issue # 이메일 인증 코드 발송 로직 구현

src/util/generator.ts

@@ -0,0 +1,5 @@
+export class Generator {
+  static getVerificationCode() {
+    return Math.random().toString().slice(2, 8);
+  }
+}

src/util/mailer/mailer.module.ts

@@ -0,0 +1,9 @@
+import { Module, Global } from '@nestjs/common';
+import { MailerService } from './mailer.service';
+
+@Global()
+@Module({
+  providers: [MailerService],
+  exports: [MailerService]
+})
+export class MailerModule {}

src/util/mailer/mailer.service.ts

@@ -0,0 +1,46 @@
+import { Injectable } from '@nestjs/common';
+import nodemailer from 'nodemailer';
+import { google } from 'googleapis';
+import SMTPTransport from 'nodemailer/lib/smtp-transport';
+
+@Injectable()
+export class MailerService {
+  private oauth2Client = new google.auth.OAuth2(
+    process.env.GMAIL_CLIENT_ID,
+    process.env.GMAIL_CLIENT_SECRET,
+    'https://developers.google.com/oauthplayground'
+  );
+
+  constructor() {
+    this.oauth2Client.setCredentials({
+      refresh_token: process.env.GMAIL_REFRESH_TOKEN
+    });
+  }
+
+  async sendMail(to: string, subject: string, html: string) {
+    const accessToken = await this.oauth2Client.getAccessToken();
+    console.log(accessToken);
+    const options: SMTPTransport.Options = {
+      host: "smtp.gmail.com",
+      port: 465,
+      secure: true,
+      auth: {
+        type: "OAuth2",
+        user: process.env.GMAIL_USER,
+        clientId: process.env.GMAIL_CLIENT_ID,
+        clientSecret: process.env.GMAIL_CLIENT_SECRET,
+        refreshToken: process.env.GMAIL_REFRESH_TOKEN,
+        accessToken: accessToken?.token || ''
+      }
+    }
+
+    const transporter = nodemailer.createTransport(options);
+
+    return transporter.sendMail({
+      from: `Scheduler ${process.env.GMAIL_USER}>`,
+      to,
+      subject,
+      html
+    })
+  }
+}