From 69ee40b21c08302adb4a4da57dc6ede3f9161a23 Mon Sep 17 00:00:00 2001
From: CheerlessCloud <nnsceg@gmail.com>
Date: Fri, 28 Sep 2018 08:50:52 +0300
Subject: [PATCH] feat(rpc/handler): add initial implementation Handler class
 and basic positive tests

---
 src/rpc/Handler.js      |  77 ++++++++++++++++++++++++++
 src/rpc/Handler.test.js | 116 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 193 insertions(+)
 create mode 100644 src/rpc/Handler.js
 create mode 100644 src/rpc/Handler.test.js

diff --git a/src/rpc/Handler.js b/src/rpc/Handler.js
new file mode 100644
index 0000000..fedd0b0
--- /dev/null
+++ b/src/rpc/Handler.js
@@ -0,0 +1,77 @@
+/* eslint-disable no-empty-function,no-unused-vars */
+// @flow
+import { type IMessage } from '../AMQPMessage';
+import RpcService from '../Service';
+import errorToObject from './errorToObject';
+
+export default class RpcHandler {
+  +_service: RpcService;
+  +_message: IMessage;
+  +context: Object = {};
+
+  get action(): string {
+    return 'default';
+  }
+
+  get payload(): $PropertyType<IMessage, 'payload'> {
+    return this._message.payload;
+  }
+
+  constructor({ service, message }: { service: RpcService, message: IMessage }) {
+    this._service = service;
+    this._message = message;
+
+    if (this.handle === RpcHandler.prototype.handle) {
+      throw new Error('You must override handle method');
+    }
+  }
+
+  async reply({ payload, error }: { payload?: ?Object, error?: Error }) {
+    const { messageId, correlationId, replyTo } = this._message._props;
+    if (!replyTo) {
+      return;
+    }
+
+    const adapter = this._service._getAdapter();
+    await adapter.send(
+      replyTo,
+      {
+        error: errorToObject(error),
+        payload,
+      },
+      { messageId, correlationId },
+    );
+  }
+
+  async beforeHandle() {}
+
+  async handle(): ?Object {}
+
+  handleFail(err: Error) {
+    // reply
+    // reject
+  }
+
+  async handleSuccess(replyPayload: ?Object) {
+    await this.reply({ payload: replyPayload });
+    await this._message.ack();
+  }
+
+  async onSuccess() {}
+  async onFail(error: Error) {}
+  async afterHandle() {}
+
+  async execute() {
+    try {
+      await this.beforeHandle();
+      const replyPayload = await this.handle();
+      await this.handleSuccess(replyPayload);
+      await this.onSuccess();
+    } catch (err) {
+      await this.handleFail(err);
+      await this.onFail(err);
+    } finally {
+      await this.afterHandle();
+    }
+  }
+}
diff --git a/src/rpc/Handler.test.js b/src/rpc/Handler.test.js
new file mode 100644
index 0000000..0767435
--- /dev/null
+++ b/src/rpc/Handler.test.js
@@ -0,0 +1,116 @@
+/* eslint-disable no-param-reassign */
+// @flow
+import test from 'ava';
+import { spy, stub } from 'sinon';
+import uuid from 'uuid/v4';
+import Handler from './Handler';
+
+test.beforeEach(t => {
+  t.context = {};
+  t.context.reply = { foo: 42 };
+  t.context.AwesomeHandler = class AwesomeHandler extends Handler {
+    async handle() {
+      return t.context.reply;
+    }
+  };
+  t.context.adapterSendStub = stub().resolves(undefined);
+  t.context.serviceStub = {
+    _getAdapter: () => ({
+      send: t.context.adapterSendStub,
+    }),
+  };
+  t.context.messageStub = {
+    id: uuid(),
+    _props: {
+      messageId: uuid(),
+      correlationId: uuid(),
+      replyTo: uuid(),
+    },
+    payload: { foo: 'bar' },
+    ack: stub().resolves(undefined),
+    reject: stub().resolves(undefined),
+  };
+});
+
+test('construct handler', async t => {
+  const { AwesomeHandler, serviceStub, messageStub } = t.context;
+  t.notThrows(
+    () =>
+      new AwesomeHandler({
+        service: serviceStub,
+        message: messageStub,
+      }),
+  );
+});
+
+test('positive execute case', async t => {
+  const { AwesomeHandler, serviceStub, messageStub } = t.context;
+  const handler = new AwesomeHandler({
+    service: serviceStub,
+    message: messageStub,
+  });
+  handler.handleFail = err => t.fail(err);
+
+  const beforeHandleSpy = spy(handler, 'beforeHandle');
+  const handleSpy = spy(handler, 'handle');
+  const afterHandleSpy = spy(handler, 'afterHandle');
+  const handleFailSpy = spy(handler, 'handleFail');
+  const handleSuccessSpy = spy(handler, 'handleSuccess');
+  const onFailSpy = spy(handler, 'onFail');
+  const onSuccessSpy = spy(handler, 'onSuccess');
+
+  await t.notThrows(handler.execute());
+
+  t.true(beforeHandleSpy.calledOnce);
+  t.true(beforeHandleSpy.calledBefore(handleSpy));
+
+  t.true(handleSpy.calledOnce);
+  t.true(handleSpy.calledBefore(handleSuccessSpy));
+
+  t.false(handleFailSpy.called);
+  t.false(onFailSpy.called);
+
+  t.true(handleSuccessSpy.calledOnce);
+  t.true(handleSuccessSpy.calledBefore(onSuccessSpy));
+  t.true(onSuccessSpy.calledOnce);
+  t.true(onSuccessSpy.calledBefore(afterHandleSpy));
+
+  t.true(messageStub.ack.calledOnce);
+  t.true(messageStub.ack.calledBefore(onSuccessSpy));
+  t.false(messageStub.reject.called);
+
+  t.true(afterHandleSpy.calledOnce);
+});
+
+test('correct reply at positive execute case', async t => {
+  const { AwesomeHandler, serviceStub, messageStub } = t.context;
+  const handler = new AwesomeHandler({
+    service: serviceStub,
+    message: messageStub,
+  });
+  handler.handleFail = err => t.fail(err);
+
+  const handleSuccessSpy = spy(handler, 'handleSuccess');
+  const replySpy = spy(handler, 'reply');
+
+  await t.notThrows(handler.execute());
+
+  t.true(handleSuccessSpy.calledOnceWith(t.context.reply));
+  t.true(replySpy.calledOnceWith({ payload: t.context.reply }));
+  t.true(t.context.adapterSendStub.calledOnce);
+  t.true(messageStub.ack.calledOnce);
+  t.false(messageStub.reject.called);
+});
+
+test('must override handle method', async t => {
+  const { serviceStub, messageStub } = t.context;
+  const HandlerClass = class AwesomeHandler2 extends Handler {};
+  t.throws(
+    () =>
+      new HandlerClass({
+        service: serviceStub,
+        message: messageStub,
+      }),
+    'You must override handle method',
+  );
+});