Just noticed that my automated backup validation pipeline is failing when attempting to simulate customer file uploads via the Web Messaging Guest API. I am using the Python SDK (genesys-cloud-purecloud-platform-client v2.0) to drive a CI job that verifies our disaster recovery configuration handles media attachments correctly. The goal is to ensure that the webmessaging resource group in Terraform has the correct limits applied, but I need to validate the API behavior at runtime.
I am constructing a multipart/form-data request to POST /api/v2/conversations/webchat/messages. The payload includes a standard text message and a file attachment. Here is the relevant Python snippet using requests:
import requests
import json
url = f"{base_url}/api/v2/conversations/webchat/messages"
headers = {
'Authorization': f'Bearer {access_token}',
'Content-Type': 'multipart/form-data'
}
# Attempting to upload a small PNG file
files = {
'file': ('test_logo.png', open('assets/test_logo.png', 'rb'), 'image/png'),
}
data = {
'from': {'id': 'guest-user-123'},
'text': {'type': 'text', 'text': 'Here is my screenshot'},
'attachments': [{
'id': 'att-1',
'name': 'test_logo.png',
'type': 'image/png',
'size': 15000
}]
}
response = requests.post(url, headers=headers, data=data, files=files)
print(response.status_code)
print(response.json())
The response is consistently 415 Unsupported Media Type with the error message: "message": "The media type 'multipart/form-data' is not supported."
I have verified that the Content-Type header is set correctly, and the file size (15KB) is well below the typical 10MB limit. The MIME type image/png is listed as supported in the documentation. However, when I remove the files parameter and send only the JSON data, the request succeeds with a 201 Created status.
Is the Web Messaging API endpoint strictly expecting a JSON body for the message metadata, with file uploads handled via a separate presigned URL flow? Or am I missing a specific header required for multipart parsing in the Genesys Cloud environment? I need to know the correct programmatic approach to attach files in a headless test environment.
You need to switch from the standard JSON request body to a proper multipart/form-data payload when sending file attachments via the Web Messaging Guest API. The 415 error occurs because the server expects the boundary-separated format required by RFC 7578, but the Python SDK or your underlying HTTP client is likely sending application/json by default. In my CI/CD automation scripts, I bypass the high-level SDK convenience methods for media uploads and use the requests library directly to have granular control over the headers and body encoding. This ensures the Content-Type header includes the correct boundary string automatically.
Here is the robust pattern I use in my Python automation scripts to handle this specific scenario. The key is passing the file as a tuple in the files parameter, which triggers the correct multipart encoding. Make sure your service account has the webmessaging:send scope and that the file size is within the tenant limits defined in your webmessaging resource group configuration.
import requests
import os
def upload_web_msg_attachment(access_token, conversation_id, file_path):
url = f"https://api.genesys.cloud/api/v2/conversations/webmessaging/{conversation_id}/messages"
headers = {
"Authorization": f"Bearer {access_token}",
"Accept": "application/json"
# Do NOT set Content-Type manually; requests handles the boundary
}
# The key 'file' must match the API spec for the attachment field
with open(file_path, 'rb') as f:
files = {'file': (os.path.basename(file_path), f)}
response = requests.post(url, headers=headers, files=files)
if response.status_code == 200:
print("Attachment uploaded successfully")
else:
print(f"Failed: {response.status_code} - {response.text}")
raise Exception("Upload failed")
# Usage
upload_web_msg_attachment("YOUR_BEARER_TOKEN", "conv_id_123", "./test_backup.pdf")
I recommend validating the files dictionary structure carefully. The SDK often assumes simple JSON payloads for text messages, so forcing multipart encoding requires this lower-level approach. If you continue to see issues, check the server response headers for Www-Authenticate clues, though 415 is almost exclusively a content-type mismatch in this context. Ensure your retry logic in the pipeline accounts for potential network timeouts during large file transfers, as the default timeout might be too aggressive for backup validation scenarios.
The root of the issue is that you are likely forcing the Python SDK to serialize a FileAttachment object into a JSON body, but the Web Messaging Guest API endpoint for uploads strictly requires multipart/form-data. The SDK’s high-level methods often default to JSON for simplicity, which triggers the 415 Unsupported Media Type error.
HTTP Error 415: Unsupported Media Type - The server does not support the media type of the request entity
As a React developer using the Client App SDK, I see this pattern often when bridging backend services to Genesys Cloud. You should bypass the SDK’s default serializer for this specific call. Instead, use the requests library directly with the files parameter. This ensures the correct Content-Type with a unique boundary is generated automatically.
Here is the working approach:
- Open the file in binary mode.
- Pass it to the
files argument in requests.post.
- Include the
conversationId and channelId in the data payload, not the headers.
import requests
url = "https://api.genesys.cloud/webmessaging/v1/conversations/{conversationId}/channels/{channelId}/messages"
headers = {
"Authorization": f"Bearer {access_token}"
}
# Critical: Do not set Content-Type manually. Let 'requests' handle the boundary.
files = {
"file": ("document.pdf", open("path/to/file.pdf", "rb"), "application/pdf")
}
data = {
"type": "file",
"from": "guest" # Ensure this matches your guest identifier
}
response = requests.post(url, headers=headers, files=files, data=data)
print(response.status_code) # Should be 201 or 202
This method avoids the SDK’s internal JSON serialization. It also aligns with how the postMessage API in our desktop apps handles media events. If you must use the SDK, check if there is a specific upload_file method that accepts raw bytes, but the raw requests approach is more reliable for CI pipelines.
If I remember correctly, switching to multipart/form-data is only half the battle for the Web Messaging Guest API. The real gotcha is that the Genesys Cloud platform often rejects uploads if the Content-Type header isn’t explicitly set by the underlying HTTP client, regardless of what the SDK attempts. In my Lambda event processors, I avoid the high-level SDK methods for media entirely. I use boto3 to sign the request manually or rely on requests with explicit boundary handling to ensure the payload structure matches RFC 7578 exactly.
Here is a snippet from my validation script that bypasses the SDK’s default JSON serialization:
import requests
url = "https://api.mypurecloud.com/api/v2/conversations/webmessaging/guests/{guestId}/messages"
files = {'file': open('attachment.pdf', 'rb')}
headers = {'Authorization': f'Bearer {access_token}'}
response = requests.post(url, files=files, headers=headers)
Warning: Ensure your Lambda execution role has permissions to read the S3 bucket where these test assets are stored, otherwise the file object will fail to open before the request even leaves the function.
You need to ensure your CI pipeline does not inadvertently trigger New Relic alert policies during these automated validation runs. While the multipart/form-data fix is technically correct for the 415 error, high-frequency automated testing often generates synthetic traffic spikes. In our monitoring stack, these spikes are frequently misinterpreted as production anomalies by default NRQL dashboards.
I recommend tagging your automated requests with a custom synthetic=true header. You can then filter this in your Genesys Cloud Webhook configuration or via a simple Architect script before data reaches New Relic.
# Example: Tagging request for observability filtering
headers = {
"X-Synthetic-Test": "true",
"Content-Type": "multipart/form-data"
}
If you skip this, you risk generating false positives in your error rate alerts. I have seen this cause unnecessary page-outs for the on-call team during off-hours. It is better to isolate test traffic from production metrics at the ingestion layer.