vue ssr 指南詳讀

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

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

if (isProd) {
 /**
 生產環境，createRenderer將已經通過webpack打包好的server-bundle.js轉化為一個可以操作的renderer對象。
 **/
 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 {
 /**
 開發環境，createRenderer將已經通過webpack打包好的server-bundle.js轉化為一個可以操作的renderer對象。
 **/
 require('./build/setup-dev-server')(app, {
 bundleUpdated: bundle => {
 renderer = createRenderer(bundle)
 },
 indexUpdated: index => {//index為入口文件及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
 })
}
/*
讀取入口文件
*/
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 compilation... 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實例，context對象上下文
 */
 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(component => {
/*
增加服務端數據預處理 start

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

 /*
 增加服務端數據預處理 end

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

/*

第一種方式
 */

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

 // 將獲取數據操作分配給 promise
 // 以便在組件中，我們可以在數據準備就緒后
 // 通過運行 `this.dataPromise.then(...)` 來執行其他任務
 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()
 }
}
})

/**
更新客戶端store，與服務端store同步
**/
// store.replaceState(window.__INITIAL_STATE__)
if (window.__INITIAL_STATE__) {
 store.replaceState(window.__INITIAL_STATE__)
}
// actually mount to DOM


router.onReady(() => {
/**
掛載實例，客戶端激活，所謂激活，指的是 Vue 在瀏覽器端接管由服務端發送的靜態 HTML，使其變為由 Vue 管理的動態 DOM 的過程。注釋掉app.$mount('#app') 可以清楚看到<div id="app" data-server-rendered="true"> 客戶端通過data-server-rendered="true"知道該html是vue在服務端渲染的，并且不會在做多余的渲染。由于在服務端無法綁定事件，只有通過客戶端vue處理。
**/
 app.$mount('#app')
})