apollo-server-express CORS issue

Question

So I am migrating to apollo-server-express 2.3.3 ( I was using 1.3.6 ) I've followed several guides, making the necessary tweaks but am stuck in a CORS issue.

According to the docs you have to use the applyMiddleware function to wire up the apollo server with express.

I am currently doing the following:

const app = express();

// CORS configuration

const corsOptions = {
    origin: 'http://localhost:3000',
    credentials: true
}

app.use(cors(corsOptions))

// Setup JWT authentication middleware

app.use(async (req, res, next) => {
    const token = req.headers['authorization'];
    if(token !== "null"){
        try {
            const currentUser = await jwt.verify(token, process.env.SECRET)
            req.currentUser = currentUser
        } catch(e) {
            console.error(e);
        }
    }
    next();
});

const server = new ApolloServer({ 
    typeDefs, 
    resolvers, 
    context: ({ req }) => ({ Property, User, currentUser: req.currentUser })
});

server.applyMiddleware({ app });


const PORT = process.env.PORT || 4000;

app.listen(PORT, () => {
    console.log(`Server listening on ${PORT}`);
})

For some reason my express middleware doesn't seem to be executing, when I try to do a request from localhost:3000 (client app) I get the typical CORS error

With apollo-server-express 1.3.6 I was doing the following without no issues:

app.use(
    '/graphql',
    graphqlUploadExpress({ maxFileSize: 10000000, maxFiles: 10 }),
    bodyParser.json(),
    graphqlExpress(({ currentUser }) => ({
        schema,
        context: {
            // Pass Mongoose models
            Property,
            User,
            currentUser
        }
    }))
);

Now with the new version, event though the docs make this look like a straightforward migration, I don't seem to be able to make it work. I've checked various articles and no one seems to be having the issue.

Answer 1

From my understanding of the Apollo Server middleware API, CORS options, body-parser options and the graphql endpoint are treated as special entities that must be passed directly to the applyMiddleware param object.

So you want to try the following configuration:

const app = express();

// CORS configuration
const corsOptions = {
    origin: 'http://localhost:3000',
    credentials: true
}

// The following is not needed, CORS middleware will be applied
// using the Apollo Server's middleware API (see further below)
// app.use(cors(corsOptions))

// Setup JWT authentication middleware
app.use(async (req, res, next) => {
    const token = req.headers['authorization'];
    if(token !== "null"){
        try {
            const currentUser = await jwt.verify(token, process.env.SECRET)
            req.currentUser = currentUser
        } catch(e) {
            console.error(e);
        }
    }
    next();
});

const server = new ApolloServer({ 
    typeDefs, 
    resolvers, 
    context: ({ req }) => ({ Property, User, currentUser: req.currentUser })
});

// There is no need to explicitly define the 'path' option in
// the configuration object as '/graphql' is the default endpoint
// If you planned on using a different endpoint location,
// this is where you would define it.
server.applyMiddleware({ app, cors: corsOptions });

const PORT = process.env.PORT || 4000;

app.listen(PORT, () => {
    console.log(`Server listening on ${PORT}`);
})

Answer 2

With Apollo Server 2.x you supply the cors field in the constructor of ApolloServer.

So in your case, it should look like the following:

const corsOptions = {
    origin: 'http://localhost:3000',
    credentials: true
}

// Setup JWT authentication middleware

app.use(async (req, res, next) => {
    const token = req.headers['authorization'];
    if(token !== "null"){
        try {
            const currentUser = await jwt.verify(token, process.env.SECRET)
            req.currentUser = currentUser
        } catch(e) {
            console.error(e);
        }
    }
    next();
});

const server = new ApolloServer({ 
    typeDefs, 
    cors: cors(corsOptions),
    resolvers, 
    context: ({ req }) => ({ Property, User, currentUser: req.currentUser })
});

server.applyMiddleware({ app });


const PORT = process.env.PORT || 4000;

app.listen(PORT, () => {
    console.log(`Server listening on ${PORT}`);
})

Here you find all params accepted by the apollo server: https://www.apollographql.com/docs/apollo-server/api/apollo-server.html#Parameters-2

Here you find the relevant discussion: https://github.com/apollographql/apollo-server/issues/1142

Answer 3

The CORS settings come from ExpressJS, not from ApolloServer. If you want to add a custom or wildcard origin you have to handle it with a callback/handler function.

const server = new ApolloServer({
    ....,
    cors: {
        credentials: true,
        origin: (origin, callback) => {
            const whitelist = [
                "http://site1.com",
                "https://site2.com"
            ];

            if (whitelist.indexOf(origin) !== -1) {
                callback(null, true)
            } else {
                callback(new Error("Not allowed by CORS"))
            }
        }
    }
});

Answer 4

By default, the express middleware will instantiate cors middleware with default options on the graphql path, overriding any cors middleware configuration you yourself have specified for other paths(!)

You can override the defaults when you apply the apollo middleware, e.g.

apollo.applyMiddleware({ app, cors: {credentials: true, origin: true} })

I'm using apollo-server-express 2.17