Cancel Order

A user can cancel an order created by himself and with status pending sending action cancel, the rumor's content of the message will look like this:

[
  {
    "order": {
      "version": 1,
      "id": "<Order Id>",
      "action": "cancel",
      "payload": null
    }
  },
  "<index N signature of the sha256 hash of the serialized first element of content>"
]

Mostro response

Mostro will send a message with action cancel confirming the order was canceled, here an example of rumor's content of the message:

[
  {
    "order": {
      "version": 1,
      "id": "<Order Id>",
      "action": "canceled",
      "payload": null
    }
  },
  null
]

Mostro updates the addressable event with d tag <Order Id> to change the status to canceled:

[
  "EVENT",
  "RAND",
  {
    "id": "<Event id>",
    "pubkey": "<Mostro's pubkey>",
    "created_at": 1702549437,
    "kind": 38383,
    "tags": [
      ["d", "<Order Id>"],
      ["k", "sell"],
      ["f", "VES"],
      ["s", "canceled"],
      ["amt", "7851"],
      ["fa", "100"],
      ["pm", "face to face"],
      ["premium", "1"],
      ["network", "mainnet"],
      ["layer", "lightning"],
      ["expiration", "1719391096"],
      ["y", "mostro", "[Mostro instance name]"],
      ["z", "order"]
    ],
    "content": "",
    "sig": "<Mostro's signature>"
  }
]

Bond race during take

A client that sent take-buy / take-sell and is waiting for pay-bond-invoice may receive Action::Canceled instead — meaning another user paid their bond first on the same order (whichever bond locks first wins; see pay bond invoice). Surface this clearly to the user, e.g. "Order was taken by another user before you locked the bond." Do not silently retry the take — the order may not be available anymore, and the supersede mechanism on the daemon side has already discarded the prior bond request.

Cancel cooperatively

A user can cancel an active order, but will need the counterparty to agree, let's look at an example where the seller initiates a cooperative cancellation:

[
  {
    "order": {
      "version": 1,
      "id": "<Order Id>",
      "action": "cancel",
      "payload": null
    }
  },
  null
]

Mostro will send this message to the seller:

[
  {
    "order": {
      "version": 1,
      "id": "<Order Id>",
      "action": "cooperative-cancel-initiated-by-you",
      "payload": null
    }
  },
  null
]

And this message to the buyer:

[
  {
    "order": {
      "version": 1,
      "id": "<Order Id>",
      "action": "cooperative-cancel-initiated-by-peer",
      "payload": null
    }
  },
  null
]

The buyer can accept the cooperative cancellation sending this message:

[
  {
    "order": {
      "version": 1,
      "id": "<Order Id>",
      "action": "cancel",
      "payload": null
    }
  },
  null
]

And Mostro will send this message to both parties:

[
  {
    "order": {
      "version": 1,
      "id": "<Order Id>",
      "action": "cooperative-cancel-accepted",
      "payload": null
    }
  },
  null
]

Mostro updates the addressable event with d tag <Order Id> to change the status to canceled:

[
  "EVENT",
  "RAND",
  {
    "id": "<Event id>",
    "pubkey": "<Mostro's pubkey>",
    "created_at": 1702549437,
    "kind": 38383,
    "tags": [
      ["d", "<Order Id>"],
      ["k", "sell"],
      ["f", "VES"],
      ["s", "canceled"],
      ["amt", "7851"],
      ["fa", "100"],
      ["pm", "face to face"],
      ["premium", "1"],
      ["network", "mainnet"],
      ["layer", "lightning"],
      ["expiration", "1719391096"],
      ["y", "mostro", "[Mostro instance name]"],
      ["z", "order"]
    ],
    "content": "",
    "sig": "<Mostro's signature>"
  }
]