Ledger Notifications API

The notification feature allows you to be notified when an API userreceives an important event.To receive a webhook notification, you must first register yourtarget endpoint via `PUT /notifications/configuration`Once done, your web server will be called via POST with a json payloadsuch as this one:``` {'payload_type': 'TRANSACTION', 'event_type': 'NEW_TRANSACTION_HAS_BEEN_RECEIVED', 'id': 10}```- `payload_type`: Enum identifying the type of the Vault object the notification is about.- `event_type`: Enum identifying uniquely the exact event that triggered the notification.Can be used to run specific actions for specific events.- `id`: Id of the Vault object. Together with `payload_type` they allow you to fetch the fullobject with the corresponding endpoint.Below is a list and short description of the event types API operators can receive:| Event Type | Payload Type | Description ||------------|--------------|-------------|| NEW_TRANSACTION_HAS_BEEN_SIGNED | TRANSACTION | A new transaction has been signed by the HSM || NEW_TRANSACTION_HAS_BEEN_BROADCASTED | TRANSACTION | An new transaction has been broadcast || NEW_TRANSACTION_HAS_FAILED | TRANSACTION | A new transaction has failed upon broadcast || NEW_TRANSACTION_HAS_BEEN_ABORTED | TRANSACTION | A new transaction has been aborted by a User || NEW_TRANSACTION_HAS_BEEN_RECEIVED | TRANSACTION | A new transaction has been received || NEW_TRANSACTION_HAS_BEEN_SCORED | TRANSACTION | A new transaction has been scored by a KYT provider || REQUEST_HAS_BEEN_CREATED | REQUEST | A new request has been created || REQUEST_HAS_RECEIVED_AN_APPROVAL | REQUEST | A request has received an approval || REQUEST_HAS_REACHED_STEP | REQUEST | A request has reached a new approval step || REQUEST_HAS_REACHED_QUORUM | REQUEST | A request has reached the required quorum || REQUEST_HAS_BEEN_ABORTED | REQUEST | A request has been aborted || REQUEST_HAS_EXPIRED | REQUEST | A request has been pending for too long and has expired || NEW_USER_HAS_BEEN_CREATED | USER | A new user has been created || USER_HAS_BEEN_EDITED | USER | A user has been edited || USER_HAS_BEEN_REVOKED | USER | A user has been revoked || USER_HAS_BEEN_SUSPENDED | USER | A user has been suspended || USER_HAS_BEEN_UNSUSPENDED | USER | A user has been unsuspended || NEW_GROUP_HAS_BEEN_CREATED | GROUP | A new group has been created || GROUP_HAS_BEEN_EDITED | GROUP | A group has been edited || GROUP_HAS_BEEN_REVOKED | GROUP | A group has been revoked || NEW_ACCOUNT_HAS_BEEN_CREATED | X_ACCOUNT | A new account has been created || ACCOUNT_HAS_BEEN_EDITED | X_ACCOUNT | An account has been edited || NEW_ENTITY_HAS_BEEN_CREATED | ENTITY | A new entity has been created || ENTITY_HAS_BEEN_EDITED | ENTITY | An entity has been edited || ENTITY_HAS_BEEN_REVOKED | ENTITY | An entity has been revoked || NEW_WHITELIST_HAS_BEEN_CREATED | WHITELIST | A new whitelist has been created || WHITELIST_HAS_BEEN_EDITED | WHITELIST | A whitelist has been edited |Note: `X_ACCOUNT` can be one of BITCOIN_ACCOUNT, ETHEREUM_ACCOUNT, ERC20_ACCOUNT, ...By design, we've reduced the number of information in the payload to the minimumas we can't guarantee the security of the channel the same way we do with the LAM.However, using the provided `id` you can query the LAM to get more information.You can also make sure the payload is genuine with the shared secret you'veprovided during registration.We send you the following HTTP Header `X-Ledger-Signature: t=,v1=` - `timestamp` is a unix epoch timestamp - `signature` is a hmac sha256 signature computed with your secret and the concatenation of the: - timestamp as a string - character "." - json payloadHere is an example of signature validation and a request to the LAM using python / flask:```pythonSECRET = "mysecret"USER = "api_lam_user"@app.route("/", methods=["POST"])def webhook(): ledger_signature = request.headers["X-Ledger-Signature"] for elem in ledger_signature.split(","): k, v = elem.split("=") if k == "t": timestamp = v elif k == "v1": signature = v if time.time() - int(timestamp) > 5 * 60: raise ValueError("message is too old, possible replay attack") to_sign = timestamp.encode() + b"." + request.data computed_signature = hmac.new(SECRET.encode(), to_sign, "sha256").hexdigest() if not hmac.compare_digest(signature, computed_signature): raise ValueError("signature mismatch") if request.json.get("payload_type") == "TRANSACTION": tx_id = request.json["id"] tx = requests.get( f"http://vault-lam:5000/transactions/{tx_id}", headers={"X-Ledger-API-User": USER, "Content-Type": "application/json"}, ) print(tx.json()) # do something with the transaction```