101 lines
3.5 KiB

package fetch
import (
// CwtchServerFetchChannel implements the ChannelHandler interface for a channel of
// type "im.cwtch.server.fetch" - this implementation only handles server side logic.
type CwtchServerFetchChannel struct {
Handler CwtchServerFetchHandler
channel *channels.Channel
// CwtchServerFetchHandler defines the interface for interacting with this Channel
type CwtchServerFetchHandler interface {
HandleFetchRequest() []*protocol.GroupMessage
// Type returns the type string for this channel, e.g. "im.ricochet.Cwtch".
func (cc *CwtchServerFetchChannel) Type() string {
return "im.cwtch.server.fetch"
// Closed is called when the channel is closed for any reason.
func (cc *CwtchServerFetchChannel) Closed(err error) {
// OnlyClientCanOpen - for Cwtch channels any side can open
func (cc *CwtchServerFetchChannel) OnlyClientCanOpen() bool {
return true
// Singleton - for Cwtch channels there can only be one instance per direction
func (cc *CwtchServerFetchChannel) Singleton() bool {
return true
// Bidirectional - for Cwtch channels are not bidrectional
func (cc *CwtchServerFetchChannel) Bidirectional() bool {
return false
// RequiresAuthentication - Cwtch channels require hidden service auth
func (cc *CwtchServerFetchChannel) RequiresAuthentication() string {
return "none"
// OpenInbound is the first method called for an inbound channel request.
// If an error is returned, the channel is rejected. If a RawMessage is
// returned, it will be sent as the ChannelResult message.
func (cc *CwtchServerFetchChannel) OpenInbound(channel *channels.Channel, raw *Protocol_Data_Control.OpenChannel) ([]byte, error) { = channel
messageBuilder := new(utils.MessageBuilder)
return messageBuilder.AckOpenChannel(channel.ID), nil
// OpenOutbound is the first method called for an outbound channel request.
// If an error is returned, the channel is not opened. If a RawMessage is
// returned, it will be sent as the OpenChannel message.
func (cc *CwtchServerFetchChannel) OpenOutbound(channel *channels.Channel) ([]byte, error) {
return nil, errors.New("server does not open Fetch channels")
// OpenOutboundResult is called when a response is received for an
// outbound OpenChannel request. If `err` is non-nil, the channel was
// rejected and Closed will be called immediately afterwards. `raw`
// contains the raw protocol message including any extension data.
func (cc *CwtchServerFetchChannel) OpenOutboundResult(err error, crm *Protocol_Data_Control.ChannelResult) {
// NOTE: Should never be called
// SendGroupMessages sends a series of group messages to the client.
func (cc *CwtchServerFetchChannel) SendGroupMessages(gms []*protocol.GroupMessage) {
for _, gm := range gms {
csp := &protocol.CwtchServerPacket{
GroupMessage: gm,
packet, _ := proto.Marshal(csp)
// Packet is called for each raw packet received on this channel.
func (cc *CwtchServerFetchChannel) Packet(data []byte) {
csp := &protocol.CwtchServerPacket{}
err := proto.Unmarshal(data, csp)
if err == nil {
if csp.GetFetchMessage() != nil {
// If we receive a packet on this channel, close the connection