javascript - 在express应用程序中异步执行res.render

Question

我尝试使该路由器响应异步:

var express = require('express'),
    router  = express.Router();

router.get('/', function(req, res, next) {
  res.render('contact', {
    titleShown: true,
    title: 'Contact'
  });
});

我尝试实现我读到的async here ，但不工作:

var express = require('express'),
    router  = express.Router(),
    async   = require('async');

router.get('/', function(req, res, next) {
  async.parallel([
    res.render('contact', {
      titleShown: true,
      title: 'Contact'
    })
  ], req);
});

我怎样才能做到这一点？

使用 --trace-sync-io 标志时收到的错误消息:

WARNING: Detected use of sync API
    at fs.statSync (fs.js:892:18)
    at tryStat (C:\www\node\website\node_modules\express\lib\view.js:169:15)
    at resolve (C:\www\node\website\node_modules\express\lib\view.js:142:14)
    at lookup (C:\www\node\website\node_modules\express\lib\view.js:110:17)
    at View (C:\www\node\website\node_modules\express\lib\view.js:85:20)
    at render (C:\www\node\website\node_modules\express\lib\application.js:569:12)
    at render (C:\www\node\website\node_modules\express\lib\response.js:961:7)
    at C:\www\node\website\routes\contact.js:9:7
    at handle (C:\www\node\website\node_modules\express\lib\router\layer.js:95:5)

Answer 1

不，res.render 并不是完全异步的(目前)。所以错误确实来自 res.render:

Yes, there are sync parts of the res.render API (which sucks), but it will be addressed in Express 5.0, as we cannot address it without breaking the view engine compatibility.

Starting your application with NODE_ENV=production or setting the cache to true for rendering will cause file system activities only once per view at startup, which makes this a non-issue while the application is fully running in production, since no sync file systems are called since the views are cached.

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