vue ssr 指南详读

git clone https://github./s249359986/learnssr.git
cd learnssr 
npm install
npm run dev

src
├── ponents
│  ├── Foo.vue
├── views
│  ├── Home.vue
├── App.vue
├── app.js 
├── client-entry.js
├── server-entry.js

if (isProd) {
 /
  生产环境，createRenderer将已经通过webpack打包好的server-bundle.js转化为一个可以操作的renderer对象。
 /
 renderer = createRenderer(fs.readFileSync(resolve('./dist/server-bundle.js'), 'utf-8'))
 
 /
 入口模板文件
 /
 indexHTML = parseIndex(fs.readFileSync(resolve('./dist/index.html'), 'utf-8'))
} else {
 /
  开发环境，createRenderer将已经通过webpack打包好的server-bundle.js转化为一个可以操作的renderer对象。
 /
 require('./build/setup-dev-server')(app, {
  bundleUpdated: bundle => {
   renderer = createRenderer(bundle)
  },
  indexUpdated: index => {//index为入口文件及index.html
   indexHTML = parseIndex(index)
  }
 })
}

function createRenderer (bundle) {

 return require('vue-server-renderer').createBundleRenderer(bundle, {
  cache: require('lru-cache')({
   max: 1,//1000,
   maxAge: 2000//1000  60  15
  }),
  runInNewContext: false
 })
}
/
读取入口文件
/
function parseIndex (template) {
 const contentMarker = '<!-- APP -->'
 const i = template.indexOf(contentMarker)
 return {
  head: template.slice(0, i),
  tail: template.slice(i + contentMarker.length)
 }
}

const serve = (path, cache) => express.static(resolve(path), {
 maxAge: cache && isProd ? 60  60  24  30 : 0
})

app.use('/dist', serve('./dist'))

app.get('', (req, res) => {
 if (!renderer) {
  return res.end('waiting for pilation... refresh in a moment.')
 }

 res.setHeader('Content-Type', 'text/html')
 res.setHeader('Server', serverInfo)

 var s = Date.now()
 const context = { url: req.url }
 /
  渲染vue实例，context对象上下文
 /
 const renderStream = renderer.renderToStream(context)

 renderStream.once('data', () => {
  res.write(indexHTML.head)
 })

 renderStream.on('data', chunk => {
  res.write(chunk)
 })

 renderStream.on('end', () => {
  if (context.initialState) {
   res.write(
    `<script>window.__INITIAL_STATE__=${
     serialize(context.initialState, { isJSON: true })
    }</script>`
   )
  }
  res.end(indexHTML.tail)
  console.log(`whole request: ${Date.now() - s}ms`)
 })

 renderStream.on('error', err => {
  if (err && err.code === '404') {
   res.status(404).end('404 | Page Not Found')
   return
  }
  res.status(500).end('Internal Error 500')
  console.error(`error during render : ${req.url}`)
  console.error(err)
 })
})

const port = process.env.PORT || 8080
app.listen(port, () => {
 console.log(`server started at localhost:${port}`)
})

export default context => {
 const s = isDev && Date.now()
 router.push(context.url)
 const matchedComponents = router.getMatchedComponents()
 if (!matchedComponents.length) {
  return Promise.reject({ code: '404' })
 }
 return Promise.all(matchedComponents.map(ponent => {
/
增加服务端数据预处理 start

/
  if (ponent.asyncData) {
     return ponent.asyncData({
      store,
      route: router.currentRoute
     })
    }

    /
    增加服务端数据预处理 end

    /
 })).then(() => {
  isDev && console.log(`data pre-fetch: ${Date.now() - s}ms`)
  context.initialState = store.state
  return app
 })
}

/

第一种方式
 /

Vue.mixin({
 beforeMount () {
  const { asyncData } = this.$options
 console.log('beforeMount',this.$store)
  if (asyncData) {

   // 将获取数据操作分配给 promise
   // 以便在组件中，我们可以在数据准备就绪后
   // 通过运行 `this.dataPromise.then(...)` 来执行其他任务
   this.dataPromise = asyncData({
    store: this.$store,
    route: this.$route
   })
  }
 },
 beforeRouteUpdate (to, from, next) {
 const { asyncData } = this.$options
 console.log('beforeRouteUpdate',this.$store)
 if (asyncData) {
 asyncData({
  store: this.$store,
  route: to
 }).then(next).catch(next)
 } else {
 next()
 }
}
})

/
更新客户端store，与服务端store同步
/
// store.replaceState(window.__INITIAL_STATE__)
if (window.__INITIAL_STATE__) {
 store.replaceState(window.__INITIAL_STATE__)
}
// actually mount to DOM


router.onReady(() => {
/
挂载实例，客户端激活，所谓激活，指的是 Vue 在浏览器端接管由服务端发送的静态 HTML，使其变为由 Vue 管理的动态 DOM 的过程。注释掉app.$mount('#app') 可以清楚看到<div id="app" data-server-rendered="true"> 客户端通过data-server-rendered="true"知道该html是vue在服务端渲染的，并且不会在做多余的渲染。由于在服务端无法绑定事件，只有通过客户端vue处理。
/
 app.$mount('#app')
})