refactor: port reqparse to BaseModel (#28993)

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

api/controllers/service_api/app/file_preview.py

@@ -1,9 +1,11 @@
 import logging
 from urllib.parse import quote
 
-from flask import Response
-from flask_restx import Resource, reqparse
+from flask import Response, request
+from flask_restx import Resource
+from pydantic import BaseModel, Field
 
+from controllers.common.schema import register_schema_model
 from controllers.service_api import service_api_ns
 from controllers.service_api.app.error import (
     FileAccessDeniedError,
@@ -17,10 +19,11 @@ from models.model import App, EndUser, Message, MessageFile, UploadFile
 logger = logging.getLogger(__name__)
 
 
-# Define parser for file preview API
-file_preview_parser = reqparse.RequestParser().add_argument(
-    "as_attachment", type=bool, required=False, default=False, location="args", help="Download as attachment"
-)
+class FilePreviewQuery(BaseModel):
+    as_attachment: bool = Field(default=False, description="Download as attachment")
+
+
+register_schema_model(service_api_ns, FilePreviewQuery)
 
 
 @service_api_ns.route("/files/<uuid:file_id>/preview")
@@ -32,7 +35,7 @@ class FilePreviewApi(Resource):
     Files can only be accessed if they belong to messages within the requesting app's context.
     """
 
-    @service_api_ns.expect(file_preview_parser)
+    @service_api_ns.expect(service_api_ns.models[FilePreviewQuery.__name__])
     @service_api_ns.doc("preview_file")
     @service_api_ns.doc(description="Preview or download a file uploaded via Service API")
     @service_api_ns.doc(params={"file_id": "UUID of the file to preview"})
@@ -55,7 +58,7 @@ class FilePreviewApi(Resource):
         file_id = str(file_id)
 
         # Parse query parameters
-        args = file_preview_parser.parse_args()
+        args = FilePreviewQuery.model_validate(request.args.to_dict())
 
         # Validate file ownership and get file objects
         _, upload_file = self._validate_file_ownership(file_id, app_model.id)
@@ -67,7 +70,7 @@ class FilePreviewApi(Resource):
             raise FileNotFoundError(f"Failed to load file content: {str(e)}")
 
         # Build response with appropriate headers
-        response = self._build_file_response(generator, upload_file, args["as_attachment"])
+        response = self._build_file_response(generator, upload_file, args.as_attachment)
 
         return response