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Version: 0.58.0-rc.42

GraphQL Development

This guide covers working with Lana's GraphQL APIs during local development.

API Endpoints​

APILocal URLDirect Port
Admin APIhttp://admin.lana-bank.localhost:1355/graphql5253
Customer APIhttp://app.lana-bank.localhost:1355/graphql5254
warning

GraphQL requests must include a Keycloak access token. The Rust servers validate Keycloak JWTs directly against the configured realm JWKS.

Apollo Client Setup​

Both frontend apps use Apollo Client for GraphQL communication.

Installation​

npm install @apollo/client graphql

Configuration​

import { ApolloClient, InMemoryCache, createHttpLink } from '@apollo/client';
import { setContext } from '@apollo/client/link/context';

const httpLink = createHttpLink({
  uri: 'http://admin.lana-bank.localhost:1355/graphql',
});

const authLink = setContext((_, { headers }) => {
  const token = localStorage.getItem('token');
  return {
    headers: {
      ...headers,
      authorization: token ? `Bearer ${token}` : '',
    },
  };
});

const client = new ApolloClient({
  link: authLink.concat(httpLink),
  cache: new InMemoryCache(),
});

Code Generation​

After modifying GraphQL schemas in Rust, regenerate the SDL and client types:

1. Regenerate GraphQL SDL​

make sdl

This must be run after any changes to async-graphql resolvers in Rust.

2. Generate TypeScript Types​

# codegen.yml
schema:
  - http://admin.lana-bank.localhost:1355/graphql:
      headers:
        Authorization: Bearer ${TOKEN}

documents:
  - 'src/**/*.graphql'

generates:
  src/generated/graphql.ts:
    plugins:
      - typescript
      - typescript-operations
      - typescript-react-apollo
pnpm codegen

Common Patterns​

Queries with Cursor Pagination​

Lana APIs use Relay-style cursor-based pagination:

query GetCustomers($first: Int!, $after: String) {
  customers(first: $first, after: $after) {
    edges {
      cursor
      node {
        id
        email
        status
      }
    }
    pageInfo {
      hasNextPage
      endCursor
    }
  }
}

Mutations​

mutation CreateCustomer($input: CustomerCreateInput!) {
  customerCreate(input: $input) {
    customer {
      id
      email
      status
    }
  }
}

React Hooks Usage​

import { useGetCustomersQuery, useCreateCustomerMutation } from './generated/graphql';

function CustomerList() {
  const { data, loading, error } = useGetCustomersQuery({
    variables: { first: 10 },
  });

  const [createCustomer] = useCreateCustomerMutation();

  if (loading) return <Loading />;
  if (error) return <Error message={error.message} />;

  return (
    <ul>
      {data?.customers?.edges?.map((edge) => (
        <li key={edge.node.id}>{edge.node.email}</li>
      ))}
    </ul>
  );
}

Error Handling​

import { onError } from '@apollo/client/link/error';

const errorLink = onError(({ graphQLErrors, networkError }) => {
  if (graphQLErrors) {
    graphQLErrors.forEach(({ message }) => {
      console.error(`GraphQL error: ${message}`);
    });
  }
  if (networkError) {
    console.error(`Network error: ${networkError}`);
  }
});

API References​