Module: Remotable::ActiveRecordExtender::ClassMethods

Includes:
Nosync
Defined in:
lib/remotable/active_record_extender.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Nosync

#nosync, #nosync!, #nosync=, #nosync_value?

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method_sym, *args, &block) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 193

def method_missing(method_sym, *args, &block)
  method_details = recognize_remote_finder_method(method_sym)
  if method_details
    local_attributes = method_details[:local_attributes]
    values = args
    
    unless values.length == local_attributes.length
      raise ArgumentError, "#{method_sym} was called with #{values.length} but #{local_attributes.length} was expected"
    end
    
    local_resource = ((0...local_attributes.length).inject(self) do |scope, i|
      scope.where(local_attributes[i] => values[i])
    end).first || fetch_by(method_details[:remote_key], *values)
    
    raise ActiveRecord::RecordNotFound if local_resource.nil? && (method_sym =~ /!$/)
    local_resource
  else
    super(method_sym, *args, &block)
  end
end

Instance Attribute Details

#local_attribute_routes ⇒ Object (readonly)

Returns the value of attribute local_attribute_routes.



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# File 'lib/remotable/active_record_extender.rb', line 114

def local_attribute_routes
  @local_attribute_routes
end

#remote_attribute_map ⇒ Object (readonly)

Returns the value of attribute remote_attribute_map.



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# File 'lib/remotable/active_record_extender.rb', line 114

def remote_attribute_map
  @remote_attribute_map
end

Instance Method Details

#all_by_remote ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 321

def all_by_remote
  find_by_remote_query(:all)
end

#attr_remote(*attrs) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 92

def attr_remote(*attrs)
  map = attrs.extract_options!
  map = attrs.map_to_self.merge(map)
  @remote_attribute_map = map
  @local_attribute_routes = {} # reset routes
end

#default_route_for(local_key, remote_key = nil) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 147

def default_route_for(local_key, remote_key=nil)
  remote_key ||= remote_attribute_name(local_key)
  if remote_key.to_s == primary_key
    ":#{local_key}"
  else
    "by_#{local_key}/:#{local_key}"
  end
end

#expire_all! ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 241

def expire_all!
  update_all(["expires_at=?", 1.day.ago])
end

#expires_after(*args) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 87

def expires_after(*args)
  @expires_after = args.first if args.any?
  @expires_after
end

#fetch_by(remote_attr, *values) ⇒ Object

Looks the resource up remotely, by the given attribute If the resource is found, wraps it in a new local resource and returns that.



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# File 'lib/remotable/active_record_extender.rb', line 250

def fetch_by(remote_attr, *values)
  remote_resource = find_remote_resource_by(remote_attr, *values)
  remote_resource && new_from_remote(remote_resource)
end

#fetch_corresponding_local_resources(remote_resources) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 362

def fetch_corresponding_local_resources(remote_resources)
  conditions = Array.wrap(remote_key).each_with_object({}) do |remote_attr, query|
    local_attr = local_attribute_name(remote_attr)
    query[local_attr] = remote_resources.map { |resource| resource[remote_attr] }
  end
  
  where(conditions)
end

#fetch_with(local_key, options = {}) ⇒ Object Also known as: find_by 



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# File 'lib/remotable/active_record_extender.rb', line 107

def fetch_with(local_key, options={})
  @local_attribute_routes.merge!(local_key => options[:path])
end

#find_by_remote_query(remote_method_name, *args) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 325

def find_by_remote_query(remote_method_name, *args)
  remote_set_timeout :list
  remote_resources = Array.wrap(remote_model.send(remote_method_name, *args))
  map_remote_resources_to_local(remote_resources)
end

#find_remote_resource_by(remote_attr, *values) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 255

def find_remote_resource_by(remote_attr, *values)
  invoke_remote_model_find_by(remote_attr, *values)
end

#find_remote_resource_for_local_by(local_resource, remote_attr, *values) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 259

def find_remote_resource_for_local_by(local_resource, remote_attr, *values)
  if remote_model.respond_to?(:find_by_for_local)
    invoke_remote_model_find_by_for_local(local_resource, remote_attr, *values)
  else
    invoke_remote_model_find_by(remote_attr, *values)
  end
end

#instantiate(*args) ⇒ Object

!nb: this method is called when associations are loaded so you can use the remoted record in associations.



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# File 'lib/remotable/active_record_extender.rb', line 160

def instantiate(*args)
  record = super
  if record.expired? && !record.nosync?
    begin
      Remotable.logger.debug "[remotable:#{name.underscore}:instantiate](#{record.fetch_value.inspect}) expired #{record.expires_at}"
      record.pull_remote_data!
      record = nil if record.destroyed?
    rescue Remotable::TimeoutError
      report_ignored_timeout_error($!)
    rescue Remotable::ServiceUnavailableError
      report_ignored_503_error($!)
    end
  end
  record
end

#invoke_remote_model_find_by(remote_attr, *values) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 267

def invoke_remote_model_find_by(remote_attr, *values)
  remote_set_timeout :fetch
  
  find_by = remote_model.method(:find_by)
  case find_by.arity
  when 1; find_by.call(remote_path_for(remote_attr, *values))
  when 2; find_by.call(remote_attr, *values)
  else
    raise InvalidRemoteModel, "#{remote_model}.find_by should take either 1 or 2 parameters"
  end
end

#invoke_remote_model_find_by_for_local(local_resource, remote_attr, *values) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 279

def invoke_remote_model_find_by_for_local(local_resource, remote_attr, *values)
  remote_set_timeout :pull
  
  find_by_for_local = remote_model.method(:find_by_for_local)
  case find_by_for_local.arity
  when 2; find_by_for_local.call(local_resource, remote_path_for(remote_attr, *values))
  when 3; find_by_for_local.call(local_resource, remote_attr, *values)
  else
    raise InvalidRemoteModel, "#{remote_model}.find_by_for_local should take either 2 or 3 parameters"
  end
end

#local_attribute_name(remote_attr) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 138

def local_attribute_name(remote_attr)
  remote_attribute_map[remote_attr] || remote_attr
end

#local_attribute_names ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 130

def local_attribute_names
  remote_attribute_map.values
end

#local_key(remote_key = nil) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 117

def local_key(remote_key=nil)
  remote_key ||= self.remote_key
  if remote_key.is_a?(Array)
    remote_key.map(&method(:local_attribute_name))
  else
    local_attribute_name(remote_key)
  end
end

#map_remote_resources_to_local(remote_resources) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 331

def map_remote_resources_to_local(remote_resources)
  return [] if remote_resources.nil? || remote_resources.empty?
  
  local_resources = nosync { fetch_corresponding_local_resources(remote_resources).to_a }
  
  # Ensure a corresponding local resource for
  # each remote resource; return the set of
  # local resources.
  remote_resources.map do |remote_resource|
    
    # Get the specific local resource that
    # corresponds to this remote one.
    local_resource = local_resources.detect { |local_resource|
      Array.wrap(remote_key).all? { |remote_attr|
        local_attr = local_attribute_name(remote_attr)
        local_resource.send(local_attr) == remote_resource[remote_attr]
      }
    }
    
    # If a local counterpart to this remote value
    # exists, update the local resource and return it.
    # If not, create a local counterpart and return it.
    if local_resource
      local_resource.instance_variable_set :@remote_resource, remote_resource
      local_resource.pull_remote_data!
    else
      new_from_remote(remote_resource)
    end
  end
end

#nosync? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/remotable/active_record_extender.rb', line 46

def nosync?
  return true if remote_model.nil?
  return super if nosync_value?
  Remotable.nosync?
end

#recognize_remote_finder_method(method_sym) ⇒ Object

If the missing method IS a Remotable finder method, returns the remote key (may be a composite key). Otherwise, returns false.



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# File 'lib/remotable/active_record_extender.rb', line 217

def recognize_remote_finder_method(method_sym)
  method_name = method_sym.to_s
  return false unless method_name =~ /find_by_([^!]*)(!?)/
  
  local_attributes = $1.split("_and_").map(&:to_sym)
  remote_attributes = local_attributes.map(&method(:remote_attribute_name))
  
  local_key, remote_key = if local_attributes.length == 1
    [local_attributes[0], remote_attributes[0]]
  else
    [local_attributes, remote_attributes]
  end
  
  generate_default_remote_key # <- Make sure we've figured out the remote
                              #    primary key if we're evaluating a finder
  
  return false unless local_attribute_routes.key?(local_key)
  
  { :local_attributes => local_attributes,
    :remote_key => remote_key }
end

#remote_attribute_name(local_attr) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 134

def remote_attribute_name(local_attr)
  remote_attribute_map.key(local_attr) || local_attr
end

#remote_attribute_names ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 126

def remote_attribute_names
  remote_attribute_map.keys
end

#remote_key(*args) ⇒ Object

Sets the key with which a resource is identified remotely. If no remote key is set, the remote key is assumed to be :id. Which could be explicitly set like this:

remote_key :id

It can can be a composite key:

remote_key [:calendar_id, :id]

You can also supply a path for the remote key which will be passed to fetch_with:

remote_key [:calendar_id, :id], :path => "calendars/:calendar_id/events/:id"



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# File 'lib/remotable/active_record_extender.rb', line 67

def remote_key(*args)
  if args.any?
    remote_key = args.shift
    options = args.shift || {}
    
    # remote_key may be a composite of several attributes
    # ensure that all of the attributs have been defined
    Array.wrap(remote_key).each do |attribute|
      raise(":#{attribute} is not the name of a remote attribute") unless remote_attribute_names.member?(attribute)
    end
    
    # Set up a finder method for the remote_key
    fetch_with(local_key(remote_key), options)
    
    @remote_key = remote_key
  else
    @remote_key || generate_default_remote_key
  end
end

#remote_path_for(remote_key, *values) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 293

def remote_path_for(remote_key, *values)
  route = route_for(remote_key)
  local_key = self.local_key(remote_key)
  
  if remote_key.is_a?(Array)
    remote_path_for_composite_key(route, local_key, values)
  else
    remote_path_for_simple_key(route, local_key, values.first)
  end
end

#remote_path_for_composite_key(route, local_key, values) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 308

def remote_path_for_composite_key(route, local_key, values)
  values.flatten!
  unless values.length == local_key.length
    raise ArgumentError, "local_key has #{local_key.length} attributes but values has #{values.length}"
  end
  
  (0...values.length).inject(route) do |route, i|
    route.gsub(/:#{local_key[i]}/, values[i].to_s)
  end
end

#remote_path_for_simple_key(route, local_key, value) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 304

def remote_path_for_simple_key(route, local_key, value)
  route.gsub(/:#{local_key}/, value.to_s)
end

#remote_timeout(*args) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 99

def remote_timeout(*args)
  if args.any?
    @remote_timeout = n = args.first
    @remote_timeout = {:list => n, :fetch => n, :pull => n, :create => n, :update => n, :destroy => n} if n.is_a?(Numeric)
  end
  @remote_timeout
end

#report_ignored_503_error(error) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 180

def report_ignored_503_error(error)
  Remotable.logger.error "[remotable:#{name.underscore}:instantiate] #{error.message}"
end

#report_ignored_timeout_error(error) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 176

def report_ignored_timeout_error(error)
  Remotable.logger.error "[remotable:#{name.underscore}:instantiate] #{error.message}"
end

#respond_to?(method_sym, include_private = false) ⇒ Boolean

!todo: create these methods on an anonymous module and mix it in

Returns:

  • (Boolean) 


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# File 'lib/remotable/active_record_extender.rb', line 188

def respond_to?(method_sym, include_private=false)
  return true if recognize_remote_finder_method(method_sym)
  super(method_sym, include_private)
end

#route_for(remote_key) ⇒ Object 



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# File 'lib/remotable/active_record_extender.rb', line 142

def route_for(remote_key)
  local_key = self.local_key(remote_key)
  local_attribute_routes[local_key] || default_route_for(local_key, remote_key)
end