Class: Checkpoint::Resource

Inherits:
Object
  • Object
show all
Defined in:
lib/checkpoint/resource.rb,
lib/checkpoint/resource/token.rb,
lib/checkpoint/resource/resolver.rb,
lib/checkpoint/resource/any_entity.rb,
lib/checkpoint/resource/all_of_type.rb,
lib/checkpoint/resource/all_of_any_type.rb,
lib/checkpoint/resource/any_entity_of_type.rb

Overview

A Resource is any application object that should be considered for restricted access.

Most commonly, these will be the core domain objects that are created by users (“model instances”, to use Rails terminology), but this is not a requirement. A Resource can represent a fixed item in the system such as the administrative password, where there might be a single ‘update’ permission to change various elements of configuration. It might also be something like a section of a site as set up in a config file.

In modeling an application, it is not always obvious whether a concept should be a Credential or a Resource, so take care to evaluate the options. As an example, consider access to derivatives of a high-quality media object based on subscription level. It may make more sense for a given application to model access to a fixed set of profiles (e.g., mobile, standard, premium) as credentials and named concepts that will appear throughout the codebase. For an application where the profiles are more dynamic, it may make more sense to model them as resources that can be listed and updated by configuration or at runtime, with a fixed set of permissions (e.g., preview, stream, download).

Checkpoint does not force this decision to be made in one way for every application, but provides the concepts of permission mapping and resource resolution to accommodate whatever fixed, dynamic, or inherited modeling is most appropriate for the credentials and resources of an application.

Direct Known Subclasses

AllOfAnyType, AllOfType

Defined Under Namespace

Classes: AllOfAnyType, AllOfType, AnyEntity, AnyEntityOfType, Resolver, Token

Constant Summary collapse

ALL =

Special string to be used when permitting or searching for permits on all types or all resources

'(all)'

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(entity) ⇒ Resource

Creates a Resource for this entity. Prefer the factory method from, which applies default conversion rules. This constructor does not consider whether the entity can covert itself with #to_resource.



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# File 'lib/checkpoint/resource.rb', line 45

def initialize(entity)
  @entity = entity
end

Instance Attribute Details

#entity ⇒ Object (readonly)

Returns the value of attribute entity.



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# File 'lib/checkpoint/resource.rb', line 36

def entity
  @entity
end

Class Method Details

.all ⇒ AllOfAnyType

Covenience factory method to get a Resource that will match all entities of any type.

Returns:



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# File 'lib/checkpoint/resource.rb', line 66

def self.all
  AllOfAnyType.new
end

.from(entity) ⇒ Object

Default conversion from an entity to a Resource. Prefer this to creating new instances by hand.

If the entity implements #to_resource, we will delegate to it. Otherwise, we will return a Resource for this entity.



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# File 'lib/checkpoint/resource.rb', line 54

def self.from(entity)
  if entity.respond_to?(:to_resource)
    entity.to_resource
  else
    new(entity)
  end
end

Instance Method Details

#==(other) ⇒ Boolean

Check whether two Resources refer to the same entity.

Parameters:

  • other (Resource) —

    Another Resource to compare with

Returns:

  • (Boolean) —

    true when the other Resource’s entity is the same as determined by comparing them with ‘#==`.



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# File 'lib/checkpoint/resource.rb', line 134

def ==(other)
  other.is_a?(Resource) && entity == other.entity
end

#all_of_type ⇒ Resource

Convert this Resource into a wildcard representing all resources of this type.

Returns:

  • (Resource) —

    A Resource of the same type, but for all members

See Also:



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# File 'lib/checkpoint/resource.rb', line 118

def all_of_type
  Resource::AllOfType.new(type)
end

#eql?(other) ⇒ Boolean

Check whether two Resources refer to the same entity.

Parameters:

  • other (Resource) —

    Another Resource to compare with

Returns:

  • (Boolean) —

    true when the other Resource’s entity is the same as determined by comparing them with ‘#eql?`.



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# File 'lib/checkpoint/resource.rb', line 126

def eql?(other)
  other.is_a?(Resource) && entity.eql?(other.entity)
end

#id ⇒ String

Get the resource ID.

If the entity implements ‘#resource_id`, we will use that. Otherwise we call `#id`. If the the entity does not implement either of these methods, we raise a NoIdentifierError.

Returns:

  • (String) —

    the entity’s ID after calling ‘#to_s` on it.



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# File 'lib/checkpoint/resource.rb', line 98

def id
  if entity.respond_to?(:resource_id)
    entity.resource_id
  elsif entity.respond_to?(:id)
    entity.id
  else
    raise NoIdentifierError, "No usable identifier on entity of type: #{entity.class}"
  end.to_s
end

#token ⇒ Resource::Token

Returns The token for this resource.

Returns:



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# File 'lib/checkpoint/resource.rb', line 109

def token
  @token ||= Token.new(type, id)
end

#type ⇒ String

Get the resource type.

Note that this is not necessarily a class/model type name. It can be whatever type name is most useful for building tokens and inspecting permits for this types. For example, there may be objects that have subtypes that are not modeled as objects, decorators, or collection objects (like a specialized type for the root of a tree) that should be treated as the element type.

If the entity implements ‘#resource_type`, we will use that. Otherwise, we use the entity’s class name.

Returns:

  • (String) —

    the name of the entity’s type after calling ‘#to_s` on it.



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# File 'lib/checkpoint/resource.rb', line 83

def type
  if entity.respond_to?(:resource_type)
    entity.resource_type
  else
    entity.class
  end.to_s
end