feat: Add comment notifications for posts (#75)

Author: saebyeok0306

backend/mail-service/src/main/kotlin/io/blog/mail/mail/controller/EmailController.kt

@@ -15,6 +15,8 @@ class EmailController {
 
     @PostMapping("/send")
     fun sendEmail(@RequestBody message: AuthenticationMessage) {
-        emailService.sendEmail(MessageType.EMAIL, message.email, message.subject, message.authCode)
+        val params = HashMap<String, String>()
+        params["authCode"] = message.authCode
+        emailService.sendEmail(MessageType.EMAIL, message.email, message.subject, params)
     }
 }

backend/mail-service/src/main/kotlin/io/blog/mail/mail/service/EmailService.kt

@@ -3,6 +3,6 @@ package io.blog.mail.mail.service
 import io.blog.mail.mail.types.MessageType
 
 interface EmailService {
-    fun sendEmail(type: MessageType, email: String, subject: String, authCode: String)
-    fun setContext(type: MessageType, authCode: String) : String
+    fun sendEmail(type: MessageType, email: String, subject: String, params: HashMap<String, String>)
+    fun setContext(type: MessageType, params: HashMap<String, String>) : String
 }

backend/mail-service/src/main/kotlin/io/blog/mail/mail/service/EmailServiceImpl.kt

@@ -17,23 +17,28 @@ class EmailServiceImpl : EmailService {
     @Autowired
     private lateinit var templateEngine: SpringTemplateEngine
 
-    override fun sendEmail(type: MessageType, email: String, subject: String, authCode: String) {
+    override fun sendEmail(type: MessageType, email: String, subject: String, params: HashMap<String, String>) {
         val mimeMessage: MimeMessage = emailSender.createMimeMessage()
 
         try {
             val helper = MimeMessageHelper(mimeMessage, true, "utf-8")
             helper.setTo(email)
             helper.setSubject(subject)
-            helper.setText(this.setContext(type, authCode), true)
+            helper.setText(this.setContext(type, params), true)
             emailSender.send(mimeMessage)
         } catch (e : Exception) {
             println("Failed to send email $e")
         }
     }
 
-    override fun setContext(type: MessageType, authCode: String): String {
+    override fun setContext(type: MessageType, params: HashMap<String, String>): String {
         val context = Context()
-        context.setVariable("authCode", authCode)
+
+        for (entry in params.entries) {
+            context.setVariable(entry.key, entry.value)
+        }
+
+//        context.setVariable("authCode", authCode)
         return templateEngine.process(type.name.lowercase(), context)
     }
 }

backend/mail-service/src/main/kotlin/io/blog/mail/mail/types/MessageType.kt

@@ -1,5 +1,5 @@
 package io.blog.mail.mail.types
 
 enum class MessageType {
-    EMAIL, PASSWORD
+    EMAIL, PASSWORD, COMMENT
 }

backend/mail-service/src/main/kotlin/io/blog/mail/redis/config/RedisConfig.kt

@@ -1,5 +1,6 @@
 package io.blog.mail.redis.config
 
+import io.blog.mail.redis.service.CommentEmailSubService
 import io.blog.mail.redis.service.VerifyEmailSubService
 import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.beans.factory.annotation.Value
@@ -17,6 +18,8 @@ import org.springframework.data.redis.listener.adapter.MessageListenerAdapter
 class RedisConfig {
     @Autowired
     private lateinit var verifyEmailSubService: VerifyEmailSubService
+    @Autowired
+    private lateinit var commentEmailSubService: CommentEmailSubService
 
     @Value("\${spring.data.redis.host}")
     var redisHost: String = "localhost"
@@ -30,21 +33,32 @@ class RedisConfig {
         return LettuceConnectionFactory(redisHost, redisPort)
     }
 
+    @Bean
+    fun verifyEmailTopic(): ChannelTopic {
+        return ChannelTopic("VerifyEmail")
+    }
+
     @Bean
     fun verifyEmailMessageListenerAdapter(): MessageListenerAdapter {
         return MessageListenerAdapter(verifyEmailSubService)
     }
 
+    @Bean
+    fun commentEmailTopic(): ChannelTopic {
+        return ChannelTopic("CommentEmail")
+    }
+
+    @Bean
+    fun commentEmailMessageListenerAdapter(): MessageListenerAdapter {
+        return MessageListenerAdapter(commentEmailSubService)
+    }
+
     @Bean
     fun redisContainer(): RedisMessageListenerContainer {
         val container = RedisMessageListenerContainer()
         container.setConnectionFactory(redisConnectionFactory())
         container.addMessageListener(verifyEmailMessageListenerAdapter(), verifyEmailTopic())
+        container.addMessageListener(commentEmailMessageListenerAdapter(), commentEmailTopic())
         return container
     }
-
-    @Bean
-    fun verifyEmailTopic(): ChannelTopic {
-        return ChannelTopic("VerifyEmail")
-    }
 }

backend/mail-service/src/main/kotlin/io/blog/mail/redis/message/CommentEmailMessage.kt

@@ -0,0 +1,12 @@
+package io.blog.mail.redis.message
+
+import com.fasterxml.jackson.annotation.JsonProperty
+
+data class CommentEmailMessage(
+        @JsonProperty("email") val email: String,
+        @JsonProperty("subject") val subject: String,
+        @JsonProperty("postName") val postName: String,
+        @JsonProperty("postUrl") val postUrl: String,
+        @JsonProperty("commentContent") val commentContent: String,
+        @JsonProperty("commentAuthor") val commentAuthor: String
+)

backend/mail-service/src/main/kotlin/io/blog/mail/redis/service/CommentEmailSubService.kt

@@ -0,0 +1,34 @@
+package io.blog.mail.redis.service
+
+import com.fasterxml.jackson.databind.ObjectMapper
+import io.blog.mail.mail.service.EmailService
+import io.blog.mail.mail.types.MessageType
+import io.blog.mail.redis.message.CommentEmailMessage
+import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.data.redis.connection.Message
+import org.springframework.data.redis.connection.MessageListener
+import org.springframework.stereotype.Service
+
+@Service
+class CommentEmailSubService : MessageListener {
+    @Autowired
+    private lateinit var emailService: EmailService
+    private val mapper = ObjectMapper()
+
+    override fun onMessage(message: Message, pattern: ByteArray?) {
+        try {
+            val emailMessage = mapper.readValue(message.body, CommentEmailMessage::class.java)
+
+            val params = HashMap<String, String>()
+            params["postName"] = emailMessage.postName
+            params["postUrl"] = emailMessage.postUrl
+            params["commentContent"] = emailMessage.commentContent
+            params["commentAuthor"] = emailMessage.commentAuthor
+
+            emailService.sendEmail(MessageType.COMMENT, emailMessage.email, emailMessage.subject, params)
+        }
+        catch (e: Exception) {
+            e.printStackTrace()
+        }
+    }
+}

backend/mail-service/src/main/kotlin/io/blog/mail/redis/service/VerifyEmailSubService.kt

@@ -24,7 +24,10 @@ class VerifyEmailSubService : MessageListener {
             println("Subject: ${verifyEmailMessage.subject}")
             println("Code: ${verifyEmailMessage.code}")
 
-            emailService.sendEmail(MessageType.EMAIL, verifyEmailMessage.email, verifyEmailMessage.subject, verifyEmailMessage.code)
+            val params = HashMap<String, String>()
+            params["authCode"] = verifyEmailMessage.code
+
+            emailService.sendEmail(MessageType.EMAIL, verifyEmailMessage.email, verifyEmailMessage.subject, params)
         }
         catch (e: Exception) {
             e.printStackTrace()

backend/mail-service/src/main/resources/templates/comment.html

@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<html xmlns:th="http://www.thymeleaf.org">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>댓글 알림</title>
+</head>
+<body style="width: 100%; height: 100%;">
+<div style="width: 100%; height: 100%; font-family: 'Noto Sans', sans-serif; background-color: #f8f9fa; margin: 0; padding: 0; text-align: center; color: #333;">
+    <div class="container" style="max-width: 600px; margin: 30px auto; background-color: #ffffff; border-radius: 8px; box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1); padding: 20px; border: 1px solid #e9ecef;">
+        <h1 style="font-size: 24px; margin-bottom: 10px; color: #007bff;">새로운 댓글이 달렸어요!</h1>
+        <p style="font-size: 16px; line-height: 1.5; margin: 10px 0;">
+            <strong th:text="${commentAuthor}">작성자</strong>님이
+            <strong th:text="${postName}">게시글 제목</strong>에 댓글을 남겼습니다.
+        </p>
+        <div style="font-size: 16px; background-color: #f1f3f5; padding: 15px; border-radius: 4px; margin: 15px 0;" th:text="${commentContent}">
+            댓글 내용
+        </div>
+        <p style="font-size: 14px; line-height: 1.5; color: #6c757d;">
+            더 많은 내용을 확인하려면 게시글을 방문해 주세요.
+        </p>
+        <!-- 방문 버튼 -->
+        <a th:href="${postUrl}"
+           style="display: inline-block; padding: 12px 24px; background-color: #007bff; color: #ffffff; text-decoration: none; border-radius: 6px; font-size: 14px; font-weight: bold; box-shadow: 0 2px 6px rgba(0, 123, 255, 0.2);">
+            댓글 보러 가기
+        </a>
+        <div class="footer" style="font-size: 12px; color: #6c757d; margin-top: 20px;">
+            <p>이 메일은 자동 발송된 메일입니다. 회신하지 마세요.</p>
+        </div>
+    </div>
+</div>
+</body>
+</html>

backend/main-service/src/main/java/io/blog/devlog/domain/comment/controller/CommentController.java

@@ -12,6 +12,8 @@
 import io.blog.devlog.domain.user.service.UserService;
 import io.blog.devlog.global.exception.NoPermissionException;
 import io.blog.devlog.global.exception.NotFoundException;
+import io.blog.devlog.global.redis.message.CommentEmailMessage;
+import io.blog.devlog.global.redis.service.CommentEmailPubService;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.http.ResponseEntity;
@@ -27,9 +29,12 @@
 @RequestMapping("/comments")
 @Slf4j
 public class CommentController {
+
     private final UserService userService;
     private final PostService postService;
     private final CommentService commentService;
+    private final CommentEmailPubService commentEmailPubService;
+
     @PostMapping
     public void uploadComment(@RequestBody RequestCommentDto requestCommentDto) {
         log.info("RequestCommentDto : " + requestCommentDto);
@@ -42,6 +47,16 @@ public void uploadComment(@RequestBody RequestCommentDto requestCommentDto) {
             throw new NoPermissionException("댓글을 작성할 권한이 없습니다.");
         }
         commentService.saveComment(user, requestCommentDto, postDetail.getPost());
+
+        CommentEmailMessage emailMessage = new CommentEmailMessage(
+                postDetail.getPost().getUser().getEmail(),
+                String.format("[devLog] {%s} 게시글에 댓글이 달렸습니다.", postDetail.getPost().getTitle()),
+                postDetail.getPost().getTitle(),
+                postDetail.getPost().getUrl(),
+                requestCommentDto.getContent(),
+                user.getUsername()
+        );
+        commentEmailPubService.sendEmail(emailMessage);
     }
 
     @PostMapping("/{commentId}")