feat: [backend] vision support (#1510)

Co-authored-by: Garfield Dai <dai.hai@foxmail.com>

api/controllers/service_api/app/file.py

@@ -0,0 +1,42 @@
+from flask import request
+from flask_restful import marshal_with
+
+from controllers.service_api import api
+from controllers.service_api.wraps import AppApiResource
+from controllers.service_api.app import create_or_update_end_user_for_user_id
+from controllers.service_api.app.error import NoFileUploadedError, TooManyFilesError, FileTooLargeError, \
+    UnsupportedFileTypeError
+import services
+from services.file_service import FileService
+from fields.file_fields import file_fields
+
+
+class FileApi(AppApiResource):
+
+    @marshal_with(file_fields)
+    def post(self, app_model, end_user):
+
+        file = request.files['file']
+        user_args = request.form.get('user')
+
+        if end_user is None and user_args is not None:
+            end_user = create_or_update_end_user_for_user_id(app_model, user_args)
+
+        # check file
+        if 'file' not in request.files:
+            raise NoFileUploadedError()
+
+        if len(request.files) > 1:
+            raise TooManyFilesError()
+
+        try:
+            upload_file = FileService.upload_file(file, end_user)
+        except services.errors.file.FileTooLargeError as file_too_large_error:
+            raise FileTooLargeError(file_too_large_error.description)
+        except services.errors.file.UnsupportedFileTypeError:
+            raise UnsupportedFileTypeError()
+
+        return upload_file, 201
+
+
+api.add_resource(FileApi, '/files/upload')