Generating utility modules

squid-evm-typegen
squid-substrate-typegen
squid-ink-typegen

The squid-evm-typegen(1) tool generates TypeScript facades for EVM transactions, logs and eth_call queries.The generated facades are assumed to be used by squids indexing EVM data.The tool takes a JSON ABIs as an input. Those can be specified in three ways:

as a plain JSON file(s):
```
npx squid-evm-typegen src/abi abi/erc20.json
```
To include all files in ./abi and add an interface for the Multicall contract, run
```
npx squid-evm-typegen ./src/abi ./abi/*.json --multicall
```
You can get JSON ABIs for explorer (Etherscan, Bscscan etc) verified contract by visiting the contract page, going to the “Contract” tab and scrolling down to the “Contract ABI” section. Do not use the “Export ABI” function! Copy the contents to the clipboard and paste them to a new JSON file.

(requires an Etherscan API key) as a contract address. One can pass multiple addresses at once.

npx squid-evm-typegen --etherscan-api-key <your_key> src/abi 0xBB9bc244D798123fDe783fCc1C72d3Bb8C189413

Please check if your contract is a proxy when using this method. If it is, consult this page for guidance.

as an arbitrary URL:

npx squid-evm-typegen src/abi https://example.com/erc721.json

In all cases typegen will use basename of the ABI as the root name for the generated files. You can change the basename of generated files using the fragment (#) suffix.

squid-evm-typegen src/abi 0xBB9bc244D798123fDe783fCc1C72d3Bb8C189413#my-contract-name

Arguments:


`output-dir`	output directory for generated definitions
`abi`	A contract address, an URL or a local path to the ABI file. Accepts multiple contracts.

Options:


`--multicall`	generate a facade for the MakerDAO multicall contract. May significantly improve the performance of contract state calls by batching RPC requests
`--etherscan-api <url>`	etherscan API to fetch contract ABI by a known address. By default, `https://api.etherscan.io/`
`--clean`	delete output directory before the run
`-h, --help`	display help for command

The generated modules depend on @subsquid/evm-abi. Please add it to your package.json as a peer dependency if it’s not there already: bash npm i @subsquid/evm-abi

Usage

The generated utility modules have three intended uses:

Constants: EVM log topic0 values and sighashes for transactions. Example:

// generated by evm-typegen
import * as weth from "./abi/weth";

const CONTRACT_ADDRESS =
  "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2".toLowerCase();

const processor = new EvmBatchProcessor()
  .setGateway("https://v2.archive.subsquid.io/network/ethereum-mainnet")
  .addLog({
    address: [CONTRACT_ADDRESS],
    topic0: [weth.events.Deposit.topic, weth.events.Withdrawal.topic],
  });

Decoding of EVM logs and transactions
Direct chain state queries, including queries to multicall.

The substrate typegen tool is a part of Squid SDK. It generates TypeScript wrappers for interfacing Substrate events and calls.Usage:

npx squid-substrate-typegen typegen.json

If necessary, multiple config files can be supplied:

npx squid-substrate-typegen typegen0.json typegen1.json ...

The structure of the typegen.json config file is best illustrated with an example:

{
  "outDir": "src/types",
  "specVersions": "https://v2.archive.subsquid.io/metadata/kusama",
  "pallets": {
    // add one such section for each pallet
    "Balances": {
      "events": [
        // list of events to generate wrappers for
        "Transfer"
      ],
      "calls": [
        // list of calls to generate wrappers for
        "transfer_allow_death"
      ],
      "storage": ["Account"],
      "constants": ["ExistentialDeposit"]
    }
  }
}

The specVersions field is either

a metadata service endpoint URL, like

https://v2.archive.subsquid.io/metadata/{network}

a path to a jsonl file generated by substrate-metadata-explorer(1).

To generate all items defined by a given pallet, set any of the events, calls, storage or constants fields to true, e.g.

{
  "outDir": "src/types",
  "specVersions": "kusamaVersions.jsonl",
  "pallets": {
    "Balances": {
      // generate wrappers for all Balances pallet constants
      "constants": true
    }
  }
}

In the rare cases when the typegen needs a types bundle, supply it alongside metadata:

{
  "outDir": "src/types",
  "specVersions": "westendVersions.jsonl",
  "typesBundle": "westendTypes.json",
  ...
}

TypeScript wrappers

Wrappers generated by the typegen command can be found in the specified outDir (src/types by convention). Assuming that this folder is imported as types (e.g. with import * as types from './types'), you’ll be able to find the wrappers at:

for events: types.events.${palletName}.${eventName}
for calls: types.calls.${palletName}.${callName}
for storage items: types.storage.${palletName}.${storageItemName}
for constants: types.constants.${palletName}.${constantName}

All identifiers (pallet name, call name etc) are lowerCamelCased. E.g. the constant Balances.ExistentialDeposit becomes types.events.balances.existentialDeposit and the call Balances.set_balance becomes types.calls.setBalance.

Usage

Item name constants (e.g. events.balances.transfer.name).
Runtime versioning-aware decoding.
Chain storage queries

Runtime constants:

import {constants} from './types'
// ...
processor.run(new TypeormDatabase(), async ctx => {
  for (let block of ctx.blocks) {
    if (constants.balances.existentialDeposit.v1020.is(block.header)) {
      let c = new constants.balances.existentialDeposit.v1020.get(block.header)
      ctx.log.info(`Balances.ExistentialDeposit (runtime version V1020): ${c}`)
    }
  }
})

Use squid-ink-typegen to generate facade classes for decoding ink! smart contract data from JSON ABI metadata.Usage:

npx squid-ink-typegen --abi abi/erc20.json --output src/abi/erc20.ts

The generated source code exposes the decoding methods, some useful types and a class for performing wrapped RPC queries, using @subsquid/ink-abi under the hood

Overview

Pipes SDK

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TypeScript wrappers

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Pipes SDK

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