Avro IO with different reader and writer schemas

gistfile1.rb

WRITER_SCHEMA = <<-JSON
{ "type": "record",
  "name": "User",
  "fields" : [
    {"name": "username", "type": "string"},
    {"name": "age", "type": "int"},
    {"name": "verified", "type": "boolean", "default": "false"}
  ]}
JSON


READER_SCHEMA = <<-JSON
{ "type": "record",
  "name": "User",
  "fields" : [
    {"name": "username", "type": "string"},
    {"name": "verified", "type": "boolean", "default": "false"}
  ]}
JSON


# write a file
file = File.open('raw.avro', 'w')
encoder = Avro::IO::BinaryEncoder.new(file)
writer_schema = Avro::Schema.parse(WRITER_SCHEMA)
writer = Avro::IO::DatumWriter.new(writer_schema)
writer.write({"username" => "tom", "age" => 25, "verified" => true }, encoder)
writer.write({"username" => "dick", "age" => 23, "verified" => false }, encoder)
writer.write({"username" => "harry", "age" => 34, "verified" => false }, encoder)
file.flush
file.close

# read the file
file = File.open('raw.avro', 'r')
decoder = Avro::IO::BinaryDecoder.new(file)
reader_schema = Avro::Schema.parse(READER_SCHEMA)
reader = Avro::IO::DatumReader.new(writer_schema, reader_schema)
p reader.read(decoder)
p reader.read(decoder)
p reader.read(decoder)