core_ext/module/aliasing'
require 'active_support/core_ext/object/blank'
require 'active_support/core_ext/object/misc'
require 'active_support/core_ext/object/to_query'
require 'set'
require 'uri'
require 'active_resource/exceptions'
require 'active_resource/connection'
require 'active_resource/formats'
require 'active_resource/schema'
module ActiveResource
# 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 link: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 <tt>http://api.people.com:3000/people/</tt>, and
# you can now use Active Resource's lifecycle 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 <tt>get</tt>,
# <tt>post</tt>, <tt>put</tt> and <tt>\delete</tt> 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. <tt>See ssl_options=</tt> 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 <tt>404</tt> (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
#
# <tt>404</tt> 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 <tt>422</tt> and an XML or JSON representation of the validation errors. The save operation will
# then fail (with a <tt>false</tt> 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
# http://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 <tt>read_timeout</tt> of the internal Net::HTTP instance to the same value. The default
# <tt>read_timeout</tt> is 60 seconds on most Ruby implementations.
class Base
##
# :singleton-method:
# The logger for diagnosing and tracing Active Resource calls.
cattr_accessor :logger
class << self
# 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 <tt>known_attributes</tt> of the
# current resource.
#
# There is no need to specify a schema for your Active Resource. If
# you do not, the <tt>known_attributes</tt> 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') # <person><name>John</name><age>34</age><num_children>3</num_children></person>
# j.respond_to? :name # => true
# j.respond_to? :age # => true
# j.name # => 'John'
# j.age # => '34' # note this is a string!
# j.num_children # => '3' # note this is a string!
#
# p.num_children # => NoMethodError
#
# Attribute-types must be one of:
# string, integer, float
#
# Note: at present the attribute-type doesn't do anything, but stay
# tuned...
# Shortly it will also *cast* the value of the returned attribute.
# ie:
# j.age # => 34 # cast to an integer
# j.weight # => '65' # still a string!
#
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
# Alternative, direct way to specify a <tt>schema</tt> for this
# Resource. <tt>schema</tt> 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 <tt>schema</tt>)
#
# 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.
#
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
# Returns the list of known attributes for this resource, gathered
# from the provided <tt>schema</tt>
# Attributes that are known will cause your resource to return 'true'
# when <tt>respond_to?</tt> is called on them. A known attribute will
# return nil if not set (rather than <t>MethodNotFound</tt>); thus
# known attributes can be used with <tt>validates_presence_of</tt>
# without a getter-method.
def known_attributes
@known_attributes ||= []
end
# Gets the URI of the REST resources to map for this class. The site variable is required for
# Active Resource's mapping to work.
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
# 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.
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
# Gets the \proxy variable if a proxy is required
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
# Sets the URI of the http proxy to the value in the +proxy+ argument.
def proxy=(proxy)
@connection = nil
@proxy = proxy.nil? ? nil : create_proxy_uri_from(proxy)
end
# Gets the \user for REST HTTP authentication.
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
# Sets the \user for REST HTTP authentication.
def user=(user)
@connection = nil
@user = user
end
# Gets the \password for REST HTTP authentication.
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
# Sets the \password for REST HTTP authentication.
def password=(password)
@connection = nil
@password = password
end
def auth_type
if defined?(@auth_type)
@auth_type
end
end
def auth_type=(auth_type)
@connection = nil
@auth_type = auth_type
end
# 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 <tt>:xml</tt>.
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
# Returns the current format, default is ActiveResource::Formats::XmlFormat.
def format
read_inheritable_attribute(:format) || ActiveResource::Formats::XmlFormat
end
# Sets the number of seconds after which requests to the REST API should time out.
def timeout=(timeout)
@connection = nil
@timeout = timeout
end
# Gets the number of seconds after which requests to the REST API should time out.
def timeout
if defined?(@timeout)
@timeout
elsif superclass != Object && superclass.timeout
superclass.timeout
end
end
# Options that will get applied to an SSL connection.
#
# * <tt>:key</tt> - An OpenSSL::PKey::RSA or OpenSSL::PKey::DSA object.
# * <tt>:cert</tt> - An OpenSSL::X509::Certificate object as client certificate
# * <tt>:ca_file</tt> - Path to a CA certification file in PEM format. The file can contrain several CA certificates.
# * <tt>:ca_path</tt> - Path of a CA certification directory containing certifications in PEM format.
# * <tt>:verify_mode</tt> - Flags for server the certification verification at begining of SSL/TLS session. (OpenSSL::SSL::VERIFY_NONE or OpenSSL::SSL::VERIFY_PEER is acceptable)
# * <tt>:verify_callback</tt> - The verify callback for the server certification verification.
# * <tt>:verify_depth</tt> - The maximum depth for the certificate chain verification.
# * <tt>:cert_store</tt> - OpenSSL::X509::Store to verify peer certificate.
# * <tt>:ssl_timeout</tt> -The SSL timeout in seconds.
def ssl_options=(opts={})
@connection = nil
@ssl_options = opts
end
# Returns the SSL options hash.
def ssl_options
if defined?(@ssl_options)
@ssl_options
elsif superclass != Object && superclass.ssl_options
superclass.ssl_options
end
end
# 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 <tt>false</tt>).
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
def headers
@headers ||= {}
end
# Do not include any modules in the default element name. This makes it easier to seclude ARes objects
# in a separate namespace without having to set element_name repeatedly.
attr_accessor_with_default(:element_name) { ActiveSupport::Inflector.underscore(to_s.split("::").last) } #:nodoc:
attr_accessor_with_default(:collection_name) { ActiveSupport::Inflector.pluralize(element_name) } #:nodoc:
attr_accessor_with_default(:primary_key, 'id') #:nodoc:
# Gets the \prefix for a resource's nested URL (e.g., <tt>prefix/collectionname/1.xml</tt>)
# This method is regenerated at runtime based on what the \prefix is set to.
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
# 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.
def prefix_source
prefix # generate #prefix and #prefix_source methods first
prefix_source
end
# Sets the \prefix for a resource's nested URL (e.g., <tt>prefix/collectionname/1.xml</tt>).
# Default value is <tt>site.path</tt>.
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}" if logger
raise
end
alias_method :set_prefix, :prefix= #:nodoc:
alias_method :set_element_name, :element_name= #:nodoc:
alias_method :set_collection_name, :collection_name= #:nodoc:
# 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., <tt>:account_id => 19</tt>
# 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
#
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
# 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., <tt>:account_id => 19</tt>
# 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.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
#
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
alias_method :set_primary_key, :primary_key= #:nodoc:
# 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 <tt>save</tt>). If the resource is invalid and
# has not been saved then <tt>valid?</tt> will return <tt>false</tt>,
# while <tt>new?</tt> will still return <tt>true</tt>.
#
# ==== 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
def create(attributes = {})
self.new(attributes).tap { |resource| resource.save }
end
# 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.
#
# * <tt>:one</tt> - Returns a single resource.
# * <tt>:first</tt> - Returns the first resource found.
# * <tt>:last</tt> - Returns the last resource found.
# * <tt>:all</tt> - Returns every resource that matches the request.
#
# ==== Options
#
# * <tt>:from</tt> - Sets the path or custom method that resources will be fetched from.
# * <tt>:params</tt> - 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
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
# A convenience wrapper for <tt>find(:first, *args)</tt>. You can pass
# in all the same arguments to this method as you can to
# <tt>find(:first)</tt>.
def first(*args)
find(:first, *args)
end
# A convenience wrapper for <tt>find(:last, *args)</tt>. You can pass
# in all the same arguments to this method as you can to
# <tt>find(:last)</tt>.
def last(*args)
find(:last, *args)
end
# This is an alias for find(:all). You can pass in all the same
# arguments to this method as you can to <tt>find(:all)</tt>
def all(*args)
find(:all, *args)
end
# 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
def delete(id, options = {})
connection.delete(element_path(id, options))
end
# Asserts the existence of a resource, returning <tt>true</tt> if the resource is found.
#
# ==== Examples
# Note.create(:title => 'Hello, world.', :body => 'Nothing more for now...')
# Note.exists?(1) # => true
#
# Note.exists(1349) # => false
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
private
# Find every resource
def find_every(options)
begin
case from = options[:from]
when Symbol
instantiate_collection(get(from, options[:params]))
when String
path = "#{from}#{query_string(options[:params])}"
instantiate_collection(connection.get(path, headers) || [])
else
prefix_options, query_options = split_options(options[:params])
path = collection_path(prefix_options, query_options)
instantiate_collection( (connection.get(path, headers) || []), prefix_options )
end
rescue ActiveResource::ResourceNotFound
# Swallowing ResourceNotFound exceptions and return nil - as per
# ActiveRecord.
nil
end
end
# Find a single resource from a one-off URL
def find_one(options)
case from = options[:from]
when Symbol
instantiate_record(get(from, options[:params]))
when String
path = "#{from}#{query_string(options[:params])}"
instantiate_record(connection.get(path, headers))
end
end
# Find a single resource from the default URL
def find_single(scope, options)
prefix_options, query_options = split_options(options[:params])
path = element_path(scope, prefix_options, query_options)
instantiate_record(connection.get(path, headers), prefix_options)
end
def instantiate_collection(collection, prefix_options = {})
collection.collect! { |record| instantiate_record(record, prefix_options) }
end
def instantiate_record(record, prefix_options = {})
new(record).tap do |resource|
resource.prefix_options = prefix_options
end
end
# Accepts a URI and creates the site URI from that.
def create_site_uri_from(site)
site.is_a?(URI) ? site.dup : uri_parser.parse(site)
end
# Accepts a URI and creates the proxy URI from that.
def create_proxy_uri_from(proxy)
proxy.is_a?(URI) ? proxy.dup : uri_parser.parse(proxy)
end
# contains a set of the current prefix parameters.
def prefix_parameters
@prefix_parameters ||= prefix_source.scan(/:\w+/).map { |key| key[1..-1].to_sym }.to_set
end
# Builds the query string for the request.
def query_string(options)
"?#{options.to_query}" unless options.nil? || options.empty?
end
# split an option hash into two hashes, one containing the prefix options,
# and the other containing the leftovers.
def split_options(options = {})
prefix_options, query_options = {}, {}
(options || {}).each do |key, value|
next if key.blank?
(prefix_parameters.include?(key.to_sym) ? prefix_options : query_options)[key.to_sym] = value
end
[ prefix_options, query_options ]
end
def uri_parser
@uri_parser ||= URI.const_defined?(:Parser) ? URI::Parser.new : URI
end
end
attr_accessor :attributes #:nodoc:
attr_accessor :prefix_options #:nodoc:
# If no schema has been defined for the class (see
# <tt>ActiveResource::schema=</tt>), the default automatic schema is
# generated from the current instance's attributes
def schema
self.class.schema || self.attributes
end
# This is a list of known attributes for this resource. Either
# gathered fromthe provided <tt>schema</tt>, or from the attributes
# set on this instance after it has been fetched from the remote system.
def known_attributes
self.class.known_attributes + self.attributes.keys.map(&:to_s)
end
# 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
def initialize(attributes = {})
@attributes = {}.with_indifferent_access
@prefix_options = {}
load(attributes)
end
# 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"}
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
# 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
#
def new?
id.nil?
end
alias :new_record? :new?
# Gets the <tt>\id</tt> attribute of the resource.
def id
attributes[self.class.primary_key]
end
# Sets the <tt>\id</tt> attribute of the resource.
def id=(id)
attributes[self.class.primary_key] = id
end
# Allows Active Resource objects to be used as parameters in Action Pack URL generation.
def to_param
id && id.to_s
end
# 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 <tt>new?</tt>, 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
#
def ==(other)
other.equal?(self) || (other.instance_of?(self.class) && other.id == id && other.prefix_options == prefix_options)
end
# Tests for equality (delegates to ==).
def eql?(other)
self == other
end
# 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)]
def hash
id.hash
end
# 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
def dup
self.class.new.tap do |resource|
resource.attributes = @attributes
resource.prefix_options = @prefix_options
end
end
# 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)
def save
new? ? create : update
end
# Saves the resource.
#
# If the resource is new, it is created via +POST+, otherwise the
# existing resource is updated via +PUT+.
#
# With <tt>save!</tt> 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 <tt>save!</tt>. If any
# of the <tt>before_*</tt> callbacks return +false+ the action is
# cancelled and <tt>save!</tt> raises ActiveResource::ResourceInvalid.
def save!
save || raise(ResourceInvalid.new(self))
end
# 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)
def destroy
connection.delete(element_path, self.class.headers)
end
# Evaluates to <tt>true</tt> if this resource is not <tt>new?</tt> 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
def exists?
!new? && self.class.exists?(to_param, :params => prefix_options)
end
# Converts the resource to an XML string representation.
#
# ==== 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.
#
# * <tt>:indent</tt> - Set the indent level for the XML output (default is +2+).
# * <tt>:dasherize</tt> - Boolean option to determine whether or not element names should
# replace underscores with dashes (default is <tt>false</tt>).
# * <tt>:skip_instruct</tt> - Toggle skipping the +instruct!+ call on the XML builder
# that generates the XML declaration (default is <tt>false</tt>).
#
# ==== 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>
def to_xml(options={})
attributes.to_xml({:root => self.class.element_name}.merge(options))
end
# 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.
#
# * <tt>:only</tt> - Only include the specified attribute or list of
# attributes in the serialized output. Attribute names must be specified
# as strings.
# * <tt>:except</tt> - 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"}
def as_json(options = nil)
attributes.as_json(options)
end
# 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.
def encode(options={})
case self.class.format
when ActiveResource::Formats::XmlFormat
self.class.format.encode(attributes, {:root => self.class.element_name}.merge(options))
else
self.class.format.encode(attributes, options)
end
end
# 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"
def reload
self.load(self.class.find(to_param, :params => @prefix_options).attributes)
end
# 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
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
# Updates a single attribute and then saves the object.
#
# Note: Unlike ActiveRecord::Base.update_attribute, this method <b>is</b>
# 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 <tt>false</tt> will be returned.
def update_attribute(name, value)
self.send("#{name}=".to_sym, value)
self.save
end
# 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 <tt>false</tt> 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.
def update_attributes(attributes)
load(attributes) && save
end
# For checking <tt>respond_to?</tt> without searching the attributes (which is faster).
alias_method :respond_to_without_attributes?, :respond_to?
# 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 <tt>true</tt> to <tt>my_person.respond_to?(:name)</tt>, <tt>my_person.respond_to?(:name=)</tt>, and
# <tt>my_person.respond_to?(:name?)</tt>.
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?($`)
true
else
# super must be called at the end of the method, because the inherited respond_to?
# would return true for generated readers, even if the attribute wasn't present
super
end
end
protected
def connection(refresh = false)
self.class.connection(refresh)
end
# Update the resource on the remote service.
def update
connection.put(element_path(prefix_options), encode, self.class.headers).tap do |response|
load_attributes_from_response(response)
end
end
# Create (i.e., \save to the remote service) the \new resource.
def create
connection.post(collection_path, encode, self.class.headers).tap do |response|
self.id = id_from_response(response)
load_attributes_from_response(response)
end
end
def load_attributes_from_response(response)
if response['Content-Length'] != "0" && response.body.strip.size > 0
load(self.class.format.decode(response.body))
end
end
# Takes a response from a typical create post and pulls the ID out
def id_from_response(response)
response['Location'][/\/([^\/]*?)(\.\w+)?$/, 1] if response['Location']
end
def element_path(options = nil)
self.class.element_path(to_param, options || prefix_options)
end
def collection_path(options = nil)
self.class.collection_path(options || prefix_options)
end
private
# Tries to find a resource for a given collection name; if it fails, then the resource is created
def find_or_create_resource_for_collection(name)
find_or_create_resource_for(ActiveSupport::Inflector.singularize(name.to_s))
end
# Tries to find a resource in a non empty list of nested modules
# Raises a NameError if it was not found in any of the given nested modules
def find_resource_in_modules(resource_name, module_names)
receiver = Object
namespaces = module_names[0, module_names.size-1].map do |module_name|
receiver = receiver.const_get(module_name)
end
if namespace = namespaces.reverse.detect { |ns| ns.const_defined?(resource_name) }
return namespace.const_get(resource_name)
else
raise NameError
end
end
# Tries to find a resource for a given name; if it fails, then the resource is created
def find_or_create_resource_for(name)
resource_name = name.to_s.camelize
ancestors = self.class.name.split("::")
if ancestors.size > 1
find_resource_in_modules(resource_name, ancestors)
else
self.class.const_get(resource_name)
end
rescue NameError
if self.class.const_defined?(resource_name)
resource = self.class.const_get(resource_name)
else
resource = self.class.const_set(resource_name, Class.new(ActiveResource::Base))
end
resource.prefix = self.class.prefix
resource.site = self.class.site
resource
end
def split_options(options = {})
self.class.__send__(:split_options, options)
end
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
end
class Base
extend ActiveModel::Naming
include CustomMethods, Observing, Validations
end
end
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