create slack-bot file in services

src/server/service/slack-bot.js

@@ -0,0 +1,93 @@
+const { EventEmitter } = require('events');
+const { createServer } = require('http');
+const { App } = require('@slack/bolt');
+
+const express = require('express');
+
+/**
+ * the service class of SlackNotificationService
+ */
+class BoltService extends EventEmitter {
+
+  constructor(signingSecret, endpoints) {
+    super();
+    this.app = express();
+    this.server = createServer(this.app);
+
+    for (const endpoint of endpoints) {
+      this.app.post(endpoint, this.requestHandler.bind(this));
+    }
+  }
+
+
+  init(app) {
+    this.bolt = app;
+  }
+
+  start(port) {
+    return new Promise((resolve, reject) => {
+      try {
+        this.server.listen(port, () => {
+          resolve(this.server);
+        });
+      }
+      catch (error) {
+        reject(error);
+      }
+    });
+  }
+
+  stop() {
+    return new Promise((resolve, reject) => {
+      this.server.close((error) => {
+        if (error) {
+          reject(error);
+          return;
+        }
+        resolve();
+      });
+    });
+  }
+
+  // This is a very simple implementation. Look at the ExpressReceiver source for more detail
+  async requestHandler(req, res) {
+    let ackCalled = false;
+    // Assume parseBody function exists to parse incoming requests
+    const parsedReq = parseBody(req);
+    const event = {
+      body: parsedReq.body,
+      // Receivers are responsible for handling acknowledgements
+      // `ack` should be prepared to be called multiple times and
+      // possibly with `response` as an error
+      ack: (response) => {
+        if (ackCalled) {
+          return;
+        }
+
+        if (response instanceof Error) {
+          res.status(500).send();
+        }
+        else if (!response) {
+          res.send('');
+        }
+        else {
+          res.send(response);
+        }
+
+        ackCalled = true;
+      },
+    };
+    await this.bolt.processEvent(event);
+
+    const receiver = new ReceiverClass(process.env.SLACK_SIGNING_SECRET, '/');
+
+    const app = new App({
+      token: process.env.SLACK_BOT_TOKEN,
+      receiver,
+    });
+  }
+
+
+}
+
+module.exports = BoltService;