Magick

SubQuery Indexer for RMRK NFT Standard

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The SubQuery Indexer is suitable for any Substrate chain which wants to parse strings into the NFTs. This readme will go through the steps to set up the SubQuery Indexer and provide some valuable hacks for ease of development. A SubQuery package defines which data The SubQuery will index from the Substrate blockchain and how it will store it.

⚠️ caveat ⚠️: This indexer is can only index RMRK 1.0.0 standard NFTs. If you plan to hack 2.0.0, we would love to welcome you with a PR.

Prerequisites 🎒

node >= 14
yarn 🧶
docker 🐳
[just](https://github.com/casey/just) 🤖

Hyper start 🚀

First, we need to install dependencies.

just quickstart

then in the terminal run:

just up

I want to change something in this project

The core of this indexer is the following files:

• Which events/extrinsics to index + configuration - project.yaml
• Entities which we want to save in DB - schema.graphql
• How map events/extrinsics to the GraphQL - src/mappings/ directory

For more information on how to write the SubQuery, check out our doc section on Define the SubQuery

I want to add/remove fields that are indexed

Open schema.graphql and modify the entities how much you want. Supported types can be found here

The example entity looks like this:

type CollectionEntity @entity {
  id: ID!
  issuer: String!
  currentOwner: String!
  metadata: String
  nfts: [NFTEntity] @derivedFrom(field: "collection")
  blockNumber: BigInt @index
  burned: Boolean!
  createdAt: Date!
}

Each entity needs to have an id: ID! field. An exclamation mark (!) says that the field is required, and without it, the entity will not be indexed, and the database will fail on null-pointer.

You can also define relationships between entities. For example, if you want to index one-to-many relation, it can be defined like nfts: [NFTEntity] @derivedFrom(field: "collection"). @derivedFrom(field: "collection") indicates that collection can be queried backwards from NFTEntity.

type NFTEntity @entity {
  id: ID!
  collection: CollectionEntity!
}

If you changed the schema, we need to regenerate it by running:

just types

I want to add a new event/extrinsic to the index

in project.yaml add the new event/extrinsic create new record under the handlers to index:

    handlers:
      - handler: handleCall
        kind: substrate/CallHandler
        filter:
          module: utility
          method: batchAll
          success: true

then in src/mappings/mappingHandlers.ts add the new mapping:

import {
  SubstrateExtrinsic,
} from '@subql/types'

export async function handleCall(extrinsic: SubstrateExtrinsic): Promise<void> {
  // your implementation should go here
}

after you implement what you need, run:

just build

Indexing and Query

To spin up the indexer, run:

just up

It will start the indexer and the SubQuery server.

Writing the first query

To query the data open your browser and head to http://localhost:3000.

Finally, you should see a GraphQL playground is showing in the explorer and the schemas that ready to query.

For example, to query first 5 nfts and their collection, you can run:

query {
  nFTEntities(first: 5) {
    nodes {
      id
      issuer
      collection {
        id
        metadata
      }
    }
  }
}

Dev hacks (FAQ) 🦇

We use just, and we recommend using it.

1. How can I turn off the indexer properly?

just down

2. I made a change in mapper. How to re-run the app again?

just bug

3. My DB is a complete mess. How to start again?

just clear

4. How can I check for the new version of the SubQuery Indexer?

just pull