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/*
Copyright 2013-2014 Canonical Ltd.
This program is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License version 3, as published
by the Free Software Foundation.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranties of
MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package protocol
// Structs representing messages.
import (
"encoding/json"
"fmt"
)
// System channel id using a shortened hex-encoded form for the NIL UUID.
const SystemChannelId = "0"
// CONNECT message
type ConnectMsg struct {
Type string `json:"T"`
ClientVer string
DeviceId string
Authorization string
Cookie string
Info map[string]interface{} `json:",omitempty"` // platform etc...
// maps channel ids (hex encoded UUIDs) to known client channel levels
Levels map[string]int64
}
// CONNACK message
type ConnAckMsg struct {
Type string `json:"T"`
Params ConnAckParams
}
// ConnAckParams carries the connection parameters from the server on
// connection acknowledgement.
type ConnAckParams struct {
// ping interval formatted time.Duration
PingInterval string
}
// SplittableMsg are messages that may require and are capable of splitting.
type SplittableMsg interface {
Split() (done bool)
}
// OnewayMsg are messages that are not to be followed by a response,
// after sending them the session either aborts or continues.
type OnewayMsg interface {
SplittableMsg
// continue session after the message?
OnewayContinue() bool
}
// CONNBROKEN message, server side is breaking the connection for reason.
type ConnBrokenMsg struct {
Type string `json:"T"`
// reason
Reason string
}
func (m *ConnBrokenMsg) Split() bool {
return true
}
func (m *ConnBrokenMsg) OnewayContinue() bool {
return false
}
// CONNBROKEN reasons
const (
BrokenHostMismatch = "host-mismatch"
)
// CONNWARN message, server side is warning about partial functionality
// because reason.
type ConnWarnMsg struct {
Type string `json:"T"`
// reason
Reason string
}
func (m *ConnWarnMsg) Split() bool {
return true
}
func (m *ConnWarnMsg) OnewayContinue() bool {
return true
}
// CONNWARN reasons
const (
WarnUnauthorized = "unauthorized"
)
// SETPARAMS message
type SetParamsMsg struct {
Type string `json:"T"`
SetCookie string
}
func (m *SetParamsMsg) Split() bool {
return true
}
func (m *SetParamsMsg) OnewayContinue() bool {
return true
}
// PING/PONG messages
type PingPongMsg struct {
Type string `json:"T"`
}
const maxPayloadSize = 62 * 1024
// BROADCAST messages
type BroadcastMsg struct {
Type string `json:"T"`
AppId string `json:",omitempty"`
ChanId string
TopLevel int64
Payloads []json.RawMessage
splitting int
}
func (m *BroadcastMsg) Split() bool {
var prevTop int64
if m.splitting == 0 {
prevTop = m.TopLevel - int64(len(m.Payloads))
} else {
prevTop = m.TopLevel
m.Payloads = m.Payloads[len(m.Payloads):m.splitting]
m.TopLevel = prevTop + int64(len(m.Payloads))
}
payloads := m.Payloads
var size int
for i := range payloads {
size += len(payloads[i])
if size > maxPayloadSize {
m.TopLevel = prevTop + int64(i)
m.splitting = len(payloads)
m.Payloads = payloads[:i]
return false
}
}
return true
}
// Reset resets the splitting state if the message storage is to be
// reused and sets the proper Type.
func (b *BroadcastMsg) Reset() {
b.Type = "broadcast"
b.splitting = 0
}
// NOTIFICATIONS message
type NotificationsMsg struct {
Type string `json:"T"`
Notifications []Notification
splitting int
}
// Reset resets the splitting state if the message storage is to be
// reused and sets the proper Type.
func (m *NotificationsMsg) Reset() {
m.Type = "notifications"
m.splitting = 0
}
func (m *NotificationsMsg) Split() bool {
if m.splitting != 0 {
m.Notifications = m.Notifications[len(m.Notifications):m.splitting]
}
notifs := m.Notifications
var size int
for i, notif := range notifs {
size += len(notif.Payload) + len(notif.AppId) + len(notif.MsgId) + notificationOverhead
if size > maxPayloadSize {
m.splitting = len(notifs)
m.Notifications = notifs[:i]
return false
}
}
return true
}
var notificationOverhead int
func init() {
buf, err := json.Marshal(Notification{})
if err != nil {
panic(fmt.Errorf("failed to compute Notification marshal overhead: %v", err))
}
notificationOverhead = len(buf) - 4 // - 4 for the null from P(ayload)
}
// A single unicast notification
type Notification struct {
AppId string `json:"A"`
MsgId string `json:"M"`
// payload
Payload json.RawMessage `json:"P"`
}
// ExtractPayloads gets only the payloads out of a slice of notications.
func ExtractPayloads(notifications []Notification) []json.RawMessage {
n := len(notifications)
if n == 0 {
return nil
}
payloads := make([]json.RawMessage, n)
for i := 0; i < n; i++ {
payloads[i] = notifications[i].Payload
}
return payloads
}
// ACKnowledgement message
type AckMsg struct {
Type string `json:"T"`
}
// xxx ... query levels messages
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