nip27 parsing improved (and with nip08 support removed) in its own package.

nip27/references.go

@@ -0,0 +1,78 @@
+package nip27
+
+import (
+	"iter"
+	"regexp"
+
+	"github.com/nbd-wtf/go-nostr"
+	"github.com/nbd-wtf/go-nostr/nip19"
+)
+
+type Reference struct {
+	Text    string
+	Start   int
+	End     int
+	Profile *nostr.ProfilePointer
+	Event   *nostr.EventPointer
+	Entity  *nostr.EntityPointer
+}
+
+var mentionRegex = regexp.MustCompile(`\bnostr:((note|npub|naddr|nevent|nprofile)1\w+)\b`)
+
+func ParseReferences(evt nostr.Event) iter.Seq[Reference] {
+	return func(yield func(Reference) bool) {
+		for _, ref := range mentionRegex.FindAllStringSubmatchIndex(evt.Content, -1) {
+			reference := Reference{
+				Text:  evt.Content[ref[0]:ref[1]],
+				Start: ref[0],
+				End:   ref[1],
+			}
+
+			nip19code := evt.Content[ref[2]:ref[3]]
+
+			if prefix, data, err := nip19.Decode(nip19code); err == nil {
+				switch prefix {
+				case "npub":
+					reference.Profile = &nostr.ProfilePointer{
+						PublicKey: data.(string), Relays: []string{},
+					}
+					tag := evt.Tags.GetFirst([]string{"p", reference.Profile.PublicKey})
+					if tag != nil && len(*tag) >= 3 {
+						reference.Profile.Relays = []string{(*tag)[2]}
+					}
+				case "nprofile":
+					pp := data.(nostr.ProfilePointer)
+					reference.Profile = &pp
+					tag := evt.Tags.GetFirst([]string{"p", reference.Profile.PublicKey})
+					if tag != nil && len(*tag) >= 3 {
+						reference.Profile.Relays = append(reference.Profile.Relays, (*tag)[2])
+					}
+				case "note":
+					// we don't even bother here because people using note1 codes aren't including relay hints anyway
+					reference.Event = &nostr.EventPointer{ID: data.(string), Relays: []string{}}
+				case "nevent":
+					evp := data.(nostr.EventPointer)
+					reference.Event = &evp
+					tag := evt.Tags.GetFirst([]string{"e", reference.Event.ID})
+					if tag != nil && len(*tag) >= 3 {
+						reference.Event.Relays = append(reference.Event.Relays, (*tag)[2])
+						if reference.Event.Author == "" && len(*tag) >= 5 {
+							reference.Event.Author = (*tag)[4]
+						}
+					}
+				case "naddr":
+					addr := data.(nostr.EntityPointer)
+					reference.Entity = &addr
+					tag := evt.Tags.GetFirst([]string{"a", reference.Entity.AsTagReference()})
+					if tag != nil && len(*tag) >= 3 {
+						reference.Entity.Relays = append(reference.Entity.Relays, (*tag)[2])
+					}
+				}
+			}
+
+			if !yield(reference) {
+				return
+			}
+		}
+	}
+}