Method Receive

pgproto3/backend.go:170–256

Receive receives a message from the frontend. The returned message is only valid until the next call to Receive.

()

// Receive receives a message from the frontend. The returned message is only valid until the next call to Receive.
func (b *Backend) Receive() (FrontendMessage, error) {
	if !b.partialMsg {
		header, err := b.cr.Next(5)
		if err != nil {
			return nil, translateEOFtoErrUnexpectedEOF(err)
		}

		b.msgType = header[0]

		msgLength := int(int32(binary.BigEndian.Uint32(header[1:])))
		if msgLength < 4 {
			return nil, fmt.Errorf("invalid message length: %d", msgLength)
		}

		b.bodyLen = msgLength - 4
		if b.maxBodyLen > 0 && b.bodyLen > b.maxBodyLen {
			return nil, &ExceededMaxBodyLenErr{b.maxBodyLen, b.bodyLen}
		}
		b.partialMsg = true
	}

	var msg FrontendMessage
	switch b.msgType {
	case 'B':
		msg = &b.bind
	case 'C':
		msg = &b._close
	case 'D':
		msg = &b.describe
	case 'E':
		msg = &b.execute
	case 'F':
		msg = &b.functionCall
	case 'f':
		msg = &b.copyFail
	case 'd':
		msg = &b.copyData
	case 'c':
		msg = &b.copyDone
	case 'H':
		msg = &b.flush
	case 'P':
		msg = &b.parse
	case 'p':
		switch b.authType {
		case AuthTypeSASL:
			msg = &SASLInitialResponse{}
		case AuthTypeSASLContinue:
			msg = &SASLResponse{}
		case AuthTypeSASLFinal:
			msg = &SASLResponse{}
		case AuthTypeGSS, AuthTypeGSSCont:
			msg = &GSSResponse{}
		case AuthTypeCleartextPassword, AuthTypeMD5Password:
			fallthrough
		default:
			// to maintain backwards compatibility
			msg = &PasswordMessage{}