Posted By : Ashish
The Graph is a tool that helps apps quickly access blockchain data. It uses a technology called GraphQL to pull data efficiently. Developers use it during blockchain app development to build faster and more reliable blockchain apps. It organizes blockchain data into something called subgraphs, making it easier to handle. This tool supports several blockchains, enhancing its usefulness for developers.
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Command:
yarn global add @graphprotocol/graph-cli` or `npm install -g @graphprotocol/graph-cli`
This installs the necessary tools to create and manage subgraphs.
Command:
`graph init --from-example /`
This sets up a new subgraph directory with starter files based on a template.
Example
yaml
specVersion: 0.0.2
description: 'Example subgraph'
repository: 'https://github.com/example/repo'
dataSources:
- kind: ethereum/contract
name: ContractName
source:
address: '0x...'
abi: ContractABI
mapping:
kind: ethereum/events
apiVersion: 0.0.4
language: wasm/assemblyscript
entities:
- EntityName
abis:
- name: ContractABI
file: ./abis/ContractABI.json
eventHandlers:
- event: Transfer(address,address,uint256)
handler: handleTransfer
file: ./src/mapping.ts
This file configures your subgraph, defining which blockchain events it listens to and how they map to the data entities.
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File: schema.graphql
Example content:
```graphql
type Transfer @entity {
id: ID!
from: Bytes!
to: Bytes!
value: BigInt!
}
```
This defines the data structures that your subgraph will store and make queryable.
File: `src/mapping.ts`
Example function:
```typescript
import { BigInt } from '@graphprotocol/graph-ts'
import { Transfer } from '../generated/Contract/Contract'
export function handleTransfer(event: Transfer): void {
let transfer = new Transfer(event.params.from, event.params.to, event.params.value)
transfer.save()
}
```
This script processes incoming blockchain events and translates them into entities defined in the GraphQL schema.
Command:
`graph deploy --product hosted-service /`
This uploads your subgraph to The Graph's hosted service, making it available for queries.
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In conclusion, The Graph Protocol is a powerful tool for developers looking to build and deploy efficient, reliable, and scalable blockchain applications. By using GraphQL to quickly access and manage blockchain data, and organizing it into subgraphs, developers can significantly enhance the performance and stability of their decentralized applications. With support for multiple blockchains, The Graph provides flexibility and a robust solution for a variety of use cases. Following the steps outlined"”installing the Graph CLI, initializing your subgraph, defining the subgraph.yaml, creating a GraphQL schema, writing AssemblyScript mappings, and deploying your subgraph"”will enable you to leverage the full potential of The Graph Protocol, streamlining your development process and improving your application's overall functionality. Connect with our skilled blockchain developers for a quick consultation regarding your blockchain or crypto project.
September 6, 2024 at 10:42 pm
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