feat: Funcion de sistema tenants

backend/app/core/file_handler.py

@@ -16,6 +16,8 @@ settings = get_settings()
 
 class FileHandler:
     """Handler simple para archivos adjuntos"""
+
+    _CHUNK_SIZE_BYTES = 1024 * 1024  # 1MB
     
     def __init__(self):
         self.upload_path = Path(settings.UPLOAD_PATH)
@@ -24,8 +26,8 @@ class FileHandler:
         # Crear directorio si no existe
         self.upload_path.mkdir(parents=True, exist_ok=True)
     
-    def _validate_file(self, filename: str, file_size: int) -> None:
-        """Validar archivo"""
+    def _validate_extension(self, filename: str) -> str:
+        """Validar extensión del archivo y retornarla."""
         extension = Path(filename).suffix.lower().lstrip('.')
         
         if extension not in self.allowed_extensions:
@@ -33,32 +35,52 @@ class FileHandler:
                 status_code=status.HTTP_400_BAD_REQUEST,
                 detail=f"Extensión no permitida: {extension}"
             )
-        
-        if file_size > self.max_size_bytes:
+
+        return extension
+
+    def _validate_magic_bytes(self, extension: str, first_bytes: bytes) -> None:
+        """Validación básica por firma (magic bytes) para tipos comunes."""
+
+        signatures = {
+            # PDFs start with %PDF-
+            "pdf": [b"%PDF-"],
+            # PNG signature
+            "png": [b"\x89PNG\r\n\x1a\n"],
+            # JPEG starts with FF D8 FF
+            "jpg": [b"\xff\xd8\xff"],
+            "jpeg": [b"\xff\xd8\xff"],
+            # Legacy MS Office (OLE Compound File)
+            "doc": [b"\xd0\xcf\x11\xe0\xa1\xb1\x1a\xe1"],
+            "xls": [b"\xd0\xcf\x11\xe0\xa1\xb1\x1a\xe1"],
+            # OOXML (zip-based)
+            "docx": [b"PK\x03\x04", b"PK\x05\x06", b"PK\x07\x08"],
+            "xlsx": [b"PK\x03\x04", b"PK\x05\x06", b"PK\x07\x08"],
+        }
+
+        # For plain text, we can't reliably validate via magic bytes.
+        if extension == "txt":
+            return
+
+        allowed = signatures.get(extension)
+        if not allowed:
+            return
+
+        if not any(first_bytes.startswith(sig) for sig in allowed):
             raise HTTPException(
-                status_code=status.HTTP_413_REQUEST_ENTITY_TOO_LARGE,
-                detail=f"Archivo muy grande. Máximo: {settings.MAX_UPLOAD_SIZE_MB}MB"
+                status_code=status.HTTP_400_BAD_REQUEST,
+                detail="Contenido de archivo no coincide con la extensión declarada",
             )
     
-    def _calculate_checksums(self, content: bytes) -> Tuple[str, str]:
-        """Calcular MD5 y SHA256"""
-        return hashlib.md5(content).hexdigest(), hashlib.sha256(content).hexdigest()
-    
     async def save_upload(self, file: UploadFile, tenant_id: uuid.UUID, ticket_id: uuid.UUID) -> dict:
         """Guardar archivo y retornar metadata"""
         if not file.filename:
             raise HTTPException(status_code=400, detail="Filename requerido")
-        
-        content = await file.read()
-        file_size = len(content)
-        
-        self._validate_file(file.filename, file_size)
-        
-        md5_hash, sha256_hash = self._calculate_checksums(content)
-        
+
+        extension = self._validate_extension(file.filename)
+
         # Nombre único
-        extension = Path(file.filename).suffix.lower()
-        safe_filename = f"{uuid.uuid4().hex}{extension}"
+        original_extension = Path(file.filename).suffix.lower()
+        safe_filename = f"{uuid.uuid4().hex}{original_extension}"
         
         # Estructura: uploads/tenant_id/tickets/ticket_id/
         file_directory = self.upload_path / str(tenant_id) / "tickets" / str(ticket_id)
@@ -66,10 +88,61 @@ class FileHandler:
         
         file_path = file_directory / safe_filename
         relative_path = str(file_path.relative_to(self.upload_path))
-        
-        # Guardar archivo
-        with open(file_path, "wb") as f:
-            f.write(content)
+
+        # Guardar archivo (streaming) + checksums incrementales
+        md5 = hashlib.md5()
+        sha256 = hashlib.sha256()
+        file_size = 0
+        validated_magic = False
+        first_bytes: bytes = b""
+
+        try:
+            with open(file_path, "wb") as f:
+                while True:
+                    chunk = await file.read(self._CHUNK_SIZE_BYTES)
+                    if not chunk:
+                        break
+
+                    if not validated_magic:
+                        first_bytes = chunk[:16]
+                        self._validate_magic_bytes(extension, first_bytes)
+                        validated_magic = True
+
+                    file_size += len(chunk)
+                    if file_size > self.max_size_bytes:
+                        raise HTTPException(
+                            status_code=status.HTTP_413_REQUEST_ENTITY_TOO_LARGE,
+                            detail=f"Archivo muy grande. Máximo: {settings.MAX_UPLOAD_SIZE_MB}MB",
+                        )
+
+                    md5.update(chunk)
+                    sha256.update(chunk)
+                    f.write(chunk)
+
+            if file_size == 0:
+                raise HTTPException(
+                    status_code=status.HTTP_400_BAD_REQUEST,
+                    detail="Archivo vacío",
+                )
+
+        except HTTPException:
+            # Eliminar archivo parcial si existe
+            try:
+                if file_path.exists():
+                    file_path.unlink()
+            except Exception:
+                pass
+            raise
+        except Exception as exc:
+            try:
+                if file_path.exists():
+                    file_path.unlink()
+            except Exception:
+                pass
+            raise HTTPException(
+                status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+                detail=f"Error guardando archivo: {exc}",
+            )
         
         import mimetypes
         mime_type = mimetypes.guess_type(file.filename)[0] or "application/octet-stream"
@@ -80,8 +153,8 @@ class FileHandler:
             "file_path": relative_path,
             "file_size": file_size,
             "mime_type": mime_type,
-            "md5_hash": md5_hash,
-            "sha256_hash": sha256_hash
+            "md5_hash": md5.hexdigest(),
+            "sha256_hash": sha256.hexdigest(),
         }
     
     def get_file_path(self, relative_path: str) -> Path: