Class: Avro::Schema

Inherits:
Object
  • Object
show all
Defined in:
lib/avro/schema.rb

Defined Under Namespace

Classes: ArraySchema, EnumSchema, Field, FixedSchema, MapSchema, NamedSchema, PrimitiveSchema, RecordSchema, UnionSchema

Constant Summary collapse

PRIMITIVE_TYPES =

Sets of strings, for backwards compatibility. See below for sets of symbols, for better performance.

Set.new(%w[null boolean string bytes int long float double])
NAMED_TYPES = 
Set.new(%w[fixed enum record error])
VALID_TYPES = 
PRIMITIVE_TYPES + NAMED_TYPES + Set.new(%w[array map union request])
PRIMITIVE_TYPES_SYM = 
Set.new(PRIMITIVE_TYPES.map(&:to_sym))
NAMED_TYPES_SYM = 
Set.new(NAMED_TYPES.map(&:to_sym))
VALID_TYPES_SYM = 
Set.new(VALID_TYPES.map(&:to_sym))
INT_MIN_VALUE = 
-(1 << 31)
INT_MAX_VALUE = 
(1 << 31) - 1
LONG_MIN_VALUE = 
-(1 << 63)
LONG_MAX_VALUE = 
(1 << 63) - 1

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(type) ⇒ Schema

Returns a new instance of Schema.



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# File 'lib/avro/schema.rb', line 131

def initialize(type)
  @type_sym = type.is_a?(Symbol) ? type : type.to_sym
end

Instance Attribute Details

#type_sym ⇒ Object (readonly)

Returns the value of attribute type_sym.



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# File 'lib/avro/schema.rb', line 135

def type_sym
  @type_sym
end

Class Method Details

.parse(json_string) ⇒ Object 



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# File 'lib/avro/schema.rb', line 35

def self.parse(json_string)
  real_parse(MultiJson.load(json_string), {})
end

.real_parse(json_obj, names = nil, default_namespace = nil) ⇒ Object

Build Avro Schema from data parsed out of JSON string.



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# File 'lib/avro/schema.rb', line 40

def self.real_parse(json_obj, names=nil, default_namespace=nil)
  if json_obj.is_a? Hash
    type = json_obj['type']
    raise SchemaParseError, %Q(No "type" property: #{json_obj}) if type.nil?

    # Check that the type is valid before calling #to_sym, since symbols are never garbage
    # collected (important to avoid DoS if we're accepting schemas from untrusted clients)
    unless VALID_TYPES.include?(type)
      raise SchemaParseError, "Unknown type: #{type}"
    end

    type_sym = type.to_sym
    if PRIMITIVE_TYPES_SYM.include?(type_sym)
      return PrimitiveSchema.new(type_sym)

    elsif NAMED_TYPES_SYM.include? type_sym
      name = json_obj['name']
      namespace = json_obj.include?('namespace') ? json_obj['namespace'] : default_namespace
      case type_sym
      when :fixed
        size = json_obj['size']
        return FixedSchema.new(name, namespace, size, names)
      when :enum
        symbols = json_obj['symbols']
        return EnumSchema.new(name, namespace, symbols, names)
      when :record, :error
        fields = json_obj['fields']
        return RecordSchema.new(name, namespace, fields, names, type_sym)
      else
        raise SchemaParseError.new("Unknown named type: #{type}")
      end

    else
      case type_sym
      when :array
        return ArraySchema.new(json_obj['items'], names, default_namespace)
      when :map
        return MapSchema.new(json_obj['values'], names, default_namespace)
      else
        raise SchemaParseError.new("Unknown Valid Type: #{type}")
      end
    end

  elsif json_obj.is_a? Array
    # JSON array (union)
    return UnionSchema.new(json_obj, names, default_namespace)
  elsif PRIMITIVE_TYPES.include? json_obj
    return PrimitiveSchema.new(json_obj)
  else
    msg = "#{json_obj.inspect} is not a schema we know about."
    raise SchemaParseError.new(msg)
  end
end

.validate(expected_schema, datum) ⇒ Object

Determine if a ruby datum is an instance of a schema



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# File 'lib/avro/schema.rb', line 95

def self.validate(expected_schema, datum)
  case expected_schema.type_sym
  when :null
    datum.nil?
  when :boolean
    datum == true || datum == false
  when :string, :bytes
    datum.is_a? String
  when :int
    (datum.is_a?(Fixnum) || datum.is_a?(Bignum)) &&
        (INT_MIN_VALUE <= datum) && (datum <= INT_MAX_VALUE)
  when :long
    (datum.is_a?(Fixnum) || datum.is_a?(Bignum)) &&
        (LONG_MIN_VALUE <= datum) && (datum <= LONG_MAX_VALUE)
  when :float, :double
    datum.is_a?(Float) || datum.is_a?(Fixnum) || datum.is_a?(Bignum)
  when :fixed
    datum.is_a?(String) && datum.size == expected_schema.size
  when :enum
    expected_schema.symbols.include? datum
  when :array
    datum.is_a?(Array) &&
      datum.all?{|d| validate(expected_schema.items, d) }
  when :map
      datum.keys.all?{|k| k.is_a? String } &&
      datum.values.all?{|v| validate(expected_schema.values, v) }
  when :union
    expected_schema.schemas.any?{|s| validate(s, datum) }
  when :record, :error, :request
    datum.is_a?(Hash) &&
      expected_schema.fields.all?{|f| validate(f.type, datum[f.name]) }
  else
    raise "you suck #{expected_schema.inspect} is not allowed."
  end
end

Instance Method Details

#==(other, seen = nil) ⇒ Object 



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# File 'lib/avro/schema.rb', line 141

def ==(other, seen=nil)
  other.is_a?(Schema) && type_sym == other.type_sym
end

#hash(seen = nil) ⇒ Object 



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# File 'lib/avro/schema.rb', line 145

def hash(seen=nil)
  type_sym.hash
end

#subparse(json_obj, names = nil, namespace = nil) ⇒ Object 



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# File 'lib/avro/schema.rb', line 149

def subparse(json_obj, names=nil, namespace=nil)
  if json_obj.is_a?(String) && names
    fullname = Name.make_fullname(json_obj, namespace)
    return names[fullname] if names.include?(fullname)
  end

  begin
    Schema.real_parse(json_obj, names, namespace)
  rescue => e
    raise e if e.is_a? SchemaParseError
    raise SchemaParseError, "Sub-schema for #{self.class.name} not a valid Avro schema. Bad schema: #{json_obj}"
  end
end

#to_avro(names = nil) ⇒ Object 



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# File 'lib/avro/schema.rb', line 163

def to_avro(names=nil)
  {'type' => type}
end

#to_s ⇒ Object 



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# File 'lib/avro/schema.rb', line 167

def to_s
  MultiJson.dump to_avro
end

#type ⇒ Object

Returns the type as a string (rather than a symbol), for backwards compatibility. Deprecated in favor of #type_sym.



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# File 'lib/avro/schema.rb', line 139

def type; @type_sym.to_s; end