Error: No default engine was specified and no extension was provided
I am working through setting up a http server using node.js and engine. However, I keep running into issues that I have little information on how to resolve I would appreciate some help solving this please.
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)
Below is what I have set up to start up this engine.
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');
};
Solution 1:
The res.render stuff will throw an error if you're not using a view engine.
If you just want to serve json replace the res.render('error', { error: err }); lines in your code with:
res.json({ error: err })
PS: People usually also have message in the returned object:
res.status(err.status || 500);
res.json({
message: err.message,
error: err
});
Solution 2:
You are missing the view engine, for example use jade:
change your
app.set('view engine', 'html');
with
app.set('view engine', 'jade');
If you want use a html friendly syntax use instead ejs
app.engine('html', require('ejs').renderFile);
app.set('view engine', 'html');
EDIT
As you can read from view.js Express View Module
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);
}
You must have installed a default engine
Express search default layout view by program.template as you can read below:
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;
}
});
and as you can read below:
program.template = 'jade';
if (program.ejs) program.template = 'ejs';
if (program.jshtml) program.template = 'jshtml';
if (program.hogan) program.template = 'hjs';
the default view engine is jade
Solution 3:
Comment out the res.render lines in your code and add in next(err); instead. If you're not using a view engine, the res.render stuff will throw an error.
Sorry, you'll have to comment out this line as well:
app.set('view engine', 'html');
My solution would result in not using a view engine though. You don't need a view engine, but if that's the goal, try this:
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');
//swap jade for ejs etc
You'll need the res.render lines when using a view engine as well. Something like this:
// 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: {}
});
});