我正在使用 node.js 和引擎设置 http 服务器。但是，我不断遇到一些问题，我对如何解决这个问题知之甚少，我希望能得到一些帮助来解决这个问题。
Error: No default engine was specified and no extension was provided.
at new View (...\node_modules\express\lib\view.js:41:42)
at Function.app.render (...\node_modules\express\lib\application.js:484:12)
at ServerResponse.res.render (...\node_modules\express\lib\response.js:783:7)
at Layer.handle (...\app.js:123:7)
at trim_prefix (...\node_modules\express\lib\router\index.js:225:17)
at c (...\node_modules\express\lib\router\index.js:198:9)
at Function.proto.process_params (...\node_modules\express\lib\router\index.js:253:12)
at next (...\node_modules\express\lib\router\index.js:189:19)
at next (...\node_modules\express\lib\router\index.js:202:7)
at next (...\node_modules\express\lib\router\index.js:166:38)
以下是我为启动该引擎而设置的内容。
var http = require('http');
var module = require("module")
var logger = require('morgan');
var express = require('express');
var app = module.exports = express();
var silent = 'test' == process.env.NODE_ENV;
var httpServer = http.createServer(app); // app middleware
app.enable('strict routing');
// app.all('*', function(req, res, next)/*** CORS support.*/
// {
// if (!req.get('Origin')) return next();// use "*" here to accept any origin
// res.set('Access-Control-Allow-Origin', 'http://localhost:3000');
// res.set('Access-Control-Allow-Methods', 'GET, POST');
// res.set('Access-Control-Allow-Headers', 'X-Requested-With, Content-Type');
// res.set('Access-Control-Allow-Max-Age', 3600);
// if ('OPTIONS' == req.method) return res.send(200);
// next();
// });
app.set('views', __dirname + '/views'); // general config
app.set('view engine', 'html');
app.get('/404', function(req, res, next){
next();// trigger a 404 since no other middleware will match /404 after this one, and we're not responding here
});
app.get('/403', function(req, res, next){// trigger a 403 error
var err = new Error('not allowed!');
err.status = 403;
next(err);
});
app.get('/500', function(req, res, next){// trigger a generic (500) error
next(new Error('keyboard cat!'));
});
app.use(express.static(__dirname + '/public'));
//error handlers
app.use(logErrors);
app.use(clientErrorHandler);
app.use(errorHandler);
// middleware with an arity of 4 are considered error handling middleware. When you next(err)
// it will be passed through the defined middleware in order, but ONLY those with an arity of 4, ignoring regular middleware.
function clientErrorHandler(err, req, res, next) {
if (req.xhr) {// whatever you want here, feel free to populate properties on `err` to treat it differently in here.
res.send(err.status || 500, { error: err.message });
}
else
{ next(err);}
};
// create an error with .status. we can then use the property in our custom error handler (Connect repects this prop as well)
function error (status, msg) {
var err = new Error(msg);
err.status = status;
return err;
};
function logErrors (err, req, res, next) {
console.error(err.stack);
next(err);
};
function errorHandler (err, req, res, next) {
res.status(500);
res.render('error', { error: err });
};
// Error handlers
// Since this is the last non-error-handling middleware use()d, we assume 404, as nothing else responded.
// $ curl http://localhost:3000/notfound
// $ curl http://localhost:3000/notfound -H "Accept: application/json"
// $ curl http://localhost:3000/notfound -H "Accept: text/plain"
app.use(function(req, res, next){
res.status(404);
if (req.accepts('html')) {// respond with html page
res.render('404', { url: req.url });
return;
}
if (req.accepts('json')) {// respond with json
res.send({ error: 'Not found' });
return;
}
res.type('txt').send('Not found');// default to plain-text. send()
});
// error-handling middleware, take the same form as regular middleware, however they require an
// arity of 4, aka the signature (err, req, res, next).when connect has an error, it will invoke ONLY error-handling middleware.
// If we were to next() here any remaining non-error-handling middleware would then be executed, or if we next(err) to
// continue passing the error, only error-handling middleware would remain being executed, however here
// we simply respond with an error page.
app.use(function(err, req, res, next){
// we may use properties of the error object here and next(err) appropriately, or if we possibly recovered from the error, simply next().
res.status(err.status || 500);
res.render('500', { error: err });
});
if (!module.parent) {// assigning to exports will not modify module, must use module.exports
app.listen(3000);
silent || console.log('Express started on port 3000');
};
如果您不使用视图引擎，res.render 的东西将会抛出错误。
如果您只想提供 json，请将代码中的
res.render('error', { error: err });res.json({ error: err })
PS：人们通常也会在返回的对象中包含消息：
res.status(err.status || 500);
res.json({
message: err.message,
error: err
});
您缺少视图引擎，例如使用jade：
改变你的
app.set('view engine', 'html');
与
app.set('view engine', 'jade');
如果你想使用 html 友好的语法，请使用 ejs
app.engine('html', require('ejs').renderFile);
app.set('view engine', 'html');
编辑
正如您可以从 view.js Express View Module 中阅读的那样
module.exports = View;
/**
* Initialize a new `View` with the given `name`.
*
* Options:
*
* - `defaultEngine` the default template engine name
* - `engines` template engine require() cache
* - `root` root path for view lookup
*
* @param {String} name
* @param {Object} options
* @api private
*/
function View(name, options) {
options = options || {};
this.name = name;
this.root = options.root;
var engines = options.engines;
this.defaultEngine = options.defaultEngine;
var ext = this.ext = extname(name);
if (!ext && !this.defaultEngine) throw new Error('No default engine was specified and no extension was provided.');
if (!ext) name += (ext = this.ext = ('.' != this.defaultEngine[0] ? '.' : '') + this.defaultEngine);
this.engine = engines[ext] || (engines[ext] = require(ext.slice(1)).__express);
this.path = this.lookup(name);
}
您必须安装了
default engineExpressprogram.templatemkdir(path + '/views', function(){
switch (program.template) {
case 'ejs':
write(path + '/views/index.ejs', ejsIndex);
break;
case 'jade':
write(path + '/views/layout.jade', jadeLayout);
write(path + '/views/index.jade', jadeIndex);
break;
case 'jshtml':
write(path + '/views/layout.jshtml', jshtmlLayout);
write(path + '/views/index.jshtml', jshtmlIndex);
break;
case 'hjs':
write(path + '/views/index.hjs', hoganIndex);
break;
}
});
您可以在下面阅读：
program.template = 'jade';
if (program.ejs) program.template = 'ejs';
if (program.jshtml) program.template = 'jshtml';
if (program.hogan) program.template = 'hjs';
默认视图引擎是
jade注释掉代码中的
res.rendernext(err);res.render抱歉，您还必须注释掉这一行：
app.set('view engine', 'html');
我的解决方案将导致不使用视图引擎。您不需要视图引擎，但如果这是目标，请尝试以下操作：
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');
//swap jade for ejs etc
使用视图引擎时，您还需要
res.render// error handlers
// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
app.use(function(err, req, res, next) {
res.status(err.status || 500);
res.render('error', {
message: err.message,
error: err
});
});
}
// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
res.status(err.status || 500);
next(err);
res.render('error', {
message: err.message,
error: {}
});
});
如果您想渲染 html 文件，请使用：
response.sendfile('index.html');
然后删除：
app.set('view engine', 'html');
将您的
*.htmlviewspublicindex.htmlpublic而不是
app.get('/', (req, res) => res.render('Hellooooo'))
使用
app.get('/', (req, res) => res.send('Hellooooo'))
请更换
app.set('view engine', 'html');
与
app.set('view engine', 'ejs');
按照以下方式设置视图引擎
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');
如果只需要在代码中内嵌发送html代码，我们可以使用下面的
var app = express();
app.get('/test.html', function (req, res) {
res.header('Content-Type', 'text/html').send("<html>my html code</html>");
});
上面的答案是正确的，但我发现一个简单的拼写错误也会产生这个错误。例如，我使用 var router = express() 而不是 var router = express.Router() 并收到此错误。所以应该是这样的：
// App.js
var express = require('express');
var app = express();
var bodyParser = require('body-parser');
app.use(bodyParser.urlencoded({ extended:false}));
// assuming you put views folder in the same directory as app.js
app.set('views', __dirname + '/views')
app.engine('ejs', ejs.renderFile);
app.set('view engine', 'ejs');
// router - wherever you put it, could be in app.js
var router = express.Router();
router.get('/', function (req,res) {
res.render('/index.ejs');
})
只需在代码中设置视图引擎即可。
var app = express();
app.set('view engine', 'ejs');
如果您使用 Express 生成器遇到此错误，我已经通过使用解决了它
express --view=ejs myapp
而不是
express --view=pug myapp
我刚刚收到此错误消息，问题是我没有正确设置中间件。
我正在 MEAN 堆栈中构建一个博客，并且需要对我在前端使用的 .jade 文件进行正文解析。这是我的项目中的“/middleware/index.js”文件中的代码片段。
var express = require('express');
var morgan = require('morgan');
var session = require('express-session');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
module.exports = function (app) {
app.use(morgan('dev'));
// Good for now
// In the future, use connect-mongo or similar
// for persistant sessions
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
extended: true
}));
app.use(cookieParser());
app.use(session({secret: 'building a blog', saveUninitialized: true, resave: true}));
另外，这是我的“package.json”文件，您可能使用不同版本的技术。 注意：因为我不确定它们之间的依赖关系，所以我在此处包含整个文件：
"dependencies": {
"body-parser": "1.12.3",
"consolidate": "0.12.1",
"cookie-parser": "1.3.4",
"crypto": "0.0.3",
"debug": "2.1.1",
"express": "4.12.2",
"express-mongoose": "0.1.0",
"express-session": "1.11.1",
"jade": "1.9.2",
"method-override": "2.3.2",
"mongodb": "2.0.28",
"mongoose": "4.0.2",
"morgan": "1.5.1",
"request": "2.55.0",
"serve-favicon": "2.2.0",
"swig": "1.4.2"
}
希望这对某人有帮助！祝一切顺利！
您可以使用express-error-handler使用静态html页面进行错误处理并避免定义视图处理程序。
该错误可能是由 404 引起的，也可能是缺少图标（如果您已包含之前的控制台消息，则很明显）。 “html”的“视图处理程序”在 4.x Express 中似乎无效。
无论原因如何，只要修改配置的其他元素，就可以避免定义（有效）视图处理程序。
解决此问题的选项是：
http://expressjs.com/en/api.html#res.render
使用不带文件路径的渲染会自动调用视图处理程序，如配置中的以下两行所示：
res.render('404', { url: req.url });
和：
res.render('500);
确保安装express-error-handler：
npm install --save express-error-handler
然后将其导入到您的app.js中
var ErrorHandler = require('express-error-handler');
然后更改错误处理以使用：
// define below all other routes
var errorHandler = ErrorHandler({
static: {
'404': 'error.html' // put this file in your Public folder
'500': 'error.html' // ditto
});
// any unresolved requests will 404
app.use(function(req,res,next) {
var err = new Error('Not Found');
err.status(404);
next(err);
}
app.use(errorHandler);
错误：未指定默认引擎且未提供扩展名
我遇到了同样的问题（为了做一个平均堆栈项目）..问题是我没有提到安装 npm 的 formate，即； pug 或 jade、ejs 等，要解决此问题，请转到 npm 并输入 express --view=pug 文件夹名称。这将在您给定的文件夹中加载必要的 pug 文件（index.pug、layout.pug 等..）。
如果您使用 NestJS，要解决此问题，您必须更改 main.ts 文件。 请考虑使用下面的示例：
import { NestFactory } from '@nestjs/core';
import { NestFastifyApplication, FastifyAdapter } from '@nestjs/platform-fastify';
import { AppModule } from './app.module';
import { join } from 'path';
async function bootstrap() {
const app = await NestFactory.create<NestFastifyApplication>(
AppModule,
new FastifyAdapter(),
);
app.useStaticAssets({
root: join(__dirname, '..', 'public'),
prefix: '/public/',
});
app.setViewEngine({
engine: {
handlebars: require('handlebars'),
},
templates: join(__dirname, '..', 'views'),
});
await app.listen(3000);
}
bootstrap();
const express = require("express");
const app = express();
app.use(errorHandler);
function errorHandler (err, req, res, next) {
if (res.headersSent) {
return next(err)
}
res.status(err.status || 500);
res.json({
message: err.message,
...(app.get('env') === 'development' && { error: err }) // no stacktraces leaked to user in production
});
}