Express 4 Middleware Fehlerhandler nicht aufgerufen

Question

Für bestimmte Seiten habe ich benutzerdefinierte 500, 404 und 403 Fehlerbehandlung in meiner App. So zum Beispiel nach einer erfolglosen Datenbankabfrage würde ich gehen:

return next({status: 404, message: 'Record not found'}); 

oder

return next(new Error('Bad things have happened')}); 

In meiner Middleware habe ich ein Fehler-Handler:

app.use(function (err, req, res, next) { 
    // handle error 
}); 

Problem ist, dass die Fehlerbehandlung wird nie aufgerufen, stattdessen wird der Fehler-Callstack in den Browser gedruckt. Ich möchte, dass der Handler eine benutzerdefinierte Fehlerseite ausgibt.

app.js

var express = require('express') 
    , app = express() 
    , swig = require('swig') 
    , config = require('./lib/config') 
    , env = process.env.NODE_ENV || 'development' 
    , path = require('path'); 

config.configure(env); 

app.engine('html', swig.renderFile); 
app.set('view cache', false); 

swig.setDefaults({ 
    cache: config.get('swigCache') 
}); 

app.set('view engine', 'html'); 
app.set('views', __dirname + '/lib/views'); 

require('./lib/util/swig'); 
require('./lib/initialisers/mongodb')(); 
require('./lib/initialisers/aws')(); 
require('./lib/middleware')(app); // first load middleware 
require('./lib/routes')(app); // then routes 

var server = app.listen(config.get('port'), function() { 
    console.info('config: ' + JSON.stringify(config.getCurrent())); 
    console.info('NODE_ENV: ' + env); 
    console.info('server running: ' + JSON.stringify(server.address())); 
}); 

routes.js

middleware.js

var express = require('express') 
    , app = express() 
    , path = require('path') 
    , logger = require('morgan') 
    , cookieParser = require('cookie-parser') 
    , bodyParser = require('body-parser') 
    , passport = require('passport') 
    , session = require('express-session') 
    , mongoStore = require('connect-mongo')(session) 
    , compression = require('compression') 
    , favicon = require('serve-favicon') 
    , config = require('./config') 
    , flash = require('connect-flash') 
    , multer = require('multer') 
    , csrf = require('csurf'); 

module.exports = function(app) { 

    app.use(bodyParser.urlencoded({ extended: false })) 
    app.use(bodyParser.json()); 
    app.use(cookieParser()); 
    app.use(csrf({ cookie: true })); 
    app.use(express.static(path.join(__dirname, config.get('staticContentPath')), { 
     maxAge: (60 * 60 * 24) * 1000 
    })); 

    app.use(session({ 
     resave: true, 
     saveUninitialized: true, 
     secret: 'da755fc0-6882-11e4-9803-0800200c9a66', 

     cookie: { 
      maxAge: 24 * 60 * 60 * 1000 // 24 hrs 
     }, 

     store: new mongoStore({ 
      url: config.getMongoConn() 
     }) 
    })); 

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

    /** 
    * 301 redirects 
    */ 
    app.use(function(req, res, next) { 

     var host = req.get('host'); 

     // AWS IP --> http 
     if (host == 'xx.xxx.xxx.xxx') { 
      return res.redirect(301, config.get('url') + req.originalUrl); 
     } 

     // AWS origin --> http 
     if(host == 'xxx-xxx-xxx-xxx-xxx.ap-southeast-2.compute.amazonaws.com'){ 
      return res.redirect(301, config.get('url') + req.originalUrl); 
     } 

     // www --> http 
     if (/^www\./.test(host)) { 
      host = host.substring(4, host.length); 
      return res.redirect(301, req.protocol + '://' + host + req.originalUrl); 
     } 

     // Trailing slash --> http 
     if (req.path.substr(-1) == '/' && req.path.length > 1) { 
      var query = req.url.slice(req.path.length); 
      return res.redirect(301, req.path.slice(0, -1) + query); 
     } 

     next(); 
    }); 

    // Delete expired Mongo sessions from DB 
    app.use(function (req, res, next) { 
     req.session._garbage = new Date(); 
     req.session.touch(); 
     next(); 
    }); 

    /** 
    * Setting Cache control header for Ajax requests to 30 minutes 
    */ 
    app.use(function (req, res, next) { 

     if(req.xhr){ 
      res.header('Cache-Control', 'max-age=' + 1800 + ', public'); 
     } 

     next(); 
    }); 

    app.use(compression()); 

    app.use(
     multer({ 
      dest: config.get('uploads').folders.temp 
     }) 
    ); 

    app.use(passport.initialize()); 
    app.use(passport.session()); 
    var initPassport = require('./passport/init'); 
    initPassport(passport); 

    app.use(function (req, res, next) { 

     res.locals = { 
      root : 'http://' + req.headers.host, 
      sitename : require('./config').get('sitename'), 
      config: config.get('env'), 
      url : config.get('url'), 
      user : req.user, 
      flash : req.flash() 
     }; 

     next(); 
    }); 

    app.use(function (err, req, res, next) { 

     if (err.code !== 'EBADCSRFTOKEN'){ 
      return next(err); 
     } 

     if(req.xhr){ 
      return res.ok({payload: null}, '403 invalid csrf token'); 
     } 

     // TODO handle CSRF token errors here 
     res.status(403); 
     res.send('form tampered with') 
    }); 

    // This is never called when throwing errors like 
    // next(new Error('some error') or 
    // next({status: 500, message:'server error'}); 
    app.use(function (err, req, res, next) { 
     console.error(err.stack); 
     // render an error page 
    }); 
}; 

Answer 1

Das Problem ist, dass Ihre Fehlerbehandlungsroutinen immer am Ende sein sollen Ihre Anwendungsstapel. Das bedeutet, dass Sie den Error-Handler entweder von Ihrer Middleware in Ihre app.js verschieben und nach Ihren Anforderungen (app.use()) oder Ihre Routen vor Ihrer Middleware einbinden können.