fix(serving): fix cannot decode base64 encoded binary data (#103)

.pre-commit-config.yaml

@@ -9,20 +9,20 @@ default_language_version:
   python: python3.10
 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v4.5.0
+    rev: v4.6.0
     hooks:
       - id: trailing-whitespace
       - id: end-of-file-fixer
       - id: check-yaml
       - id: check-added-large-files
   - repo: https://github.com/compilerla/conventional-pre-commit
-    rev: v3.0.0
+    rev: v3.3.0
     hooks:
       - id: conventional-pre-commit
         stages: [commit-msg]
         args: []
   - repo: https://github.com/psf/black
-    rev: 23.12.1
+    rev: 24.4.2
     hooks:
       - id: black
         args: [--safe, --quiet]
@@ -40,7 +40,7 @@ repos:
         types: [python]
         args: [-rn, -sn, --rcfile=pyproject.toml]
   - repo: https://github.com/pycqa/flake8
-    rev: 7.0.0
+    rev: 7.1.0
     hooks:
       - id: flake8
         args: [--config=.flake8]
@@ -51,15 +51,15 @@ repos:
         additional_dependencies:
           - tomli # for reading config from pyproject.toml
   - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v1.8.0
+    rev: v1.10.1
     hooks:
       - id: mypy
         exclude: "^tests/" # See: https://github.com/pre-commit/mirrors-mypy/issues/1
         args: [--ignore-missing-imports] # Needed because pre-commit runs mypy in a venv
         additional_dependencies:
           - typing_extensions
   - repo: https://github.com/PyCQA/bandit
-    rev: 1.7.6
+    rev: 1.7.9
     hooks:
       - id: bandit
         args: [--skip, B101, --recursive, clumper]

CHANGELOG.md

@@ -28,3 +28,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - Added a simple server to test with multiple handlers
+
+## [0.2.1] - 2024-07-15
+
+### Fixed
+
+- Returning a base64 encoded response would not be decoded by the framework

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "scaleway-functions-python"
-version = "0.2.0"
+version = "0.2.1"
 description = "Utilities for testing your Python handlers for Scaleway Serverless Functions."
 authors = ["Scaleway Serverless Team <[email protected]>"]
 

scaleway_functions_python/local/serving.py

@@ -1,7 +1,7 @@
 import logging
 from base64 import b64decode
 from json import JSONDecodeError
-from typing import TYPE_CHECKING, Any, ClassVar, List, Optional, cast
+from typing import TYPE_CHECKING, Any, ClassVar, List, Optional, Union, cast
 
 from flask import Flask, json, jsonify, make_response, request
 from flask.views import View
@@ -128,9 +128,9 @@ def resp_record_to_flask_response(
         self, record: "hints.ResponseRecord"
     ) -> "FlaskResponse":
         """Transform the ReponseRecord into an http reponse."""
-        body = record.get("body", "")
+        body: Union[str, bytes] = record.get("body", "")
         if record.get("isBase64Encoded") and body:
-            body = b64decode(body.encode("utf-8"), validate=True).decode("utf-8")
+            body = b64decode(cast(str, body).encode("utf-8"), validate=True)
 
         resp = make_response(body, record.get("statusCode"))
 

tests/handlers.py

@@ -5,6 +5,7 @@
 
 HELLO_WORLD = "Hello World"
 EXCEPTION_MESSAGE = "oops"
+NON_UTF8_BINARY_DATA = b"\x80\x81\x82\x83\x84\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f"
 
 # pylint: disable=missing-function-docstring
 
@@ -39,7 +40,7 @@ def handler_returns_is_base_64_encoded(event, _context):  # noqa
 
 def handler_returns_base64_encoded_body(_event, _context):  # noqa
     return {
-        "body": base64.b64encode(HELLO_WORLD.encode("utf-8")).decode("utf-8"),
+        "body": base64.b64encode(NON_UTF8_BINARY_DATA).decode("utf-8"),
         "isBase64Encoded": True,
     }
 

tests/test_local/test_serving.py

@@ -61,7 +61,7 @@ def test_serve_handler_b64_parameter_correct(client):
 )
 def test_serve_handler_with_b64_encoded_body(client):
     resp = client.get("/")
-    assert resp.text == h.HELLO_WORLD
+    assert resp.data == h.NON_UTF8_BINARY_DATA
 
 
 @pytest.mark.parametrize("client", [h.handler_returns_exception], indirect=True)