graphql-query-complexity causing schema introspection error in apollo graphql

[arijit-itobuz]

import 'reflect-metadata';
import http from 'node:http';
import { ApolloServer } from '@apollo/server';
import { expressMiddleware } from '@apollo/server/express4';
import { ApolloServerPluginDrainHttpServer } from '@apollo/server/plugin/drainHttpServer';
import cors from 'cors';
import express, { type NextFunction, type Request, type Response } from 'express';
import graphqlUploadExpress from 'graphql-upload/graphqlUploadExpress.mjs';
import { config } from './config/config.js';
// import { graphqlQueryComplexity } from './graphql/lib/graphqlQueryComplexity.lib.js';
import { typegraphqlSchema } from './graphql/typegraphqlSchema.js';
import { restRouter } from './rest/routes/route.js';

async function main() {
try {
const port = config.app.APP_PORT;
const app = express();
const http_server = http.createServer(app);

/* apollo server */
const apolloServer = new ApolloServer({
  schema: typegraphqlSchema,
  introspection: config.app.APP_ENV === 'dev',
  plugins: [
    ApolloServerPluginDrainHttpServer({ httpServer: http_server }),
    // graphqlQueryComplexity.   // commenting fixes the error
  ],
});
await apolloServer.start();

/* middlewares */
app.use(cors());
app.use(express.json({ limit: '50mb', type: 'application/json' }));
app.use(express.urlencoded({ limit: '50mb', extended: true, type: 'application/x-www-form-urlencoded' }));
app.use(graphqlUploadExpress({ maxFileSize: 1 * 1024 * 1024, maxFiles: 5 }));

/* api */
app.get('/', (req: Request, res: Response, next: NextFunction) => res.status(200).send('root'));
app.use('/rest', restRouter);
app.use(
  '/graphql',
  expressMiddleware(apolloServer, { context: async ({ req }) => ({ req: req, api: 'graphql' }) })
);
app.use((req: Request, res: Response, next: NextFunction) => res.status(404).send('Page Not Found'));

/* start */
await new Promise<void>((resolve) => http_server.listen({ port: port }, resolve));

console.log(`[rest]: http://localhost:${port}/rest/`);
console.log(`[graphql]: http://localhost:${port}/graphql/`);

} catch (error) {
console.log('[Error]:', error);
}
}

main();

---

import type { GraphQLRequest } from '@apollo/server';
import type { DocumentNode } from 'graphql';
import { fieldExtensionsEstimator, getComplexity, simpleEstimator } from 'graphql-query-complexity';
import { config } from '../../config/config.js';
import { typegraphqlSchema } from '../typegraphqlSchema.js';

export const graphqlQueryComplexity = {
requestDidStart: async () => ({
async didResolveOperation({ request, document }: { request: GraphQLRequest; document: DocumentNode }) {
const complexity = getComplexity({
schema: typegraphqlSchema,
operationName: request.operationName,
query: document,
variables: request.variables,
estimators: [fieldExtensionsEstimator(), simpleEstimator({ defaultComplexity: 1 })],
});

  if (complexity > config.graphql.GRAPHQL_QUERY_COMPLEXITY) {
    throw new Error(
      `Sorry, too complicated query! ${complexity} exceeded the maximum allowed complexity of ${config.graphql.GRAPHQL_QUERY_COMPLEXITY}`
    );
  }
  console.log('[Graphql Query Complexity]:', { Operation: request.operationName, Complexity: complexity });
},

}),
};

---

error

Schema Introspection Failure

Introspection is disabled on this endpoint. Enable introspection to populate your schema.
Unable to reach server

We were unable to introspect your endpoint. Please enable introspection on your server. (You might still be able to submit operations!)