pubsub.proxy module

class pubsub.proxy.PubSubWebSocketHandler(*args: Any, **kwargs: Any)

Bases: WebsocketHandler

POX WebSocket server for interfacing with the pubsub service hoststack. Run with:

./pox.py web --no-cookieguard --port=[PORT] ext.ei.pubsub.scripts.pubsub --hssock=[SOCKNAME]

IPC messages are sent and received as JSON blobs. IPC JSON messages must always have a field “ipc” with a (string) value containing the message type. The remainder of the fields depend on the message type:

Client → Server IPCs:

  • PubSub (un)publish/subscribe request (“PUBSUB_REQUEST”):

    • request_type: one of “PUBLISH”, “SUBSCRIBE”, “UNPUBLISH”, “UNSUBSCRIBE”

    • topic: topic to (un)publish/subscribe to

  • Sending a message (“PUBSUB_OUTGOING_MESSAGE”):

    • seqno (optional): local sequence number of message

    • topic: topic to send message on

    • msg: message data

Example client publish request:

{ "ipc": "PUBSUB_REQUEST",
  "request_type": "PUBLISH",
  "topic": "example topic" }

Server → Client IPCs:

  • Incoming message (“PUBSUB_INCOMING_MESSAGE”):

    • archive_seqno: sequence number of this message in the pubsub core

    • topic: topic that this message was published to

    • msg: message data

  • Request ACK (“PUBSUB_REQUEST_ACK”):

    • request_type: request type being ack’d

    • archive_seqno: sequence number of this request in the pubsub core

    • topic: topic that was (un)published/subscribed

  • Outgoing message ACK (“PUBSUB_MSG_ACK”):

    • seqno: matches the seqno field of the outgoing message if given, otherwise zero

    • archive_seqno: sequence number of this message in the pubsub core

Example incoming message from server:

{ "ipc": "PUBSUB_INCOMING_MESSAGE",
  "archive_seqno": 17,
  "topic": "example topic",
  "msg": "This is a PubSub message." }
pubsub.proxy.launch(hssock)