The query-node project contains an input schema (schema.graphql) and mappings for the Joystream content-directory runtime module.

We use Hydra-cli to generate a graphql server and a block indexer for joystream chain:

$ cd query-node
$ hydra-cli codegen

After codegen process is done, we must add this lines to the indexer/tsconfig.json file. It is required because we are using joystream/types for decoding chain data in the mappings:

{
  "compilerOptions":
    ...
    "baseUrl": ".",
    "paths": {
      "@polkadot/types/augment": ["../../node_modules/@joystream/types/augment-codec/augment-types.ts"]
    }
}

Before running mappings make sure indexer(yarn indexer:start) and indexer-api-server (mappings get the chain data from this graphql server) are both running:

yarn processor:start

Once processor start to store event data you will be able to query this data from http://localhost:4002/graphql.

query {
  channels {
    title
  }
}