feat: improve caching

lib/cache/cache.go

@@ -0,0 +1,106 @@
+package cache
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"sync"
+	"time"
+
+	"github.com/isabelroses/izrss/lib"
+)
+
+// CacheEntry represents a cached item with its expiration time
+type CacheEntry struct {
+	Value      lib.Post  // Store Post object
+	Expiration time.Time // Expiration time
+}
+
+// Cache represents a cache with a map to store cached items
+type Cache struct {
+	data map[string]CacheEntry
+	dir  string
+	mu   sync.RWMutex
+}
+
+// NewCache creates a new instance of Cache
+func NewCache(dir string) *Cache {
+	return &Cache{
+		data: make(map[string]CacheEntry),
+		dir:  dir,
+	}
+}
+
+// Get retrieves a value from the cache by key
+func (c *Cache) Get(key string) (lib.Post, bool) {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	entry, found := c.data[key]
+	if !found {
+		return lib.Post{}, false
+	}
+
+	// Check if the entry has expired
+	if time.Now().After(entry.Expiration) {
+		// If expired, delete the entry from the cache
+		c.mu.Lock()
+		delete(c.data, key)
+		c.mu.Unlock()
+		return lib.Post{}, false
+	}
+
+	return entry.Value, true
+}
+
+// Set adds or updates a value in the cache with a specified expiration time
+func (c *Cache) Set(key string, value lib.Post, expiration time.Duration) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	c.data[key] = CacheEntry{
+		Value:      value,
+		Expiration: time.Now().Add(expiration),
+	}
+
+	// Save the cache entry to a file
+	c.saveToFile(key, value)
+}
+
+// saveToFile saves a cache entry to a file in the cache directory
+func (c *Cache) saveToFile(key string, value lib.Post) error {
+	data, err := json.Marshal(value)
+	if err != nil {
+		return err
+	}
+
+	filename := filepath.Join(c.dir, key+".json")
+	return os.WriteFile(filename, data, 0644)
+}
+
+// LoadCache loads cache entries from files in the cache directory
+func (c *Cache) LoadCache() error {
+	files, err := os.ReadDir(c.dir)
+	if err != nil {
+		return err
+	}
+
+	for _, file := range files {
+		if !file.IsDir() {
+			filename := filepath.Join(c.dir, file.Name())
+			data, err := os.ReadFile(filename)
+			if err != nil {
+				return err
+			}
+
+			var post lib.Post
+			if err := json.Unmarshal(data, &post); err != nil {
+				return err
+			}
+
+			c.Set(post.UUID, post, time.Until(post.Expiration))
+		}
+	}
+
+	return nil
+}

lib/feeds.go

@@ -4,13 +4,14 @@ import "sort"
 
 // Post represents a single post in a feed
 type Post struct {
-	UUID    string `json:"uuid"`
-	Title   string `json:"-"`
-	Content string `json:"-"`
-	Link    string `json:"-"`
-	Date    string `json:"-"`
-	ID      int    `json:"-"`
-	Read    bool   `json:"read"`
+	UUID       string `json:"uuid"`
+	Title      string `json:"-"`
+	Expiration string `json:"-"`
+	Content    string `json:"-"`
+	Link       string `json:"-"`
+	Date       string `json:"-"`
+	ID         int    `json:"-"`
+	Read       bool   `json:"read"`
 }
 
 // Feed represents a single feed