Gnosis Quick Start
Gnosis Quick Start
Gnosis Chain is an EVM compatible, community owned network that prioritizes credible neutrality and resiliency, open to everyone without privilege or prejudice. It aims to provide infrastructure and tools for creating, trading, and governing decentralized finance (DeFi) applications. There are several components that make up Gnosis such as the CoW Protocol, Safe, Gnosis Beacon Chain and GnosisDAO.
The goal of this quick start guide is to index all POAP mints and transactions on the Gnosis mainnet.
In the earlier Quickstart section , you should have taken note of three crucial files. To initiate the setup of a project from scratch, you can proceed to follow the steps outlined in the initialisation description.
As a prerequisite, you will need to generate types from the ABI files of each smart contract. Additionally, you can kickstart your project by using the EVM Scaffolding approach (detailed here). You'll find all the relevant events to be scaffolded in the documentation for each type of smart contract.
Note
The final code of this project can be found here.
Your Project Manifest File
The Project Manifest file is an entry point to your project. It defines most of the details on how SubQuery will index and transform the chain data.
For EVM chains, there are three types of mapping handlers (and you can have more than one in each project):
- BlockHanders: On each and every block, run a mapping function
- TransactionHandlers: On each and every transaction that matches optional filter criteria, run a mapping function
- LogHanders: On each and every log that matches optional filter criteria, run a mapping function
Important
We use Ethereum packages, runtimes, and handlers (e.g. @subql/node-ethereum, ethereum/Runtime, and ethereum/*Handler) for Gnosis. Since Gnosis is a EVM implementation, we can use the core Ethereum framework to index it.
As we are indexing all transfers and mints for the POAP ERC721 contract, the first step is to import the contract abi definition which can be obtained from here. Copy the entire contract ABI and save it as a file called poap.abi.json in the /abis directory.
This section in the Project Manifest now imports all the correct definitions and lists the triggers that we look for on the blockchain when indexing.
Since we are indexing all mints and transfers for the POAP ERC721 contract, you need to update the datasources section as follows:
{
dataSources: [
{
kind: EthereumDatasourceKind.Runtime,
// When the POAP contract was deployed https://gnosisscan.io/tx/0x2e4873cb1390f5328d389276624d1ffa833e3934657d5a791ee145defff663a2
startBlock: 12188423,
options: {
// Must be a key of assets
abi: "poap",
// this is the contract address for POAPs on Gnosis https://gnosisscan.io/token/0x22c1f6050e56d2876009903609a2cc3fef83b415
address: "0x22c1f6050e56d2876009903609a2cc3fef83b415",
},
assets: new Map([["poap", { file: "./abis/poap.abi.json" }]]),
mapping: {
file: "./dist/index.js",
handlers: [
{
kind: EthereumHandlerKind.Call,
handler: "handleTokenMint",
filter: {
/**
* The function can either be the function fragment or signature
* function: '0xaf68b302'
*/
function: "mintToken(uint256 eventId, address to)",
},
},
{
kind: EthereumHandlerKind.Event,
handler: "handleLog",
filter: {
/**
* Follows standard log filters https://docs.ethers.io/v5/concepts/events/
* address: "0x60781C2586D68229fde47564546784ab3fACA982"
*/
topics: [
"Transfer(address indexed from, address indexed to, uint256 amount)",
],
},
},
],
},
},
],
}
The above code indicates that you will be running handleTokenMint and handleTokenTransfer mapping functions whenever there is a transaction with the function mintToken or a log with the signature Transfer on any transaction from the POAP smart contract.
Check out our Manifest File documentation to get more information about the Project Manifest (project.ts) file.
Update Your GraphQL Schema File
The schema.graphql file determines the shape of your data from SubQuery due to the mechanism of the GraphQL query language. Hence, updating the GraphQL Schema file is the perfect place to start. It allows you to define your end goal right at the start.
Remove all existing entities and update the schema.graphql file as follows. Here you can see we are indexing token information such as the id and the mintBlockHeight along with all transfers of that token. There are foreign keys between all entities.
type Event @entity {
id: ID!
}
type Token @entity {
id: ID!
mintBlockHeight: BigInt!
mintTx: String
mintDate: Date!
mintReceiver: Address!
currentHolder: Address!
event: Event
}
type Address @entity {
id: ID!
}
type TokenTransfer @entity {
id: ID! # transactionHash
txHash: String!
date: Date!
blockHeight: BigInt!
from: Address!
to: Address!
token: Token!
}
Note
Importantly, these relationships can not only establish one-to-many connections but also extend to include many-to-many associations. To delve deeper into entity relationships, you can refer to this section. If you prefer a more example-based approach, our dedicated Hero Course Module can provide further insights.
SubQuery simplifies and ensures type-safety when working with GraphQL entities, smart contracts, events, transactions, and logs. The SubQuery CLI will generate types based on your project's GraphQL schema and any contract ABIs included in the data sources.
yarn codegen
npm run-script codegen
This action will generate a new directory (or update the existing one) named src/types. Inside this directory, you will find automatically generated entity classes corresponding to each type defined in your schema.graphql. These classes facilitate type-safe operations for loading, reading, and writing entity fields. You can learn more about this process in the GraphQL Schema section.
It will also generate a class for every contract event, offering convenient access to event parameters, as well as information about the block and transaction from which the event originated. You can find detailed information on how this is achieved in the EVM Codegen from ABIs section. All of these types are stored in the src/types/abi-interfaces and src/types/contracts directories.
You can conveniently import all these types:
import { Token, Event, Address, TokenTransfer } from "../types";
import {
EventTokenLog,
MintTokenTransaction,
TransferLog,
} from "../types/abi-interfaces/PoapAbi";
Check out the GraphQL Schema documentation to get in-depth information on schema.graphql file.
Now that you have made essential changes to the GraphQL Schema file, let’s proceed ahead with the Mapping Function’s configuration.
Add a Mapping Function
Mapping functions define how blockchain data is transformed into the optimised GraphQL entities that we previously defined in the schema.graphql file.
Navigate to the default mapping function in the src/mappings directory. You will be able to see two exported functions: handleLog, and handleTransaction.
import { Token, Event, Address, TokenTransfer } from "../types";
import assert from "assert";
import {
EventTokenLog,
MintTokenTransaction,
TransferLog,
} from "../types/abi-interfaces/PoapAbi";
import { BigNumberish } from "ethers";
async function checkGetEvent(id: BigNumberish): Promise<Event> {
let event = await Event.get(id.toString().toLowerCase());
if (!event) {
event = Event.create({
id: id.toString().toLowerCase(),
});
await event.save();
}
return event;
}
async function checkGetAddress(id: string): Promise<Event> {
let address = await Address.get(id.toLowerCase());
if (!address) {
address = Address.create({
id: id.toLowerCase(),
});
await address.save();
}
return address;
}
export async function handleTokenMint(tx: MintTokenTransaction): Promise<void> {
logger.info(`New Token Mint transaction at block ${tx.blockNumber}`);
assert(tx.args, "No tx.args");
// logger.info(JSON.stringify(tx.args));
const [eventId, receiverId] = tx.args;
const event = await checkGetEvent(await eventId);
const receiver = await checkGetAddress(await receiverId);
// The tokenID is from the logs from this transaction
// This searches by the function fragment signature to get the right log
const log = tx.logs?.find((log) =>
log.topics.includes(
"0x4b3711cd7ece062b0828c1b6e08d814a72d4c003383a016c833cbb1b45956e34",
),
) as EventTokenLog;
if (log) {
const tokenId = log.args?.tokenId;
assert(tokenId, "No tokenID");
const newToken = Token.create({
id: tokenId.toString(),
mintTx: tx.hash,
mintBlockHeight: BigInt(tx.blockNumber),
mintDate: new Date(Number(tx.blockTimestamp) * 1000), // Saved as a seconds epoch
mintReceiverId: receiver.id,
currentHolderId: receiver.id,
eventId: event.id,
});
await newToken.save();
}
}
export async function handleTokenTransfer(log: TransferLog) {
logger.info(`New Token Transfer log at block ${log.blockNumber}`);
assert(log.args, "No log.args");
// We ignore all transfers from 0x0000000000000000000000000000000000000000 since they are from the original mint
if (log.args.from != "0x0000000000000000000000000000000000000000") {
const from = await checkGetAddress(await log.args.from);
const to = await checkGetAddress(await log.args.to);
let token = await Token.get(await log.args.tokenId.toString());
if (!token) {
token = Token.create({
id: log.args.tokenId.toString(),
mintBlockHeight: BigInt(log.blockNumber),
mintDate: new Date(Number(log.block.timestamp) * 1000), // Saved as a seconds epoch
mintReceiverId: to.id,
currentHolderId: to.id,
});
}
const newTokenTransfer = TokenTransfer.create({
id: log.transactionHash,
txHash: log.transactionHash,
date: new Date(Number(log.block.timestamp) * 1000), // Saved as a seconds epoch
blockHeight: BigInt(log.blockNumber),
fromId: from.id,
toId: to.id,
tokenId: token.id,
});
await newTokenTransfer.save();
token.currentHolderId = to.id;
await token.save();
}
}
The handleTokenMint function receives a tx parameter of type MintTokenTransaction which is typed from the POAP ABI. This includes transaction function payload data. We first check that we already have an entity for the Event and receiver address. We then also search through the attached transaction logs for the specific log that includes the resulting tokenId that was minted. We extract this data and then save this to the store using the .save() function (Note that SubQuery will automatically save this to the database).
The handleTokenTransfer receives a typed TransferLog that contains information about a transfer event of a specific POAP token. It extracts this, ignores if the transfer is from the root account (0x0000000000000000000000000000000000000000), and then saves this transfer data. It also retrieves and updates the currentHolderId of the token itself.
Note
For more information on mapping functions, please refer to our Mappings documentation.
Build Your Project
Next, build your work to run your new SubQuery project. Run the build command from the project's root directory as given here:
yarn build
npm run-script build
Important
Whenever you make changes to your mapping functions, you must rebuild your project.
Now, you are ready to run your first SubQuery project. Let’s check out the process of running your project in detail.
Whenever you create a new SubQuery Project, first, you must run it locally on your computer and test it and using Docker is the easiest and quickiest way to do this.
Run Your Project Locally with Docker
The docker-compose.yml file defines all the configurations that control how a SubQuery node runs. For a new project, which you have just initialised, you won't need to change anything.
However, visit the Running SubQuery Locally to get more information on the file and the settings.
Run the following command under the project directory:
yarn start:docker
npm run-script start:docker
Note
It may take a few minutes to download the required images and start the various nodes and Postgres databases.
Query your Project
Next, let's query our project. Follow these three simple steps to query your SubQuery project:
Open your browser and head to
http://localhost:3000.You will see a GraphQL playground in the browser and the schemas which are ready to query.
Find the Docs tab on the right side of the playground which should open a documentation drawer. This documentation is automatically generated and it helps you find what entities and methods you can query.
Try the following queries to understand how it works for your new SubQuery starter project. Don’t forget to learn more about the GraphQL Query language.
# Write your query or mutation here
query {
tokens(first: 5, orderBy: MINT_BLOCK_HEIGHT_DESC) {
nodes {
id
mintBlockHeight
mintReceiverId
mintDate
eventId
}
}
addresses(first: 5, orderBy: TOKENS_BY_CURRENT_HOLDER_ID_COUNT_DESC) {
nodes {
id
tokensByCurrentHolderId(first: 5) {
totalCount
nodes {
id
}
}
}
}
}
You will see the result similar to below:
{
"data": {
"tokens": {
"nodes": [
{
"id": "16947",
"mintBlockHeight": "12293177",
"mintReceiverId": "0xbcb0d39073ad99aa68fb6d7b2c2a433892af6fb3",
"mintDate": "2020-10-01T17:04:40",
"eventId": "361"
},
{
"id": "16946",
"mintBlockHeight": "12292651",
"mintReceiverId": "0x05b512f909daae5575afb47b3eeb0b0afeb14c00",
"mintDate": "2020-10-01T16:20:30",
"eventId": "69"
},
{
"id": "16945",
"mintBlockHeight": "12291133",
"mintReceiverId": "0x0542e8f95f765b81cd6a08db37d914f664db5d3e",
"mintDate": "2020-10-01T14:13:20",
"eventId": "405"
},
{
"id": "16944",
"mintBlockHeight": "12290462",
"mintReceiverId": "0xa615f34b170329507b37c142f8f812b8e1393beb",
"mintDate": "2020-10-01T13:16:35",
"eventId": "405"
},
{
"id": "16943",
"mintBlockHeight": "12290460",
"mintReceiverId": "0xe07e487d5a5e1098bbb4d259dac5ef83ae273f4e",
"mintDate": "2020-10-01T13:16:25",
"eventId": "405"
}
]
},
"addresses": {
"nodes": [
{
"id": "0xb8d7b045d299c9c356bc5ee4fe2dddc8a31280a5",
"tokensByCurrentHolderId": {
"totalCount": 1,
"nodes": [
{
"id": "16924"
}
]
}
},
{
"id": "0xba993c1fee51a4a937bb6a8b7b74cd8dffdca1a4",
"tokensByCurrentHolderId": {
"totalCount": 1,
"nodes": [
{
"id": "16912"
}
]
}
},
{
"id": "0x2b098ce1d5a4f9c2729268a4a3f04b387d4cc7ec",
"tokensByCurrentHolderId": {
"totalCount": 1,
"nodes": [
{
"id": "16921"
}
]
}
},
{
"id": "0x60df279f7cc51d2f0ff903f68c3a8dfcf65419f7",
"tokensByCurrentHolderId": {
"totalCount": 1,
"nodes": [
{
"id": "16916"
}
]
}
},
{
"id": "0x626ea6d1e5ea3fbaba22f5d4005d98e7039d0c99",
"tokensByCurrentHolderId": {
"totalCount": 1,
"nodes": [
{
"id": "16919"
}
]
}
}
]
}
}
}
Note
The final code of this project can be found here.
What's next?
Congratulations! You have now a locally running SubQuery project that accepts GraphQL API requests for transferring data.
Tip
Find out how to build a performant SubQuery project and avoid common mistakes in Project Optimisation.
Click here to learn what should be your next step in your SubQuery journey.