From 074be02a6553ef51c7df5d4d229d7a50d867393a Mon Sep 17 00:00:00 2001 From: John Beisley Date: Sun, 7 Jun 2015 12:28:34 +0100 Subject: [PATCH] Make the SSDP registry minimally useful. --- .../example_ssdp_registry.go | 27 ++++ ssdp/registry.go | 132 ++++++++++++++++-- 2 files changed, 148 insertions(+), 11 deletions(-) create mode 100644 cmd/example_ssdp_registry/example_ssdp_registry.go diff --git a/cmd/example_ssdp_registry/example_ssdp_registry.go b/cmd/example_ssdp_registry/example_ssdp_registry.go new file mode 100644 index 0000000..05f0df0 --- /dev/null +++ b/cmd/example_ssdp_registry/example_ssdp_registry.go @@ -0,0 +1,27 @@ +package main + +import ( + "log" + + "github.com/huin/goupnp/ssdp" +) + +func main() { + c := make(chan ssdp.Update) + srv, reg := ssdp.NewServerAndRegistry() + reg.AddListener(c) + go listener(c) + if err := srv.ListenAndServe(); err != nil { + log.Print("ListenAndServe failed: ", err) + } +} + +func listener(c <-chan ssdp.Update) { + for u := range c { + if u.Entry != nil { + log.Printf("Event: %v USN: %s Entry: %#v", u.EventType, u.USN, *u.Entry) + } else { + log.Printf("Event: %v USN: %s Entry: ", u.EventType, u.USN) + } + } +} diff --git a/ssdp/registry.go b/ssdp/registry.go index 38d1020..2f84bea 100644 --- a/ssdp/registry.go +++ b/ssdp/registry.go @@ -21,6 +21,40 @@ var ( maxAgeRx = regexp.MustCompile("max-age=([0-9]+)") ) +const ( + EventAlive = EventType(iota) + EventUpdate + EventByeBye +) + +type EventType int8 + +func (et EventType) String() string { + switch et { + case EventAlive: + return "EventAlive" + case EventUpdate: + return "EventUpdate" + case EventByeBye: + return "EventByeBye" + default: + return fmt.Sprintf("EventUnknown(%d)", int8(et)) + } +} + +type Update struct { + // The USN of the service. + USN string + // What happened. + EventType EventType + // The entry, which is nil if the service was not known and + // EventType==EventByeBye. The contents of this must not be modified as it is + // shared with the registry and other listeners. Once created, the Registry + // does not modify the Entry value - any updates are replaced with a new + // Entry value. + Entry *Entry +} + type Entry struct { // The address that the entry data was actually received from. RemoteAddr string @@ -32,7 +66,7 @@ type Entry struct { Server string Host string // Location of the UPnP root device description. - Location *url.URL + Location url.URL // Despite BOOTID,CONFIGID being required fields, apparently they are not // always set by devices. Set to -1 if not present. @@ -83,7 +117,7 @@ func newEntryFromRequest(r *http.Request) (*Entry, error) { NT: r.Header.Get("NT"), Server: r.Header.Get("SERVER"), Host: r.Header.Get("HOST"), - Location: loc, + Location: *loc, BootID: bootID, ConfigID: configID, SearchPort: uint16(searchPort), @@ -125,17 +159,73 @@ func parseUpnpIntHeader(headers http.Header, headerName string, def int32) (int3 var _ httpu.Handler = new(Registry) // Registry maintains knowledge of discovered devices and services. +// +// NOTE: the interface for this is experimental and may change, or go away +// entirely. type Registry struct { lock sync.Mutex byUSN map[string]*Entry + + listenersLock sync.RWMutex + listeners map[chan<- Update]struct{} } func NewRegistry() *Registry { return &Registry{ - byUSN: make(map[string]*Entry), + byUSN: make(map[string]*Entry), + listeners: make(map[chan<- Update]struct{}), } } +// NewServerAndRegistry is a convenience function to create a registry, and an +// httpu server to pass it messages. Call ListenAndServe on the server for +// messages to be processed. +func NewServerAndRegistry() (*httpu.Server, *Registry) { + reg := NewRegistry() + srv := &httpu.Server{ + Addr: ssdpUDP4Addr, + Multicast: true, + Handler: reg, + } + return srv, reg +} + +func (reg *Registry) AddListener(c chan<- Update) { + reg.listenersLock.Lock() + defer reg.listenersLock.Unlock() + reg.listeners[c] = struct{}{} +} + +func (reg *Registry) RemoveListener(c chan<- Update) { + reg.listenersLock.Lock() + defer reg.listenersLock.Unlock() + delete(reg.listeners, c) +} + +func (reg *Registry) sendUpdate(u Update) { + reg.listenersLock.RLock() + defer reg.listenersLock.RUnlock() + for c := range reg.listeners { + c <- u + } +} + +// GetService returns known service (or device) entries for the given service +// URN. +func (reg *Registry) GetService(serviceURN string) []*Entry { + // Currently assumes that the map is small, so we do a linear search rather + // than indexed to avoid maintaining two maps. + var results []*Entry + reg.lock.Lock() + defer reg.lock.Unlock() + for _, entry := range reg.byUSN { + if entry.NT == serviceURN { + results = append(results, entry) + } + } + return results +} + // ServeMessage implements httpu.Handler, and uses SSDP NOTIFY requests to // maintain the registry of devices and services. func (reg *Registry) ServeMessage(r *http.Request) { @@ -156,7 +246,9 @@ func (reg *Registry) ServeMessage(r *http.Request) { default: err = fmt.Errorf("unknown NTS value: %q", nts) } - log.Printf("In %s request from %s: %v", nts, r.RemoteAddr, err) + if err != nil { + log.Printf("goupnp/ssdp: failed to handle %s message from %s: %v", nts, r.RemoteAddr, err) + } } func (reg *Registry) handleNTSAlive(r *http.Request) error { @@ -166,9 +258,14 @@ func (reg *Registry) handleNTSAlive(r *http.Request) error { } reg.lock.Lock() - defer reg.lock.Unlock() - reg.byUSN[entry.USN] = entry + reg.lock.Unlock() + + reg.sendUpdate(Update{ + USN: entry.USN, + EventType: EventAlive, + Entry: entry, + }) return nil } @@ -185,18 +282,31 @@ func (reg *Registry) handleNTSUpdate(r *http.Request) error { entry.BootID = nextBootID reg.lock.Lock() - defer reg.lock.Unlock() - reg.byUSN[entry.USN] = entry + reg.lock.Unlock() + + reg.sendUpdate(Update{ + USN: entry.USN, + EventType: EventUpdate, + Entry: entry, + }) return nil } func (reg *Registry) handleNTSByebye(r *http.Request) error { - reg.lock.Lock() - defer reg.lock.Unlock() + usn := r.Header.Get("USN") - delete(reg.byUSN, r.Header.Get("USN")) + reg.lock.Lock() + entry := reg.byUSN[usn] + delete(reg.byUSN, usn) + reg.lock.Unlock() + + reg.sendUpdate(Update{ + USN: usn, + EventType: EventByeBye, + Entry: entry, + }) return nil }