Class: Schemable::RelationshipSchemaGenerator

Inherits:
Object
  • Object
show all
Defined in:
lib/schemable/relationship_schema_generator.rb

Overview

The RelationshipSchemaGenerator class is responsible for generating the ‘relationships’ part of a JSON:API compliant response. This class generates schemas for each relationship of a model, including ‘belongs_to’ (and has_many) and ‘has_many’ relationships.

See Also:

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(model_definition) ⇒ RelationshipSchemaGenerator

Initializes a new RelationshipSchemaGenerator instance.

Examples:

generator = RelationshipSchemaGenerator.new(model_definition)

Parameters:

  • model_definition (ModelDefinition) —

    The model definition to generate the schema for.



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# File 'lib/schemable/relationship_schema_generator.rb', line 15

def initialize(model_definition)
  @model_definition = model_definition
  @schema_modifier = SchemaModifier.new
  @relationships = model_definition.relationships
end

Instance Attribute Details

#model_definition ⇒ Object (readonly)

Returns the value of attribute model_definition.



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# File 'lib/schemable/relationship_schema_generator.rb', line 7

def model_definition
  @model_definition
end

#relationships ⇒ Object (readonly)

Returns the value of attribute relationships.



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# File 'lib/schemable/relationship_schema_generator.rb', line 7

def relationships
  @relationships
end

#schema_modifier ⇒ Object (readonly)

Returns the value of attribute schema_modifier.



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# File 'lib/schemable/relationship_schema_generator.rb', line 7

def schema_modifier
  @schema_modifier
end

Instance Method Details

#generate(relationships_to_exclude_from_expansion: [], expand: false) ⇒ Hash

Generates the ‘relationships’ part of the JSON:API response. It iterates over each relationship type (belongs_to, has_many) and for each relationship, it prepares a schema unless the relationship is excluded from expansion. If the ‘expand’ option is true, it changes the schema to include type and id properties inside the ‘meta’ property.

Examples:

schema = generator.generate(expand: true, relationships_to_exclude_from_expansion: [:some_relationship])

Parameters:

  • relationships_to_exclude_from_expansion (Array) (defaults to: []) —

    The relationships to exclude from expansion.

  • expand (Boolean) (defaults to: false) —

    Whether to include the relationships of the related resource in the schema.

Returns:

  • (Hash) —

    The generated schema.



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# File 'lib/schemable/relationship_schema_generator.rb', line 33

def generate(relationships_to_exclude_from_expansion: [], expand: false)
  return {} if @relationships.blank? || @relationships == { belongs_to: {}, has_many: {} }

  schema = {
    type: :object,
    properties: {}
  }

  %i[belongs_to has_many].each do |relation_type|
    @relationships[relation_type]&.each do |relation, definition|
      non_expanded_data_properties = {
        type: :object,
        properties: {
          meta: {
            type: :object,
            properties: {
              included: { type: :boolean, default: false }
            }
          }
        }
      }

      result = relation_type == :belongs_to ? generate_schema(definition.model_name) : generate_schema(definition.model_name, collection: true)

      result = non_expanded_data_properties if !expand || relationships_to_exclude_from_expansion.include?(definition.model_name)

      schema[:properties].merge!(relation => result)
    end
  end

  # Modify the schema to include additional response relations
  schema = @schema_modifier.add_properties(schema, @model_definition.additional_response_relations, 'properties')

  # Modify the schema to exclude response relations
  @model_definition.excluded_response_relations.each do |key|
    schema = @schema_modifier.delete_properties(schema, "properties.#{key}")
  end

  schema
end

#generate_schema(type_name, collection: false) ⇒ Hash

Generates the schema for a specific relationship. If the ‘collection’ option is true, it generates a schema for a ‘has_many’ relationship, otherwise it generates a schema for a ‘belongs_to’ relationship. The difference between the two is that ‘data’ is an array in the ‘has_many’ relationship and an object in the ‘belongs_to’ relationship.

Examples:

relationship_schema = generator.generate_schema('resource_type', collection: true)

Parameters:

  • type_name (String) —

    The type of the related resource.

  • collection (Boolean) (defaults to: false) —

    Whether the relationship is a ‘has_many’ relationship.

Returns:

  • (Hash) —

    The generated schema for the relationship.



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# File 'lib/schemable/relationship_schema_generator.rb', line 86

def generate_schema(type_name, collection: false)
  schema = if collection
             {
               type: :object,
               properties: {
                 data: {
                   type: :array,
                   items: {
                     type: :object,
                     properties: {
                       id: { type: :string },
                       type: { type: :string, default: type_name }
                     }
                   }
                 }
               }
             }
           else
             {
               type: :object,
               properties: {
                 data: {
                   type: :object,
                   properties: {
                     id: { type: :string },
                     type: { type: :string, default: type_name }
                   }
                 }
               }
             }
           end

  # Modify the schema to nullable if the relationship is in nullable
  is_relation_nullable = @model_definition.nullable_relationships.include?(type_name)

  return schema unless is_relation_nullable

  @schema_modifier.add_properties(schema, { nullable: true }, 'properties.data')
end