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DiscoveryMessageCodec.go
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/
DiscoveryMessageCodec.go
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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package ads
import (
"context"
"github.com/apache/plc4x/plc4go/protocols/ads/discovery/readwrite/model"
"github.com/apache/plc4x/plc4go/spi"
"github.com/apache/plc4x/plc4go/spi/default"
"github.com/apache/plc4x/plc4go/spi/options"
"github.com/apache/plc4x/plc4go/spi/transports"
"github.com/pkg/errors"
"github.com/rs/zerolog"
)
type DiscoveryMessageCodec struct {
_default.DefaultCodec
passLogToModel bool
log zerolog.Logger
}
func NewDiscoveryMessageCodec(transportInstance transports.TransportInstance, _options ...options.WithOption) *DiscoveryMessageCodec {
passLoggerToModel, _ := options.ExtractPassLoggerToModel(_options...)
customLogger := options.ExtractCustomLoggerOrDefaultToGlobal(_options...)
codec := &DiscoveryMessageCodec{
passLogToModel: passLoggerToModel,
log: customLogger,
}
codec.DefaultCodec = _default.NewDefaultCodec(codec, transportInstance, _options...)
return codec
}
func (m *DiscoveryMessageCodec) GetCodec() spi.MessageCodec {
return m
}
func (m *DiscoveryMessageCodec) Send(message spi.Message) error {
m.log.Trace().Msg("Sending message")
// Cast the message to the correct type of struct
tcpPaket := message.(model.AdsDiscovery)
// Serialize the request
bytes, err := tcpPaket.Serialize()
if err != nil {
return errors.Wrap(err, "error serializing request")
}
// Send it to the PLC
err = m.GetTransportInstance().Write(bytes)
if err != nil {
return errors.Wrap(err, "error sending request")
}
return nil
}
func (m *DiscoveryMessageCodec) Receive() (spi.Message, error) {
// We need at least 6 bytes in order to know how big the packet is in total
if num, err := m.GetTransportInstance().GetNumBytesAvailableInBuffer(); (err == nil) && (num >= 6) {
m.log.Debug().Uint32("num", num).Msg("we got num readable bytes")
data, err := m.GetTransportInstance().PeekReadableBytes(6)
if err != nil {
m.log.Warn().Err(err).Msg("error peeking")
// TODO: Possibly clean up ...
return nil, nil
}
// Get the size of the entire packet little endian plus size of header
packetSize := (uint32(data[5]) << 24) + (uint32(data[4]) << 16) + (uint32(data[3]) << 8) + (uint32(data[2])) + 6
if num < packetSize {
m.log.Debug().Uint32("num", num).Uint32("packetSize", packetSize).Msg("Not enough bytes. Got: num Need: packetSize")
return nil, nil
}
data, err = m.GetTransportInstance().Read(packetSize)
if err != nil {
// TODO: Possibly clean up ...
return nil, nil
}
ctxForModel := options.GetLoggerContextForModel(context.TODO(), m.log, options.WithPassLoggerToModel(m.passLogToModel))
tcpPacket, err := model.AdsDiscoveryParse(ctxForModel, data)
if err != nil {
m.log.Warn().Err(err).Msg("error parsing")
// TODO: Possibly clean up ...
return nil, nil
}
return tcpPacket, nil
} else if err != nil {
m.log.Warn().Err(err).Msg("Got error reading")
return nil, nil
}
// TODO: maybe we return here a not enough error error
return nil, nil
}