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require 'active_resource/connection'
require 'cgi'
require 'set'
module ActiveResource
class Base
# The logger for diagnosing and tracing ARes calls.
cattr_accessor :logger
class << self
# Gets the URI of the resource's site
def site
if defined?(@site)
@site
elsif superclass != Object and superclass.site
superclass.site.dup.freeze
end
end
# Set the URI for the REST resources
def site=(site)
@connection = nil
@site = create_site_uri_from(site)
end
# Base connection to remote service
def connection(refresh = false)
@connection = Connection.new(site) if refresh || @connection.nil?
@connection
end
attr_accessor_with_default(:element_name) { to_s.underscore } #:nodoc:
attr_accessor_with_default(:collection_name) { element_name.pluralize } #:nodoc:
attr_accessor_with_default(:primary_key, 'id') #:nodoc:
# Gets the resource prefix
# prefix/collectionname/1.xml
def prefix(options={})
default = site.path
default << '/' unless default[-1..-1] == '/'
self.prefix = default
prefix(options)
end
# Sets the resource prefix
# prefix/collectionname/1.xml
def prefix=(value = '/')
# Replace :placeholders with '#{embedded options[:lookups]}'
prefix_call = value.gsub(/:\w+/) { |key| "\#{options[#{key}]}" }
# 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
alias_method :set_prefix, :prefix= #:nodoc:
alias_method :set_element_name, :element_name= #:nodoc:
alias_method :set_collection_name, :collection_name= #:nodoc:
def element_path(id, options = {})
"#{prefix(options)}#{collection_name}/#{id}.xml#{query_string(options)}"
end
def collection_path(options = {})
"#{prefix(options)}#{collection_name}.xml#{query_string(options)}"
end
alias_method :set_primary_key, :primary_key= #:nodoc:
# Create a new resource instance and request to the remote service
# that it be saved. This is equivalent to the following simultaneous calls:
#
# ryan = Person.new(:first => 'ryan')
# ryan.save
#
# The newly created resource is returned. If a failure has occurred an
# exception will be raised (see save). If the resource is invalid and
# has not been saved then <tt>resource.valid?</tt> will return <tt>false</tt>,
# while <tt>resource.new?</tt> will still return <tt>true</tt>.
#
def create(attributes = {}, prefix_options = {})
returning(self.new(attributes, prefix_options)) { |res| res.save }
end
# Core method for finding resources. Used similarly to ActiveRecord's find method.
# Person.find(1) # => GET /people/1.xml
# StreetAddress.find(1, :person_id => 1) # => GET /people/1/street_addresses/1.xml
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
else find_single(scope, options)
end
end
def delete(id)
connection.delete(element_path(id))
end
# Evalutes to <tt>true</tt> if the resource is found.
def exists?(id, options = {})
id && !find_single(id, options).nil?
rescue ActiveResource::ResourceNotFound
false
end
private
# Find every resource.
def find_every(options)
collection = connection.get(collection_path(options)) || []
collection.collect! { |element| new(element, options) }
end
# Find a single resource.
# { :person => person1 }
def find_single(scope, options)
new(connection.get(element_path(scope, options)), options)
end
# Accepts a URI and creates the site URI from that.
def create_site_uri_from(site)
site.is_a?(URI) ? site.dup : URI.parse(site)
end
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)
# Omit parameters which appear in the URI path.
query_params = options.reject { |key, value| prefix_parameters.include?(key) }
# Accumulate a list of escaped key=value pairs for the given parameters.
pairs = []
query_params.each do |key, value|
key = CGI.escape(key.to_s)
# a => b becomes a=b
# a => [b, c] becomes a[]=b&a[]=c
case value
when Array
value.each { |val| pairs << "#{key}[]=#{CGI.escape(val.to_s)}" }
else
pairs << "#{key}=#{CGI.escape(value.to_s)}"
end
end
"?#{pairs * '&'}" unless pairs.empty?
end
end
attr_accessor :attributes #:nodoc:
attr_accessor :prefix_options #:nodoc:
def initialize(attributes = {}, prefix_options = {})
@attributes = {}
self.load attributes
@prefix_options = prefix_options
end
# Is the resource a new object?
def new?
id.nil?
end
# Get the id of the object.
def id
attributes[self.class.primary_key]
end
# Set the id of the object.
def id=(id)
attributes[self.class.primary_key] = id
end
# True 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+.
def ==(other)
other.equal?(self) || (other.instance_of?(self.class) && !other.new? && other.id == id)
end
# 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
# Delegates to +create+ if a new object, +update+ if its old.
def save
new? ? create : update
end
# Delete the resource.
def destroy
connection.delete(element_path)
end
# Evaluates to <tt>true</tt> if this resource is found.
def exists?
!new? && self.class.exists?(id, prefix_options)
end
# Convert the resource to an XML string
def to_xml(options={})
attributes.to_xml({:root => self.class.element_name}.merge(options))
end
# Reloads the attributes of this object from the remote web service.
def reload
self.load self.class.find(id, @prefix_options).attributes
end
# Manually load attributes from a hash. Recursively loads collections of
# resources.
def load(attributes)
raise ArgumentError, "expected an attributes Hash, got #{attributes.inspect}" unless attributes.is_a?(Hash)
attributes.each do |key, value|
@attributes[key.to_s] =
case value
when Array
resource = find_or_create_resource_for_collection(key)
value.map { |attrs| resource.new(attrs) }
when Hash
resource = find_or_create_resource_for(key)
resource.new(value)
when ActiveResource::Base
value.class.new(value.attributes, value.prefix_options)
else
value.dup rescue value
end
end
self
end
protected
def connection(refresh = false)
self.class.connection(refresh)
end
# Update the resource on the remote service.
def update
connection.put(element_path, to_xml)
end
# Create (i.e., save to the remote service) the new resource.
def create
returning connection.post(collection_path, to_xml) do |response|
self.id = id_from_response(response)
end
end
# Takes a response from a typical create post and pulls the ID out
def id_from_response(response)
response['Location'][/\/([^\/]*?)(\.\w+)?$/, 1]
end
def element_path(options = nil)
self.class.element_path(id, 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(name.to_s.singularize)
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
resource_name.constantize
rescue NameError
resource = self.class.const_set(resource_name, Class.new(ActiveResource::Base))
resource.prefix = self.class.prefix
resource.site = self.class.site
resource
end
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)] == true
else
attributes.has_key?(method_name) ? attributes[method_name] : super
end
end
end
end
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