Class: Plumb::JSONSchemaVisitor

Inherits:

Object

• Object
• Plumb::JSONSchemaVisitor

Includes:

VisitorHandlers

Defined in:

lib/plumb/json_schema_visitor.rb

Constant Summary

InvalidJSONValueError =

Raised when a value that has no JSON-native representation would end up in the generated schema. Register a handler (via .on(...)) that converts the offending type to a JSON-native value to resolve it.

Class.new(StandardError)

TYPE =

'type'

PROPERTIES =

'properties'

REQUIRED =

'required'

DEFAULT =

'default'

ANY_OF =

'anyOf'

ALL_OF =

'allOf'

NOT =

'not'

ENUM =

'enum'

CONST =

'const'

REF =

'$ref'

DEFS =

'$defs'

ITEMS =

'items'

PATTERN =

'pattern'

MINIMUM =

'minimum'

MAXIMUM =

'maximum'

MIN_ITEMS =

'minItems'

MAX_ITEMS =

'maxItems'

MIN_LENGTH =

'minLength'

MAX_LENGTH =

'maxLength'

FORMAT =

'format'

EXCLUSIVE_MAXIMUM =

'exclusiveMaximum'

FORMAT_MINIMUM =

'formatMinimum'

FORMAT_MAXIMUM =

'formatMaximum'

FORMAT_EXCLUSIVE_MAXIMUM =

'formatExclusiveMaximum'

ENVELOPE =

{
  '$schema' => 'https://json-schema.org/draft-08/schema#'
}.freeze

Constants included from VisitorHandlers

VisitorHandlers::NODE_NAME_FALLBACKS

Class Method Summary

• .call(node, root: true) ⇒ Object
• .normalize_json(value) ⇒ Object

  Recursively normalize the generated schema into JSON-native values and fail loudly on anything that has no JSON representation.

Instance Method Summary

• #defs ⇒ Object

  The $defs table of materialized Deferred schemas built during this visit, hoisted to the document root by .call.

Methods included from VisitorHandlers

included, #on_missing_handler, #visit, #visit_children, #visit_name

Class Method Details

.call(node, root: true) ⇒ Object

# File 'lib/plumb/json_schema_visitor.rb', line 43

def self.call(node, root: true)
  visitor = new
  data = visitor.visit(node)
  # Deferred types register named entries in a `$defs` table and reference
  # them by `$ref` (see the :deferred handler). Hoist that table to the top of
  # the document so the root-relative `#/$defs/...` pointers resolve.
  defs = visitor.defs
  data = data.merge(DEFS => defs) unless defs.empty?
  data = ENVELOPE.merge(data) if root
  normalize_json(data)
end

.normalize_json(value) ⇒ Object

Recursively normalize the generated schema into JSON-native values and fail loudly on anything that has no JSON representation. Symbols are coerced to strings; everything that isn't a JSON-native value raises, so the user knows they need to register a custom visitor handler.

# File 'lib/plumb/json_schema_visitor.rb', line 59

def self.normalize_json(value)
  case value
  when ::Hash
    value.each_with_object({}) do |(key, val), hash|
      hash[normalize_json(key)] = normalize_json(val)
    end
  when ::Array
    value.map { |val| normalize_json(val) }
  when ::Symbol
    value.to_s
  when ::String, ::Numeric, true, false, nil
    value
  else
    raise InvalidJSONValueError,
          "#{value.class} value #{value.inspect} cannot be serialized to JSON Schema. " \
          'Register a Plumb::JSONSchemaVisitor.on(...) handler that converts it to a JSON-native value.'
  end
end

Instance Method Details

#defs ⇒ Object

The $defs table of materialized Deferred schemas built during this visit, hoisted to the document root by .call. Empty unless a Deferred was visited.

# File 'lib/plumb/json_schema_visitor.rb', line 89

def defs = @defs || BLANK_HASH