encoding

Documentation

Overview

Package encoding defines the interface for the compressor and codec, and functions to register and retrieve compressors and codecs.

Experimental

Notice: This package is EXPERIMENTAL and may be changed or removed in a later release.

Index

• Constants
• func RegisterCodec(codec Codec)
• func RegisterCompressor(c Compressor)
• type Codec
  • func GetCodec(contentSubtype string) Codec
• type Compressor
  • func GetCompressor(name string) Compressor

Constants

const Identity = "identity"

Identity specifies the optional encoding for uncompressed streams. It is intended for grpc internal use only.

Functions

func RegisterCodec

func RegisterCodec(codec Codec)

RegisterCodec registers the provided Codec for use with all gRPC clients and servers.

The Codec will be stored and looked up by result of its Name() method, which should match the content-subtype of the encoding handled by the Codec. This is case-insensitive, and is stored and looked up as lowercase. If the result of calling Name() is an empty string, RegisterCodec will panic. See Content-Type on https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for more details.

NOTE: this function must only be called during initialization time (i.e. in an init() function), and is not thread-safe. If multiple Codecs are registered with the same name, the one registered last will take effect.

func RegisterCompressor

func RegisterCompressor(c Compressor)

RegisterCompressor registers the compressor with gRPC by its name. It can be activated when sending an RPC via grpc.UseCompressor(). It will be automatically accessed when receiving a message based on the content coding header. Servers also use it to send a response with the same encoding as the request.

NOTE: this function must only be called during initialization time (i.e. in an init() function), and is not thread-safe. If multiple Compressors are registered with the same name, the one registered last will take effect.

Types

type Codec

type Codec interface {
	// Marshal returns the wire format of v.
	Marshal(v any) ([]byte, error)
	// Unmarshal parses the wire format into v.
	Unmarshal(data []byte, v any) error
	// Name returns the name of the Codec implementation. The returned string
	// will be used as part of content type in transmission.  The result must be
	// static; the result cannot change between calls.
	Name() string
}

Codec defines the interface gRPC uses to encode and decode messages. Note that implementations of this interface must be thread safe; a Codec's methods can be called from concurrent goroutines.

func GetCodec

func GetCodec(contentSubtype string) Codec

GetCodec gets a registered Codec by content-subtype, or nil if no Codec is registered for the content-subtype.

The content-subtype is expected to be lowercase.

type Compressor

type Compressor interface {
	// Compress writes the data written to wc to w after compressing it.  If an
	// error occurs while initializing the compressor, that error is returned
	// instead.
	Compress(w io.Writer) (io.WriteCloser, error)
	// Decompress reads data from r, decompresses it, and provides the
	// uncompressed data via the returned io.Reader.  If an error occurs while
	// initializing the decompressor, that error is returned instead.
	Decompress(r io.Reader) (io.Reader, error)
	// Name is the name of the compression codec and is used to set the content
	// coding header.  The result must be static; the result cannot change
	// between calls.
	Name() string
}

Compressor is used for compressing and decompressing when sending or receiving messages.

If a Compressor implements `DecompressedSize(compressedBytes []byte) int`, gRPC will invoke it to determine the size of the buffer allocated for the result of decompression. A return value of -1 indicates unknown size.

func GetCompressor

func GetCompressor(name string) Compressor

GetCompressor returns Compressor for the given compressor name.