Sample project showcasing Hydra for Subsocial substrate chain

• Yarn
• Node v12.x
• Docker (Optional)

First, run the database:

docker-compose up -d db

Then run hydra codegen together with all the necessary schema migrations. There is a convenient script to make everything in one shot

yarn bootstrap

Now run the processor:

yarn processor:start

This will run Hydra processor running the event handlers in ./mappings against the Subsocial indexer

In a separate terminal running

yarn server:start:dev

This will run a GraphQL API against the entity schema defined in schema.graphl. The playground opens up at localhost:4000.

Let's query some posts:

query {
  posts(limit: 5) {
    content
    id
    author
  }
}

• Extend the schema by adding new fields and entities to scheama.graphql. There are lot of possibilities explained in the docs
• Add new mappings (event listeners) to ./mappings. Remember that all event handlers must be imported in ./mappings/index.ts and follow the naming convention <module>_<eventName>.

Make sure the model classes and the database schema are rebuilt after a model or mappings change. There is a separate script for it:

yarn rebuild