Create WriteFile() so backend handles files

cmd/backend/files.go

@@ -3,6 +3,7 @@ package backend
 import (
 	"fmt"
 	"io"
+	"log"
 	"os"
 )
 
@@ -19,10 +20,30 @@ func CopyFile(src, dst string) error {
 	}
 	defer dstFile.Close()
 
-	_, err = io.Copy(dstFile, srcFile)
-	if err != nil {
+	if _, err = io.Copy(dstFile, srcFile); err != nil {
 		return fmt.Errorf("error copying file: %v", err)
 	}
 
 	return dstFile.Sync()
 }
+
+func WriteFile(path string, src io.Reader) error {
+	file, err := os.Create(path)
+	if err != nil {
+		log.Println(err)
+		return fmt.Errorf("error creating file: %v", err)
+	}
+	defer file.Close()
+
+	if _, err = io.Copy(file, src); err != nil {
+		log.Println(err)
+		return fmt.Errorf("error copying file: %v", err)
+	}
+
+	if err = file.Sync(); err != nil {
+		log.Println(err)
+		return fmt.Errorf("error syncing file: %v", err)
+	}
+
+	return nil
+}