api.httpCall: Endpoint Fails to Respond With Large Payload

When calling an external webservice via api.httpCall with large payloads, the request:

Sometimes fails when sent from Pricefx despite the endpoint being available
Succeeds when sent from Postman

Reason

The issue depends on how HTTP connections are managed. For example, the SAP webservice endpoint is sensitive to persistent (keep-alive) HTTP connections, and may fail to respond correctly unless the connection is explicitly closed after each request.

Solution (Workaround)

Add the Connection: Close header to force the connection to close after the request:

Groovy

def props = [
  "basicAuthenticationUserName" : "userName",
  "basicAuthenticationPassword" : "password",
  "additionalHeaders" : [ "Connection": "Close" ]  // ✅ this is the fix
]

Object result = api.httpCall(wsUrl, payload, "POST", "JSON", props)

The "Connection": "Close" header ensures that the TCP connection is not reused, avoiding compatibility issues with connection/threading model that may cause timeouts or dropped responses with large or repeated payloads.