add NOTICE and OK envelope encoders with marshal/unmarshal support and comprehensive tests

pkg/encoders/envelopes/okenvelope/okenvelope.go

@@ -0,0 +1,133 @@
+// Package okenvelope is a codec for the OK message, which is an acknowledgement
+// for an EVENT eventenvelope.Submission, containing true/false and if false a
+// message with a machine readable error type as found in the messages package.
+package okenvelope
+
+import (
+	"io"
+
+	"lol.mleku.dev/chk"
+	"lol.mleku.dev/errorf"
+	"lol.mleku.dev/log"
+	"next.orly.dev/pkg/crypto/sha256"
+	"next.orly.dev/pkg/encoders/envelopes"
+	"next.orly.dev/pkg/encoders/hex"
+	"next.orly.dev/pkg/encoders/text"
+	"next.orly.dev/pkg/interfaces/codec"
+)
+
+// L is the label associated with this type of codec.Envelope.
+const L = "OK"
+
+// T is an OK envelope, used to signal acceptance or rejection, with a reason,
+// to an eventenvelope.Submission.
+type T struct {
+	EventID []byte
+	OK      bool
+	Reason  []byte
+}
+
+var _ codec.Envelope = (*T)(nil)
+
+// New creates a new empty OK T.
+func New() *T { return &T{} }
+
+// NewFrom creates a new okenvelope.T with a string for the subscription.Id and
+// the optional reason.
+func NewFrom[V string | []byte](eid V, ok bool, msg ...V) *T {
+	var m []byte
+	if len(msg) > 0 {
+		m = []byte(msg[0])
+	}
+	if len(eid) != sha256.Size {
+		log.W.F(
+			"event ID unexpected length, expect %d got %d",
+			len(eid), sha256.Size,
+		)
+	}
+	return &T{EventID: []byte(eid), OK: ok, Reason: m}
+}
+
+// Label returns the label of an okenvelope.T.
+func (en *T) Label() string { return L }
+
+// ReasonString returns the Reason in the form of a string.
+func (en *T) ReasonString() string { return string(en.Reason) }
+
+// Write the okenvelope.T to a provided io.Writer.
+func (en *T) Write(w io.Writer) (err error) {
+	_, err = w.Write(en.Marshal(nil))
+	return
+}
+
+// Marshal a okenvelope.T from minified JSON, appending to a provided
+// destination slice. Note that this ensures correct string escaping on the
+// subscription.Id and Reason fields.
+func (en *T) Marshal(dst []byte) (b []byte) {
+	var err error
+	_ = err
+	b = dst
+	b = envelopes.Marshal(
+		b, L,
+		func(bst []byte) (o []byte) {
+			o = bst
+			o = append(o, '"')
+			o = hex.EncAppend(o, en.EventID)
+			o = append(o, '"')
+			o = append(o, ',')
+			o = text.MarshalBool(o, en.OK)
+			o = append(o, ',')
+			o = append(o, '"')
+			o = text.NostrEscape(o, en.Reason)
+			o = append(o, '"')
+			return
+		},
+	)
+	return
+}
+
+// Unmarshal a okenvelope.T from minified JSON, returning the remainder after
+// the end of the envelope. Note that this ensures the Reason and
+// subscription.Id strings are correctly unescaped by NIP-01 escaping rules.
+func (en *T) Unmarshal(b []byte) (r []byte, err error) {
+	r = b
+	var idBytes []byte
+	// Parse event id as quoted hex (NIP-20 compliant)
+	if idBytes, r, err = text.UnmarshalHex(r); err != nil {
+		return
+	}
+	if len(idBytes) != sha256.Size {
+		err = errorf.E(
+			"invalid size for ID, require %d got %d",
+			sha256.Size, len(idBytes),
+		)
+		return
+	}
+	en.EventID = idBytes
+	if r, err = text.Comma(r); chk.E(err) {
+		return
+	}
+	if r, en.OK, err = text.UnmarshalBool(r); chk.E(err) {
+		return
+	}
+	if r, err = text.Comma(r); chk.E(err) {
+		return
+	}
+	if en.Reason, r, err = text.UnmarshalQuoted(r); chk.E(err) {
+		return
+	}
+	if r, err = envelopes.SkipToTheEnd(r); chk.E(err) {
+		return
+	}
+	return
+}
+
+// Parse reads a OK envelope in minified JSON into a newly allocated
+// okenvelope.T.
+func Parse(b []byte) (t *T, rem []byte, err error) {
+	t = New()
+	if rem, err = t.Unmarshal(b); chk.E(err) {
+		return
+	}
+	return
+}