Expose composed middleware via getMiddleware().

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ### vNEXT
 
+### v2.4.9
+
+- `apollo-server-koa`: Expose `server.getMiddleware()` function for getting access to koa middleware directly. [PR #2435](https://github.com/apollographql/apollo-server/pull/2435)
+
 ### v2.4.8
 
 - No functional changes in this version.  The patch version has been bumped to fix the `README.md` displayed on the [npm package for `apollo-server`](https://npm.im/apollo-server) as a result of a broken publish.  Apologies for the additional noise!

packages/apollo-server-koa/README.md

@@ -36,6 +36,8 @@ const server = new ApolloServer({ typeDefs, resolvers });
 
 const app = new Koa();
 server.applyMiddleware({ app });
+// alternatively you can get a composed middleware from the apollo server
+// app.use(server.getMiddleware());
 
 app.listen({ port: 4000 }, () =>
   console.log(`🚀 Server ready at http://localhost:4000${server.graphqlPath}`),

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

@@ -1,4 +1,4 @@
-import Koa from 'koa';
+import Koa, { Middleware } from 'koa';
 import corsMiddleware from '@koa/cors';
 import bodyParser from 'koa-bodyparser';
 import compose from 'koa-compose';
@@ -19,15 +19,18 @@ import { graphqlKoa } from './koaApollo';
 export { GraphQLOptions, GraphQLExtension } from 'apollo-server-core';
 import { GraphQLOptions, FileUploadOptions } from 'apollo-server-core';
 
-export interface ServerRegistration {
-  app: Koa;
+export interface GetMiddlewareOptions {
   path?: string;
   cors?: corsMiddleware.Options | boolean;
   bodyParserConfig?: bodyParser.Options | boolean;
   onHealthCheck?: (ctx: Koa.Context) => Promise<any>;
   disableHealthCheck?: boolean;
 }
 
+export interface ServerRegistration extends GetMiddlewareOptions {
+  app: Koa;
+}
+
 const fileUploadMiddleware = (
   uploadsConfig: FileUploadOptions,
   server: ApolloServerBase,
@@ -80,18 +83,22 @@ export class ApolloServer extends ApolloServerBase {
     return true;
   }
 
+  public applyMiddleware({ app, ...rest }: ServerRegistration) {
+    const middleware = this.getMiddleware(rest);
+    app.use(middleware);
+  }
+
   // TODO: While Koa is Promise-aware, this API hasn't been historically, even
   // though other integration's (e.g. Hapi) implementations of this method
   // are `async`.  Therefore, this should become `async` in a major release in
   // order to align the API with other integrations.
-  public applyMiddleware({
-    app,
+  public getMiddleware({
     path,
     cors,
     bodyParserConfig,
     disableHealthCheck,
     onHealthCheck,
-  }: ServerRegistration) {
+  }: GetMiddlewareOptions): Middleware {
     if (!path) path = '/graphql';
 
     // Despite the fact that this `applyMiddleware` function is `async` in
@@ -107,15 +114,16 @@ export class ApolloServer extends ApolloServerBase {
     // work has finished.  Any errors will be surfaced to Koa through its own
     // native Promise-catching facilities.
     const promiseWillStart = this.willStart();
-    app.use(
+    const middlewares = [];
+    middlewares.push(
       middlewareFromPath(path, async (_ctx: Koa.Context, next: Function) => {
         await promiseWillStart;
         return next();
       }),
     );
 
     if (!disableHealthCheck) {
-      app.use(
+      middlewares.push(
         middlewareFromPath(
           '/.well-known/apollo/server-health',
           (ctx: Koa.Context) => {
@@ -147,22 +155,22 @@ export class ApolloServer extends ApolloServerBase {
     this.graphqlPath = path;
 
     if (cors === true) {
-      app.use(middlewareFromPath(path, corsMiddleware()));
+      middlewares.push(middlewareFromPath(path, corsMiddleware()));
     } else if (cors !== false) {
-      app.use(middlewareFromPath(path, corsMiddleware(cors)));
+      middlewares.push(middlewareFromPath(path, corsMiddleware(cors)));
     }
 
     if (bodyParserConfig === true) {
-      app.use(middlewareFromPath(path, bodyParser()));
+      middlewares.push(middlewareFromPath(path, bodyParser()));
     } else if (bodyParserConfig !== false) {
-      app.use(middlewareFromPath(path, bodyParser(bodyParserConfig)));
+      middlewares.push(middlewareFromPath(path, bodyParser(bodyParserConfig)));
     }
 
     if (uploadsMiddleware) {
-      app.use(middlewareFromPath(path, uploadsMiddleware));
+      middlewares.push(middlewareFromPath(path, uploadsMiddleware));
     }
 
-    app.use(
+    middlewares.push(
       middlewareFromPath(path, (ctx: Koa.Context, next: Function) => {
         if (ctx.request.method === 'OPTIONS') {
           ctx.status = 204;
@@ -199,6 +207,7 @@ export class ApolloServer extends ApolloServerBase {
         })(ctx, next);
       }),
     );
+    return compose(middlewares);
   }
 }