apollo-server-koa: Respond to OPTIONS

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ### vNEXT
 
+- `apollo-server-koa`: Support OPTIONS requests [PR #2288](https://github.com/apollographql/apollo-server/pull/2288)
+
 ### v2.4.2
 
 - `apollo-server-fastify` is now on Apollo Server and lives within the `apollo-server` repository.  This is being introduced in a _patch_ version, however it's a _major_ version bump from the last time `apollo-server-fastify` was published under `1.0.2`.  [PR #1971](https://github.com/apollostack/apollo-server/pull/1971)

packages/apollo-server-koa/src/ApolloServer.ts

@@ -164,6 +164,12 @@ export class ApolloServer extends ApolloServerBase {
 
     app.use(
       middlewareFromPath(path, (ctx: Koa.Context, next: Function) => {
+        if (ctx.request.method === 'OPTIONS') {
+          ctx.status = 204;
+          ctx.body = '';
+          return;
+        }
+
         if (this.playgroundOptions && ctx.request.method === 'GET') {
           // perform more expensive content-type check only if necessary
           const accept = accepts(ctx.req);
@@ -187,6 +193,7 @@ export class ApolloServer extends ApolloServerBase {
             return;
           }
         }
+
         return graphqlKoa(() => {
           return this.createGraphQLServerOptions(ctx);
         })(ctx, next);