BlockchainEvent

Table of contents

1. BlockchainEvent
   1. Protocol ID
   2. Example
   3. Field Descriptions
2. BlockchainTransactionRef

BlockchainEvent

Blockchain Events are detected by the blockchain plugin:

1. When a ContractListener has been configured against any custom smart contract through the FireFly API
2. Indirectly via a Token Connector, which understands the correct events to listen to for a Token Pool configured against a standard such as ERC-20/ERC-721/ERC-1155
3. Automatically by FireFly core, for the BatchPin contract that can be used for high throughput batched pinning of off-chain data transfers to the blockchain (complementary to using your own smart contracts).

Protocol ID

Each Blockchain Event (once final) exists in an absolute location somewhere in the transaction history of the blockchain. A particular slot, in a particular block.

How to describe that position contains blockchain specifics - depending on how a particular blockchain represents transactions, blocks and events (or “logs”).

So FireFly is flexible with a string protocolId in the core object to represent this location, and then there is a convention that is adopted by the blockchain plugins to try and create some consistency.

An example protocolId string is: 000000000041/000020/000003

• 000000000041 - this is the block number
• 000020 - this is the transaction index within that block
• 000003 - this is the event (/log) index within that transaction

The string is alphanumerically sortable as a plain string;

Sufficient zero padding is included at each layer to support future expansion without creating a string that would no longer sort correctly.

Example

{
    "id": "e9bc4735-a332-4071-9975-b1066e51ab8b",
    "source": "ethereum",
    "namespace": "ns1",
    "name": "MyEvent",
    "listener": "c29b4595-03c2-411a-89e3-8b7f27ef17bb",
    "protocolId": "000000000048/000000/000000",
    "output": {
        "addr1": "0x55860105d6a675dbe6e4d83f67b834377ba677ad",
        "value2": "42"
    },
    "info": {
        "address": "0x57A9bE18CCB50D06B7567012AaF6031D669BBcAA",
        "blockHash": "0xae7382ef2573553f517913b927d8b9691ada8d617266b8b16f74bb37aa78cae8",
        "blockNumber": "48",
        "logIndex": "0",
        "signature": "Changed(address,uint256)",
        "subId": "sb-e4d5efcd-2eba-4ed1-43e8-24831353fffc",
        "timestamp": "1653048837",
        "transactionHash": "0x34b0327567fefed09ac7b4429549bc609302b08a9cbd8f019a078ec44447593d",
        "transactionIndex": "0x0"
    },
    "timestamp": "2022-05-16T01:23:15Z",
    "tx": {
        "blockchainId": "0x34b0327567fefed09ac7b4429549bc609302b08a9cbd8f019a078ec44447593d"
    }
}

Field Descriptions

BlockchainTransactionRef