// Logs creates a subscription that fires for all new log that match the given filter criteria.
func (s *PublicFilterAPI) Logs(ctx context.Context, args NewFilterArgs) (rpc.Subscription, error) {
notifier, supported := rpc.NotifierFromContext(ctx)
if !supported {
return nil, rpc.ErrNotificationsUnsupported
}
var (
externalId string
subscription rpc.Subscription
err error
)
if externalId, err = newFilterId(); err != nil {
return nil, err
}
// uninstall filter when subscription is unsubscribed/cancelled
if subscription, err = notifier.NewSubscription(func(string) {
s.UninstallFilter(externalId)
}); err != nil {
return nil, err
}
notifySubscriber := func(log *vm.Log, removed bool) {
rpcLog := toRPCLogs(vm.Logs{log}, removed)
if err := subscription.Notify(rpcLog); err != nil {
subscription.Cancel()
}
}
// from and to block number are not used since subscriptions don't allow you to travel to "time"
var id int
if len(args.Addresses) > 0 {
id, err = s.newLogFilter(-1, -1, args.Addresses, args.Topics, notifySubscriber)
} else {
id, err = s.newLogFilter(-1, -1, nil, args.Topics, notifySubscriber)
}
if err != nil {
subscription.Cancel()
return nil, err
}
s.filterMapMu.Lock()
s.filterMapping[externalId] = id
s.filterMapMu.Unlock()
return subscription, err
}
// Syncing provides information when this nodes starts synchronising with the Ethereum network and when it's finished.
func (api *PublicDownloaderAPI) Syncing(ctx context.Context) (rpc.Subscription, error) {
notifier, supported := rpc.NotifierFromContext(ctx)
if !supported {
return nil, rpc.ErrNotificationsUnsupported
}
subscription, err := notifier.NewSubscription(func(id string) {
api.muSyncSubscriptions.Lock()
delete(api.syncSubscriptions, id)
api.muSyncSubscriptions.Unlock()
})
if err != nil {
return nil, err
}
api.muSyncSubscriptions.Lock()
api.syncSubscriptions[subscription.ID()] = subscription
api.muSyncSubscriptions.Unlock()
return subscription, nil
}