fix(assets): send correct Content-Type for update and replace (v1.10.1)

Asset.update() forced Content-Type: multipart/form-data while sending a JSON
body, and Asset.replace() set a bare multipart/form-data header (no boundary)
while passing files=. Both made the CMA API reject the request with 422
'Please send a valid multipart/form-data payload', and both leaked the wrong
Content-Type onto subsequent requests on the shared client.

- update(): send the JSON body as application/json (matches the JS SDK and the
  live API, which returns 200)
- replace(): let the HTTP layer build the multipart body with a proper boundary

Bump version to 1.10.1 and update the asset update unit test accordingly.

Author: aniket-shikhare-cstk

CHANGELOG.md

@@ -1,6 +1,14 @@
 # CHANGELOG
 
 ## Content Management SDK For Python
+---
+## v1.10.1
+
+#### Date: 26 June 2026
+
+- Fixed `Asset.update()` to send the JSON body with `Content-Type: application/json` instead of an invalid bare `multipart/form-data`, which the API rejected with 422.
+- Fixed `Asset.replace()` to let the HTTP layer set `multipart/form-data` with a proper boundary (a bare `multipart/form-data` header without a boundary previously caused a 422). Both fixes also remove a side effect that leaked the wrong `Content-Type` onto subsequent requests.
+
 ---
 ## v1.10.0
 

contentstack_management/__init__.py

@@ -102,7 +102,7 @@ def get_contentstack_endpoint(region='us', service='', omit_https=False):
 __author__ = 'dev-ex'
 __status__ = 'debug'
 __region__ = 'na'
-__version__ = '1.10.0'
+__version__ = '1.10.1'
 __host__ = 'api.contentstack.io'
 __protocol__ = 'https://'
 __api_version__ = 'v3'

contentstack_management/assets/assets.py

@@ -174,7 +174,10 @@ def replace(self, file_path):
         """
 
         url = f"assets/{self.asset_uid}"
-        Parameter.add_header(self, "Content-Type", "multipart/form-data")
+        # Let requests build the multipart body and set Content-Type WITH a boundary.
+        # Setting a bare "multipart/form-data" (no boundary) makes the API reject the
+        # upload with 422 "Please send a valid multipart/form-data payload".
+        self.client.headers.pop("Content-Type", None)
         files = {"asset": open(f"{file_path}",'rb')}
         return self.client.put(url, headers = self.client.headers, params = self.params, files = files)
 
@@ -407,7 +410,9 @@ def update(self, data):
         if self.asset_uid is None or '':
             raise Exception(ASSET_UID_REQUIRED)
         url = f"assets/{self.asset_uid}"
-        Parameter.add_header(self, "Content-Type", "multipart/form-data")
+        # Updating an asset's title/description sends a JSON body, so it must use
+        # application/json. Forcing multipart/form-data here makes the API reject
+        # the request with 422 "Please send a valid multipart/form-data payload".
         return self.client.put(url, headers = self.client.headers, params = self.params, data = data)
 
     def publish(self, data):

tests/unit/assets/test_assets_unit.py

@@ -167,7 +167,9 @@ def test_update(self):
         response = self.client.stack(api_key).assets(asset_uid).update(data)
         self.assertEqual(response.request.url, f"{self.client.endpoint}assets/{asset_uid}")
         self.assertEqual(response.request.method, "PUT")
-        self.assertEqual(response.request.headers["Content-Type"], "multipart/form-data")
+        # Asset update sends a JSON body, so Content-Type must be application/json
+        # (it previously forced multipart/form-data, which the API rejects).
+        self.assertEqual(response.request.headers["Content-Type"], "application/json")
 
     def test_publish(self):
         data = {