init

db.go

@@ -0,0 +1,55 @@
+package main
+
+import (
+	"encoding/json"
+	"log"
+	"os"
+	"path"
+	"stream-poc2/model"
+)
+
+func pathForMedia(mediaID string) string {
+	return path.Join("db", mediaID)
+}
+
+var metadataCache = make(map[string]model.MediaMetadata) // metadata is currently immutable, so we can make it simple here
+
+func loadMediaMetadata(id string) (model.MediaMetadata, error) {
+	var metadata model.MediaMetadata
+	var ok bool
+
+	metadata, ok = metadataCache[id]
+	if ok {
+		return metadata, nil
+	}
+
+	log.Printf("metadata for %s not found in cache... loading...", id)
+
+	mediaPath := pathForMedia(id)
+	if !isDir(mediaPath) {
+		log.Println("media path dir does not exists", mediaPath)
+		return model.MediaMetadata{}, os.ErrNotExist
+	}
+
+	f, err := os.OpenFile(path.Join(mediaPath, "meta.json"), os.O_RDONLY, 0)
+	if err != nil {
+		log.Println("Failed ot open file:", err)
+		return model.MediaMetadata{}, err
+	}
+	defer func(f *os.File) {
+		err := f.Close()
+		if err != nil {
+			log.Println("failed to close metadata file:", err)
+		}
+	}(f)
+
+	err = json.NewDecoder(f).Decode(&metadata)
+	if err != nil {
+		log.Println("Failed to load metadata:", metadata)
+		return model.MediaMetadata{}, err
+	}
+
+	metadataCache[id] = metadata
+
+	return metadata, nil
+}