Awesome
Go-CoAP
<!-- [![Go Report](https://goreportcard.com/badge/github.com/plgd-dev/go-coap)](https://goreportcard.com/report/github.com/plgd-dev/go-coap) -->The Constrained Application Protocol (CoAP) is a specialized web transfer protocol for use with constrained nodes and constrained networks in the Internet of Things. The protocol is designed for machine-to-machine (M2M) applications such as smart energy and building automation.
The go-coap provides servers and clients for DTLS, TCP-TLS, UDP, TCP in golang language.
Features
- CoAP over UDP RFC 7252.
- CoAP over TCP/TLS RFC 8232
- Observe resources in CoAP RFC 7641
- Block-wise transfers in CoAP RFC 7959
- request multiplexer
- multicast
- CoAP NoResponse option in CoAP RFC 7967
- CoAP over DTLS pion/dtls
- Too many requests response code RFC 8516
Requirements
- Go 1.20 or higher
Samples
Simple
Server UDP/TCP
// Server
// Middleware function, which will be called for each request.
func loggingMiddleware(next mux.Handler) mux.Handler {
return mux.HandlerFunc(func(w mux.ResponseWriter, r *mux.Message) {
log.Printf("ClientAddress %v, %v\n", w.Conn().RemoteAddr(), r.String())
next.ServeCOAP(w, r)
})
}
// See /examples/simple/server/main.go
func handleA(w mux.ResponseWriter, req *mux.Message) {
err := w.SetResponse(codes.GET, message.TextPlain, bytes.NewReader([]byte("hello world")))
if err != nil {
log.Printf("cannot set response: %v", err)
}
}
func main() {
r := mux.NewRouter()
r.Use(loggingMiddleware)
r.Handle("/a", mux.HandlerFunc(handleA))
r.Handle("/b", mux.HandlerFunc(handleB))
log.Fatal(coap.ListenAndServe("udp", ":5688", r))
// for tcp
// log.Fatal(coap.ListenAndServe("tcp", ":5688", r))
// for tcp-tls
// log.Fatal(coap.ListenAndServeTLS("tcp", ":5688", &tls.Config{...}, r))
// for udp-dtls
// log.Fatal(coap.ListenAndServeDTLS("udp", ":5688", &dtls.Config{...}, r))
}
Client
// Client
// See /examples/simpler/client/main.go
func main() {
co, err := udp.Dial("localhost:5688")
// for tcp
// co, err := tcp.Dial("localhost:5688")
// for tcp-tls
// co, err := tcp.Dial("localhost:5688", tcp.WithTLS(&tls.Config{...}))
// for dtls
// co, err := dtls.Dial("localhost:5688", &dtls.Config{...}))
if err != nil {
log.Fatalf("Error dialing: %v", err)
}
ctx, cancel := context.WithTimeout(context.Background(), time.Second)
defer cancel()
resp, err := co.Get(ctx, "/a")
if err != nil {
log.Fatalf("Cannot get response: %v", err)
return
}
log.Printf("Response: %+v", resp)
}
Observe / Notify
Server example.
Client example.
Multicast
Server example.
Client example.
License
Apache 2.0
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