Feat/assistant app (#2086)

Co-authored-by: chenhe <guchenhe@gmail.com>
Co-authored-by: Pascal M <11357019+perzeuss@users.noreply.github.com>

api/controllers/files/tool_files.py

@@ -0,0 +1,47 @@
+from controllers.files import api
+from flask import Response
+from flask_restful import Resource, reqparse
+from libs.exception import BaseHTTPException
+from werkzeug.exceptions import NotFound, Forbidden
+
+from core.tools.tool_file_manager import ToolFileManager
+
+class ToolFilePreviewApi(Resource):
+    def get(self, file_id, extension):
+        file_id = str(file_id)
+
+        parser = reqparse.RequestParser()
+
+        parser.add_argument('timestamp', type=str, required=True, location='args')
+        parser.add_argument('nonce', type=str, required=True, location='args')
+        parser.add_argument('sign', type=str, required=True, location='args')
+
+        args = parser.parse_args()
+
+        if not ToolFileManager.verify_file(file_id=file_id,
+                                            timestamp=args['timestamp'],
+                                            nonce=args['nonce'],
+                                            sign=args['sign'],
+        ):
+            raise Forbidden('Invalid request.')
+        
+        try:
+            result = ToolFileManager.get_file_generator_by_message_file_id(
+                file_id,
+            )
+
+            if not result:
+                raise NotFound(f'file is not found')
+            
+            generator, mimetype = result
+        except Exception:
+            raise UnsupportedFileTypeError()
+
+        return Response(generator, mimetype=mimetype)
+
+api.add_resource(ToolFilePreviewApi, '/files/tools/<uuid:file_id>.<string:extension>')
+
+class UnsupportedFileTypeError(BaseHTTPException):
+    error_code = 'unsupported_file_type'
+    description = "File type not allowed."
+    code = 415