Wrote roots-ws golang implementation.

envelope/envelope.go

@@ -0,0 +1,55 @@
+// Package envelope provides types and functions for working with Nostr protocol
+// websocket messages. It defines the Envelope type representing a Nostr message
+// and offers utilities for creating, parsing, and validating standardized message
+// formats.
+package envelope
+
+import (
+	"encoding/json"
+	"fmt"
+	"git.wisehodl.dev/jay/go-roots-ws/errors"
+)
+
+// Envelope represents a Nostr websocket message.
+type Envelope []byte
+
+// GetLabel extracts the message label from an envelope.
+// Returns the label as a string or an error if the envelope is malformed.
+func GetLabel(env Envelope) (string, error) {
+	var arr []json.RawMessage
+	if err := json.Unmarshal(env, &arr); err != nil {
+		return "", fmt.Errorf("%w: %v", errors.InvalidJSON, err)
+	}
+
+	if len(arr) < 1 {
+		return "", fmt.Errorf("%w: empty envelope", errors.InvalidEnvelope)
+	}
+
+	var label string
+	if err := json.Unmarshal(arr[0], &label); err != nil {
+		return "", fmt.Errorf("%w: label is not a string", errors.WrongFieldType)
+	}
+
+	return label, nil
+}
+
+// GetStandardLabels returns a set of standard Nostr websocket message labels
+func GetStandardLabels() map[string]struct{} {
+	return map[string]struct{}{
+		"EVENT":  {},
+		"REQ":    {},
+		"CLOSE":  {},
+		"CLOSED": {},
+		"EOSE":   {},
+		"NOTICE": {},
+		"OK":     {},
+		"AUTH":   {},
+	}
+}
+
+// IsStandardLabel checks if the given label is a standard Nostr websocket message label
+func IsStandardLabel(label string) bool {
+	labels := GetStandardLabels()
+	_, ok := labels[label]
+	return ok
+}