How to enable cors for apollo-server-lambda

Question

Ok so I see a lot of answers for how to enable cors for apollo-express, but I haven't found one really for apollo-server-lambda.

This is the error that I'm getting from chrome:

Access to XMLHttpRequest at 'https://5j3gae3086.execute-api.us-east-2.amazonaws.com/alpha/'
from origin 'http://localhost:4200' has been blocked by CORS policy: Response to preflight
request doesn't pass access control check: The 'Access-Control-Allow-Origin' header
has a value 'https://example.com' that is not equal to the supplied origin.

I do not know how to change the value "https://example.com." Here is my code of how I'm trying to create the server:

const { ApolloServer } = require('apollo-server-lambda')
const typeDefs = require('./schema')
const resolvers = require ('./resolvers')

const server = new ApolloServer({
    typeDefs,
    resolvers,
    introspection: true,
    playground: {
        endpoint: "/alpha/graphql",
    },
  });

exports.graphqlHandler = server.createHandler({
    cors: {
        // origin: true,
        origin: "http://localhost:4200", // <-- This is not changing the header value. Do I need to do it from the frontend?
        credentials: true,
    },
  });

What else do I need to do here?

Edit I'm not sure if this is relevant, but here is my graphql.module.ts file. This is how I'm setting grahql in the frontend:

import { NgModule } from '@angular/core';
import { APOLLO_OPTIONS } from 'apollo-angular';
import { ApolloClientOptions, InMemoryCache } from '@apollo/client/core';
import { HttpLink } from 'apollo-angular/http';

const uri = 'https://5j3gae3086.execute-api.us-east-2.amazonaws.com/alpha/'; // <-- add the URL of the GraphQL server here
export function createApollo(httpLink: HttpLink): ApolloClientOptions<any> {
  return {
    link: httpLink.create({ uri,
      // these comments are things that I tried with no luck :(
      // fetchOptions: {
      //   mode: 'no-cors',
      // },
      //  headers: {
      // 'Access-Control-Allow-Origin': 'http://localhost:4200',
      // 'Access-Control-Allow-Methods': 'POST',
      // 'Access-Control-Allow-Headers': 'application/json'
      // "Access-Control-Allow-Credentials" : true
      // "X-CSRFToken": Cookies.get('csrftoken')
    // },
  }),
    cache: new InMemoryCache(),
  };
}



@NgModule({
  providers: [
    {
      provide: APOLLO_OPTIONS,
      useFactory: createApollo,
      deps: [HttpLink],
    },
  ],
})
export class GraphQLModule { }

Also in case anyone is curious, I'm using AWS Api Gateway to use the lambda, but I believe I have the configuration for cors added correctly on that.

I'm at a loss with this. What do I need to change?

Answer 1

Following the CORS setup instructions here I can successfully use apollo-angular to return results for a simple query. No special headers etc. were needed.

https://www.apollographql.com/docs/apollo-server/deployment/lambda/

// serverless.yml
events:
  - http:
      path: graphql
      method: post
      cors: true
  - http:
      path: graphql
      method: get
      cors: true

// graphql.js
exports.graphqlHandler = server.createHandler({
  cors: {
    origin: '*',
    credentials: true,
  },
});

// graphql.module.ts
import {NgModule} from '@angular/core';
import {APOLLO_OPTIONS} from 'apollo-angular';
import {ApolloClientOptions, InMemoryCache} from '@apollo/client/core';
import {HttpLink} from 'apollo-angular/http';

const uri = 'https://xxx/dev/graphql';
export function createApollo(httpLink: HttpLink): ApolloClientOptions<any> {
  return {
    link: httpLink.create({uri}),
    cache: new InMemoryCache(),
  };
}

@NgModule({
  providers: [
    {
      provide: APOLLO_OPTIONS,
      useFactory: createApollo,
      deps: [HttpLink],
    },
  ],
})
export class GraphQLModule {}

// In Angular 10
this.apollo
  .watchQuery({
    query: gql`
      {
        users {
          email
        }
      }
    `,
  })
  .valueChanges.subscribe(result => {
    console.log(result.data);
  });

Answer 2

Unlike an initial question, graphql.js is replaced to typescript as following.

// graphql.ts
exports.graphqlHandler = server.createHandler({
  expressGetMiddlewareOptions: {
    cors: {
      origin: '*',
      credentials: true,
    },
  },
});