go-nostr

A set of useful things for Nostr Protocol implementations.

go get github.com/nbd-wtf/go-nostr

Generating a key

package main

import (
    "fmt"

    "github.com/nbd-wtf/go-nostr"
    "github.com/nbd-wtf/go-nostr/nip19"
)

func main() {
    sk := nostr.GeneratePrivateKey()
    pk, _ := nostr.GetPublicKey(sk)
    nsec, _ := nip19.EncodePrivateKey(sk)
    npub, _ := nip19.EncodePublicKey(pk)

    fmt.Println("sk:", sk)
    fmt.Println("pk:", pk)
    fmt.Println(nsec)
    fmt.Println(npub)
}

Subscribing to a single relay

ctx := context.Background()
relay, err := nostr.RelayConnect(ctx, "wss://relay.stoner.com")
if err != nil {
	panic(err)
}

npub := "npub1422a7ws4yul24p0pf7cacn7cghqkutdnm35z075vy68ggqpqjcyswn8ekc"

var filters nostr.Filters
if _, v, err := nip19.Decode(npub); err == nil {
	pub := v.(string)
	filters = []nostr.Filter{{
		Kinds:   []int{nostr.KindTextNote},
		Authors: []string{pub},
		Limit:   1,
	}}
} else {
	panic(err)
}

ctx, cancel := context.WithTimeout(ctx, 3*time.Second)
defer cancel()

sub, err := relay.Subscribe(ctx, filters)
if err != nil {
	panic(err)
}

for ev := range sub.Events {
	// handle returned event.
	// channel will stay open until the ctx is cancelled (in this case, context timeout)
	fmt.Println(ev.ID)
}

Publishing to two relays

sk := nostr.GeneratePrivateKey()
pub, _ := nostr.GetPublicKey(sk)

ev := nostr.Event{
	PubKey:    pub,
	CreatedAt: nostr.Now(),
	Kind:      nostr.KindTextNote,
	Tags:      nil,
	Content:   "Hello World!",
}

// calling Sign sets the event ID field and the event Sig field
ev.Sign(sk)

// publish the event to two relays
ctx := context.Background()
for _, url := range []string{"wss://relay.stoner.com", "wss://nostr-pub.wellorder.net"} {
	relay, err := nostr.RelayConnect(ctx, url)
	if err != nil {
		fmt.Println(err)
		continue
	}
	if err := relay.Publish(ctx, ev); err != nil {
		fmt.Println(err)
		continue
	}

	fmt.Printf("published to %s\n", url)
}

Logging

To get more logs from the interaction with relays printed to STDOUT you can compile or run your program with -tags debug.

To remove the info logs completely, replace nostr.InfoLogger with something that prints nothing, like

nostr.InfoLogger = log.New(io.Discard, "", 0)

Example script

go run example/example.go

Using libsecp256k1

libsecp256k1 is very fast:

goos: linux
goarch: amd64
cpu: Intel(R) Core(TM) i5-2400 CPU @ 3.10GHz
BenchmarkWithoutLibsecp256k1/sign-4          	    2794	    434114 ns/op
BenchmarkWithoutLibsecp256k1/check-4         	    4352	    297416 ns/op
BenchmarkWithLibsecp256k1/sign-4             	   12559	     94607 ns/op
BenchmarkWithLibsecp256k1/check-4            	   13761	     84595 ns/op
PASS

But to use it you need the host to have it installed as a shared library and CGO to be supported, so we don't compile against it by default.

To use it, use -tags=libsecp256k1 whenever you're compiling your program that uses this library.

Warning: risk of goroutine bloat (if used incorrectly)

Remember to cancel subscriptions, either by calling .Unsub() on them or ensuring their context.Context will be canceled at some point. If you don't do that they will keep creating a new goroutine for every new event that arrives and if you have stopped listening on the sub.Events channel that will cause chaos and doom in your program.

Contributing to this repository

Use NIP-34 to send your patches to naddr1qqyxwmeddehhxarjqy28wumn8ghj7un9d3shjtnyv9kh2uewd9hsz9nhwden5te0wfjkccte9ehx7um5wghxyctwvsq3vamnwvaz7tmjv4kxz7fwwpexjmtpdshxuet5qgsrhuxx8l9ex335q7he0f09aej04zpazpl0ne2cgukyawd24mayt8grqsqqqaueuwmljc.