Struct: eventstream.Encoder

import "../ibm-cos-sdk-go-v2/aws/protocol/eventstream"

Overview

Encoder provides EventStream message encoding.

Implemented Interfaces

types.AnalyticsFilter, v4.HTTPPresigner, s3.HTTPPresignerV4, types.MetricsFilter, s3.PresignPost, arn.S3ObjectLambdaARN, types.SelectObjectContentEventStream

Method Summary collapse

Method Details

func (e *Encoder) Encode(w io.Writer, msg Message) (err error)

Encode encodes a single EventStream message to the io.Writer the Encoder was created with. An error is returned if writing the message fails.



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// File 'aws/protocol/eventstream/encode.go', line 46


func (e *Encoder) Encode(w io.Writer, msg Message) (err error) {
	e.headersBuf.Reset()
	e.messageBuf.Reset()

	var writer io.Writer = e.messageBuf
	if e.options.Logger != nil && e.options.LogMessages {
		encodeMsgBuf := bytes.NewBuffer(nil)
		writer = io.MultiWriter(writer, encodeMsgBuf)
		defer func() {
			logMessageEncode(e.options.Logger, encodeMsgBuf, msg, err)
		}()
	}

	if err = EncodeHeaders(e.headersBuf, msg.Headers); err != nil {
		return err
	}

	crc := crc32.New(crc32IEEETable)
	hashWriter := io.MultiWriter(writer, crc)

	headersLen := uint32(e.headersBuf.Len())
	payloadLen := uint32(len(msg.Payload))

	if err = encodePrelude(hashWriter, crc, headersLen, payloadLen); err != nil {
		return err
	}

	if headersLen > 0 {
		if _, err = io.Copy(hashWriter, e.headersBuf); err != nil {
			return err
		}
	}

	if payloadLen > 0 {
		if _, err = hashWriter.Write(msg.Payload); err != nil {
			return err
		}
	}

	msgCRC := crc.Sum32()
	if err := binary.Write(writer, binary.BigEndian, msgCRC); err != nil {
		return err
	}

	_, err = io.Copy(w, e.messageBuf)

	return err
}