Subgraph Development and Querying Workshop

Video presentation of this workshop

Workshop Slides

Open These Tabs to Code Along with Live Workshop:

• Subgraph Studio
• Cryptopunks contract address (Etherscan) 0xb47e3cd837ddf8e4c57f05d70ab865de6e193bbb
• Jerry Okolo's Published CryptoPunks Subgraph
  • This subgraph's repo
  • This subgraph's schema.graphql
• Build a dapp with ScaffoldETH-2 and Subgraphs

Prerequisites

• Install graph-cli: yarn global add @graphprotocol/graph-cli

Learning Environment 1 :

Compare a Starter Subgraph with a Published Cryptopunks Subgraph Thats Live on The Graph Network

Deploy a Starter Subgraph

1. Gather information

Miniscan.xyz was deprecated.

Instead, use Cana to find important information relevant to your subgraph (smart contract name, ABI, startblock).

• Cryptopunks contract on Etherscan: 0xb47e3cd837ddf8e4c57f05d70ab865de6e193bbb

2. Go to Subgraph Studio, and create a new subgraph

• Follow the instructions in Subgraph Studio to spin up a new subgraph on your local computer using graph-cli.

• Choose "yes" when asked if wanting to index events as entites.

• graph deploy... to deploy your subgraph

Review Key Files in your Starter Cryptopunks Subgraph.

• subgraph.yaml (Subgraph Manifest)
• src/mappings.ts (Subgraph Logic)
• schema.graphql (Presented Subgraph Data)

Compare Starter Subgraph's Key Files to Published Cryptopunks Subgraph Key Files

• Jerry Okolo's Published Cryptopunks Subgraph published on The Graph Network.

• https://github.com/itsjerryokolo/CryptoPunks

• See what strategies Jerry uses in his subgraph and if you'd like to incorporate his strategies into your subgraph.

• An an exercise, try answering these questions with Jerry's Cryptopunks subgraph and your Cryptopunks subgraph with well-designed queries in the subgraph Playground.

- What are the first 10 transfers in Cryptopunks history
- Find the total value in Eth sales all punks, the total supply, and the total number of sales?
- 10 highest value Cryptopunks transactions of all time?
- How much ETH sales in total?
- Does Vitalik have a Cryptopunk?
- How many Cryptopunks wear a Pilot Helmet?
- What account has made the most transactions ever?
- Provenance (Who owned it before? Is it really the right one?)
- If available (only on-chain market places), what is the current asking price?
- What’s the highest current bid?
- Number of transfers made in the first block of Cryptopunks deployment?

Next steps:

Try out Learning Environment 2!

Learning Environment 2:

Deploy a Starter Subgraph and Extend an Entity

1. Gather information

Use Miniscan to find important information relevant to your subgraph (smart contract name, ABI, startblock).

• Cryptopunks contract on Etherscan

2. Go to Subgraph Studio, and create a new subgraph

• Follow the instructions in Subgraph Studio to spin up a new subgraph on your local computer using graph-cli.

• Enter information gathered from MiniScan into graph-cli as prompted.

• Choose "yes" when asked if wanting to index events as entites.

• graph deploy... to deploy your subgraph

Review key files in your starter Cryptopunks subgraph.

• subgraph.yaml (Subgraph Manifest)
• src/mappings.ts (Subgraph Logic)
• schema.graphql (Presented Subgraph Data)

Understand the Generated Transfer Entity in Schema.graphql

# schema.graphql
type Transfer @entity(immutable: true) {
	id: Bytes!
	from: Bytes! # address
	to: Bytes! # address
	value: BigInt! # uint256
	blockNumber: BigInt!
	blockTimestamp: BigInt!
	transactionHash: Bytes!
}

Extend the Transfer Entity

Lets create a property in the Transfer entity that records the gas price of the transfer.

Add gasPrice to Transfer entity:

# schema.graphql
type Transfer @entity(immutable: true) {
	id: Bytes!
	from: Bytes! # address
	to: Bytes! # address
	value: BigInt! # uint256
	blockNumber: BigInt!
	blockTimestamp: BigInt!
	transactionHash: Bytes!
	gasPrice: BigInt! ## ADDED HERE
}

Update mappings.ts to send event data to the gasPrice property on the Transfer entity

// mappings.ts
export function handleTransfer(event: TransferEvent): void {
	let entity = new Transfer(
		event.transaction.hash.concatI32(event.logIndex.toI32())
	);
	entity.from = event.params.from;
	entity.to = event.params.to;
	entity.value = event.params.value;

	entity.blockNumber = event.block.number;
	entity.blockTimestamp = event.block.timestamp;
	entity.transactionHash = event.transaction.hash;

	entity.gasPrice = event.transaction.gasPrice;

	entity.save();
}

Add a new entity to store Account information

This new gasSpent property will total gas spent by an Account.

# schema.graphql
type Transfer @entity(immutable: true) {
	id: Bytes!
	from: Bytes! # address
	to: Bytes! # address
	value: BigInt! # uint256
	blockNumber: BigInt!
	blockTimestamp: BigInt!
	transactionHash: Bytes!
	gasPrice: BigInt!
}
type Account @entity {
	id: Bytes! # address
	gasSpent: BigInt! # uint256
}

Update mappings.ts to populate new Account entity

You must import BigInt from the graph-ts typscript helper library to perform the plus() function described below.

// src/mappings.ts
import { BigInt } from "@graphprotocol/graph-ts";

Read more about the graph-ts helper library.

// mappings.ts
export function handleTransfer(event: TransferEvent): void {
	let entity = new Transfer(
		event.transaction.hash.concatI32(event.logIndex.toI32())
	);
	entity.from = event.params.from;
	entity.to = event.params.to;
	entity.value = event.params.value;

	entity.blockNumber = event.block.number;
	entity.blockTimestamp = event.block.timestamp;
	entity.transactionHash = event.transaction.hash;
	entity.gasPrice = event.transaction.gasPrice;

	entity.save();

	// Load account from store. If account does not exist, create an account and set the gasSpent to 0.

	let account = Account.load(
		event.transaction.hash.concatI32(event.block.hash.toI32())
	);
	if (account == null) {
		account = new Account(
			event.transaction.hash.concatI32(event.block.hash.toI32())
		);
		account.gasSpent = BigInt.fromI32(0);
	}

	// Add the gas price of the current transaction to the total gas spent
	account.gasSpent = account.gasSpent.plus(event.transaction.gasPrice);

	account.save();
}

Next Steps:

• Add more entities and mappings logic as desired.

• Build queries using the Playground Explorer and reference the The Graph GraphQL docs to improve query accuracy.

• Try building with Kevin Jones' blog that combines ScaffoldETH-2 and Subgraphs

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Happy hacking,

Marcus Rein

Developer Relations and Developer Success

Edge & Node

https://www.twitter.com/Marcus_Rein_

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Other resources

• https://github.com/schmidsi/hackathon-starterkit
• https://github.com/scaffold-eth/scaffold-eth#-scaffold-eth
• https://github.com/Developer-DAO/resources
• https://dev.to/dabit3/the-complete-guide-to-full-stack-ethereum-development-3j13
• https://github.com/itsjerryokolo/CryptoPunks
• https://github.com/dabit3/building-a-subgraph-workshop
• https://thegraph.com/docs/developer/quick-start
• https://thegraph.com/discord
• https://protean-labs.github.io/subgrounds/