added: add slack module & service

Author: sideseal

Diff for: src/slack/slack.module.ts

@@ -0,0 +1,8 @@
+import { Module } from '@nestjs/common';
+import { SlackService } from './slack.service';
+
+@Module({
+  providers: [SlackService],
+  exports: [SlackService],
+})
+export class SlackModule {}

Diff for: src/slack/slack.service.ts

@@ -0,0 +1,37 @@
+import { Injectable, Logger } from '@nestjs/common';
+import axios from 'axios';
+
+@Injectable()
+export class SlackService {
+  private readonly logger = new Logger(SlackService.name);
+
+  constructor() {}
+
+  async sendDirectMessage(slackId: string, message: string): Promise<void> {
+    if (slackId.length === 0 || slackId === undefined || slackId === null) {
+      this.logger.warn('Slack ID is not defined');
+      return;
+    }
+
+    const slackToken = process.env.SLACK_BOT_USER_OAUTH_ACCESS_TOKEN;
+    const postMessageUrl = 'https://slack.com/api/chat.postMessage';
+
+    try {
+      await axios.post(
+        postMessageUrl,
+        {
+          channel: slackId,
+          text: message,
+        },
+        {
+          headers: {
+            Authorization: `Bearer ${slackToken}`,
+            'Content-Type': 'application/json',
+          },
+        },
+      );
+    } catch (error) {
+      this.logger.error(error);
+    }
+  }
+}