SPA 单页应用版本更新与无刷新部署方案

// vue.config.js
const fs = require('fs');
const path = require('path');

const buildManifestContent = {
  appVersion: require('./package.json').version,
  version: new Date().getTime(),
  buildEnv: process.env.NODE_ENV,
  buildHash: new Date().getTime().toString(16),
  needRefresh: false,
  msg: "更新内容如下：\n--1.更新提示机制"
};

module.exports = {
  configureWebpack: {
    plugins: [
      {
        apply(compiler) {
          const writeManifest = () => {
            const manifestPath = path.resolve(__dirname, 'public/manifest.json');
            try {
              let originalContent = {};
              if (fs.existsSync(manifestPath)) {
                const fileStr = fs.readFileSync(manifestPath, 'utf-8');
                originalContent = JSON.parse(fileStr);
              }
              const finalContent = { ...originalContent, ...buildManifestContent };
              fs.writeFileSync(manifestPath, JSON.stringify(finalContent, null, 2), 'utf-8');
              console.log('✅ 成功合并并写入 public/manifest.json');
            } catch (error) {
              console.error('❌ 写入 manifest.json 失败：', error);
            }
          };
          compiler.hooks.beforeRun.tap('WriteManifestPlugin', writeManifest);
          compiler.hooks.watchRun.tap('WriteManifestPlugin', writeManifest);
        }
      }
    ]
  }
};

具体实现方案

1. 在 App.vue 入口监听路由变化

核心思路是在路由守卫或组件挂载时检查版本。这里以 Vue Router 为例，在 App.vue 中监听 $route 变化来触发检测。

// App.vue
watch: {
  $route(to, from) {
    fetch(`/manifest.json?v=${Date.now()}`)
      .then(response => {
        if (!response.ok) throw new Error('Network response was not ok');
        return response.json();
      })
      .then(data => {
        const newVersion = data?.version;
        const oldVersion = Number(localStorage.getItem('lastVersion'));
        
        if (!oldVersion || oldVersion !== data?.version) {
          console.log('版本升级了，强制刷新');
          localStorage.setItem('lastVersion', newVersion);
          setTimeout(() => {
            window.location.reload(true);
          }, 1000);
        }
      })
      .catch(err => {
        console.error('There was a problem with the fetch operation:', err);
      });
  }
}

2. 轮询方式检查版本更新

对于长期在线的系统，轮询是一个简单有效的方案。我们封装一个 VersionManager 类来处理版本比对和提示。

// VersionManager.js
class VersionManager {
  constructor() {
    this.currentVersion = null;
    this.updateCallback = null;
    this.pollingInterval = 300000; // 5 分钟轮询一次
    this.isUpdateAvailable = false;
  }

  init(versionUrl, onUpdate) {
    this.updateCallback = onUpdate;
    return this.fetchVersion(versionUrl)
      .then(version => {
        this.currentVersion = version;
        this.startPolling(versionUrl);
        return version;
      });
  }

  fetchVersion(url) {
    return fetch(url, {
      cache: 'no-cache',
      headers: {
        'Cache-Control': 'no-cache, no-store, must-revalidate',
        'Pragma': 'no-cache',
        'Expires': '0'
      }
    })
    .then(res => res.json())
    .then(data => data.version || data.buildTime)
    .catch(err => {
      console.error('版本获取失败:', err);
      return null;
    });
  }

  startPolling(url) {
    setInterval(() => {
      this.fetchVersion(url)
        .then(newVersion => {
          if (newVersion && this.isNewVersion(newVersion)) {
            this.isUpdateAvailable = true;
            this.promptUserToUpdate();
          }
        });
    }, this.pollingInterval);
  }

  isNewVersion(newVersion) {
    if (!this.currentVersion) return true;
    if (this.currentVersion.includes('.')) {
      const current = this.currentVersion.split('.').map(Number);
      const latest = newVersion.split('.').map(Number);
      for (let i = 0; i < current.length; i++) {
        if (latest[i] > current[i]) return true;
        if (latest[i] < current[i]) return false;
      }
      return false;
    }
    return newVersion > this.currentVersion;
  }

  promptUserToUpdate() {
    if (!this.updateCallback) return;
    const updateConfirm = confirm('检测到新版本，是否立即刷新页面？');
    if (updateConfirm) {
      this.updateCallback();
    }
  }
}

// 在应用中使用
const versionManager = new VersionManager();
versionManager.init('manifest.json', () => {
  location.reload();
});

3. 服务器推送 Server-Sent Events (SSE)

SSE 适合单向通知场景，比轮询更节省资源。

服务器端（Node.js 示例）

const http = require('http');
const fs = require('fs');
const path = require('path');

const server = http.createServer((req, res) => {
  if (req.url === '/updates' && req.method === 'GET') {
    res.writeHead(200, {
      'Content-Type': 'text/event-stream',
      'Cache-Control': 'no-cache',
      'Connection': 'keep-alive'
    });
    res.write(': keep-alive\n\n');

    let lastVersion = '1.0.0';
    fs.watch(path.join(__dirname, 'version.json'), (event, filename) => {
      if (event === 'change') {
        const newVersion = JSON.parse(fs.readFileSync(path.join(__dirname, 'version.json'))).version;
        if (newVersion !== lastVersion) {
          res.write(`event: update\n`);
          res.write(`data: ${newVersion}\n\n`);
          lastVersion = newVersion;
        }
      }
    });

    req.on('close', () => {
      console.log('客户端连接关闭');
    });
  }
});

server.listen(3000, () => {
  console.log('服务器运行在 3000 端口');
});

客户端实现

class SSEUpdateNotifier {
  constructor() {
    this.sse = null;
    this.currentVersion = null;
  }

  init(versionUrl, sseUrl, onUpdate) {
    return this.fetchVersion(versionUrl)
      .then(version => {
        this.currentVersion = version;
        this.startListening(sseUrl, onUpdate);
        return version;
      });
  }

  fetchVersion(url) {
    return fetch(url, { cache: 'no-cache' })
      .then(res => res.json())
      .then(data => data.version);
  }

  startListening(url, onUpdate) {
    this.sse = new EventSource(url);
    this.sse.onmessage = event => {
      if (event.data && this.isNewVersion(event.data)) {
        onUpdate();
      }
    };
    this.sse.onerror = error => {
      console.error('SSE 连接错误:', error);
      setTimeout(() => this.startListening(url, onUpdate), 5000);
    };
  }

  isNewVersion(newVersion) {
    return !this.currentVersion || newVersion > this.currentVersion;
  }

  close() {
    if (this.sse) this.sse.close();
  }
}

4. 使用 WebSocket 实现

如果需要双向通信或更高实时性，WebSocket 是更好的选择。

class WebSocketUpdateNotifier {
  constructor() {
    this.ws = null;
    this.currentVersion = null;
    this.reconnectAttempts = 0;
    this.maxReconnects = 10;
  }

  init(versionUrl, wsUrl, onUpdate) {
    this.onUpdate = onUpdate;
    return this.fetchVersion(versionUrl)
      .then(version => {
        this.currentVersion = version;
        this.connectToWebSocket(wsUrl);
        return version;
      });
  }

  connectToWebSocket(url) {
    this.ws = new WebSocket(url);
    this.ws.onopen = () => {
      console.log('WebSocket 连接已建立');
      this.reconnectAttempts = 0;
      this.ws.send(JSON.stringify({ type: 'version', data: this.currentVersion }));
    };

    this.ws.onmessage = event => {
      const message = JSON.parse(event.data);
      if (message.type === 'update' && this.isNewVersion(message.data)) {
        this.onUpdate();
      }
    };

    this.ws.onclose = (event) => {
      console.log('WebSocket 连接关闭:', event);
      if (this.reconnectAttempts < this.maxReconnects) {
        this.reconnectAttempts++;
        setTimeout(() => this.connectToWebSocket(url), 2000 * this.reconnectAttempts);
      }
    };

    this.ws.onerror = error => {
      console.error('WebSocket 错误:', error);
    };
  }

  isNewVersion(newVersion) {
    return !this.currentVersion || newVersion > this.currentVersion;
  }
}

用户体验优化策略

1. 渐进式提示设计

检测到更新后不要直接弹窗打断用户，而是采用多级提示策略。

let updatePromptLevel = 0;
const MAX_PROMPT_LEVEL = 3;

function showUpdatePrompt() {
  updatePromptLevel++;
  if (updatePromptLevel === 1) {
    // 轻度提示（页面角落通知）
    const notification = document.createElement('div');
    notification.className = 'update-notification';
    notification.innerHTML = '发现新版本，点击查看详情';
    notification.onclick = showUpdateModal;
    document.body.appendChild(notification);
  } else if (updatePromptLevel === 2) {
    // 中度提示（半透明遮罩）
    showUpdateModal();
  } else if (updatePromptLevel === 3) {
    // 重度提示（全屏模态框）
    showForceUpdateModal();
  }
}

function showUpdateModal() {
  // 带更多信息的模态框
  // 包含版本更新日志、更新按钮、稍后提醒选项
}

function showForceUpdateModal() {
  const modal = document.createElement('div');
  modal.className = 'force-update-modal';
  modal.innerHTML = `
    <h2>必须更新</h2>
    <p>旧版本已不再支持，请刷新页面使用最新版本</p>
    <button onclick="location.reload()">立即更新</button>
  `;
  document.body.appendChild(modal);
}

结合版本文件中的更新说明展示 changelog：

fetch('manifest.json')
  .then(res => res.json())
  .then(versionInfo => {
    if (versionInfo.changelog) {
      const changelog = versionInfo.changelog.map(item => `
        <div>
          <h4>${item.title}</h4>
          <p>${item.description}</p>
        </div>
      `).join('');
      updateModal.innerHTML = `
        <h3>版本 ${versionInfo.version} 已更新</h3>
        <div>${changelog}</div>
        <button>立即更新</button>
        <button>1 小时后提醒</button>
      `;
    }
  });

2. 智能延迟策略

根据用户行为动态调整提醒时机，避免在用户专注工作时打断。

function shouldShowPrompt() {
  // 用户活跃状态检测
  const isActive = document.hidden === false;
  
  // 用户操作频率检测
  const userActivity = {
    clicks: 0,
    scrolls: 0,
    lastAction: 0
  };

  document.addEventListener('click', () => {
    userActivity.clicks++;
    userActivity.lastAction = Date.now();
  });

  document.addEventListener('scroll', () => {
    userActivity.scrolls++;
    userActivity.lastAction = Date.now();
  });

  // 如果用户正在频繁操作，暂缓提示
  if (Date.now() - userActivity.lastAction < 60000) {
    return false;
  }
  return isActive;
}

3. 开源参考

社区中已有成熟的实现方案可供参考，如 version-polling 和 plugin-web-update-notification，可根据实际需求集成或复用其逻辑。