refactor (graphql.js): Upgrade to the v2 of apollo (#18)

We used to get the 'graphqlKoa' and 'graphiqlKoa' before as the
middle-wares,
but now they have been either removed or hidden from the public. And
since v2
of apollo we've faced with a BREAKING CHANGE
(See:apollographql/apollo-server@dbaa465#diff-64af8fdf76996fa3ed4e498d44124800
).
In order to be compatible with the older codes users are referring,
we have to do some tricks:

1) Directly refer 'graphqlKoa' from 'apollo-server-koa/dist/koaApollo'
instead
of 'apollo-server-koa', because it's NOT exposed through 'index.js'.

2) 'apollo-server-module-graphiql' is removed, so in order to compatible
with
what it was, we have to add this in our package and reuse that. And then
we should
rewrite 'graphiqlKoa' function as the middle-ware copied from:
https://github.com/apollographql/apollo-server/blob/300c0cd12b56be439b206d55131e1b93a9e6dade/packages/apollo-server-koa/src/koaApollo.ts#L51

Notice: This change is also a BREAKING one, so please DO NOT apply to
apollo's
version that is less than 2.x. And there're many ambigious problems
about this
design of v2 for apollo (See:
apollographql/apollo-server#1308).
So according to chentsulin's ideas, maybe the middle-ware functions
would be re-added
in the future (See:
apollographql/apollo-server#1282 (comment)).

app/middleware/graphql.js

@@ -1,6 +1,37 @@
 'use strict';
 
-const { graphqlKoa, graphiqlKoa } = require('apollo-server-koa');
+// Notice that this path is totally changed, because this function isn't
+// directly exposed to the public, now we must still use that for the middle-
+// ware.
+const { graphqlKoa } = require('apollo-server-koa/dist/koaApollo');
+
+// This has been newly imported, because in v2 of apollo-server, this is removed.
+const { resolveGraphiQLString } = require('apollo-server-module-graphiql');
+
+/**
+ This function is directly copied from:
+ https://github.com/apollographql/apollo-server/blob/300c0cd12b56be439b206d55131e1b93a9e6dade/packages/apollo-server-koa/src/koaApollo.ts#L51
+
+ And now this has been removed since v2 at:
+ https://github.com/apollographql/apollo-server/commit/dbaa465646b0acb839860a85bfd68fb4379d64ab#diff-64af8fdf76996fa3ed4e498d44124800
+
+ So we must keep this here to be compatible with what it was before.
+ Thus users can directly use that by upgrading graphql to the v2 WITHOUT
+ doing any other big changes.
+
+ * @param {Object} options The `options` of graphiqlKoa.
+ * @return {Promise} The result of the graphiqlKoa.
+ */
+function graphiqlKoa(options) {
+  return ctx => {
+    const query = ctx.request.query;
+    return resolveGraphiQLString(query, options, ctx)
+      .then(graphiqlString => {
+        ctx.set('Content-Type', 'text/html');
+        ctx.body = graphiqlString;
+      });
+  };
+}
 
 module.exports = (_, app) => {
   const options = app.config.graphql;

package.json

@@ -13,11 +13,12 @@
     "orm"
   ],
   "dependencies": {
-    "apollo-server-koa": "^1.2.0",
-    "graphql": "^0.11.7",
-    "graphql-tag": "^2.5.0",
-    "graphql-tools": "^2.19.0",
-    "lodash": "4.17.4"
+    "apollo-server-koa": "^2.0.4",
+    "apollo-server-module-graphiql": "^1.4.0",
+    "graphql": "^0.13.2",
+    "graphql-tag": "^2.9.2",
+    "graphql-tools": "^3.1.1",
+    "lodash": "^4.17.10"
   },
   "devDependencies": {
     "autod": "^2.9.0",

test/app/graphiql/closeGraphiql.test.js

@@ -15,15 +15,16 @@ describe('test/closeGraphiql.test.js', () => {
 
   after(mm.restore);
 
-  it('should get graphql json response', function* () {
+  it('should get graphql json response', async () => {
     app.mockHttpclient('/graphql', 'GET', {
       headers: {
         'accept-language': 'zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2',
         Accept: 'text/html',
         'user-agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:57.0) Gecko/20100101 Firefox/57.0',
       },
     });
-    return app.httpRequest()
+
+    await app.httpRequest()
       .get('/graphql')
       .expect('GET query missing.');
   });

test/app/graphiql/graphiql.test.js

@@ -15,14 +15,13 @@ describe('test/graphiql.test.js', () => {
 
   after(mm.restore);
 
-  it('should get graphiql html response', function* () {
+  it('should get graphiql html response', async () => {
     app.mockHttpclient('/graphql', 'GET', {});
-    return app.httpRequest()
+    const result = await app.httpRequest()
       .get('/graphql')
       .set('Accept', 'text/html')
-      .expect(200)
-      .then(response => {
-        assert(response.type, 'text/html');
-      });
+      .expect(200);
+
+    assert(result.type, 'text/html');
   });
 });