Class: Avro::Schema

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

Defined Under Namespace

Classes: ArraySchema, BytesSchema, 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))
NAME_REGEX = 
/^([A-Za-z_][A-Za-z0-9_]*)(\.([A-Za-z_][A-Za-z0-9_]*))*$/.freeze
INT_MIN_VALUE = 
-(1 << 31)
INT_MAX_VALUE = 
(1 << 31) - 1
LONG_MIN_VALUE = 
-(1 << 63)
LONG_MAX_VALUE = 
(1 << 63) - 1
DEFAULT_VALIDATE_OPTIONS = 
{ recursive: true, encoded: false }.freeze
DECIMAL_LOGICAL_TYPE = 
'decimal'
CRC_EMPTY = 
0xc15d213aa4d7a795
SINGLE_OBJECT_MAGIC_NUMBER = 
[0xC3, 0x01].freeze
@@fp_table =

The java library caches this value after initialized, so this pattern mimics that.

nil

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(type, logical_type = nil) ⇒ Schema

Returns a new instance of Schema.



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# File 'lib/avro/schema.rb', line 126

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

Instance Attribute Details

#logical_type ⇒ Object (readonly)

Returns the value of attribute logical_type.



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# File 'lib/avro/schema.rb', line 132

def logical_type
  @logical_type
end

#type_sym ⇒ Object (readonly)

Returns the value of attribute type_sym.



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

def type_sym
  @type_sym
end

Class Method Details

.parse(json_string) ⇒ Object 



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# File 'lib/avro/schema.rb', line 44

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 49

def self.real_parse(json_obj, names=nil, default_namespace=nil)
  if json_obj.is_a? Hash
    type = json_obj['type']
    logical_type = json_obj['logicalType']
    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)
      case type_sym
      when :bytes
        precision = json_obj['precision']
        scale = json_obj['scale']
        return BytesSchema.new(type_sym, logical_type, precision, scale)
      else
        return PrimitiveSchema.new(type_sym, logical_type)
      end
    elsif NAMED_TYPES_SYM.include? type_sym
      name = json_obj['name']
      if !Avro.disable_schema_name_validation && name !~ NAME_REGEX
        raise SchemaParseError, "Name #{name} is invalid for type #{type}!"
      end
      namespace = json_obj.include?('namespace') ? json_obj['namespace'] : default_namespace
      aliases = json_obj['aliases']
      case type_sym
      when :fixed
        size = json_obj['size']
        precision = json_obj['precision']
        scale = json_obj['scale']
        return FixedSchema.new(name, namespace, size, names, logical_type, aliases, precision, scale)
      when :enum
        symbols = json_obj['symbols']
        doc     = json_obj['doc']
        default = json_obj['default']
        return EnumSchema.new(name, namespace, symbols, names, doc, default, aliases)
      when :record, :error
        fields = json_obj['fields']
        doc    = json_obj['doc']
        return RecordSchema.new(name, namespace, fields, names, type_sym, doc, aliases)
      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
    raise UnknownSchemaError.new(json_obj)
  end
end

.validate(expected_schema, logical_datum, options = DEFAULT_VALIDATE_OPTIONS) ⇒ Object

Determine if a ruby datum is an instance of a schema



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# File 'lib/avro/schema.rb', line 119

def self.validate(expected_schema, logical_datum, options = DEFAULT_VALIDATE_OPTIONS)
  SchemaValidator.validate!(expected_schema, logical_datum, options)
  true
rescue SchemaValidator::ValidationError
  false
end

Instance Method Details

#==(other, _seen = nil) ⇒ Object 



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# File 'lib/avro/schema.rb', line 209

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

#be_read?(other_schema) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/avro/schema.rb', line 201

def be_read?(other_schema)
  other_schema.read?(self)
end

#crc_64_avro_fingerprint ⇒ Object 



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# File 'lib/avro/schema.rb', line 170

def crc_64_avro_fingerprint
  parsing_form = Avro::SchemaNormalization.to_parsing_form(self)
  data_bytes = parsing_form.unpack("C*")

  initFPTable unless @@fp_table

  fp = CRC_EMPTY
  data_bytes.each do |b|
    fp = (fp >> 8) ^ @@fp_table[ (fp ^ b) & 0xff ]
  end
  fp
end

#hash(_seen = nil) ⇒ Object 



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# File 'lib/avro/schema.rb', line 213

def hash(_seen=nil)
  type_sym.hash
end

#initFPTable ⇒ Object 



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# File 'lib/avro/schema.rb', line 159

def initFPTable
  @@fp_table = Array.new(256)
  256.times do |i|
    fp = i
    8.times do
      fp = (fp >> 1) ^ ( CRC_EMPTY & -( fp & 1 ) )
    end
    @@fp_table[i] = fp
  end
end

#md5_fingerprint ⇒ Object

Returns the MD5 fingerprint of the schema as an Integer.



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# File 'lib/avro/schema.rb', line 143

def md5_fingerprint
  parsing_form = SchemaNormalization.to_parsing_form(self)
  Digest::MD5.hexdigest(parsing_form).to_i(16)
end

#mutual_read?(other_schema) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/avro/schema.rb', line 205

def mutual_read?(other_schema)
  SchemaCompatibility.mutual_read?(other_schema, self)
end

#read?(writers_schema) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/avro/schema.rb', line 197

def read?(writers_schema)
  SchemaCompatibility.can_read?(writers_schema, self)
end

#sha256_fingerprint ⇒ Object

Returns the SHA-256 fingerprint of the schema as an Integer.



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

def sha256_fingerprint
  parsing_form = SchemaNormalization.to_parsing_form(self)
  Digest::SHA256.hexdigest(parsing_form).to_i(16)
end

#single_object_encoding_header ⇒ Object 



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# File 'lib/avro/schema.rb', line 184

def single_object_encoding_header
  [SINGLE_OBJECT_MAGIC_NUMBER, single_object_schema_fingerprint].flatten
end

#single_object_schema_fingerprint ⇒ Object 



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# File 'lib/avro/schema.rb', line 187

def single_object_schema_fingerprint
  working = crc_64_avro_fingerprint
  bytes = Array.new(8)
  8.times do |i|
    bytes[i] = (working & 0xff)
    working = working >> 8
  end
  bytes
end

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



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# File 'lib/avro/schema.rb', line 217

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 231

def to_avro(_names=nil)
  props = {'type' => type}
  props['logicalType'] = logical_type if logical_type
  props
end

#to_s ⇒ Object 



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# File 'lib/avro/schema.rb', line 237

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 136

def type; @type_sym.to_s; end

#type_adapter ⇒ Object 



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# File 'lib/avro/schema.rb', line 138

def type_adapter
  @type_adapter ||= LogicalTypes.type_adapter(type, logical_type, self) || LogicalTypes::Identity
end