implement auth, closed and close envelopes

pkg/encoders/envelopes/closeenvelope/closeenvelope.go

@@ -0,0 +1,78 @@
+// Package closeenvelope provides the encoder for the client message CLOSE which
+// is a request to terminate a subscription.
+package closeenvelope
+
+import (
+	"io"
+
+	"lol.mleku.dev/chk"
+	"next.orly.dev/pkg/encoders/envelopes"
+	"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 = "CLOSE"
+
+// T is a CLOSE envelope, which is a signal from client to relay to stop a
+// specified subscription.
+type T struct {
+	ID []byte
+}
+
+var _ codec.Envelope = (*T)(nil)
+
+// New creates an empty new standard formatted closeenvelope.T.
+func New() *T { return new(T) }
+
+// NewFrom creates a new closeenvelope.T populated with subscription ID.
+func NewFrom(id []byte) *T { return &T{ID: id} }
+
+// Label returns the label of a closeenvelope.T.
+func (en *T) Label() string { return L }
+
+// Write the closeenvelope.T to a provided io.Writer.
+func (en *T) Write(w io.Writer) (err error) {
+	_, err = w.Write(en.Marshal(nil))
+	return
+}
+
+// Marshal a closeenvelope.T envelope in minified JSON, appending to a provided
+// destination slice.
+func (en *T) Marshal(dst []byte) (b []byte) {
+	b = dst
+	b = envelopes.Marshal(
+		b, L,
+		func(bst []byte) (o []byte) {
+			o = bst
+			o = append(o, '"')
+			o = append(o, en.ID...)
+			o = append(o, '"')
+			return
+		},
+	)
+	return
+}
+
+// Unmarshal a closeenvelope.T from minified JSON, returning the remainder after
+// the end of the envelope.
+func (en *T) Unmarshal(b []byte) (r []byte, err error) {
+	r = b
+	if en.ID, r, err = text.UnmarshalQuoted(r); chk.E(err) {
+		return
+	}
+	if r, err = envelopes.SkipToTheEnd(r); chk.E(err) {
+		return
+	}
+	return
+}
+
+// Parse reads a CLOSE envelope from minified JSON into a newly allocated
+// closeenvelope.T.
+func Parse(b []byte) (t *T, rem []byte, err error) {
+	t = New()
+	if rem, err = t.Unmarshal(b); chk.E(err) {
+		return
+	}
+	return
+}