When I'm trying to publish activity event I'm getting "source can't be blank" error. The easiest way to reproduce:
❯ curl -X POST -u USER:PASS https://api.flowdock.com/flows/ORG/FLOW/messages -d 'source=SOURCE&event=activity&thread_id=THREADID&content=test' | jq
"message": "Validation error",
"can't be blank"
Is there any way to publish activity event without knowing flow_token? I couldn't find any way to get flow_token via API.