project-inter-server/src/index.ts

import { readFileSync } from "fs";
import { ApolloServer } from "@apollo/server";
import { MergedResolvers } from "./MergedResolvers";
import { ServerContext } from "./ServerContext";
import { InterchangeSystem, InterchangeSystemBuilderArguments } from "./entities/InterchangeSystem";
import { ChapmanApiBasedParkingRepositoryLoader } from "./loaders/parking/ChapmanApiBasedParkingRepositoryLoader";
import express from "express";
import { expressMiddleware } from "@as-integrations/express5";
import {
  RATE_LIMIT_DELAY_AFTER_REQUESTS,
  RATE_LIMIT_DELAY_MULTIPLIER_MS,
  RATE_LIMIT_WINDOW_MS,
  RATE_LIMITS_DISABLED
} from "./environment";
import slowDown from "express-slow-down";

const typeDefs = readFileSync("./schema.graphqls", "utf8");

// In the future this can be stored as a separate file
const supportedSystems: InterchangeSystemBuilderArguments[] = [
  {
    id: "1",
    passioSystemId: "263",
    parkingSystemId: ChapmanApiBasedParkingRepositoryLoader.id,
    name: "Chapman University",
    useSelfUpdatingEtas: true,
  }
]

async function main() {
  const server = new ApolloServer<ServerContext>({
    typeDefs,
    resolvers: MergedResolvers,
    introspection: process.env.NODE_ENV !== "production",
  });
  await server.start();

  let systems: InterchangeSystem[];

  systems = await Promise.all(supportedSystems.map(
    async (systemArguments) => {
      return await InterchangeSystem.build(systemArguments);
    },
  ));

  const app = express();
  const options = {
    context: async () => {
      return {
        systems,
        findSystemById: (id: string) => {
          const system = systems.find((system) => system.id === id);
          if (!system) {
            return null;
          }
          return system;
        },
      }
    },
  };

  if (RATE_LIMITS_DISABLED) {
    app.use(
      "/",
      express.json(),
      expressMiddleware(server, options)
    );
  } else {
    const limiter = slowDown({
      windowMs: RATE_LIMIT_WINDOW_MS,
      delayAfter: RATE_LIMIT_DELAY_AFTER_REQUESTS,
      delayMs: (hits) => {
        return hits * RATE_LIMIT_DELAY_MULTIPLIER_MS;
      }
    });
    app.use(
      "/",
      express.json(),
      limiter,
      expressMiddleware(server, options),
    );
  }

  const port = process.env.PORT ? parseInt(process.env.PORT) : 4000;
  app.listen(port, () => {
    console.log(`Server ready at port ${port}`);
  });
}

main();