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package inform
import (
"bytes"
"encoding/json"
"errors"
"fmt"
"github.com/mitchellh/mapstructure"
)
const (
PROTOCOL_MAGIC int32 = 1414414933 // TNBU
INFORM_VERSION int32 = 0
DATA_VERSION int32 = 1
ENCRYPTED_FLAG = 1
COMPRESSED_FLAG = 2
)
// Wrapper around an inform message, serializes directly into the wire
// protocol
type InformWrapper struct {
Version int32
MacAddr []byte
Flags int16
DataVersion int32
Payload []byte
}
// Create InformWrapper with sane defaults
func NewInformWrapper() *InformWrapper {
return &InformWrapper{
Version: INFORM_VERSION,
MacAddr: make([]byte, 6),
Flags: 0,
DataVersion: DATA_VERSION,
}
}
// Update the payload data with JSON value
func (i *InformWrapper) UpdatePayload(v interface{}) error {
if d, err := json.Marshal(v); err != nil {
return err
} else {
i.Payload = d
return nil
}
}
// Format Mac address bytes as lowercase string with colons
func (i *InformWrapper) FormattedMac() string {
return fmt.Sprintf("%02x:%02x:%02x:%02x:%02x:%02x",
i.MacAddr[0], i.MacAddr[1], i.MacAddr[2],
i.MacAddr[3], i.MacAddr[4], i.MacAddr[5])
}
func (i *InformWrapper) String() string {
b := &bytes.Buffer{}
fmt.Fprintf(b, "Version: \t%d\n", i.Version)
fmt.Fprintf(b, "Mac Addr: \t%s\n", i.FormattedMac())
fmt.Fprintf(b, "Flags: \t%d\n", i.Flags)
fmt.Fprintf(b, " Encrypted: \t%t\n", i.IsEncrypted())
fmt.Fprintf(b, " Compressed: \t%t\n", i.IsCompressed())
fmt.Fprintf(b, "Data Version: \t%d\n", i.DataVersion)
fmt.Fprintf(b, "Payload: \t%q\n", i.Payload)
return b.String()
}
func (i *InformWrapper) IsEncrypted() bool {
return i.Flags&ENCRYPTED_FLAG != 0
}
func (i *InformWrapper) SetEncrypted(e bool) {
if e {
i.Flags |= ENCRYPTED_FLAG
} else {
i.Flags &= ENCRYPTED_FLAG
}
}
func (i *InformWrapper) IsCompressed() bool {
return i.Flags&COMPRESSED_FLAG != 0
}
func (i *InformWrapper) SetCompressed(c bool) {
if c {
i.Flags |= COMPRESSED_FLAG
} else {
i.Flags &= COMPRESSED_FLAG
}
}
// Decode payload to a map and try to determine the inform type
func (i *InformWrapper) decodePayload() (map[string]interface{}, string, error) {
var m map[string]interface{}
if err := json.Unmarshal(i.Payload, &m); err != nil {
return nil, "", err
}
t, ok := m["_type"]
if !ok {
return nil, "", errors.New("Message contains no type")
}
st, ok := t.(string)
if !ok {
return nil, "", errors.New("Message type is not a string")
}
return m, st, nil
}
// Decode payload JSON as a inform message
func (i *InformWrapper) JsonMessage() (interface{}, error) {
msg, t, err := i.decodePayload()
if err != nil {
return nil, err
}
switch t {
case "noop":
var o NoopMessage
if err := mapstructure.Decode(msg, &o); err != nil {
return nil, err
}
return o, nil
}
return nil, errors.New(fmt.Sprintf("Message type %s is invalid", t))
}
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