Merge pull request #72 from hashicorp/fix-empty-list-responses

fix: 🐛 prenormalize findAll responses in application adapter

addons/api/addon/adapters/application.js

@@ -6,6 +6,36 @@ import { dasherize } from '@ember/string';
 import { pluralize } from 'ember-inflector';
 import { isArray } from '@ember/array';
 
+/**
+ * Returns true if the payload is an empty object, false otherwise.
+ * Taken from Ember Data fetch-manager and "positivized" the name.
+ * @param {object} adapterPayload
+ * @return {boolean}
+ */
+function payloadIsBlank(adapterPayload) {
+  if (Array.isArray(adapterPayload)) {
+    return false;
+  } else {
+    return Object.keys(adapterPayload || {}).length === 0;
+  }
+}
+
+/**
+ * If the resonse is empty, returns a new payload containing an empty `items`
+ * array, as expected by the serializer.  Otherwise, returns the response.
+ *
+ * Normally this would be performed 100% inside the serializer.
+ * However, the fetch manager, which we cannot easily override, glues the
+ * adapter and serializers together.  Before it forwards a response from the
+ * adapter on to the serializer, it checks for an "empty" response.  If the
+ * response is empty, fetch manager throws and error and never forwards it on.
+ * @param {object} response
+ * @return {object}
+ */
+function prenormalizeArrayResponse(response) {
+  return payloadIsBlank(response) ? {items: []} : response;
+}
+
 export default class ApplicationAdapter extends RESTAdapter {
   // =attributes
 
@@ -36,6 +66,26 @@ export default class ApplicationAdapter extends RESTAdapter {
     return dasherize(pluralize(type));
   }
 
+  /**
+   * Intercepts "empty" responses and adds an empty `items` array.
+   * @override
+   * @method findAll
+   * @return {Promise} promise
+   */
+  findAll() {
+    return super.findAll(...arguments).then(prenormalizeArrayResponse);
+  }
+
+  /**
+   * Intercepts "empty" responses and adds an empty `items` array.
+   * @override
+   * @method query
+   * @return {Promise} promise
+   */
+  query() {
+    return super.query(...arguments).then(prenormalizeArrayResponse);
+  }
+
   /**
    * Overrides default ajax method by rewritting PUT requests as PATCH.
    * PATCH is the request method used by our API for updates.

addons/api/package.json

@@ -35,6 +35,7 @@
     "ember-cli-dependency-checker": "^3.2.0",
     "ember-cli-eslint": "^5.1.0",
     "ember-cli-inject-live-reload": "^2.0.2",
+    "ember-cli-mirage": "^1.1.7",
     "ember-cli-sri": "^2.1.1",
     "ember-cli-template-lint": "^1.0.0-beta.3",
     "ember-cli-uglify": "^3.0.0",

addons/api/tests/dummy/mirage/config.js

@@ -0,0 +1,26 @@
+export default function() {
+
+  // These comments are here to help you get started. Feel free to delete them.
+
+  /*
+    Config (with defaults).
+
+    Note: these only affect routes defined *after* them!
+  */
+
+  // this.urlPrefix = '';    // make this `http://localhost:8080`, for example, if your API is on a different server
+  // this.namespace = '';    // make this `/api`, for example, if your API is namespaced
+  // this.timing = 400;      // delay for each request, automatically set to 0 during testing
+
+  /*
+    Shorthand cheatsheet:
+
+    this.get('/posts');
+    this.post('/posts');
+    this.get('/posts/:id');
+    this.put('/posts/:id'); // or this.patch
+    this.del('/posts/:id');
+
+    https://www.ember-cli-mirage.com/docs/route-handlers/shorthands
+  */
+}

addons/api/tests/dummy/mirage/scenarios/default.js

@@ -0,0 +1,9 @@
+export default function(/* server */) {
+
+  /*
+    Seed your development database using your factories.
+    This data will not be loaded in your tests.
+  */
+
+  // server.createList('post', 10);
+}

addons/api/tests/dummy/mirage/serializers/application.js

@@ -0,0 +1,4 @@
+import { JSONAPISerializer } from 'ember-cli-mirage';
+
+export default JSONAPISerializer.extend({
+});

addons/api/tests/unit/adapters/application-test.js

@@ -3,9 +3,12 @@ import { setupTest } from 'ember-qunit';
 import config from 'ember-get-config';
 import RESTAdapter from '@ember-data/adapter/rest';
 import { InvalidError } from '@ember-data/adapter/error';
+import setupMirage from 'ember-cli-mirage/test-support/setup-mirage';
+import { Response } from 'miragejs';
 
 module('Unit | Adapter | application', function (hooks) {
   setupTest(hooks);
+  setupMirage(hooks);
 
   test('its namespace is equal to the configured namespace', function (assert) {
     assert.expect(2);
@@ -24,12 +27,23 @@ module('Unit | Adapter | application', function (hooks) {
     assert.expect(1);
     const adapter = this.owner.lookup('adapter:application');
     // TODO this is icky, should be changed to a spy or stub
+    const originalAjax = RESTAdapter.prototype.ajax;
     RESTAdapter.prototype.ajax = (url, type) => {
       assert.equal(type, 'PATCH');
+      RESTAdapter.prototype.ajax = originalAjax;
     };
     adapter.ajax('/', 'PUT');
   });
 
+  test('it prenormalizes "empty" responses into a form that the fetch-manager will not reject', async function (assert) {
+    assert.expect(1);
+    const adapter = this.owner.lookup('adapter:project');
+    const store = this.owner.lookup('service:store');
+    this.server.get('/v1/projects', () => new Response({}));
+    const prenormalized = await adapter.findAll(store, {modelName: 'project'}, null, []);
+    assert.deepEqual(prenormalized, {items: []});
+  });
+
   test('it correctly identifies 400 responses as invalid', function (assert) {
     assert.expect(2);
     const adapter = this.owner.lookup('adapter:application');

yarn.lock

@@ -7330,6 +7330,21 @@ ember-cli-mirage@^1.1.6:
     lodash-es "^4.17.11"
     miragejs "^0.1.31"
 
+ember-cli-mirage@^1.1.7:
+  version "1.1.7"
+  resolved "https://registry.yarnpkg.com/ember-cli-mirage/-/ember-cli-mirage-1.1.7.tgz#846ec8e5199b15fa670da30dfa1708a8ee11e9dc"
+  integrity sha512-4kVLXXvgHYlv30ChM47U4xYnUtphIoEj+BQwXX0QT7pvD3KQxYnmfZSwlevSEVUy2UhbsBUPw6merENb+dIQ0A==
+  dependencies:
+    broccoli-file-creator "^2.1.1"
+    broccoli-funnel "^3.0.2"
+    broccoli-merge-trees "^4.2.0"
+    ember-auto-import "^1.2.19"
+    ember-cli-babel "^7.5.0"
+    ember-get-config "^0.2.2"
+    ember-inflector "^2.0.0 || ^3.0.0"
+    lodash-es "^4.17.11"
+    miragejs "^0.1.31"
+
 ember-cli-normalize-entity-name@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/ember-cli-normalize-entity-name/-/ember-cli-normalize-entity-name-1.0.0.tgz#0b14f7bcbc599aa117b5fddc81e4fd03c4bad5b7"