class Kafka::Protocol::Encoder
An encoder wraps an IO object, making it easy to write specific data types to it.
Public Class Methods
Encodes an object into a new buffer.
@param object [#encode] the object that will encode itself. @return [String] the encoded data.
# File lib/kafka/protocol/encoder.rb, line 174 def self.encode_with(object) buffer = StringIO.new encoder = new(buffer) object.encode(encoder) buffer.string end
Initializes a new encoder.
@param io [IO] an object that acts as an IO.
# File lib/kafka/protocol/encoder.rb, line 13 def initialize(io) @io = io @io.set_encoding(Encoding::BINARY) end
Public Instance Methods
Writes bytes directly to the IO object.
@param bytes [String] @return [nil]
# File lib/kafka/protocol/encoder.rb, line 22 def write(bytes) @io.write(bytes) nil end
Writes an array to the IO object.
Each item in the specified array will be yielded to the provided block; it's the responsibility of the block to write those items using the encoder.
@param array [Array] @return [nil]
# File lib/kafka/protocol/encoder.rb, line 76 def write_array(array, &block) if array.nil? # An array can be null, which is different from it being empty. write_int32(-1) else write_int32(array.size) array.each(&block) end end
Writes an 8-bit boolean to the IO object.
@param boolean [Boolean] @return [nil]
# File lib/kafka/protocol/encoder.rb, line 32 def write_boolean(boolean) boolean ? write_int8(1) : write_int8(0) end
Writes a byte string to the IO object.
@param bytes [String] @return [nil]
# File lib/kafka/protocol/encoder.rb, line 148 def write_bytes(bytes) if bytes.nil? write_int32(-1) else write_int32(bytes.bytesize) write(bytes) end end
Writes a 16-bit integer to the IO object.
@param int [Integer] @return [nil]
# File lib/kafka/protocol/encoder.rb, line 48 def write_int16(int) write([int].pack("s>")) end
Writes a 32-bit integer to the IO object.
@param int [Integer] @return [nil]
# File lib/kafka/protocol/encoder.rb, line 56 def write_int32(int) write([int].pack("l>")) end
Writes a 64-bit integer to the IO object.
@param int [Integer] @return [nil]
# File lib/kafka/protocol/encoder.rb, line 64 def write_int64(int) write([int].pack("q>")) end
Writes an 8-bit integer to the IO object.
@param int [Integer] @return [nil]
# File lib/kafka/protocol/encoder.rb, line 40 def write_int8(int) write([int].pack("C")) end
Writes a string to the IO object.
@param string [String] @return [nil]
# File lib/kafka/protocol/encoder.rb, line 104 def write_string(string) if string.nil? write_int16(-1) else write_int16(string.bytesize) write(string) end end
Writes an integer under varints serializing to the IO object. developers.google.com/protocol-buffers/docs/encoding#varints
@param string [Integer] @return [nil]
# File lib/kafka/protocol/encoder.rb, line 131 def write_varint(int) int = int << 1 int = ~int | 1 if int < 0 chunks = [] while int >> 7 != 0 chunks << (int & 0x7f | 0x80) int >>= 7 end chunks << int write(chunks.pack("C*")) end
Writes an array to the IO object. Just like write_array
, unless the size is under varint format
@param array [Array] @return [nil]
# File lib/kafka/protocol/encoder.rb, line 91 def write_varint_array(array, &block) if array.nil? write_varint(-1) else write_varint(array.size) array.each(&block) end end
Writes a byte string to the IO object, the size is under varint format
@param bytes [String] @return [nil]
# File lib/kafka/protocol/encoder.rb, line 161 def write_varint_bytes(bytes) if bytes.nil? write_varint(-1) else write_varint(bytes.bytesize) write(bytes) end end
Writes a string to the IO object, the size is under varint format
@param string [String] @return [nil]
# File lib/kafka/protocol/encoder.rb, line 117 def write_varint_string(string) if string.nil? write_varint(-1) else write_varint(string.bytesize) write(string) end end