Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/hiddentao/ethereum-event-logs
Ethereum event logs parser
https://github.com/hiddentao/ethereum-event-logs
Last synced: 8 days ago
JSON representation
Ethereum event logs parser
- Host: GitHub
- URL: https://github.com/hiddentao/ethereum-event-logs
- Owner: hiddentao
- License: mit
- Created: 2018-09-14T15:52:11.000Z (about 6 years ago)
- Default Branch: master
- Last Pushed: 2022-12-10T17:04:44.000Z (almost 2 years ago)
- Last Synced: 2024-10-13T23:06:45.918Z (25 days ago)
- Language: JavaScript
- Homepage:
- Size: 1.79 MB
- Stars: 48
- Watchers: 6
- Forks: 7
- Open Issues: 15
-
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
- License: LICENSE.md
Awesome Lists containing this project
README
# ethereum-event-logs
[](https://travis-ci.org/hiddentao/ethereum-event-logs)
[](https://coveralls.io/github/hiddentao/ethereum-event-logs?branch=master)
Parse Ethereum event logs with ease! 🎡
Features:
* Can parse logs for multiple event ABIs at the same time
* Accurately decodes event parameter values (both indexed and non-indexed)
* Automatically decodes non-indexable values as `bytes32` ([read more](https://ethereum.stackexchange.com/a/7170))
* Not tied to on any particular web3 library, can be used independently
## Install
* NPM/Yarn: `ethereum-event-logs`
## Example usage
Imagine the following contract:
```solidity
pragma solidity ^0.4.24;
contract Events {
event Event1(string indexed stringVar1, string stringVar2);
event Event2(bytes32 indexed bytes32Var, bool indexed boolVar, string stringVar);
event Event3(address indexed addressVar, uint uintVar, uint64[] indexed uint64Var1, uint64[] uint64Var2);
event Event4(bytes bytesVar) anonymous;
constructor () public {}
function emit() public {
emit Event1('test1', 'test2');
emit Event2(keccak256('test1'), false, 'test2');
uint64[] memory numbers = new uint64[](3);
numbers[0] = 100;
numbers[1] = 101;
numbers[2] = 102;
emit Event3(address(this), 2342, numbers, numbers);
emit Event4('0x123');
}
}
```
Let's say we deploy it and call `emit()` via an on-chain transaction. The
receipt for this transaction will contain the event logs.
Here is how we can parse the logs using this library:
```js
// import the parser
const { parseLog } = require('ethereum-event-logs')
const { abi } = require('./ExampleContract.json')
const receipt = /* execute tx on chain and wait for receipt */
// we can parse all events in the contract by passing through the ABI:
const events = parseLog(receipt.logs, abi)
console.log(events)
/*
[
{
name: 'Event1',
address: '0x...',
blockNumber: 123...,
blockHash: '0x...',
transactionHash: '0x...',
args: {
stringVar1: '0x...', // === web3.utils.sha3('test1')
stringVar2: 'test2'
},
log: {
... // the log object which represents this event
}
},
{
name: 'Event2',
address: '0x...',
blockNumber: 123...,
blockHash: '0x...',
transactionHash: '0x...',
args: {
bytes32Var: '0x...', // === web3.utils.sha3('test1')
boolVar: false,
stringVar: 'test2'
},
log: {
... // the log object which represents this event
}
},
{
name: 'Event3',
address: '0x...',
blockNumber: 123...,
blockHash: '0x...',
transactionHash: '0x...',
args: {
addressVar: '0x...', // address of contract
uintVar: '2342',
uint64Var1: '0x...',
uint64Var2: [ '100', '101', '102' ],
},
log: {
... // the log object which represents this event
}
}
// Event4 is defined as anonymous, hence it doesn't get parsed
]
*/
```
_Notice above that `Event1.stringVar1` is returned as a SHA3 hash instead of the
actual string. This is because only finite-sized scalar types (i.e. that fit within
a 64 byte hex code) can be `indexed` as an event argument. All other types have their
values hashed prior to indexing._
To only search for an individual event just pass that event's ABI on its own:
```js
const eventAbi = abi.find(({ name }) => name === 'Event1')
const events = parseLog(receipt.log, [ eventAbi ])
```
You can filter by contract address:
```js
const events = parseLog(receipt.log, [ eventAbi ], {
address: '0x....'
})
```
You can also filter by block number:
```js
const events = parseLog(receipt.log, [ eventAbi ], {
blockNumber: 1234...
})
```
If there is an argument decoding failure then the corresponding event instance
won't be included in the final results.
## Dev guide
* Install deps: `yarn`
* Tests: `yarn test`
* Tests with coverage: `yarn test:coverage`
* Build final lib: `yarn build`
* Lint: `yarn lint`
## License
MIT