把发消息写入数据库的时间都交给数据库来创建

websocket/index.js

@@ -129,21 +129,21 @@ function handleSendMessage(data, ws) {
     `${senderName} → ${receiverName}：${content}`
   );
 
-  const sql = `
+  const insertSql = `
     INSERT INTO messages
     (message_id, sender_name, receiver_name, content)
     VALUES (?, ?, ?, ?)
   `;
-  db.query(sql, [
+  db.query(insertSql, [
     messageId,
     senderName,
     receiverName,
     content
   ], (error, result) => {
+    const senderWs = getConnection(senderName);
     if (error) {
       console.error(error);
 
-      const senderWs = getConnection(senderName);
       if (senderWs) {
         senderWs.send(
           JSON.stringify({
@@ -156,34 +156,79 @@ function handleSendMessage(data, ws) {
       return;
     }
 
-    // 数据库确认写入后，才确认发送并推送给接收者
-    const senderWs = getConnection(senderName);
-    if (senderWs) {
-      senderWs.send(
+    // 插入新消息之后，用messageID查询这条新消息的时间点（为了使用数据库插入时创建的时间点，不能用前端自己生成的）
+    const timeSql = `
+      SELECT created_at
+      FROM messages
+      WHERE message_id = ?
+    `;
+    db.query(timeSql, [messageId], (error, results) => {
+      if (error) {
+        console.error("查询消息失败：", error);
+
+        if (senderWs) {
+          senderWs.send(
+            JSON.stringify({
+              type: "sendError",
+              messageId: messageId,
+              message: "获取消息失败"
+            })
+          );
+        }
+        return;
+      }
+
+      if (results.length === 0) {
+        if (senderWs) {
+          senderWs.send(
+            JSON.stringify({
+              type: "sendError",
+              messageId: messageId,
+              message: "获取消息失败"
+            })
+          );
+        }
+        return;
+      }
+
+      const createdAt = results[0].created_at;
+
+      // 数据库确认写入后，才把成功写入的消息推送给发送者
+      if (senderWs) {
+        senderWs.send(
+          JSON.stringify({
+            type: "sendSuccess",
+            message: {
+              messageId,
+              senderName,
+              receiverName,
+              content,
+              createdAt
+            }
+          })
+        );
+      }
+
+      // 把写入的新消息推送给接收者，如果接收者不在线，就不用发送websocket消息给他了，但数据库里是有的
+      const receiverWs = getConnection(receiverName);
+      if (!receiverWs) {
+        console.log(`${receiverName} 当前不在线`);
+        return;
+      }
+
+      receiverWs.send(
         JSON.stringify({
-          type: "sendSuccess",
-          messageId: messageId
+          type: "newMessage",
+          message: {
+            messageId,
+            senderName,
+            receiverName,
+            content,
+            createdAt
+          },
         })
       );
-    }
-
-    const receiverWs = getConnection(receiverName);
-    if (!receiverWs) {
-      console.log(`${receiverName} 当前不在线`);
-      return;
-    }
-
-    receiverWs.send(
-      JSON.stringify({
-        type: "newMessage",
-        message: {
-          messageId,
-          senderName,
-          receiverName,
-          content
-        },
-      })
-    );
+    });
   });
 }