The XYO Foundation provides this source code available in our efforts to advance the understanding of the XYO Procotol and its possible uses. We continue to maintain this software in the interest of developer education. Usage of this source code is not intended for production.
An ethereum smart contract event cache. Query your smart contract events in ways that you can't do directly on the blockchain. A helpful development tool or a helpful addition to your production Dapp.
There are three components that dAche uses to track events:
- Rebase starts from the block the contract was created and imports events from then until the block that the dAche was started at. This is disabled by default since the included contract has a lot of events !
- Watch listens live for events on the contracts and immediately pulls them in
- Scan runs at a defined offset from the newest block on chain, and re-imports events from this range. This is to compensate for any missed live events, which can happen.
First copy config/default.example.json and rename to default.json.
By default, dAche will run with an in-memory database (NeDB) to get you up and running quick.
Postgres is also supported, so if you prefer that fill out the storage section of the config file with your database info:
"storage": {
"type": "postgres",
"database": "mydb",
"host": "mydb.db.com",
"password": "password",
"user": "admin",
"port": 5432
}
To start dAche, npm install then npm start.
There is a simple GraphQL layer for the dAche API implemented.
Visit http://localhost:4000/graphql to view the built-in GrapgQL query interface.
To see the latest events (ordered by newest blocks by default (order: -1):
{
events {
items {
contractName
eventName
blockNumber
returnValues
}
}
}
We have implemented example queries to show how you can query the events in a way you can't directly on the blockchain. To query all events by a given return value key/value:
{
events (
returnValuesKey: "kittyId",
returnValuesValue: "5436") {
items {
contractName
eventName
blockNumber
returnValues
}
}
}
This is an example of a non-grapql use of the Dache. This is a GET endpoint that will return all current token holders of a token contract (a csv of address, balance). We have included the XYO Token contract as an example.
Stop the dAche. Update the contractSource.contracts, replace CryptoKittiesCore with XYO. Change rebase.enabled to true. Start the dAche.
Visit http://localhost:4000/balances/XYO and
By default, you will see rebase.enabled is turned off in the config file. If you enable this option, dAche will historically scan all events since contract creation and import them in.
Would not recommend enabling this for the CryptoKittiesCore contract unless you have a big database ;)
rebase.blockScanIncrement is the page size for scanning blocks for events to import. You can adjust this for performance reasons if needed.
Options for ethereum.network:
- mainnet
- ropsten
- rinkeby
- kovan
To us IPFS to load contracts, update the config to have the following entries:
"contractSource": {
"type": "ipfs",
"directoryHash": "QmWA8zB1zkEMGmKnD8PNHrJuQPW5hfV5NrYjYMvB6jB1Ac",
"host": "ipfs.xyo.network",
"protocol": "https",
"port": 5002
}
To use S3 to load contracts instead of a local directory, update the config to have the following entries:
"aws": {
"accessKeyId": "123",
"secretAccessKey": "456",
"region": "us-east-1"
},
"contractSource": {
"type": "s3",
"bucketName": "mybucket",
"keyPrefix": "abi/mainnet/"
}
To only load specific contract(s) from a source, include the "contracts" key as noted below
"contractSource": {
"type": "local",
"directory": "./examples/contracts",
"contracts": [
"CryptoKittiesCore"
]
}
For the Scan component, you can adjust sync.blockScanOffset. This is how many blocks you want to wait before reimporting events that were picked up live.
- Arie Trouw
See the LICENSE file for license details.
Made with 🔥and ❄️ by XYO