Fix return type for decrypt_attachment

Author: skylander86

README.md

@@ -18,16 +18,15 @@ pip install formsg
 
 The SDK provides two main utility functions for handling FormSG webhook:
 
-- [`webhook_uri: str, signature_header: str, signature_expiry_seconds: float = 60)`](formsg/utils.py) verifies that the incoming webhook's signature is valid based on the FormSG production public key.
+- [`webhook_uri: str, signature_header: str, signature_expiry_seconds: float = 60) -> Mapping[str, Any]`](formsg/utils.py) verifies that the incoming webhook's signature is valid based on the FormSG production public key.
 It raises a `nacl.exceptions.BadSignatureError` if the signature is invalid.
 The signature header is usually found in the `X-FormSG-Signature` header.
 Details on how the signature is constructed can be found [here](https://github.com/opengovsg/formsg-javascript-sdk/#verifying-signatures-manually).
 
-- [`decrypt_content(body: Mapping[str, Any], secret_key: str)`](formsg/utils.py) will decrypt the encrypted content using the given Base-64 encoded secret key.
+- [`decrypt_content(body: Mapping[str, Any], secret_key: str) -> Mapping[str, Any]`](formsg/utils.py) will decrypt the encrypted content using the given Base-64 encoded secret key.
 `body` is expected to be a dictionary-like object.
 
-- [`decrypt_attachment(body: Mapping[str, Any], field_id: str, secret_key: str)`](formsg/utils.py) will decrypt the encrypted content using the given Base-64 encoded secret key.
-`body` is expected to be a dictionary-like object.
+- [`decrypt_attachment(body: Mapping[str, Any], field_id: str, secret_key: str) -> bytes`](formsg/utils.py) will download and decrypt the encrypted attachment for a `field` and using the given Base-64 encoded secret key. `body` is expected to be a dictionary-like object.
 
 For convenience, the SDK implements a [`decrypt_django_request`](formsg/django.py) and [`decrypt_flask_request`](formsg/flask.py) which returns the decrypted FormSG content from a Django/Flask request object directly.
 

formsg/utils.py

@@ -79,7 +79,7 @@ def decrypt_attachment(
     body: Mapping[str, Any],
     field_id: str,
     secret_key: str,  # Base64 encoded secret key
-):
+) -> bytes:
     body = body.get('data', body)  # Some FormSG submissions are in a data field while others are not.
     url = body['attachmentDownloadUrls'][field_id]
     r = requests.get(url)

setup.py

@@ -6,7 +6,7 @@
 
 setup(
     name='formsg',
-    version='0.1.3',
+    version='0.1.4',
     packages=['formsg'],
     description='A Python SDK for handling FormSG webhooks.',
     long_description=README,