Merge pull request #58 from DepshubHQ/55-implement-data-cache

Implement data cache

pkg/sources/cache.go

@@ -0,0 +1,135 @@
+// The cache file will be stored in:
+
+// Windows: %USERPROFILE%\.cache\depshub\
+// Linux/macOS: ~/.cache/depshub/
+
+package sources
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"sync"
+	"time"
+)
+
+type CacheItem struct {
+	Value      []byte    `json:"value"` // Store as raw JSON bytes
+	ExpiresAt  time.Time `json:"expires_at"`
+	CreateTime time.Time `json:"create_time"`
+}
+
+type FileCache struct {
+	filename string
+	mutex    sync.RWMutex
+	data     map[string]CacheItem
+}
+
+// NewFileCache creates a new cache instance
+func NewFileCache(cacheName string) (*FileCache, error) {
+	homeDir, err := os.UserHomeDir()
+	if err != nil {
+		return nil, err
+	}
+
+	cacheDir := filepath.Join(homeDir, ".cache", "depshub")
+	if err := os.MkdirAll(cacheDir, 0755); err != nil {
+		return nil, err
+	}
+
+	cacheFile := filepath.Join(cacheDir, cacheName+".json")
+	cache := &FileCache{
+		filename: cacheFile,
+		data:     make(map[string]CacheItem),
+	}
+
+	// Load existing cache if it exists
+	if err := cache.load(); err != nil && !os.IsNotExist(err) {
+		return nil, err
+	}
+
+	return cache, nil
+}
+
+// Set adds or updates a cache entry with optional expiration duration
+func (c *FileCache) Set(key string, value any, expiration time.Duration) error {
+	fmt.Println("Setting cache")
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+
+	// Marshal the value to JSON bytes
+	jsonBytes, err := json.Marshal(value)
+	if err != nil {
+		return err
+	}
+
+	c.data[key] = CacheItem{
+		Value:      jsonBytes,
+		CreateTime: time.Now(),
+		ExpiresAt:  time.Now().Add(expiration),
+	}
+
+	return c.save()
+}
+
+// Get retrieves a value from the cache and unmarshals it into the provided destination
+func (c *FileCache) Get(key string, dest any) (bool, error) {
+	c.mutex.RLock()
+	defer c.mutex.RUnlock()
+
+	item, exists := c.data[key]
+	if !exists {
+		return false, nil
+	}
+
+	// Check if item has expired
+	if !item.ExpiresAt.IsZero() && time.Now().After(item.ExpiresAt) {
+		delete(c.data, key)
+		c.save()
+		return false, nil
+	}
+
+	// Unmarshal the JSON bytes into the destination
+	if err := json.Unmarshal(item.Value, dest); err != nil {
+		return true, err
+	}
+
+	return true, nil
+}
+
+// Delete removes an item from the cache
+func (c *FileCache) Delete(key string) error {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+
+	delete(c.data, key)
+	return c.save()
+}
+
+// Clear removes all items from the cache
+func (c *FileCache) Clear() error {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+
+	c.data = make(map[string]CacheItem)
+	return c.save()
+}
+
+// save writes the cache to disk
+func (c *FileCache) save() error {
+	data, err := json.Marshal(c.data)
+	if err != nil {
+		return err
+	}
+	return os.WriteFile(c.filename, data, 0644)
+}
+
+// load reads the cache from disk
+func (c *FileCache) load() error {
+	data, err := os.ReadFile(c.filename)
+	if err != nil {
+		return err
+	}
+	return json.Unmarshal(data, &c.data)
+}