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
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) { to_s.split("::").last.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] == '/'
# generate the actual method based on the current site path
self.prefix = default
prefix(options)
end
def prefix_source
prefix # generate #prefix and #prefix_source methods first
prefix_source
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:
# Gets the element path for the given ID. If no query_options are given, they are split from the prefix options:
#
# 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}.xml#{query_string(query_options)}"
end
# Gets the collection path. If no query_options are given, they are split from the prefix options:
#
# 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}.xml#{query_string(query_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 = {})
returning(self.new(attributes)) { |res| res.save }
end
# Core method for finding resources. Used similarly to Active Record's find method.
#
# 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(:all, :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(: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
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 :one then find_one(options)
else find_single(scope, options)
end
end
def delete(id, options = {})
connection.delete(element_path(id, options))
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)
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
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 = {})
returning new(record) 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.parse(site)
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
end
attr_accessor :attributes #:nodoc:
attr_accessor :prefix_options #:nodoc:
def initialize(attributes = {})
@attributes = {}
@prefix_options = {}
load(attributes)
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
def dup
returning new do |resource|
resource.attributes = @attributes
resource.prefix_options = @prefix_options
end
end
# Delegates to +create+ if a new object, +update+ if its old. 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 wasn't part of the original submit).
def save
new? ? create : update
end
# Delete the resource.
def destroy
connection.delete(element_path, self.class.headers)
end
# Evaluates to <tt>true</tt> if this resource is found.
def exists?
!new? && self.class.exists?(id, :params => 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)
@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 { |attrs| resource.new(attrs) }
when Hash
resource = find_or_create_resource_for(key)
resource.new(value)
else
value.dup rescue value
end
end
self
end
# For checking respond_to? without searching the attributes (which is faster).
alias_method :respond_to_without_attributes?, :respond_to?
# A Person object with a name attribute can ask person.respond_to?("name"), person.respond_to?("name="), and
# person.respond_to?("name?") which will all return true.
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
protected
def connection(refresh = false)
self.class.connection(refresh)
end
# Update the resource on the remote service.
def update
returning connection.put(element_path(prefix_options), to_xml, self.class.headers) do |response|
load_attributes_from_response(response)
end
end
# Create (i.e., save to the remote service) the new resource.
def create
returning connection.post(collection_path, to_xml, self.class.headers) do |response|
self.id = id_from_response(response)
load_attributes_from_response(response)
end
end
def load_attributes_from_response(response)
if response['Content-size'] != "0" && response.body.strip.size > 0
load(connection.xml_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
# FIXME: Make it generic enough to support any depth of module nesting
if (ancestors = self.class.name.split("::")).size > 1
begin
ancestors.first.constantize.const_get(resource_name)
rescue NameError
self.class.const_get(resource_name)
end
else
self.class.const_get(resource_name)
end
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 split_options(options = {})
self.class.send(:split_options, options)
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)]
else
attributes.has_key?(method_name) ? attributes[method_name] : super
end
end
end
end
