Herokuでは「ObjectIdへのキャスト」エラーが発生するが、LocalHostではない。

Question

私の 'lessons/new'ページがローカルホストで正常に読み込まれますが、herokuでエラーが発生します。ページはロードされますが、ヒロクの直後にクラッシュします。私はgetClassesByIdのconsole.log（foundClass）を追加し、foundClassは正しく表示されませんでした。誰かが私を正しい方向に向けることができますか？

class.jsライン27-33

module.exports.getClassesById = function(id, callback){ 
    Class.findById(id) 
    .populate(
     {path: 'lessons', 
     model: 'Lesson', $ne: null} 
    ).exec(callback) 
} 

classes.js

router.get('/:id/lessons/new', function(req, res, next) { 
    Class.getClassesById([req.params.id], function(err, foundClass){ 
     if (err){ 
      console.log(err) 
      throw err 
     } else { 
      if (req.user && req.user.email == foundClass.instructor_email){ 
       res.render('lessons/new', {class_id: req.params.id}) 
      } else { 
       res.redirect('/'); 
      } 
     } 
    }) 
}); 

Herokuのログ

2016-10-24T17:31:08.413872+00:00 app[web.1]: [0mGET /classes/580e0e820a1e5d00118e6159/lessons/new [36m304 [0m30.674 ms - -[0m 
2016-10-24T17:31:08.486402+00:00 app[web.1]: [0mGET /stylesheets/bootstrap.min.css [36m304 [0m2.559 ms - -[0m 
2016-10-24T17:31:08.486823+00:00 app[web.1]: [0mGET /stylesheets/style.css [36m304 [0m2.326 ms - -[0m 
2016-10-24T17:31:08.487513+00:00 app[web.1]: [0mGET /stylesheets/ie10-viewport-bug-workaround.css [36m304 [0m2.315 ms - -[0m 
2016-10-24T17:31:08.489252+00:00 app[web.1]: [0mGET /stylesheets/jumbotron.css [36m304 [0m3.708 ms - -[0m 
2016-10-24T17:31:08.529026+00:00 app[web.1]: [0mGET /js/bootstrap.min.js [36m304 [0m2.226 ms - -[0m 
2016-10-24T17:31:08.530994+00:00 app[web.1]: [0mGET /js/ie10-viewport-bug-workaround.js [36m304 [0m0.699 ms - -[0m 
2016-10-24T17:31:09.037191+00:00 app[web.1]: { CastError: Cast to ObjectId failed for value "[ 'favicon.ico' ]" at path "_id" 
2016-10-24T17:31:09.037205+00:00 app[web.1]:  at MongooseError.CastError (/app/node_modules/mongoose/lib/error/cast.js:26:11) 
2016-10-24T17:31:09.037206+00:00 app[web.1]:  at ObjectId.cast (/app/node_modules/mongoose/lib/schema/objectid.js:147:13) 
2016-10-24T17:31:09.037207+00:00 app[web.1]:  at ObjectId.castForQuery (/app/node_modules/mongoose/lib/schema/objectid.js:187:15) 
2016-10-24T17:31:09.037208+00:00 app[web.1]:  at cast (/app/node_modules/mongoose/lib/cast.js:225:32) 
2016-10-24T17:31:09.037209+00:00 app[web.1]:  at Query.cast (/app/node_modules/mongoose/lib/query.js:2737:10) 
2016-10-24T17:31:09.037209+00:00 app[web.1]:  at Query.findOne (/app/node_modules/mongoose/lib/query.js:1350:10) 
2016-10-24T17:31:09.037210+00:00 app[web.1]:  at /app/node_modules/mongoose/lib/query.js:2296:21 
2016-10-24T17:31:09.037210+00:00 app[web.1]:  at new Promise.ES6 (/app/node_modules/mongoose/lib/promise.js:45:3) 
2016-10-24T17:31:09.037211+00:00 app[web.1]:  at Query.exec (/app/node_modules/mongoose/lib/query.js:2290:17) 
2016-10-24T17:31:09.037211+00:00 app[web.1]:  at Function.module.exports.getClassesById (/app/models/class.js:32:4) 
2016-10-24T17:31:09.037212+00:00 app[web.1]:  at /app/routes/classes.js:105:8 
2016-10-24T17:31:09.037213+00:00 app[web.1]:  at Layer.handle [as handle_request] (/app/node_modules/express/lib/router/layer.js:82:5) 
2016-10-24T17:31:09.037213+00:00 app[web.1]:  at next (/app/node_modules/express/lib/router/route.js:110:13) 
2016-10-24T17:31:09.037214+00:00 app[web.1]:  at Route.dispatch (/app/node_modules/express/lib/router/route.js:91:3) 
2016-10-24T17:31:09.037214+00:00 app[web.1]:  at Layer.handle [as handle_request] (/app/node_modules/express/lib/router/layer.js:82:5) 
2016-10-24T17:31:09.037214+00:00 app[web.1]:  at /app/node_modules/express/lib/router/index.js:267:22 
2016-10-24T17:31:09.037215+00:00 app[web.1]:  at param (/app/node_modules/express/lib/router/index.js:340:14) 
2016-10-24T17:31:09.037215+00:00 app[web.1]:  at param (/app/node_modules/express/lib/router/index.js:356:14) 
2016-10-24T17:31:09.037216+00:00 app[web.1]:  at Function.proto.process_params (/app/node_modules/express/lib/router/index.js:400:3) 
2016-10-24T17:31:09.037216+00:00 app[web.1]:  at next (/app/node_modules/express/lib/router/index.js:261:10) 
2016-10-24T17:31:09.037216+00:00 app[web.1]:  at Function.proto.handle (/app/node_modules/express/lib/router/index.js:166:3) 
2016-10-24T17:31:09.037217+00:00 app[web.1]:  at router (/app/node_modules/express/lib/router/index.js:35:12) 
2016-10-24T17:31:09.037217+00:00 app[web.1]: message: 'Cast to ObjectId failed for value "[ \'favicon.ico\' ]" at path "_id"', 
2016-10-24T17:31:09.037218+00:00 app[web.1]: name: 'CastError', 
2016-10-24T17:31:09.037218+00:00 app[web.1]: kind: 'ObjectId', 
2016-10-24T17:31:09.037218+00:00 app[web.1]: value: [ 'favicon.ico' ], 
2016-10-24T17:31:09.037219+00:00 app[web.1]: path: '_id', 
2016-10-24T17:31:09.037219+00:00 app[web.1]: reason: undefined } 
2016-10-24T17:31:09.038731+00:00 app[web.1]: 
2016-10-24T17:31:09.038733+00:00 app[web.1]: events.js:160 
2016-10-24T17:31:09.038734+00:00 app[web.1]:  throw er; // Unhandled 'error' event 
2016-10-24T17:31:09.038734+00:00 app[web.1]:  ^
2016-10-24T17:31:09.038768+00:00 app[web.1]: CastError: Cast to ObjectId failed for value "[ 'favicon.ico' ]" at path "_id" 
2016-10-24T17:31:09.038769+00:00 app[web.1]:  at MongooseError.CastError (/app/node_modules/mongoose/lib/error/cast.js:26:11) 
2016-10-24T17:31:09.038770+00:00 app[web.1]:  at ObjectId.cast (/app/node_modules/mongoose/lib/schema/objectid.js:147:13) 
2016-10-24T17:31:09.038771+00:00 app[web.1]:  at ObjectId.castForQuery (/app/node_modules/mongoose/lib/schema/objectid.js:187:15) 
2016-10-24T17:31:09.038771+00:00 app[web.1]:  at cast (/app/node_modules/mongoose/lib/cast.js:225:32) 
2016-10-24T17:31:09.038772+00:00 app[web.1]:  at Query.cast (/app/node_modules/mongoose/lib/query.js:2737:10) 
2016-10-24T17:31:09.038773+00:00 app[web.1]:  at Query.findOne (/app/node_modules/mongoose/lib/query.js:1350:10) 
2016-10-24T17:31:09.038773+00:00 app[web.1]:  at /app/node_modules/mongoose/lib/query.js:2296:21 
2016-10-24T17:31:09.038774+00:00 app[web.1]:  at new Promise.ES6 (/app/node_modules/mongoose/lib/promise.js:45:3) 
2016-10-24T17:31:09.038774+00:00 app[web.1]:  at Query.exec (/app/node_modules/mongoose/lib/query.js:2290:17) 
2016-10-24T17:31:09.038775+00:00 app[web.1]:  at Function.module.exports.getClassesById (/app/models/class.js:32:4) 
2016-10-24T17:31:09.038776+00:00 app[web.1]:  at /app/routes/classes.js:105:8 
2016-10-24T17:31:09.038776+00:00 app[web.1]:  at Layer.handle [as handle_request] (/app/node_modules/express/lib/router/layer.js:82:5) 
2016-10-24T17:31:09.038777+00:00 app[web.1]:  at next (/app/node_modules/express/lib/router/route.js:110:13) 
2016-10-24T17:31:09.038778+00:00 app[web.1]:  at Route.dispatch (/app/node_modules/express/lib/router/route.js:91:3) 
2016-10-24T17:31:09.038778+00:00 app[web.1]:  at Layer.handle [as handle_request] (/app/node_modules/express/lib/router/layer.js:82:5) 
2016-10-24T17:31:09.038779+00:00 app[web.1]:  at /app/node_modules/express/lib/router/index.js:267:22 
2016-10-24T17:31:09.038779+00:00 app[web.1]:  at param (/app/node_modules/express/lib/router/index.js:340:14) 
2016-10-24T17:31:09.038780+00:00 app[web.1]:  at param (/app/node_modules/express/lib/router/index.js:356:14) 
2016-10-24T17:31:09.038780+00:00 app[web.1]:  at Function.proto.process_params (/app/node_modules/express/lib/router/index.js:400:3) 
2016-10-24T17:31:09.038781+00:00 app[web.1]:  at next (/app/node_modules/express/lib/router/index.js:261:10) 
2016-10-24T17:31:09.038781+00:00 app[web.1]:  at Function.proto.handle (/app/node_modules/express/lib/router/index.js:166:3) 
2016-10-24T17:31:09.038782+00:00 app[web.1]:  at router (/app/node_modules/express/lib/router/index.js:35:12) 
2016-10-24T17:31:09.051877+00:00 app[web.1]: 
2016-10-24T17:31:09.059912+00:00 app[web.1]: npm ERR! Linux 3.13.0-100-generic 
2016-10-24T17:31:09.060095+00:00 app[web.1]: npm ERR! argv "/app/.heroku/node/bin/node" "/app/.heroku/node/bin/npm" "start" 
2016-10-24T17:31:09.060223+00:00 app[web.1]: npm ERR! node v6.6.0 
2016-10-24T17:31:09.060321+00:00 app[web.1]: npm ERR! npm v3.10.3 
2016-10-24T17:31:09.060423+00:00 app[web.1]: npm ERR! code ELIFECYCLE 
2016-10-24T17:31:09.060516+00:00 app[web.1]: npm ERR! eTeacher@0.0.1 start: `node ./bin/www` 
2016-10-24T17:31:09.060581+00:00 app[web.1]: npm ERR! Exit status 1 
2016-10-24T17:31:09.060664+00:00 app[web.1]: npm ERR! 
2016-10-24T17:31:09.060738+00:00 app[web.1]: npm ERR! Failed at the eTeacher@0.0.1 start script 'node ./bin/www'. 
2016-10-24T17:31:09.060808+00:00 app[web.1]: npm ERR! Make sure you have the latest version of node.js and npm installed. 
2016-10-24T17:31:09.060873+00:00 app[web.1]: npm ERR! If you do, this is most likely a problem with the eTeacher package, 
2016-10-24T17:31:09.060940+00:00 app[web.1]: npm ERR! not with npm itself. 
2016-10-24T17:31:09.061016+00:00 app[web.1]: npm ERR! Tell the author that this fails on your system: 
2016-10-24T17:31:09.061085+00:00 app[web.1]: npm ERR!  node ./bin/www 
2016-10-24T17:31:09.061153+00:00 app[web.1]: npm ERR! You can get information on how to open an issue for this project with: 
2016-10-24T17:31:09.061212+00:00 app[web.1]: npm ERR!  npm bugs eTeacher 
2016-10-24T17:31:09.061280+00:00 app[web.1]: npm ERR! Or if that isn't available, you can get their info via: 
2016-10-24T17:31:09.061347+00:00 app[web.1]: npm ERR!  npm owner ls eTeacher 
2016-10-24T17:31:09.061415+00:00 app[web.1]: npm ERR! There is likely additional logging output above. 
2016-10-24T17:31:09.065020+00:00 app[web.1]: 
2016-10-24T17:31:09.065328+00:00 app[web.1]: npm ERR! Please include the following file with any support request: 
2016-10-24T17:31:09.065465+00:00 app[web.1]: npm ERR!  /app/npm-debug.log 

クラススキーマ

var classSchema = new Schema({ 
    title: { type: String, required: true }, 
    description: { type: String, required: true }, 
    instructor: { type: String, required: true }, 
    instructor_email: { type: String, required: true }, 
    //Lessons for the class 
    lessons: [ 
     { type: mongoose.Schema.Types.ObjectId, ref: 'Lesson' } 
    ], 
    category: { type: mongoose.Schema.Types.ObjectId, ref: 'Category' }, 
    created : { type : Date, default : Date.now } 
}); 

「クラス/ショー」は、MongoのIDを特定の形式であると想定しているので、それはそのエラーを与えている classes.js 104-114

router.get('/:id', function(req, res, next) { 
    Class.getClassesById([req.params.id], function(err, foundClass){ 
     if (err){ 
      console.log(err) 
      throw err 
     } else { 
      console.log('Found class.') 
      res.render('classes/show', {"class": foundClass}) 
     } 
    }); 
}); 

Answer 1

から来ているページです。エラーログには、Mongo ID形式に違反するparamとして "favicon.ico"があることが示されています。

DB操作を行う前に必ずデータを検証する必要があります。

文字列の検証とサニタイズのためのパッケージがあります：https://www.npmjs.com/package/validator

paramはで適切な形式であるかどうかをチェックすることができます：あなたのルートで、その後

var validator = require('validator'); 

：

if (!validator.isMongoId(req.params.id)) { 
    // Param is not mongoId, throw error 
}