is a framework for building indexer apps using TypeScript (or JavaScript). Its main strength is its versatility - it can be used to rapidly develop a simple smart contract indexer or collect particular block data, but also to index data from the entire blockchain or compose multiple indexers.
Prerequisites
Before you start, you will need the following:
16 or higher
(to check the stored data). If you want to use Dappetizer with PostgreSQL, please also check our to learn more.
Generating a new indexer
For this example, we will create a simple app that tracks registrations of new domain names in . Start by creating a new folder:
mkdir dappetizer-quickstart
cd dappetizer-quickstart
Install Dappetizer itself:
npm install @tezos-dappetizer/cli
To initialize a new indexer for our registration contract, run Dappetizer with the command:
To add the Registration entity to the module, you will need to edit the index.ts file and add Registration to the dbEntities property:
src/index.ts
import { IndexerModuleUsingDb } from '@tezos-dappetizer/database';
import { createContractIndexerFromDecorators } from '@tezos-dappetizer/decorators';
import { Registration } from './entities';
import { TezosDomainsIndexer } from './tezos-domains-indexer';
export const indexerModule: IndexerModuleUsingDb = {
name: 'MyModule',
dbEntities: [
// Register your DB entity classes to TypeORM here:
Registration,
],
contractIndexers: [
// Create your contract indexers here:
createContractIndexerFromDecorators(new TezosDomainsIndexer()),
],
};
Implementing indexing logic
The smart contract we are going to index has a fairly simple structure. The buy entrypoint accepts a few parameters, like the label (i.e. the domain name without .tez), the new owner and the registration duration in days.
If you wish to learn more details about this particular contract, you can check:
All we need to do now is compiling the source code...
npm run build
... and running the indexer app.
npx dappetizer start
If everything works, you should see a console output showing the indexing progress with each individual block. For now, let's kill the process by Ctrl+C after letting it run for a short while.
Checking the generated data
sqlite3 database.sqlite
To select what registrations have been saved by the indexer, we will run a short SELECT query:
As you can see, the indexer is saving successful registrations. If you run the indexer again it will pick up from the last indexed block and continue on until it reaches the latest block. After that, it will wait for each new block and index it as well.
We will have one that represents a successful domain registration:
Our generated indexer module already has an indexer for the contract in tezos-domains-indexer.ts. It contains an empty method called indexBuy where we can put the code that will take care of saving the parameters of each call to the database using . We can get rid of the remaining indexing methods which we won't need for this example.