Express-错误:未指定默认引擎,也未提供扩展名

时间:2018-09-20 17:20:52

标签: node.js express

我无法使我的api与我的Express服务器一起使用,总是出现错误:

  

错误:未指定默认引擎,也未提供扩展名。

我很确定它来自快递路由器,但我找不到错误的来源...

我是否正确使用快递路由器?因为我以前从未使用过。

server.js:

const createError = require('http-errors');
const express = require("express");
const bodyParser = require("body-parser");
const cookieParser = require('cookie-parser');
const logger = require('morgan');
const api = require('./routes/api');
const app = express();
const MongoClient = require('mongodb').MongoClient;

const MONGODB_URI = process.env.MONGODB_URI;
const PORT = process.env.PORT || 5000;

app.use('/', api);

app.use(logger('dev'));

app.use(bodyParser.json());

app.use(bodyParser.urlencoded({ extended: true }));
app.use(cookieParser());

// catch 404 and forward to error handler
app.use(function(req, res, next) {
    next(createError(404));
});

// error handler
app.use(function(err, req, res, next) {
    // set locals, only providing error in development
    res.locals.message = err.message;
    res.locals.error = req.app.get('env') === 'development' ? err : {};

    // render the error page
    res.status(err.status || 500);
    res.render('error');
});

// Database object
var db;

// Initialize connection once with db
MongoClient.connect(MONGODB_URI, function(err, database) {
    if(err) throw err;

    db = database;

    // Start the application after the database connection is ready
    app.listen(PORT, () => console.log(`Server listening on port ${PORT}`));
});

module.exports = db;
module.exports = app;

routes / api.js:

// const app = require("../server");
var db = require("../server");
const { videos } = require("../helpers/videos");
const { videoLinksValidator } = require("../helpers/video-links-validator");
const { getTitleType } = require("../helpers/title-type-extractor");
const express = require('express');
const router = express.Router();

router.get('/', (req, res) => {
    console.log("RESPONSE", res) 
});

// Create a GET route
router.get("/express_backend", (req, res) => {
    res.send({ express: "YOUR EXPRESS BACKEND IS CONNECTED TO REACT" });
});

router.post("/video_url", async (req, res)=> {
    const videoURL = req.body.videoURL.videoURL;

    let titleType = await getTitleType(videoURL);

    let videosAndTitle = await videos(videoURL, titleType);

    let videoAndTitleReady = await videoLinksValidator(videosAndTitle);
    console.log(videoAndTitleReady)
    return res.send(videoAndTitleReady);
});

module.exports = router;

3 个答案:

答案 0 :(得分:2)

此错误是因为您使用的是res.render。 res.render将尝试渲染您必须设置视图引擎(如玉石等)的页面。但是在这里您不需要这样做,因此将E:\更改为res.render
试试这个

res.send

对于第二个问题,必须在server.js中将bodyParser置于顶部

app.use(function(err, req, res, next) {
    // set locals, only providing error in development
    res.locals.message = err.message;
    res.locals.error = req.app.get('env') === 'development' ? err : {};
// render the error page
res.status(err.status || 500);
res.send('error');//this or res.status(err.status || 500).send('error')
});

答案 1 :(得分:1)

我有同样的错误。我忘记将下面的语法添加到server.js文件中

//set default engine, and provide [handlebars as] extension
app.set('view engine', 'handlebars');

答案 2 :(得分:0)

在您的代码中,您正在渲染,而如果您的视图引擎无法正常工作,则将导致错误

   res.status(err.status || 500);
    res.render('error');

因此,如果您将应用程序用作API网关,则必须发送这些响应。 res.send当前不推荐使用

  res.status(err.status || 500).send('error');