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clientObserveHandler.go
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/
clientObserveHandler.go
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package service
import (
"bytes"
"context"
"errors"
"fmt"
"io"
"sync"
"sync/atomic"
coapMessage "github.com/plgd-dev/go-coap/v3/message"
coapCodes "github.com/plgd-dev/go-coap/v3/message/codes"
"github.com/plgd-dev/go-coap/v3/message/pool"
"github.com/plgd-dev/go-coap/v3/mux"
"github.com/plgd-dev/hub/v2/coap-gateway/coapconv"
"github.com/plgd-dev/hub/v2/coap-gateway/service/message"
"github.com/plgd-dev/hub/v2/grpc-gateway/pb"
"github.com/plgd-dev/hub/v2/grpc-gateway/subscription"
"github.com/plgd-dev/hub/v2/pkg/strings"
"github.com/plgd-dev/hub/v2/resource-aggregate/commands"
"github.com/plgd-dev/hub/v2/resource-aggregate/events"
)
const errFmtObserveResource = "cannot handle observe resource%v: %w"
func getObserveResourceErr(err error) error {
if err == nil {
return nil
}
return fmt.Errorf(errFmtObserveResource, "", err)
}
func clientObserveHandler(req *mux.Message, client *session, observe uint32) (*pool.Message, error) {
authCtx, err := client.GetAuthorizationContext()
if err != nil {
return nil, statusErrorf(coapCodes.Unauthorized, "%w", getObserveResourceErr(err))
}
deviceID, href, err := message.URIToDeviceIDHref(req)
if err != nil {
return nil, statusErrorf(coapCodes.BadRequest, "%w", getObserveResourceErr(err))
}
switch observe {
case 0:
return startResourceObservation(req, client, authCtx, deviceID, href)
case 1:
return stopResourceObservation(req, client, deviceID, href)
default:
return nil, statusErrorf(coapCodes.BadRequest, errFmtObserveResource, fmt.Sprintf(" /%v%v", deviceID, href), fmt.Errorf("invalid Observe value(%v)", observe))
}
}
func CreateResourceContentToObserver(client *session, resourceChanged *events.ResourceChanged, observe uint32, token coapMessage.Token) (*pool.Message, error) {
msg := client.server.messagePool.AcquireMessage(client.coapConn.Context())
msg.SetCode(coapCodes.Content)
msg.SetObserve(observe)
msg.SetToken(token)
if resourceChanged.GetContent() != nil {
mediaType, err := coapconv.MakeMediaType(-1, resourceChanged.GetContent().GetContentType())
if err != nil {
return nil, statusErrorf(coapCodes.BadRequest, "cannot set content format for observer: %v", err)
}
msg.SetContentFormat(mediaType)
msg.SetBody(bytes.NewReader(resourceChanged.GetContent().GetData()))
}
return msg, nil
}
type resourceSubscription struct {
client *session
authCtx *authorizationContext
sub *subscription.Sub
deviceID string
href string
token coapMessage.Token
seqNum uint32
private struct {
mutex sync.Mutex
version uint64
versionInitialized bool
}
}
func (s *resourceSubscription) cancelSubscription(code coapCodes.Code) {
x := struct {
s *resourceSubscription
code coapCodes.Code
}{
s: s,
code: code,
}
err := s.client.server.taskQueue.Submit(func() {
if _, err := x.s.client.cancelResourceSubscription(x.s.token.String()); err != nil {
x.s.client.Errorf("failed to cancel resource /%v%v subscription: %w", x.s.deviceID, x.s.href, err)
}
err := statusErrorf(x.code, "cannot observe resource /%v%v, device response: %v", x.s.deviceID, x.s.href, x.code)
resp := x.s.client.createErrorResponse(err, x.s.token)
defer x.s.client.ReleaseMessage(resp)
x.s.client.WriteMessage(resp)
x.s.client.logRequestResponse(nil, resp, err)
})
if err != nil {
s.client.Errorf("failed to cancel resource /%v%v subscription: %w", s.deviceID, s.href, err)
}
}
func (s *resourceSubscription) isDuplicateEvent(ev *events.ResourceChanged) bool {
s.private.mutex.Lock()
defer s.private.mutex.Unlock()
if s.private.versionInitialized && s.private.version >= ev.GetEventMetadata().GetVersion() {
return true
}
s.private.versionInitialized = true
s.private.version = ev.GetEventMetadata().GetVersion()
return false
}
func (s *resourceSubscription) eventHandler(e *pb.Event) error {
switch {
case e.GetResourceUnpublished() != nil:
if !strings.Contains(e.GetResourceUnpublished().GetHrefs(), s.href) {
return nil
}
s.cancelSubscription(coapCodes.ServiceUnavailable)
case e.GetDeviceUnregistered() != nil:
s.cancelSubscription(coapCodes.ServiceUnavailable)
case e.GetResourceChanged() != nil:
// deduplicate events
if s.isDuplicateEvent(e.GetResourceChanged()) {
return nil
}
if e.GetResourceChanged().GetStatus() != commands.Status_OK {
s.cancelSubscription(coapconv.StatusToCoapCode(e.GetResourceChanged().GetStatus(), coapconv.Retrieve))
return nil
}
seqNum := atomic.AddUint32(&s.seqNum, 1)
x := struct {
client *session
seqNum uint32
e *pb.Event
s *resourceSubscription
}{
client: s.client,
seqNum: seqNum,
e: e,
s: s,
}
err := s.client.server.taskQueue.Submit(func() {
msg, err := CreateResourceContentToObserver(x.client, x.e.GetResourceChanged(), x.seqNum, x.s.token)
if err != nil {
x.s.client.Errorf("failed to create resource content for observer: %w", err)
}
defer x.s.client.ReleaseMessage(msg)
x.s.client.WriteMessage(msg)
x.s.client.logNotificationToClient(x.e.GetResourceChanged().GetResourceId().GetHref(), msg)
})
if err != nil {
s.client.Errorf("failed to send event resource /%v%v to observer: %w", s.deviceID, s.href, err)
}
return nil
}
return nil
}
func (s *resourceSubscription) Init(ctx context.Context) error {
res := &commands.ResourceId{DeviceId: s.deviceID, Href: s.href}
client, err := s.client.server.rdClient.GetResources(ctx, &pb.GetResourcesRequest{
ResourceIdFilter: []*pb.ResourceIdFilter{
{
ResourceId: res,
},
},
})
if err != nil {
return err
}
var d *events.ResourceChanged
for {
resource, errR := client.Recv()
if errors.Is(errR, io.EOF) {
break
}
if errR != nil {
return errR
}
d = resource.GetData()
}
authCtx, err := s.client.GetAuthorizationContext()
if err != nil {
return err
}
err = s.sub.Init(authCtx.GetUserID(), s.client.server.subscriptionsCache)
if err != nil {
return err
}
if d == nil {
return nil
}
return s.eventHandler(&pb.Event{
SubscriptionId: s.sub.Id(),
CorrelationId: s.sub.CorrelationId(),
Type: &pb.Event_ResourceChanged{
ResourceChanged: d,
},
})
}
func (s *resourceSubscription) Close() error {
return s.sub.Close()
}
func newResourceSubscription(req *mux.Message, client *session, authCtx *authorizationContext, deviceID string, href string) *resourceSubscription {
r := &resourceSubscription{
client: client,
token: req.Token(),
authCtx: authCtx,
deviceID: deviceID,
href: href,
seqNum: 2,
}
sub := subscription.New(r.eventHandler, req.Token().String(), &pb.SubscribeToEvents_CreateSubscription{
ResourceIdFilter: []*pb.ResourceIdFilter{
{
ResourceId: &commands.ResourceId{DeviceId: deviceID, Href: href},
},
},
EventFilter: []pb.SubscribeToEvents_CreateSubscription_Event{pb.SubscribeToEvents_CreateSubscription_RESOURCE_CHANGED, pb.SubscribeToEvents_CreateSubscription_UNREGISTERED, pb.SubscribeToEvents_CreateSubscription_RESOURCE_UNPUBLISHED},
})
r.sub = sub
return r
}
const errFmtStartObserveResource = "cannot start resource observation /%v%v: %w"
func getStartObserveResourceErr(deviceID, href string, err error) error {
if err == nil {
return nil
}
return fmt.Errorf(errFmtStartObserveResource, deviceID, href, err)
}
func startResourceObservation(req *mux.Message, client *session, authCtx *authorizationContext, deviceID, href string) (*pool.Message, error) {
ok, err := client.server.ownerCache.OwnsDevice(req.Context(), deviceID)
if err != nil {
return nil, statusErrorf(coapconv.GrpcErr2CoapCode(err, coapconv.Retrieve), "%w", getStartObserveResourceErr(deviceID, href, err))
}
if !ok {
return nil, statusErrorf(coapCodes.Unauthorized, "%w", getStartObserveResourceErr(deviceID, href, errors.New("unauthorized access")))
}
token := req.Token().String()
sub := newResourceSubscription(req, client, authCtx, deviceID, href)
_, loaded := client.resourceSubscriptions.LoadOrStore(token, sub)
if loaded {
if errC := sub.Close(); errC != nil {
client.Errorf("failed to close resource /%v%v subscription: %w", deviceID, href, errC)
}
return nil, statusErrorf(coapCodes.BadRequest, "%w", getStartObserveResourceErr(deviceID, href, fmt.Errorf("resource subscription with token %v already exist", token)))
}
err = sub.Init(req.Context())
if err != nil {
_, _ = client.resourceSubscriptions.PullOut(token)
if errC := sub.Close(); errC != nil {
client.Errorf("failed to close resource /%v%v subscription: %w", deviceID, href, errC)
}
return nil, statusErrorf(coapCodes.BadRequest, "%w", getStartObserveResourceErr(deviceID, href, err))
}
// response will be send from projection
return nil, nil
}
const errFmtStopObserveResource = "cannot stop resource observation /%v%v: %w"
func getStopObserveResourceErr(deviceID, href string, err error) error {
if err == nil {
return nil
}
return fmt.Errorf(errFmtStopObserveResource, deviceID, href, err)
}
func stopResourceObservation(req *mux.Message, client *session, deviceID, href string) (*pool.Message, error) {
token := req.Token().String()
canceled, err := client.cancelResourceSubscription(token)
if err != nil {
return nil, statusErrorf(coapCodes.BadRequest, "%w", getStopObserveResourceErr(deviceID, href, err))
}
if !canceled {
return nil, statusErrorf(coapCodes.BadRequest, "%w", getStopObserveResourceErr(deviceID, href, errors.New("subscription not found")))
}
return CreateResourceContentToObserver(client, nil, 1, req.Token())
}
func clientResetObservationHandler(req *mux.Message, client *session) (*pool.Message, error) {
token := req.Token().String()
canceled, err := client.cancelResourceSubscription(token)
if err != nil {
return nil, statusErrorf(coapCodes.BadRequest, "%w", fmt.Errorf("cannot reset resource observation: %w", err))
}
if !canceled {
return nil, statusErrorf(coapCodes.BadRequest, "%w", errors.New("cannot reset resource observation: not found"))
}
// reset does not send response
return nil, nil
}