node.js - 将@angular/cli 与服务器端 EJS 模板集成

Question

目标:在网络爬虫访问不同路径时修改 Open Graph 元标记。

我知道 Angular2 4.0.0 有一个 MetaService，而且总是有 jQuery，但是除了 Googlebot 之外的网络爬虫不执行 Javascript，所以它对我的目的有点无用。虽然 Angular Universal 听起来像是更改几个元标记的矫枉过正。

目前我的解决方案是将/dist中编译好的index.html复制粘贴到index.ejs中，修改必要的字段。是否可以通过将入口点从 index.html 更改为 index.ejs 来将工作流与 angular-cli 编译过程集成？如果不是，我应该探索哪些替代方案？

在我的 index.ejs 中:

<meta property="og:url" content="<%= url %>" />

在我的 Express 路线 index.js 中:

res.render('index', {
  url: site_url,
});

在我的 server.js 中:

app.set('views', path.join(__dirname, '/dist'));
app.set('view engine', 'ejs');

请不要回答当前@angular/cli 版本(v1.0.1 兼容)。

一些相关讨论: Add customization options for HtmlWebpackPlugin #3338 Conditional template logic in index.html for beta.11-webpack #1544 Provide config to rename index.html in dist folder #2241

Answer 1

我使用 Nunjucks 解决了这个问题渲染通过 Angular Universal 提供的模板。我确信也可以使用其他引擎，例如 EJS。以下是我的 server.ts 的相关部分:

import * as dotenv from 'dotenv';
dotenv.config();

import 'zone.js/dist/zone-node';
import 'reflect-metadata';
import * as nunjucks from 'nunjucks';

import { renderModuleFactory } from '@angular/platform-server';
import { enableProdMode } from '@angular/core';

import * as express from 'express';
import { join } from 'path';
import { readFileSync } from 'fs';

// Faster server renders w/ Prod mode (dev mode never needed)
enableProdMode();

// Express server
const app = express();

const PORT = process.env.PORT || 4201;
const DIST_FOLDER = join(process.cwd(), 'dist');

// Our index.html we'll use as our template
const template = readFileSync(join(DIST_FOLDER, 'index.html')).toString();

// * NOTE :: leave this as require() since this file is built Dynamically from webpack
const { AppServerModuleNgFactory, LAZY_MODULE_MAP } = require('./dist-server/main.bundle');

const { provideModuleMap } = require('@nguniversal/module-map-ngfactory-loader');

nunjucks.configure(DIST_FOLDER, {
  autoescape: true,
  express: app,
});

app.engine('html', (_, options, callback) => {
  renderModuleFactory(AppServerModuleNgFactory, {
    // Our index.html
    document: template,
    url: options.req.url,
    // DI so that we can get lazy-loading to work differently (since we need it to just instantly render it)
    extraProviders: [
      provideModuleMap(LAZY_MODULE_MAP)
    ]
  }).then(html => {
    callback(null, html);
  });
});

app.set('view engine', 'html');

// Server static files from dist folder
app.get('*.*', express.static(DIST_FOLDER));

// All regular routes use the Universal engine
// You can pass in server-side values here to have Nunjucks render them
app.get('*', (req, res) => {
  res.render('index', { req, yourVar: 'some-value' });
});

// Start up the Node server
app.listen(PORT, () => {
  console.log(`Node server listening on http://localhost:${PORT}`);
});