# go-coap
**Repository Path**: itcloudy/go-coap
## Basic Information
- **Project Name**: go-coap
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: Apache-2.0
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No
## Statistics
- **Stars**: 0
- **Forks**: 0
- **Created**: 2024-01-24
- **Last Updated**: 2024-01-24
## Categories & Tags
**Categories**: Uncategorized
**Tags**: None
## README
# Go-CoAP
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[](https://pkg.go.dev/github.com/plgd-dev/go-coap/v3?utm_source=godoc)
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].
* CoAP over TCP/TLS [RFC 8232][coap-tcp]
* Observe resources in CoAP [RFC 7641][coap-observe]
* Block-wise transfers in CoAP [RFC 7959][coap-block-wise-transfers]
* request multiplexer
* multicast
* CoAP NoResponse option in CoAP [RFC 7967][coap-noresponse]
* CoAP over DTLS [pion/dtls][pion-dtls]
* Too many requests response code [RFC 8516][coap-429]
[coap]: http://tools.ietf.org/html/rfc7252
[coap-tcp]: https://tools.ietf.org/html/rfc8323
[coap-block-wise-transfers]: https://tools.ietf.org/html/rfc7959
[coap-observe]: https://tools.ietf.org/html/rfc7641
[coap-noresponse]: https://tools.ietf.org/html/rfc7967
[pion-dtls]: https://github.com/pion/dtls
[coap-429]: https://datatracker.ietf.org/doc/html/rfc8516
## Requirements
* Go 1.20 or higher
## Samples
### Simple
#### Server UDP/TCP
```go
// 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
```go
// 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](examples/observe/server/main.go) example.
[Client](examples/observe/client/main.go) example.
### Multicast
[Server](examples/mcast/server/main.go) example.
[Client](examples/mcast/client/main.go) example.
## License
Apache 2.0
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Sponsors
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Backers
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