GraphQL Gateway with AUTH

require("dotenv").config();

const { setContext } = require("apollo-link-context");
const { HttpLink } = require("apollo-link-http");
const { ApolloServer } = require("apollo-server-express");
const express = require("express");
const bodyParser = require("body-parser");
const { graphqlExpress } = require("apollo-server-express/dist/expressApollo");

const {
  makeRemoteExecutableSchema,
  mergeSchemas,
  introspectSchema
} = require("graphql-tools");
const fetch = require("node-fetch");

function getAuthContextLink() {
  return setContext((request, previousContext) => {
    console.log(
      "Authorization:",
      previousContext.graphqlContext.headers.authorization
    );

    return {
      headers: {
        authorization: previousContext.graphqlContext.headers.authorization
      }
    };
  });
}

const createRemoteSchema = async (uri, settings) => {
  const config = { uri: uri, fetch, ...settings };

  try {
    const link = new HttpLink(config);
    const authLink = getAuthContextLink().concat(link);
    const schema = await introspectSchema(link);

    return makeRemoteExecutableSchema({
      schema,
      link: authLink
    });
  } catch (error) {
    console.log(error);
  }
};

const { FBR_API, NELSON_API } = process.env;

console.log("^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^");
console.log(FBR_API);
console.log(NELSON_API);
console.log("--------------------------------");

async function run() {
  const nelsonApi = await createRemoteSchema(NELSON_API);
  const fbrApi = await createRemoteSchema(FBR_API);

  // Extend the FBR Change object to associate it with a Ship
  const linkTypeDefs = `
    extend type Change {
      ship: Ship
    }
  `;

  const schema = mergeSchemas({
    schemas: [nelsonApi, fbrApi, linkTypeDefs],

    // Resolver to fetch the ship associated with a change
    resolvers: {
      Change: {
        ship: {
          fragment: `... on Change { shipId }`,
          resolve(response, args, context, info) {
            return info.mergeInfo.delegateToSchema({
              schema: nelsonApi,
              operation: "query",
              fieldName: "ship",
              args: {
                id: response.shipId
              },
              context,
              info,
              transforms: fbrApi.transforms
            });
          }
        }
      }
    }
  });

  const port = process.env.SERVER_PORT || 8000;

  const app = express();
  app.use(
    "/graphql",

    bodyParser.json(),
    graphqlExpress(async request => ({
      schema,
      context: { headers: request ? request.headers : null }
    }))
  );
  app.listen(port, () =>
    console.log(`🚀 Gateway Server ready on port ${port}!`)
  );
}

try {
  console.log("get ready");
  run();
} catch (e) {
  console.log(e);
}