Add login and post cache helpers

cache.go

@@ -0,0 +1,59 @@
+package writefreely
+
+import (
+	"sync"
+	"time"
+)
+
+const (
+	postsCacheTime = 4 * time.Second
+)
+
+type (
+	postsCacheItem struct {
+		Expire time.Time
+		Posts  *[]PublicPost
+		ready  chan struct{}
+	}
+
+	AuthCache struct {
+		Alias, Pass, Token string
+		BadPasses          map[string]bool
+
+		expire time.Time
+	}
+)
+
+var (
+	userPostsCache = struct {
+		sync.RWMutex
+		users map[int64]postsCacheItem
+	}{
+		users: map[int64]postsCacheItem{},
+	}
+)
+
+func CachePosts(userID int64, p *[]PublicPost) {
+	close(userPostsCache.users[userID].ready)
+	userPostsCache.Lock()
+	userPostsCache.users[userID] = postsCacheItem{
+		Expire: time.Now().Add(postsCacheTime),
+		Posts:  p,
+	}
+	userPostsCache.Unlock()
+}
+
+func GetPostsCache(userID int64) *[]PublicPost {
+	userPostsCache.RLock()
+	pci, ok := userPostsCache.users[userID]
+	userPostsCache.RUnlock()
+	if !ok {
+		return nil
+	}
+
+	if pci.Expire.Before(time.Now()) {
+		// Cache is expired
+		return nil
+	}
+	return pci.Posts
+}