initial interface for notifications

app/rest/cache.go

@@ -24,6 +24,7 @@ func NewLoadingCache(defaultExpiration, cleanupInterval time.Duration, postFlush
 	return &loadingCache{bytesCache: cache.New(defaultExpiration, cleanupInterval), postFlushFn: postFlushFn}
 }
 
+// Get is loading cache method to get value by key or load via fn if not found
 func (lc *loadingCache) Get(key string, ttl time.Duration, fn func() ([]byte, error)) (data []byte, err error) {
 	if b, ok := lc.bytesCache.Get(key); ok {
 		log.Printf("[DEBUG] cache hit %s", key)
@@ -38,6 +39,7 @@ func (lc *loadingCache) Get(key string, ttl time.Duration, fn func() ([]byte, er
 	return data, nil
 }
 
+// Flush clears cache and calls postFlushFn async
 func (lc *loadingCache) Flush() {
 	lc.bytesCache.Flush()
 	if lc.postFlushFn != nil {

app/store/comment.go

@@ -58,6 +58,12 @@ type BlockedUser struct {
 	Timestamp time.Time `json:"time"`
 }
 
+// NotifUser holds id and destination for notifiable user
+type NotifUser struct {
+	ID          string `json:"id"`
+	Destination string `json:"destination"`
+}
+
 // Sanitize clean dangerous html/js from the comment
 func (c *Comment) Sanitize() {
 	p := bluemonday.UGCPolicy()

app/store/store.go

@@ -33,6 +33,23 @@ type Admin interface {
 	Blocked(siteID string) ([]BlockedUser, error)             // get list of blocked users
 }
 
+// Notifier defines all store ops for update modifications
+type Notifier interface {
+	Set(locator Locator, user NotifUser, scope NotifScope, status bool) error // subscribe / unsubscribe user to locator updates
+	Status(locator Locator, userID string) bool                               // get subscription status for user & locator
+	List(locator Locator) ([]NotifUser, error)                                // list all subscribed users
+}
+
+// NotifScope defines "enum" of notification scopes
+type NotifScope int
+
+// All NotifScope values
+const (
+	ScopeSite  NotifScope = 1
+	ScopePost  NotifScope = 2
+	ScopeReply NotifScope = 3
+)
+
 func sortComments(comments []Comment, sortFld string) []Comment {
 	sort.Slice(comments, func(i, j int) bool {
 		switch sortFld {