Wrote roots-ws golang implementation.

envelope/find.go

@@ -0,0 +1,324 @@
+package envelope
+
+import (
+	"encoding/json"
+	"fmt"
+	"git.wisehodl.dev/jay/go-roots-ws/errors"
+)
+
+// CheckArrayLength is a helper function that ensures the JSON array has at
+// least the minimum length required
+func CheckArrayLength(arr []json.RawMessage, minLen int) error {
+	if len(arr) < minLen {
+		return fmt.Errorf("%w: expected %d elements, got %d", errors.InvalidEnvelope, minLen, len(arr))
+	}
+	return nil
+}
+
+// CheckLabel is a helper function that verifies that the envelope label
+// matches the expected one
+func CheckLabel(got, want string) error {
+	if got != want {
+		return fmt.Errorf("%w: expected %s, got %s", errors.WrongEnvelopeLabel, want, got)
+	}
+	return nil
+}
+
+// ParseElement is a helper function that unmarshals an array element into the
+// provided value
+func ParseElement(element json.RawMessage, value interface{}, position string) error {
+	if err := json.Unmarshal(element, value); err != nil {
+		return fmt.Errorf("%w: %s is not the expected type", errors.WrongFieldType, position)
+	}
+	return nil
+}
+
+// FindEvent extracts an event from an EVENT envelope with no subscription ID.
+// Expected Format: ["EVENT", event]
+func FindEvent(env Envelope) ([]byte, error) {
+	var arr []json.RawMessage
+	if err := json.Unmarshal(env, &arr); err != nil {
+		return nil, fmt.Errorf("%w: %v", errors.InvalidJSON, err)
+	}
+
+	if err := CheckArrayLength(arr, 2); err != nil {
+		return nil, err
+	}
+
+	var label string
+	if err := ParseElement(arr[0], &label, "envelope label"); err != nil {
+		return nil, err
+	}
+
+	if err := CheckLabel(label, "EVENT"); err != nil {
+		return nil, err
+	}
+
+	return arr[1], nil
+}
+
+// FindSubscriptionEvent extracts an event and subscription ID from an EVENT envelope.
+// Expected Format: ["EVENT", subID, event]
+func FindSubscriptionEvent(env Envelope) (subID string, event []byte, err error) {
+	var arr []json.RawMessage
+	if err = json.Unmarshal(env, &arr); err != nil {
+		return "", nil, fmt.Errorf("%w: %v", errors.InvalidJSON, err)
+	}
+
+	if err = CheckArrayLength(arr, 3); err != nil {
+		return "", nil, err
+	}
+
+	var label string
+	if err := ParseElement(arr[0], &label, "envelope label"); err != nil {
+		return "", nil, err
+	}
+
+	if err = CheckLabel(label, "EVENT"); err != nil {
+		return "", nil, err
+	}
+
+	if err = ParseElement(arr[1], &subID, "subscription ID"); err != nil {
+		return "", nil, err
+	}
+
+	return subID, arr[2], nil
+}
+
+// FindOK extracts eventID, status, and message from an OK envelope.
+// Expected Format: ["OK", eventID, status, message]
+func FindOK(env Envelope) (eventID string, status bool, message string, err error) {
+	var arr []json.RawMessage
+	if err = json.Unmarshal(env, &arr); err != nil {
+		return "", false, "", fmt.Errorf("%w: %v", errors.InvalidJSON, err)
+	}
+
+	if err = CheckArrayLength(arr, 4); err != nil {
+		return "", false, "", err
+	}
+
+	var label string
+	if err := ParseElement(arr[0], &label, "envelope label"); err != nil {
+		return "", false, "", err
+	}
+
+	if err = CheckLabel(label, "OK"); err != nil {
+		return "", false, "", err
+	}
+
+	if err = ParseElement(arr[1], &eventID, "event ID"); err != nil {
+		return "", false, "", err
+	}
+
+	if err = ParseElement(arr[2], &status, "status"); err != nil {
+		return "", false, "", err
+	}
+
+	if err = ParseElement(arr[3], &message, "message"); err != nil {
+		return "", false, "", err
+	}
+
+	return eventID, status, message, nil
+}
+
+// FindReq extracts subscription ID and filters from a REQ envelope.
+// Expected Format: ["REQ", subID, filter1, filter2, ...]
+func FindReq(env Envelope) (subID string, filters [][]byte, err error) {
+	var arr []json.RawMessage
+	if err = json.Unmarshal(env, &arr); err != nil {
+		return "", nil, fmt.Errorf("%w: %v", errors.InvalidJSON, err)
+	}
+
+	if err = CheckArrayLength(arr, 2); err != nil {
+		return "", nil, err
+	}
+
+	var label string
+	if err := ParseElement(arr[0], &label, "envelope label"); err != nil {
+		return "", nil, err
+	}
+
+	if err = CheckLabel(label, "REQ"); err != nil {
+		return "", nil, err
+	}
+
+	if err = ParseElement(arr[1], &subID, "subscription ID"); err != nil {
+		return "", nil, err
+	}
+
+	filters = make([][]byte, 0, len(arr)-2)
+	for i := 2; i < len(arr); i++ {
+		filters = append(filters, arr[i])
+	}
+
+	return subID, filters, nil
+}
+
+// FindEOSE extracts subscription ID from an EOSE envelope.
+// Expected Format: ["EOSE", subID]
+func FindEOSE(env Envelope) (subID string, err error) {
+	var arr []json.RawMessage
+	if err = json.Unmarshal(env, &arr); err != nil {
+		return "", fmt.Errorf("%w: %v", errors.InvalidJSON, err)
+	}
+
+	if err = CheckArrayLength(arr, 2); err != nil {
+		return "", err
+	}
+
+	var label string
+	if err := ParseElement(arr[0], &label, "envelope label"); err != nil {
+		return "", err
+	}
+
+	if err = CheckLabel(label, "EOSE"); err != nil {
+		return "", err
+	}
+
+	if err = ParseElement(arr[1], &subID, "subscription ID"); err != nil {
+		return "", err
+	}
+
+	return subID, nil
+}
+
+// FindClose extracts subscription ID from a CLOSE envelope.
+// Expected Format: ["CLOSE", subID]
+func FindClose(env Envelope) (subID string, err error) {
+	var arr []json.RawMessage
+	if err = json.Unmarshal(env, &arr); err != nil {
+		return "", fmt.Errorf("%w: %v", errors.InvalidJSON, err)
+	}
+
+	if err = CheckArrayLength(arr, 2); err != nil {
+		return "", err
+	}
+
+	var label string
+	if err := ParseElement(arr[0], &label, "envelope label"); err != nil {
+		return "", err
+	}
+
+	if err = CheckLabel(label, "CLOSE"); err != nil {
+		return "", err
+	}
+
+	if err = ParseElement(arr[1], &subID, "subscription ID"); err != nil {
+		return "", err
+	}
+
+	return subID, nil
+}
+
+// FindClosed extracts subscription ID and message from a CLOSED envelope.
+// Expected Format: ["CLOSED", subID, message]
+func FindClosed(env Envelope) (subID string, message string, err error) {
+	var arr []json.RawMessage
+	if err = json.Unmarshal(env, &arr); err != nil {
+		return "", "", fmt.Errorf("%w: %v", errors.InvalidJSON, err)
+	}
+
+	if err = CheckArrayLength(arr, 3); err != nil {
+		return "", "", err
+	}
+
+	var label string
+	if err := ParseElement(arr[0], &label, "envelope label"); err != nil {
+		return "", "", err
+	}
+
+	if err = CheckLabel(label, "CLOSED"); err != nil {
+		return "", "", err
+	}
+
+	if err = ParseElement(arr[1], &subID, "subscription ID"); err != nil {
+		return "", "", err
+	}
+
+	if err = ParseElement(arr[2], &message, "message"); err != nil {
+		return "", "", err
+	}
+
+	return subID, message, nil
+}
+
+// FindNotice extracts message from a NOTICE envelope.
+// Expected Format: ["NOTICE", message]
+func FindNotice(env Envelope) (message string, err error) {
+	var arr []json.RawMessage
+	if err = json.Unmarshal(env, &arr); err != nil {
+		return "", fmt.Errorf("%w: %v", errors.InvalidJSON, err)
+	}
+
+	if err = CheckArrayLength(arr, 2); err != nil {
+		return "", err
+	}
+
+	var label string
+	if err := ParseElement(arr[0], &label, "envelope label"); err != nil {
+		return "", err
+	}
+
+	if err = CheckLabel(label, "NOTICE"); err != nil {
+		return "", err
+	}
+
+	if err = ParseElement(arr[1], &message, "message"); err != nil {
+		return "", err
+	}
+
+	return message, nil
+}
+
+// FindAuthChallenge extracts challenge from an AUTH challenge envelope.
+// Expected Format: ["AUTH", challenge]
+func FindAuthChallenge(env Envelope) (challenge string, err error) {
+	var arr []json.RawMessage
+	if err = json.Unmarshal(env, &arr); err != nil {
+		return "", fmt.Errorf("%w: %v", errors.InvalidJSON, err)
+	}
+
+	if err = CheckArrayLength(arr, 2); err != nil {
+		return "", err
+	}
+
+	var label string
+	if err := ParseElement(arr[0], &label, "envelope label"); err != nil {
+		return "", err
+	}
+
+	if err = CheckLabel(label, "AUTH"); err != nil {
+		return "", err
+	}
+
+	// Check if the second element is a string (AUTH challenge)
+	if err = ParseElement(arr[1], &challenge, "challenge"); err != nil {
+		return "", err
+	}
+
+	return challenge, nil
+}
+
+// FindAuthResponse extracts event from an AUTH response envelope.
+// Expected Format: ["AUTH", event]
+func FindAuthResponse(env Envelope) (event []byte, err error) {
+	var arr []json.RawMessage
+	if err = json.Unmarshal(env, &arr); err != nil {
+		return nil, fmt.Errorf("%w: %v", errors.InvalidJSON, err)
+	}
+
+	if err = CheckArrayLength(arr, 2); err != nil {
+		return nil, err
+	}
+
+	var label string
+	if err := ParseElement(arr[0], &label, "envelope label"); err != nil {
+		return nil, err
+	}
+
+	if err = CheckLabel(label, "AUTH"); err != nil {
+		return nil, err
+	}
+
+	return arr[1], nil
+}