feat: file_save_disk, file_delete, file_serve, upload_parse, upload_handler, thumbnail_generate (issue 0014 fase 3)

functions/infra/file_save_disk.go

@@ -0,0 +1,53 @@
+package infra
+
+import (
+	"fmt"
+	"io"
+	"mime"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+// FileSaveDisk escribe el contenido de data en baseDir con un nombre unico generado a
+// partir de filename original. Crea baseDir si no existe.
+//
+// Retorna el UploadedFile con la metadata y la ruta completa en disco. El campo
+// ContentType se infiere de la extension via mime.TypeByExtension; si la app necesita
+// validacion mas estricta, debe usar FileValidateType antes y/o sobreescribir el campo.
+func FileSaveDisk(baseDir string, filename string, data io.Reader) (UploadedFile, error) {
+	if err := os.MkdirAll(baseDir, 0o755); err != nil {
+		return UploadedFile{}, fmt.Errorf("file_save_disk: mkdir %s: %w", baseDir, err)
+	}
+
+	stored := FileUniqueName(filename)
+	dst := filepath.Join(baseDir, stored)
+
+	f, err := os.Create(dst)
+	if err != nil {
+		return UploadedFile{}, fmt.Errorf("file_save_disk: create %s: %w", dst, err)
+	}
+	defer f.Close()
+
+	n, err := io.Copy(f, data)
+	if err != nil {
+		_ = os.Remove(dst)
+		return UploadedFile{}, fmt.Errorf("file_save_disk: copy: %w", err)
+	}
+
+	ext := strings.ToLower(filepath.Ext(stored))
+	ct := mime.TypeByExtension(ext)
+	if ct == "" {
+		ct = "application/octet-stream"
+	}
+
+	return UploadedFile{
+		Filename:    filename,
+		StoredName:  stored,
+		Size:        n,
+		ContentType: ct,
+		Path:        dst,
+		CreatedAt:   time.Now().UTC(),
+	}, nil
+}