Question

我正在使用node.js和engine设置http服务器。但是，我一直在遇到一些问题，我几乎没有关于如何解决的信息我会很感激帮助解决这个问题。提前谢谢。

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)

以下是我为启动此引擎而设置的内容。

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');
};

Answer 1

如果你没有使用视图引擎，res.render的东西会抛出错误。

如果您只想提供json，请使用以下代码替换代码中的res.render('error', { error: err });行

res.json({ error: err })

PS：人们通常在返回的对象中也有消息：

res.status(err.status || 500);
res.json({
  message: err.message,
  error: err
});

Answer 2

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');

如果您想使用html友好语法，请改用ejs

app.engine('html', require('ejs').renderFile);
app.set('view engine', 'html');

修改

正如您可以从view.js Express View模块中读取的那样

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); }

您必须已安装default engine

Express按program.template搜索默认布局视图，如下所示：

mkdir(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; } });

如下所示：

program.template = 'jade'; if (program.ejs) program.template = 'ejs'; if (program.jshtml) program.template = 'jshtml'; if (program.hogan) program.template = 'hjs';

默认视图引擎为jade

Answer 3

在代码中注释掉res.render行，然后添加next(err);。如果您不使用视图引擎，则res.render内容会引发错误。

对不起，您还必须注释掉这一行：

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

我的解决方案会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行。像这样：

// 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: {}
  });
});

Answer 4

如果您希望使用

渲染html文件

response.sendfile('index.html');

然后你删除了

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

唯一的事情是将index.html放在视图中。或将公用文件夹设为静态文件夹并将index.html放在公共文件夹中

Answer 5

如果只需要在代码中内联发送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>");
});

Answer 6

按照以下方式设置视图引擎

app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');

Answer 7

您可以使用express-error-handler来使用静态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，也许是一个缺少的图标（如果你已经包含了之前的控制台消息，则显而易见）。 'html'的'视图处理程序'似乎在4.x express中无效。

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。

您可以选择解决此问题：

像在其他答案中一样定义有效的视图处理程序
使用send（）代替render直接返回内容

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：

res.render('404', { url: req.url });

和

res.render('500);

确保使用以下命令安装express-error-handler：

npm install --save express-error-handler

然后在app.js中导入

var ErrorHandler = require('express-error-handler');

然后更改您的错误处理以使用：

// 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);

Answer 8

请替换

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

使用

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

Answer 9

我刚收到此错误消息，问题是我没有正确设置我的中间件。

我正在MEAN堆栈中构建一个博客，需要正面解析我在前端使用的 .jade 文件。以下是我项目中“ /middleware/index.js ”文件的代码片段。

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}));

此外，这是我的“ package.json ”文件，您可能正在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，所以我在这里包含整个文件：

"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"
  }

希望这有助于某人！一切顺利！

Answer 10

以上答案是正确的，但我发现一个简单的拼写错误也会产生这个错误。例如，我有var router = express（）而不是var router = express.Router（）并得到了这个错误。所以它应该如下：

// 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');
})

Answer 11

只需在代码中设置视图引擎即可。

var app = express(); 
app.set('view engine', 'ejs');

Answer 12

错误：未指定默认引擎，也未提供扩展名

我遇到了相同的问题（用于执行平均堆栈项目）。问题是我没有提到安装npm的方法，即； pug或jade，ejs等，因此要解决此问题，请输入express --view = pug文件夹名称。这将在您指定的文件夹中加载必要的pug文件（index.pug，layout.pug等）。

Answer 13

如果您使用Express生成器遇到此错误，我已经通过使用

解决了该错误

express --view=ejs myapp

代替

express --view=pug myapp

Answer 14

代替

app.get('/', (req, res) => res.render('Hellooooo'))

使用

app.get('/', (req, res) => res.send('Hellooooo'))

错误：未指定默认引擎且未提供扩展名

14 个答案: