Subsquid

Indexers provide an easy solution to query on-chain data. They process smart contract events in the background and store them in a database, which you can query using GraphQL. This enables efficient access to all smart contract events and allows for filtering the data as needed.

Prerequisites

Node.js 20.x or later is installed.
Docker is installed, and you have basic knowledge of using it.

Instructions

Install Subquid

Create a Squid: Follow the instructions for creating a Squid.

During setup, create a new Squid with a name of your choice. This will be used later.

Create the Indexer

Initialize the JavaScript environment

npm init

Install required packages

npm i dotenv typeorm @subsquid/evm-processor @subsquid/typeorm-store @subsquid/typeorm-migration @subsquid/graphql-server @subsquid/evm-abi

npm i typescript @subsquid/typeorm-codegen @subsquid/evm-typegen --save-dev

Add `tsconfig.json`

Create a tsconfig.json file in your project root with the following configuration:

{
  "compilerOptions": {
    "rootDir": "src",
    "outDir": "lib",
    "module": "commonjs",
    "target": "es2020",
    "esModuleInterop": true,
    "skipLibCheck": true,
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true
  }
}

Define the schema

Create a schema.graphql file and define the database schema. For example:

type Transfer @entity {
  id: ID!
  from: String! @index
  to: String! @index
  value: BigInt!
}

This schema represents the structure of the events you want to store in your database.

Generate TypeORM entities

Run the following command to generate TypeORM entities based on the schema:

npx squid-typeorm-codegen

Create a `.env` file

Define the database credentials in a .env file:

DB_NAME=peaq
DB_PORT=23798

Create `docker-compose.yaml`

Create a docker-compose.yaml file to set up a PostgreSQL database:

version: "3"
services:
  db:
    image: postgres:15
    environment:
      POSTGRES_DB: "${DB_NAME}"
      POSTGRES_PASSWORD: postgres
    ports:
      - "${DB_PORT}:5432"

Start the database container:

docker compose up -d

Compile TypeORM classes

Compile the generated TypeORM classes:

npx tsc

Generate and apply migrations

Generate the migration file:

npx squid-typeorm-migration generate

Apply the migration:

npx squid-typeorm-migration apply

Tie the code together

Create a src/main.ts file and add the following code:

import { EvmBatchProcessor } from '@subsquid/evm-processor';
import { TypeormDatabase } from '@subsquid/typeorm-store';
import { DataStoredEvent } from './model';

const DataStoredEventTopic = '0x9455957c3b77d1d4ed071e2b469dd77e37fc5dfd3b4d44dc8a997cc97c7b3d49';
const CONTRACT_ADDRESS = '0xdbdac2ef52681230f996624a5fa2624b06972671';

const processor = new EvmBatchProcessor()
  .setRpcEndpoint({
    url: 'https://rpcpc1-qa.agung.peaq.network',
  })
  .setFinalityConfirmation(5)
  .setBlockRange({ from: 3564900 })
  .addLog({
    address: [CONTRACT_ADDRESS]
  })
  .setFields({
    log: {
      transactionHash: true,
    },
  });

const db = new TypeormDatabase();

processor.run(db, async (ctx) => {
  const events: DataStoredEvent[] = [];
  for (let block of ctx.blocks) {
    for (let log of block.logs) {
      if (log.topics[0] === DataStoredEventTopic) {
        const data = BigInt(log.data);
        console.log("ID: ", log.id);
        console.log("DATA: ", data);
        console.log("BLOCK_NUMBER: ", block.header.height);
        console.log("TX_HASH: ", log.block.hash);

        events.push(new DataStoredEvent({
          id: log.id,
          data: Number(data),
          blockNumber: block.header.height,
          transactionHash: log.block.hash,
        }));
      }
    }
  }
  await ctx.store.insert(events);
});

Compile and start the processor

Compile the code:

npx tsc

Start the processor:

node -r dotenv/config lib/main.js

Start the GraphQL server

In a separate terminal, start the GraphQL server:

npx squid-graphql-server

About

Build

SDK Reference

Prerequisites

Instructions

Install Subquid

Create the Indexer

Initialize the JavaScript environment

Install required packages

Add `tsconfig.json`

Define the schema

Generate TypeORM entities

Create a `.env` file

Create `docker-compose.yaml`

Compile TypeORM classes

Generate and apply migrations

Tie the code together

Compile and start the processor

Start the GraphQL server

​Prerequisites

​Instructions

​Install Subquid

​Create the Indexer

​Initialize the JavaScript environment

​Install required packages

​Add tsconfig.json

​Define the schema

​Generate TypeORM entities

​Create a .env file

​Create docker-compose.yaml

​Compile TypeORM classes

​Generate and apply migrations

​Tie the code together

​Compile and start the processor

​Start the GraphQL server

Prerequisites

Instructions

Install Subquid

Create the Indexer

Initialize the JavaScript environment

Install required packages

Add `tsconfig.json`

Define the schema

Generate TypeORM entities

Create a `.env` file

Create `docker-compose.yaml`

Compile TypeORM classes

Generate and apply migrations

Tie the code together

Compile and start the processor

Start the GraphQL server