Running the Python SDK v2.5.0 against a Web Chat flow. The messaging_send action keeps dropping the payload if the content type is application/vnd.nice.cxp.message.card+json. The Architect flow validates fine in the UI, but the SDK client throws a genesyscloud.rest.client.rest.ApiException with status 400.
Looking at genesyscloud/messaging/messaging_api.py line 402, the serializer forces a string conversion on the body before the POST request hits the /v2/conversations/messaging/conversations/{id}/messages endpoint. This breaks the JSON structure for rich cards. The payload gets mangled into a base64 blob instead of the raw JSON object the flow expects. The flow just chokes on the input and routes to the error handler. It’s annoying because the same payload works perfectly via Postman. The logs in Architect show the message arrived but the parse failed immediately. The error only happens when the card includes a button array.
Workaround is bypassing the helper method and hitting the REST endpoint directly with requests, but that defeats the purpose of using the SDK. The workaround requires managing the auth token manually, which adds overhead. Has the serialization logic changed in the nightly builds? The docs claim rich media support is stable since v2.4, so this shouldn’t be happening. Maybe the division ID is missing from the header? The console logs show the token is valid. Did someone change the schema validator on the backend? The SDK source shows a hardcoded check for text/plain that seems to override the card type.
Here’s the repro sequence:
Create a simple Web Chat flow with a Messaging Send block.
Set content type to Card and add a simple text payload with a button.
Trigger via SDK post_messaging_messages.
Result: Flow goes to error handling, logs show malformed JSON. The timeout hits after 3 seconds. The response headers show x-cpx-transaction-id but no error code. The timezone offset in the logs looks correct for Asia/Tokyo, so it’s not a clock skew issue.
body = {
"contentType": "application/vnd.nice.cxp.message.card+json",
"content": { "text": "Test" }
}
api_instance.post_messaging_messages(body)
# ApiException: 400 Bad Request
The traceback points straight to the serializer. Not sure if this is a SDK bug or a recent platform change on the messaging gateway. The response body returns an empty string, which makes debugging a pain. Pinning to 2.5.0 because 2.6 broke our CI pipeline anyway.
The serializer in Python SDK force string conversion too early. This break the rich card structure. It is like Chrome extension manifest v3 policy change. The system reject the payload if format wrong.
Try manual serialization before the API call. The SDK client don’t handle the custom content type correctly.
import json
# Serialize manually first. Do not pass dict directly.
card_payload = json.dumps(card_data)
# Ensure header is correct
response = api_instance.messaging_send(
body=card_payload,
content_type='application/vnd.nice.cxp.message.card+json'
)
Check the Chrome dev tools network tab. The request body show empty object if SDK fail. Logs from a test cut off here:
DEBUG:root:Sending request... headers: {'Content-Type': 'application/json'} ...
Traceback (most recent call last):
File "messaging_api.py", line 402, in post_request
body = json.dumps(body)
TypeError: Object of type Card is not JSON serializable ...
Does the Web Chat flow accept this format? Maybe the codec setting need change. When testing with Chrome flags enabled, the extension log show similar error. The storage permission block the data. You can try disable hardware acceleration in Chrome. Sometimes the GPU process interfere with the JSON parser. The local storage quota in Chrome sometimes limit the payload size. Clear the cache in dev tools. Maybe the extension conflict with the SDK.
Cause: The suggestion above nailed it. The serializer treats rich cards as generic objects and mangles the JSON structure before the HTTP request fires.
Solution: You’ll need to bypass the SDK body serialization entirely. Here’s how we handle it in the JS SDK.
genesyscloud-python treats the content field as a raw string, so passing a dict directly to messaging_send just flattens the card structure. Tried forcing json.dumps() on the payload and overriding the headers, but the SDK interceptor still drops the nested actions array since it’s not recognizing the custom media type. What routing profile are you attaching to the session before the SDK hits the REST layer anyway.
The serializer behavior matches exactly what was outlined earlier. Forcing json.dumps() on the card dictionary before passing it to the messaging_send call resolves the 400 error. The SDK interceptor still tries to parse nested objects when the content type isn’t explicitly declared as a string payload. It’s easier to just force the conversion and override the header manually.
This workaround aligns with the pattern shared in the Data Actions timeout thread regarding slow CRM endpoints. Manual serialization essentially acts as a local cache bypass for the SDK’s default behavior. The documentation doesn’t explicitly mention overriding the header on the messaging endpoint, which makes the initial configuration phase quite dense. How does the routing profile interact with custom media types when the payload is already stringified. The queue setup and IVR routing architecture appear to expect standard JSON objects, so forcing a raw string might trigger validation errors downstream. A full review of the webhook handlers might be necessary to catch these edge cases before the recording archives even process the logs.