chat-widget

实时支持聊天小组件

构建一个实时支持聊天系统，包含面向用户的浮动小组件和面向支持人员的管理员仪表盘。

何时使用此技能

在用户想要以下操作时使用：

• 向其应用添加实时聊天小组件
• 构建客户支持聊天功能
• 创建用户与管理员之间的实时消息传递
• 添加应用内支持渠道

架构概览

┌─────────────────────────────────────────────────────────────────┐
│                        FRONTEND                                 │
├─────────────────────────────┬───────────────────────────────────┤
│   User Widget               │   Admin Dashboard                 │
│   - Floating chat button    │   - Chat list (active/archived)   │
│   - Message panel           │   - Conversation view             │
│   - Unread badge            │   - Archive/restore controls      │
│   - Connection indicator    │   - User info display             │
└─────────────┬───────────────┴───────────────┬───────────────────┘
              │                               │
              │     WebSocket + REST API      │
              ▼                               ▼
┌─────────────────────────────────────────────────────────────────┐
│                        BACKEND                                  │
├─────────────────────────────────────────────────────────────────┤
│   Channels                  │   Controllers                     │
│   - ChatChannel (per chat)  │   - User: get/create chat         │
│   - AdminChannel (global)   │   - Admin: list, view, archive    │
├─────────────────────────────┼───────────────────────────────────┤
│   Models                    │   Jobs                            │
│   - Chat (1 per user)       │   - Email notification (delayed)  │
│   - Message (many per chat) │                                   │
└─────────────────────────────────────────────────────────────────┘

实现指南

步骤 1：数据模型

创建两张表：support_chats 和 support_messages。

support_chats

id              - primary key (UUID recommended)
user_id         - foreign key to users (UNIQUE - one chat per user)
last_message_at - timestamp (for sorting chats by recency)
admin_viewed_at - timestamp (tracks when admin last viewed)
archived_at     - timestamp (null = active, set = archived)
created_at
updated_at

support_messages

id              - primary key (UUID recommended)
chat_id         - foreign key to support_chats
content         - text (required)
sender_type     - enum: 'user' | 'admin'
read_at         - timestamp (null = unread)
created_at
updated_at

关键索引：

• support_chats.user_id（唯一）
• support_chats.last_message_at（用于排序）
• support_chats.archived_at（用于筛选）
• support_messages.chat_id
• support_messages.(chat_id, created_at)（复合，用于排序）

模型关系：

User has_one SupportChat
SupportChat belongs_to User
SupportChat has_many SupportMessages
SupportMessage belongs_to SupportChat

需要实现的模型方法：

Chat 模型：

function touch_last_message()
  update last_message_at = now()

function unread_for_admin?()
  return exists message where sender_type = 'user'
    and created_at > admin_viewed_at

function mark_viewed_by_admin()
  update admin_viewed_at = now()

function archive()
  update archived_at = now()

function unarchive()
  update archived_at = null

function archived?()
  return archived_at != null

Message 模型：

after_create:
  chat.touch_last_message()
  if sender_type == 'user' and chat.archived?:
    chat.unarchive()  // Auto-reactivate on new user message

after_create_commit:
  broadcast_to_chat_channel(message_data)
  if sender_type == 'user':
    broadcast_to_admin_notification_channel(message_data, chat_info)
  if sender_type == 'admin':
    schedule_email_notification(delay: 5.minutes)

步骤 2：API 端点

面向用户：

GET  /support_chat       - Get or create user's chat with messages
PATCH /support_chat/mark_read - Mark admin messages as read

面向管理员：

GET  /admin/chats              - List chats (query: archived=true/false)
GET  /admin/chats/:id          - Get chat with messages
POST /admin/chats/:id/archive  - Archive chat
POST /admin/chats/:id/unarchive - Restore chat

控制器逻辑：

用户 GET /support_chat：

function show()
  chat = current_user.support_chat || create_chat(user: current_user)
  return {
    id: chat.id,
    messages: chat.messages.map(m => serialize_message(m))
  }

管理员 GET /admin/chats：

function index()
  chats = SupportChat
    .where(archived_at: params.archived ? not_null : null)
    .includes(:user, :messages)
    .order(last_message_at: desc)

  return chats.map(c => {
    id: c.id,
    user_email: c.user.email,
    last_message_preview: c.messages.last?.content.truncate(100),
    last_message_sender: c.messages.last?.sender_type,
    message_count: c.messages.count,
    unread: c.unread_for_admin?,
    archived: c.archived?
  })

步骤 3：WebSocket 频道

创建两个频道用于实时通信。

ChatChannel（特定于每个聊天）：

class ChatChannel
  on_subscribe(chat_id):
    chat = find_chat(chat_id)
    if not authorized(chat):
      reject()
      return
    stream_from "support_chat:#{chat_id}"

  function authorized(chat):
    return chat.user_id == current_user.id OR current_user.is_admin

  action send_message(content):
    if content.blank: return
    sender_type = current_user.is_admin ? 'admin' : 'user'
    chat.messages.create(content: content, sender_type: sender_type)

AdminNotificationChannel（对所有管理员全局）：

class AdminNotificationChannel
  on_subscribe:
    if not current_user.is_admin:
      reject()
      return
    stream_from "admin_support_notifications"

广播（来自 Message 模型）：

function broadcast_message():
  message_data = {
    id: id,
    content: content,
    sender_type: sender_type,
    read_at: read_at,
    created_at: created_at
  }

  // Broadcast to chat subscribers (user + any viewing admins)
  broadcast("support_chat:#{chat.id}", {
    type: "new_message",
    message: message_data
  })

  // Notify all admins when user sends message
  if sender_type == 'user':
    broadcast("admin_support_notifications", {
      type: "new_user_message",
      chat_id: chat.id,
      user_email: chat.user.email,
      message: message_data
    })

步骤 4：前端 - 用户小组件

创建包含以下组件的浮动聊天小组件：

组件结构：

ChatWidget (root container)
├── ChatButton (fixed position, bottom-right)
│   ├── Icon (message bubble when closed, X when open)
│   └── UnreadBadge (shows count, caps at "9+")
└── ChatPanel (slides up when open)
    ├── Header (title + connection status dot)
    ├── MessageList (scrollable)
    │   └── MessageBubble (styled by sender_type)
    └── InputArea
        ├── Textarea (auto-expanding)
        └── SendButton

状态管理 hook：

function useSupportChat():
  state:
    chat: Chat | null
    connected: boolean
    loading: boolean

  refs:
    consumer: WebSocketConsumer
    subscription: ChannelSubscription
    seenMessageIds: Set<string>  // For deduplication

  on_mount:
    fetch('/support_chat')
      .then(data => {
        chat = data
        seenMessageIds.addAll(data.messages.map(m => m.id))
      })

  when chat.id changes:
    subscription = consumer.subscribe('ChatChannel', { chat_id: chat.id })
    subscription.on_received(data => {
      if data.type == 'new_message':
        if seenMessageIds.has(data.message.id): return  // Dedupe
        seenMessageIds.add(data.message.id)
        chat.messages.push(data.message)
        if data.message.sender_type == 'admin':
          play_notification_sound()
    })
    subscription.on_connected(() => connected = true)
    subscription.on_disconnected(() => connected = false)

  on_unmount:
    subscription.unsubscribe()

  function sendMessage(content):
    subscription.perform('send_message', { content: content.trim() })

  function markAsRead():
    fetch('/support_chat/mark_read', { method: 'PATCH' })
    // Update local state to mark admin messages as read

  return { chat, connected, loading, sendMessage, markAsRead }

小组件行为：

• 在右下角显示浮动按钮（固定位置）
• 显示未读数量徽章（统计 sender_type='admin' 且 read_at=null 的消息）
• 点击按钮切换面板打开/关闭
• 面板打开时自动调用 markAsRead()
• 新消息到达时自动滚动到底部
• 显示连接状态指示器（绿点 = 已连接）
• 键盘：Enter 发送，Shift+Enter 换行

消息样式：

• 用户消息：右对齐，主色背景
• 管理员消息：左对齐，次要/柔和背景
• 每条消息显示时间戳

步骤 5：前端 - 管理员仪表盘

创建两个页面：聊天列表和聊天详情。

聊天列表页面：

Header: "Support Chats"
Tabs: [Active] [Archived]

Chat cards (sorted by last_message_at desc):
┌─────────────────────────────────────────┐
│ [Unread indicator] [email protected]     │
│ Last message preview text...            │
│ 5 messages · 2 minutes ago              │
└─────────────────────────────────────────┘

功能：

• 标签筛选（活跃 vs 已归档）
• 未读指示器（高亮边框或徽章）
• 点击导航到详情
• 如果最后一条消息来自管理员，显示 "You: " 前缀

聊天详情页面：

Header: [email protected] [Archive/Restore button]
Back link

Messages (grouped by date):
──── Monday, January 29 ────
[User bubble]  Message content
               10:30 AM

          [Admin bubble] Reply content
                         10:35 AM

Input area (same as widget)

功能：

• 按日期分组消息并带分隔线
• 用户消息在左，管理员消息在右（与用户小组件相反）
• 显示发送者标签（管理员显示 "You"，用户显示邮箱/名称）
• 归档/恢复切换按钮
• 与用户小组件相同的 WebSocket 订阅，用于实时更新
• 页面加载时调用 mark_viewed_by_admin()（服务端）

步骤 6：邮件通知

当管理员回复且用户尚未查看时，向用户发送邮件。

Job/worker：

class SupportReplyNotificationJob
  perform(message):
    if message.sender_type != 'admin': return
    if message.read_at != null: return  // Already read, skip

    send_email(
      to: message.chat.user.email,
      subject: "New reply from Support",
      body: "You have a new message from our support team..."
    )

调度：

• 管理员发送消息时，以 5 分钟延迟调度 job
• 这给用户时间在应用内看到消息，然后再发邮件
• Job 在发送前检查是否仍未读

步骤 7：TypeScript 类型

interface SupportMessage {
  id: string
  content: string
  sender_type: 'user' | 'admin'
  read_at: string | null  // ISO8601
  created_at: string      // ISO8601
}

interface SupportChat {
  id: string
  messages: SupportMessage[]
}

interface SupportChatListItem {
  id: string
  user_id: string
  user_email: string
  last_message_at: string | null
  last_message_preview: string | null
  last_message_sender: 'user' | 'admin' | null
  message_count: number
  unread: boolean
  archived: boolean
}

interface AdminSupportChat {
  id: string
  user_id: string
  user_email: string
  archived: boolean
  messages: SupportMessage[]
}

// WebSocket message types
interface ChatChannelMessage {
  type: 'new_message'
  message: SupportMessage
}

interface AdminNotificationMessage {
  type: 'new_user_message'
  chat_id: string
  user_email: string
  message: SupportMessage
}

关键设计决策

1. 每个用户一个聊天 - 简化用户体验，用户始终拥有相同的对话历史
2. 通过归档进行软删除 - 保留历史，允许恢复
3. 自动取消归档 - 当用户向已归档聊天发送消息时，重新激活它
4. 延迟邮件通知 - 5 分钟延迟可防止快速回复时的垃圾邮件
5. 消息去重 - 跟踪已见 ID，以防止发送 + 广播回显造成的重复
6. 独立管理员频道 - 允许未来功能，如全局未读计数、桌面通知

测试清单

实现后：

• 用户可以打开小组件并发送消息
• 管理员可以在仪表板上实时看到消息
• 管理员可以回复，用户也能立即看到回复
• 未读徽标显示正确的数量
• 打开小组件时清除徽标
• 连接指示器反映实际状态
• 归档和恢复功能正常
• 用户发送消息时会触发自动取消归档
• 消息未读 5 分钟后发送电子邮件
• 如果用户已阅读消息，则不发送电子邮件
• 消息按时间顺序显示
• 不会出现重复消息

常见陷阱

1. 忘记去重 - 当前用户发送的消息会通过广播回传
2. 读取状态的竞态条件 - 使用数据库事务
3. WebSocket 身份验证 - 验证用户是否可以访问特定聊天
4. 连接状态过期 - 妥善处理重新连接
5. 缺少索引 - 在 (chat_id, created_at) 上添加复合索引
6. 电子邮件发送时机 - 使用后台任务，而不是同步发送

---

框架专属指南

Ruby on Rails

模型：

# app/models/support_chat.rb
class SupportChat < ApplicationRecord
  belongs_to :user
  has_many :support_messages, dependent: :destroy

  scope :active, -> { where(archived_at: nil) }
  scope :archived, -> { where.not(archived_at: nil) }
  scope :recent_first, -> { order(last_message_at: :desc) }

  def touch_last_message
    update_column(:last_message_at, Time.current)
  end

  def unread_for_admin?
    support_messages.where(sender_type: :user)
      .where("created_at > ?", admin_viewed_at || Time.at(0)).exists?
  end

  def archive!
    update_column(:archived_at, Time.current)
  end

  def unarchive!
    update_column(:archived_at, nil)
  end
end

# app/models/support_message.rb
class SupportMessage < ApplicationRecord
  belongs_to :support_chat
  enum :sender_type, { user: 0, admin: 1 }
  validates :content, presence: true

  after_create :update_chat_timestamp
  after_create :auto_unarchive, if: :user?
  after_create_commit :broadcast_message
  after_create_commit :schedule_notification, if: :admin?

  private

  def broadcast_message
    ActionCable.server.broadcast("support_chat:#{support_chat_id}", {
      type: "new_message",
      message: { id:, content:, sender_type:, read_at:, created_at: }
    })
  end

  def schedule_notification
    SupportReplyNotificationJob.set(wait: 5.minutes).perform_later(self)
  end
end

频道：

# app/channels/support_chat_channel.rb
class SupportChatChannel < ApplicationCable::Channel
  def subscribed
    @chat = SupportChat.find(params[:chat_id])
    reject unless @chat.user_id == current_user.id || current_user.admin?
    stream_from "support_chat:#{@chat.id}"
  end

  def send_message(data)
    @chat.support_messages.create!(
      content: data["content"],
      sender_type: current_user.admin? ? :admin : :user
    )
  end
end

迁移：

create_table :support_chats, id: :uuid do |t|
  t.references :user, type: :uuid, null: false, foreign_key: true, index: { unique: true }
  t.datetime :last_message_at
  t.datetime :admin_viewed_at
  t.datetime :archived_at
  t.timestamps
end

create_table :support_messages, id: :uuid do |t|
  t.references :support_chat, type: :uuid, null: false, foreign_key: true
  t.text :content, null: false
  t.integer :sender_type, default: 0
  t.datetime :read_at
  t.timestamps
end
add_index :support_messages, [:support_chat_id, :created_at]

React（搭配任意后端）

Hook：

// hooks/useSupportChat.ts
import { useEffect, useState, useRef, useCallback } from 'react'

export function useSupportChat(websocketUrl: string) {
  const [chat, setChat] = useState<Chat | null>(null)
  const [connected, setConnected] = useState(false)
  const wsRef = useRef<WebSocket | null>(null)
  const seenIds = useRef(new Set<string>())

  useEffect(() => {
    fetch('/api/support_chat').then(r => r.json()).then(data => {
      setChat(data)
      data.messages.forEach((m: Message) => seenIds.current.add(m.id))
    })
  }, [])

  useEffect(() => {
    if (!chat?.id) return
    const ws = new WebSocket(`${websocketUrl}?chat_id=${chat.id}`)
    wsRef.current = ws

    ws.onopen = () => setConnected(true)
    ws.onclose = () => setConnected(false)
    ws.onmessage = (event) => {
      const data = JSON.parse(event.data)
      if (data.type === 'new_message' && !seenIds.current.has(data.message.id)) {
        seenIds.current.add(data.message.id)
        setChat(prev => prev ? { ...prev, messages: [...prev.messages, data.message] } : prev)
      }
    }
    return () => ws.close()
  }, [chat?.id])

  const sendMessage = useCallback((content: string) => {
    wsRef.current?.send(JSON.stringify({ action: 'send_message', content }))
  }, [])

  return { chat, connected, sendMessage }
}

小组件：

// components/ChatWidget.tsx
export function ChatWidget() {
  const [isOpen, setIsOpen] = useState(false)
  const { chat, connected, sendMessage } = useSupportChat('/ws/chat')
  const [input, setInput] = useState('')
  const messagesEndRef = useRef<HTMLDivElement>(null)

  const unreadCount = chat?.messages.filter(
    m => m.sender_type === 'admin' && !m.read_at
  ).length ?? 0

  useEffect(() => {
    messagesEndRef.current?.scrollIntoView({ behavior: 'smooth' })
  }, [chat?.messages])

  const handleSend = () => {
    if (!input.trim()) return
    sendMessage(input.trim())
    setInput('')
  }

  return (
    <div className="fixed bottom-4 right-4 z-50">
      {isOpen ? (
        <div className="w-80 h-96 bg-white rounded-lg shadow-xl flex flex-col">
          <header className="p-3 border-b flex justify-between items-center">
            <span>Support Chat</span>
            <span className={`w-2 h-2 rounded-full ${connected ? 'bg-green-500' : 'bg-gray-400'}`} />
          </header>
          <div className="flex-1 overflow-y-auto p-3 space-y-2">
            {chat?.messages.map(m => (
              <div key={m.id} className={`p-2 rounded ${m.sender_type === 'user' ? 'bg-blue-100 ml-auto' : 'bg-gray-100'}`}>
                {m.content}
              </div>
            ))}
            <div ref={messagesEndRef} />
          </div>
          <div className="p-3 border-t flex gap-2">
            <input value={input} onChange={e => setInput(e.target.value)}
              onKeyDown={e => e.key === 'Enter' && !e.shiftKey && handleSend()}
              className="flex-1 border rounded px-2" placeholder="Type a message..." />
            <button onClick={handleSend} className="px-3 py-1 bg-blue-500 text-white rounded">Send</button>
          </div>
        </div>
      ) : (
        <button onClick={() => setIsOpen(true)} className="w-14 h-14 bg-blue-500 rounded-full text-white relative">
          💬
          {unreadCount > 0 && (
            <span className="absolute -top-1 -right-1 bg-red-500 text-xs w-5 h-5 rounded-full flex items-center justify-center">
              {unreadCount > 9 ? '9+' : unreadCount}
            </span>
          )}
        </button>
      )}
    </div>
  )
}

Next.js（App Router）

API 路由：

// app/api/support-chat/route.ts
import { getServerSession } from 'next-auth'
import { prisma } from '@/lib/prisma'

export async function GET() {
  const session = await getServerSession()
  if (!session?.user) return Response.json({ error: 'Unauthorized' }, { status: 401 })

  let chat = await prisma.supportChat.findUnique({
    where: { userId: session.user.id },
    include: { messages: { orderBy: { createdAt: 'asc' } } }
  })

  if (!chat) {
    chat = await prisma.supportChat.create({
      data: { userId: session.user.id },
      include: { messages: true }
    })
  }

  return Response.json(chat)
}

使用 Pusher/Ably 的 WebSocket（适合无服务器环境）：

// For serverless, use Pusher, Ably, or similar
import Pusher from 'pusher'
const pusher = new Pusher({ appId, key, secret, cluster })

// When message is created:
await pusher.trigger(`support-chat-${chatId}`, 'new-message', messageData)

// Client-side with pusher-js:
const channel = pusher.subscribe(`support-chat-${chatId}`)
channel.bind('new-message', (data) => { /* update state */ })

PHP/Laravel

模型：

// app/Models/SupportChat.php
class SupportChat extends Model
{
    protected $casts = ['last_message_at' => 'datetime', 'archived_at' => 'datetime'];

    public function user() { return $this->belongsTo(User::class); }
    public function messages() { return $this->hasMany(SupportMessage::class); }

    public function scopeActive($query) { return $query->whereNull('archived_at'); }
    public function scopeArchived($query) { return $query->whereNotNull('archived_at'); }

    public function isUnreadForAdmin(): bool {
        return $this->messages()
            ->where('sender_type', 'user')
            ->where('created_at', '>', $this->admin_viewed_at ?? '1970-01-01')
            ->exists();
    }
}

// app/Models/SupportMessage.php
class SupportMessage extends Model
{
    protected static function booted() {
        static::created(function ($message) {
            $message->supportChat->update(['last_message_at' => now()]);
            broadcast(new NewSupportMessage($message))->toOthers();

            if ($message->sender_type === 'admin') {
                SendSupportReplyNotification::dispatch($message)->delay(now()->addMinutes(5));
            }
        });
    }
}

广播事件：

// app/Events/NewSupportMessage.php
class NewSupportMessage implements ShouldBroadcast
{
    public function __construct(public SupportMessage $message) {}

    public function broadcastOn() {
        return new PrivateChannel('support-chat.' . $this->message->support_chat_id);
    }

    public function broadcastAs() { return 'new-message'; }
}

Vue.js

组合式函数：

// composables/useSupportChat.ts
import { ref, onMounted, onUnmounted } from 'vue'

export function useSupportChat() {
  const chat = ref<Chat | null>(null)
  const connected = ref(false)
  let ws: WebSocket | null = null
  const seenIds = new Set<string>()

  onMounted(async () => {
    const res = await fetch('/api/support-chat')
    chat.value = await res.json()
    chat.value?.messages.forEach(m => seenIds.add(m.id))

    ws = new WebSocket(`/ws/chat?id=${chat.value?.id}`)
    ws.onopen = () => connected.value = true
    ws.onclose = () => connected.value = false
    ws.onmessage = (e) => {
      const data = JSON.parse(e.data)
      if (data.type === 'new_message' && !seenIds.has(data.message.id)) {
        seenIds.add(data.message.id)
        chat.value?.messages.push(data.message)
      }
    }
  })

  onUnmounted(() => ws?.close())

  const sendMessage = (content: string) => {
    ws?.send(JSON.stringify({ action: 'send_message', content }))
  }

  return { chat, connected, sendMessage }
}

---

数据库建议

PostgreSQL（推荐）

• 使用 UUID 主键以确保安全（ID 不可猜测）
• 所有日期时间列都使用 timestamptz
• 在内容上添加 GIN 索引以支持全文搜索（可选）

MySQL

• UUID 使用 CHAR(36) 或 BINARY(16)
• 使用 DATETIME(6) 以支持微秒精度
• 考虑使用 utf8mb4 字符集以支持表情符号

SQLite（开发/小规模场景）

• 适合原型开发
• 将 UUID 存储为 TEXT
• 没有原生日期时间类型，应存储为 ISO8601 字符串

MongoDB（文档存储）

• 如果消息数量有上限，将消息嵌入聊天文档中
• 或使用带有 chat_id 引用的独立集合
• 对已归档聊天使用 TTL 索引以自动清理（可选）

---

电子邮件处理建议

事务性电子邮件服务

• Postmark - 投递能力最佳，API 简单
• SendGrid - 免费套餐不错，功能稳健
• AWS SES - 大规模使用时成本最低
• Resend - 现代化的开发者体验，支持 React 邮件模板

实现模式

// Always use background jobs for email
Job: SendSupportReplyNotification
  delay: 5 minutes after admin message

  perform(message_id):
    message = find_message(message_id)

    // Guard clauses - don't send if:
    if message.sender_type != 'admin': return
    if message.read_at != null: return        // Already read
    if message.chat.archived?: return         // Chat archived

    send_email(
      to: message.chat.user.email,
      template: 'support_reply',
      data: { message_preview: message.content.truncate(200) }
    )

电子邮件模板提示

• 包含消息预览（截断显示）
• 添加打开聊天的直接链接（如果是 Web 应用）
• 主题保持简洁：“来自 [App] 支持团队的新回复”
• 包含退订链接以满足合规要求

---

实时技术选项

技术	最适合	支持无服务器？
ActionCable (Rails)	Rails 应用	否
Socket.IO	Node.js 应用	否
Pusher	任意技术栈	是
Ably	任意技术栈	是
Supabase Realtime	Supabase 用户	是
Firebase RTDB	Firebase 用户	是
Server-Sent Events	简单的单向通信	是

回退策略

如果 WebSocket 不可用，则实现轮询：

// Poll every 5 seconds when disconnected
if (!websocket.connected) {
  setInterval(() => {
    fetch('/api/support-chat/messages?since=' + lastMessageTime)
      .then(newMessages => appendMessages(newMessages))
  }, 5000)
}