Contents

# encoding: utf-8

require 'json'

module SchemaTools
  class RefResolver

  #
  # super basic resolving of JSON Pointer stuff in order
  # to be able to load $ref parameter.
  #
  # $refs in JSON Schema are defined in JSON Pointer syntax:
  # http://tools.ietf.org/html/draft-ietf-appsawg-json-pointer-07
  #
  # @param [String] json_pointer the JSON Pointer expression to evaluate
  # @param [Hash] schema if the pointer refers to a local schema, this is this
  # the hash to evaluate it against. If the pointer contains a uri to a
  # referenced schema, an attempt is made to load
  def self.load_json_pointer json_pointer, schema = {}
    # JSON Pointer is a big, abandoned WIP and we're going to
    # start by only implementing the part's we need ...
    if nil ==  (json_pointer =~ /^(.*)#(.*)/ )
      raise "invalid json pointer: #{json_pointer}"
    end

    uri     = $1.strip
    pointer = $2

    if ! uri.empty?
      uri = URI.parse(uri)
      raise "must currently be a relative uri: #{json_pointer}" if uri.absolute?
      path = SchemaTools.schema_path + "/" + uri.path
      open (path) {|f|
        schema = JSON.parse(f.read)
      }
    end

    return self._retrieve_pointer_from_object pointer, schema
  end


  def self._retrieve_pointer_from_object pointer, object
    # assume path to be the JSONPointer expression:
    #  json/pointer/expression
    # and obj to be the ruby hash representation of the json
    path = pointer.is_a?(Array) ? pointer : pointer.split("/")

    while object != nil && component = path.shift
      prev   = object
      component = component.to_i if object.is_a?(Array) && component =~ /^\d+$/
      object = object[component]
    end

    return object
  end

  end # module
end # module

Version data entries

3 entries across 3 versions & 1 rubygems

Version	Path
json_schema_tools-0.2.6	lib/schema_tools/ref_resolver.rb
json_schema_tools-0.2.5	lib/schema_tools/ref_resolver.rb
json_schema_tools-0.2.4	lib/schema_tools/ref_resolver.rb