TypeError：db.collection不是一个函数，CAN NOT GET [英] TypeError: db.collection is not a function, CANNOT GET
本文介绍了TypeError：db.collection不是一个函数，CAN NOT GET的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我试图从 apiRoutes.get（'/ resources / productinfo /：name'）获取一些数据，我有这个错误，我不知道是什么出错了......还有 apiRoutes.get（'/ book /：title'）似乎不起作用！我不知道我在做什么错误
更新：
> ; TypeError：无法读取属性< findOne&＃39;未定义的< br> &安培; NBSP; & nbsp; at Object.module.exports.findBookByTitle
> （/home/themis/firstapp/api/config/database.js:22:26）< br> &安培; NBSP;
> & nbsp; at /home/themis/firstapp/api/server.js:109:22< br> &安培; NBSP;
> & nbsp;在Layer.handle [作为handle_request]
> （/home/themis/firstapp/api/node_modules/express/lib/router/layer.js:82:5）
> <峰; br> &安培; NBSP; & nbsp;在下一个
> （/home/themis/firstapp/api/node_modules/express/lib/router/route.js:100:13）
> <峰; br> &安培; NBSP; & nbsp;在Route.dispatch
> （/home/themis/firstapp/api/node_modules/express/lib/router/route.js:81:3）
> <峰; br> &安培; NBSP; & nbsp;在Layer.handle [作为handle_request]
> （/home/themis/firstapp/api/node_modules/express/lib/router/layer.js:82:5）
> <峰; br> &安培; NBSP; & nbsp; at
> /home/themis/firstapp/api/node_modules/express/lib/router/index.js:234:24
> <峰; br> &安培; NBSP; & nbsp; at param
> （/home/themis/firstapp/api/node_modules/express/lib/router/index.js:331:14）
> <峰; br> &安培; NBSP; & nbsp; at param
> （/home/themis/firstapp/api/node_modules/express/lib/router/index.js:347:14）
> <峰; br> &安培; NBSP; & nbsp; at Function.proto.process_params
> （/home/themis/firstapp/api/node_modules/express/lib/router/index.js:391:3）
> <峰; br> &安培; NBSP; & nbsp; at
> /home/themis/firstapp/api/node_modules/express/lib/router/index.js:228:12
> <峰; br> &安培; NBSP; & nbsp;在Function.match_layer
> （/home/themis/firstapp/api/node_modules/express/lib/router/index.js:295:3）
> <峰; br> &安培; NBSP; & nbsp;在下一个
> （/home/themis/firstapp/api/node_modules/express/lib/router/index.js:189:10）
> <峰; br> &安培; NBSP; & nbsp; at
> /home/themis/firstapp/api/node_modules/express/lib/router/index.js:191:16
> <峰; br> &安培; NBSP; & nbsp;在Function.match_layer
> （/home/themis/firstapp/api/node_modules/express/lib/router/index.js:295:3）
> <峰; br> &安培; NBSP; & nbsp;在下一个
> （/home/themis/firstapp/api/node_modules/express/lib/router/index.js:189:10）
这里是server.js
var express = require（'express'）;
MongoClient = require（'mongodb'）。MongoClient，
app = express（），
mongoUrl ='mongodb：// localhost：27017 / firstapp';
var bodyParser = require（'body-parser'）;
var morgan = require（'morgan'）;
var mongoose = require（'mongoose'）;
var passport = require（'passport'）;
var redisClient = require（'redis'）。createClient;
var redis = redisClient（6379，'localhost'）;
var config = require（'./ config / database'）; //获取数据库配置文件
var User = require（'./app/ models / user'）; //获取猫鼬模型
var Products = require（'./app/ models / products'）; //获取猫鼬模型
var Makeissue = require（'./ app / models / makeissue'）; //获取mongoose模型
var port = process.env.PORT || 8080;
var jwt = require（'jwt-simple'）;
var access = require（'./ config / database.js'）;
MongoClient.connect（mongoUrl，函数（err，db）{
if（err）throw'连接数据库时出错 - '+ err;
//获取我们的请求参数
app.use（bodyParser.urlencoded（{extended：false}））;
app.use（bodyParser.json（））;
//登录到控制台
应用程序。使用（morgan（'dev'））;
//在我们的应用程序中使用护照包
app.use（passport.initialize（））;
//示例Route（GET http：// localhost：8080）
app.get（'/'，function（req，res）{
res.send（'API位于http：// localhost：'+ port +'/ api'）;
}）;
//连接数据库
mongoose.connect（config.database）;
//通过护照配置
require（'./ config / passport'）（护照）;
//捆绑我们的路线
var apiRoutes = express.Router（）;
//创建一个新的用户帐户（POST http：// localhost：8080 / api / signup）
apiRoutes.post（'/ signup'，function（req， res）{
if（！req.body.name ||！req.body.password ||！req.body.email）{
res.json（{success：false，msg：'Please '））;
} else {
var newUser = new User（{
name：req.body.name，
password：req.body .password，
email：req.body.email
}）;
//保存用户
newUser.save（function（err）{
if（err ）{
return res.json（{success：false，msg：'Username already exists。'））;
}
res.json（{success：true，msg：'Successful created新用户。'））;
}）;
}
}）;
$ b $ //路由认证用户（POST http：// localhost：8080 / api / authenticate）
apiRoutes.post（'/ authenticate'，function（req，res）{
User.findOne（{
name：req.body.name
}，function（err，user）{
if（err）throw err;
）if（！user）{
res.send（{success：false，msg：'Authentication failed。User not found。'））;
} else {
//检查密码匹配
user.comparePassword（req.body.password，function（err，isMatch）{
if（isMatch&&！err）{
//如果找到用户且密码为右创建一个令牌
var token = jwt.encode（user，config.secret）;
//返回包含令牌的信息为JSON
res.json（{success：true，token： Ĵ WT'+令牌}）;
} else {
res.send（{success：false，msg：'Authentication failed。Passwords password。'}）;
}
}）;
}
}）;
}）;
apiRoutes.post（'/ book'，function（req，res）{
if（！req.body.title ||！req.body.author）res.status（400 ）.send（请为该书发送标题和作者）;
else if（！req.body.text）res.status（400）.send（请为该书发送一些文本 ）;
else {
access.saveBook（db，req.body.title，req.body.author，req.body.text，function（err）{
if（err）res （服务器错误）;
else res.status（201）.send（Saved）;
}）;
}
} .status ）;
$ b $ apiRoutes.get（'/ book /：title'，function（req，res）{
if（！req.param（'title'））res.status（400）。发送（请发送正确的标题）;
else {
access.findBookByTitle（db，req.param（'title'），function（book）{
if（！req。 （500）.send（Server error）;
else res.status（200）.send（book）;
}）;
}
}）;
$ b apiRoutes.get（'/ productinfo'，function（req，res，next）{
Products.find（function（err，result）{$ （err）return console.error（err）;
res.json（result）;
}）;
}）;
apiRoutes.get（'/ resources / productinfo /：name'，function（req，res）{
if（！req.param（'name'））res.status（400 ）.send（请发送一个专用名称）;
else {
access.findProductsByName（Products，req.param（'name'），function（Products）{
if（！产品）res.status（500）.send（服务器错误）;
}）;
}
}）;
//创建一个新产品（POST http：// localhost：8080 / api / productsignup）
apiRoutes.post（'/ resources / productsignup'，function（req，res）{
if（！req.body.name ||！req.body.serialnumber）{
res.json（{success：false，msg：'请传递名称和序列号。'））;
} else {
var newProducts = new Products（{
name：req.body.name，
serialnumber：req.body.serialnumber
}）;
//保存产品
newProducts.save（function（err）{
if（err）{
return res.json（{success：false，msg：'Product already exists。' }）;
}
res.json（{success：true，msg：'Successful created new Product。'}）;
}）;
}
} ）;
$ b $ apiRoutes.post（'/ resources / createpost'，function（req，res）{
if（！req.body.issue）{
res.json（{success ：false，msg：'Please pass a issue。'））;
} else {
var newMakeissue = new Makeissue（{
issue：req.body.issue
}） ;
//保存产品
newMakeissue.save（function（err）{
if（err）{
return res.json（{success：false，msg：'Post '））;
}
res.json（{success：true，msg：'Successful created new post。'}）;
}）;
}
}）;
//路由到受限信息（GET http：// localhost：8080 / api / memberinfo）
apiRoutes.get（'/ memberinfo'，passport.authenticate（'jwt'，{session：false}），function（req，res）{
var token = getToken（req.headers ）;
if（token）{
var decoded = jwt.decode（token，config.secret）;
User.findOne（{
name：decoded.name $ b $如果（！用户）{
返回res.status（403）.send（{b}}，函数（err，user）{
if（err）throw err;
成功：false，msg：'认证失败，用户未找到'）};
} else {
res.json（{success：true，msg：'欢迎在成员区'+ user。 name +'！'}）;
}
}）;
} else {
return res.status（403）.send（{success：false，msg：'No token provided。'}）;
}
}）;
$ b $ getToken = function（headers）{
if（headers&& headers.authorization）{
var parted = headers.authorization.split（''）;
if（parted.length === 2）{
return parted [1];
} else {
return null;
}
} else {
return null;
}
};
//连接/ api / *
下的api路由app.use（'/ api'，apiRoutes）;
module.exports = apiRoutes;
$ b app.listen（8080，function（）{
console.log（'listening on 8080'）;
}）;
}）;
和database.js
module.exports = {
'secret'：'di.ionio.gr'，
'database'：'mongodb：// localhost / firstapp'
};
module.exports.saveBook = function（db，title，author，text，callback）{
db.collection ['text']。save（{
title：title ，
author：author，
text：text
，callback）;
};
module.exports.findBookByTitle =函数（db，title，callback）{
db.collection ['text']。findOne（{
title：title
}，function（err，doc）{
if（err ||！doc）callback（null）;
else callback（doc.text）;
}）;
};
module.exports.findProductsByName =函数（分贝，姓名，回叫）{
db.collection [ '产品'] findOne（{
名称：名称
}，function（err，doc）{
if（err ||！doc）callback（null）;
else callback（doc.products）;
}）;
};
和package.json
<$ p $
{
name：firstapp，
main：server.js，
依赖关系：{
bcrypt ：^ 0.8.5，
body-parser：〜1.9.2，
express：〜4.9.8，
jwt-simple ：^ 0.3.1，
mongoose：〜4.2.4，
mongodb：〜1.2.5，
morgan：〜1.5。 0，
passport：^ 0.3.0，
passport-jwt：^ 1.2.1，
redis：〜0.10.1
}
}
解决方案
incorect语法，你必须读取db.collection的属性，但是你调用它。示例：
db.collection ['products'] !!!
$ b db.collection ['text']。save（{
title：title，
author：author，
text：text
}，回调）;
};
module.exports.findBookByTitle =函数（db，title，callback）{
db.collection ['text']。findOne（{
title：title
}，function（err，doc）{
if（err ||！doc）callback（null）;
else callback（doc.text）;
}）;
};
module.exports.findProductsByName = function（db，name，callback）{
db.collection ['products']。findOne（{
例如
var object = {
'some_value'：'value' ，
'some_methid'：function（）{return'method result'}
}
您可以读取和设置属性'some_value'例如：
对象[ 'SOME_VALUE'] //返回 '值'
object.some_value //返回值'
//第2步
好的在你的database.js方法中，你传递了db变量，但这不是db实例，它是mongoose模型，你必须这样写：
module.exports.findBookByTitle = function（model，title，callback）{
model.findOne（{
title：title
}，function（err，doc） {
if（err ||！doc）callback（null）;
else callback（doc.text）;
}）;
$;
module.exports.findProductsByName = function（model，name，callback）{
model.findOne（{$ b $ name：name
} ，函数（err，doc）{
if（err || ！doc）callback（null）;
else callback（doc.products）;
}）;
};
i'm trying to get some data from the
apiRoutes.get('/resources/productinfo/:name')and i have this error, i dont know whats going wrong... also theapiRoutes.get('/book/:title')doesnt seems to work! i dont know what am i doing wrongUPDATED:
> TypeError: Cannot read property 'findOne' of undefined <br> at Object.module.exports.findBookByTitle > (/home/themis/firstapp/api/config/database.js:22:26) <br> > at /home/themis/firstapp/api/server.js:109:22 <br> > at Layer.handle [as handle_request] > (/home/themis/firstapp/api/node_modules/express/lib/router/layer.js:82:5) > <br> at next > (/home/themis/firstapp/api/node_modules/express/lib/router/route.js:100:13) > <br> at Route.dispatch > (/home/themis/firstapp/api/node_modules/express/lib/router/route.js:81:3) > <br> at Layer.handle [as handle_request] > (/home/themis/firstapp/api/node_modules/express/lib/router/layer.js:82:5) > <br> at > /home/themis/firstapp/api/node_modules/express/lib/router/index.js:234:24 > <br> at param > (/home/themis/firstapp/api/node_modules/express/lib/router/index.js:331:14) > <br> at param > (/home/themis/firstapp/api/node_modules/express/lib/router/index.js:347:14) > <br> at Function.proto.process_params > (/home/themis/firstapp/api/node_modules/express/lib/router/index.js:391:3) > <br> at > /home/themis/firstapp/api/node_modules/express/lib/router/index.js:228:12 > <br> at Function.match_layer > (/home/themis/firstapp/api/node_modules/express/lib/router/index.js:295:3) > <br> at next > (/home/themis/firstapp/api/node_modules/express/lib/router/index.js:189:10) > <br> at > /home/themis/firstapp/api/node_modules/express/lib/router/index.js:191:16 > <br> at Function.match_layer > (/home/themis/firstapp/api/node_modules/express/lib/router/index.js:295:3) > <br> at next > (/home/themis/firstapp/api/node_modules/express/lib/router/index.js:189:10)here is the server.js
var express = require('express'); MongoClient = require('mongodb').MongoClient, app = express(), mongoUrl = 'mongodb://localhost:27017/firstapp'; var bodyParser = require('body-parser'); var morgan = require('morgan'); var mongoose = require('mongoose'); var passport = require('passport'); var redisClient = require('redis').createClient; var redis = redisClient(6379, 'localhost'); var config = require('./config/database'); // get db config file var User = require('./app/models/user'); // get the mongoose model var Products = require('./app/models/products'); //get the mongoose model var Makeissue = require('./app/models/makeissue'); //get the mongoose model var port = process.env.PORT || 8080; var jwt = require('jwt-simple'); var access = require('./config/database.js'); MongoClient.connect(mongoUrl, function(err, db) { if (err) throw 'Error connecting to database - ' + err; // get our request parameters app.use(bodyParser.urlencoded({ extended: false })); app.use(bodyParser.json()); // log to console app.use(morgan('dev')); // Use the passport package in our application app.use(passport.initialize()); // demo Route (GET http://localhost:8080) app.get('/', function(req, res) { res.send('The API is at http://localhost:' + port + '/api'); }); // connect to database mongoose.connect(config.database); // pass passport for configuration require('./config/passport')(passport); // bundle our routes var apiRoutes = express.Router(); // create a new user account (POST http://localhost:8080/api/signup) apiRoutes.post('/signup', function(req, res) { if (!req.body.name || !req.body.password || !req.body.email) { res.json({success: false, msg: 'Please pass name and password and email.'}); } else { var newUser = new User({ name: req.body.name, password: req.body.password, email: req.body.email }); // save the user newUser.save(function(err) { if (err) { return res.json({success: false, msg: 'Username already exists.'}); } res.json({success: true, msg: 'Successful created new user.'}); }); } }); // route to authenticate a user (POST http://localhost:8080/api/authenticate) apiRoutes.post('/authenticate', function(req, res) { User.findOne({ name: req.body.name }, function(err, user) { if (err) throw err; if (!user) { res.send({success: false, msg: 'Authentication failed. User not found.'}); } else { // check if password matches user.comparePassword(req.body.password, function (err, isMatch) { if (isMatch && !err) { // if user is found and password is right create a token var token = jwt.encode(user, config.secret); // return the information including token as JSON res.json({success: true, token: 'JWT ' + token}); } else { res.send({success: false, msg: 'Authentication failed. Wrong password.'}); } }); } }); }); apiRoutes.post('/book', function (req, res) { if (!req.body.title || !req.body.author) res.status(400).send("Please send a title and an author for the book"); else if (!req.body.text) res.status(400).send("Please send some text for the book"); else { access.saveBook(db, req.body.title, req.body.author, req.body.text, function (err) { if (err) res.status(500).send("Server error"); else res.status(201).send("Saved"); }); } }); apiRoutes.get('/book/:title', function (req, res) { if (!req.param('title')) res.status(400).send("Please send a proper title"); else { access.findBookByTitle(db, req.param('title'), function (book) { if (!req.body.text) res.status(500).send("Server error"); else res.status(200).send(book); }); } }); apiRoutes.get('/productinfo' , function(req, res, next) { Products.find( function (err, result) { if (err) return console.error(err); res.json(result); }); }); apiRoutes.get('/resources/productinfo/:name' , function(req, res) { if (!req.param('name')) res.status(400).send("Please send a proper name"); else{ access.findProductsByName(Products, req.param('name'), function(Products) { if (!products) res.status(500).send("server error"); }); } }); // create a new Product (POST http://localhost:8080/api/productsignup) apiRoutes.post('/resources/productsignup', function(req, res) { if (!req.body.name || !req.body.serialnumber) { res.json({success: false, msg: 'Please pass name and serial number.'}); } else { var newProducts = new Products({ name: req.body.name, serialnumber: req.body.serialnumber }); // save the Product newProducts.save(function(err) { if (err) { return res.json({success: false, msg: 'Product already exists.'}); } res.json({success: true, msg: 'Successful created new Product.'}); }); } }); apiRoutes.post('/resources/createpost', function(req, res) { if (!req.body.issue) { res.json({success: false, msg: 'Please pass a issue.'}); } else { var newMakeissue = new Makeissue({ issue: req.body.issue }); // save the Product newMakeissue.save(function(err) { if (err) { return res.json({success: false, msg: 'Post already exists.'}); } res.json({success: true, msg: 'Successful created new post.'}); }); } }); // route to a restricted info (GET http://localhost:8080/api/memberinfo) apiRoutes.get('/memberinfo', passport.authenticate('jwt', { session: false}), function(req, res) { var token = getToken(req.headers); if (token) { var decoded = jwt.decode(token, config.secret); User.findOne({ name: decoded.name }, function(err, user) { if (err) throw err; if (!user) { return res.status(403).send({success: false, msg: 'Authentication failed. User not found.'}); } else { res.json({success: true, msg: 'Welcome in the member area ' + user.name + '!'}); } }); } else { return res.status(403).send({success: false, msg: 'No token provided.'}); } }); getToken = function (headers) { if (headers && headers.authorization) { var parted = headers.authorization.split(' '); if (parted.length === 2) { return parted[1]; } else { return null; } } else { return null; } }; // connect the api routes under /api/* app.use('/api', apiRoutes); module.exports = apiRoutes; app.listen(8080, function() { console.log('listening on port 8080'); }); });and the database.js
module.exports = { 'secret': 'di.ionio.gr', 'database': 'mongodb://localhost/firstapp' }; module.exports.saveBook = function (db, title, author, text, callback) { db.collection['text'].save({ title: title, author: author, text: text }, callback); }; module.exports.findBookByTitle = function (db, title, callback) { db.collection['text'].findOne({ title: title }, function (err, doc) { if (err || !doc) callback(null); else callback(doc.text); }); }; module.exports.findProductsByName = function (db, name, callback) { db.collection['products'].findOne({ name: name }, function (err, doc) { if (err || !doc) callback(null); else callback(doc.products); }); };and the package.json
{ "name": "firstapp", "main": "server.js", "dependencies": { "bcrypt": "^0.8.5", "body-parser": "~1.9.2", "express": "~4.9.8", "jwt-simple": "^0.3.1", "mongoose": "~4.2.4", "mongodb" : "~1.2.5", "morgan": "~1.5.0", "passport": "^0.3.0", "passport-jwt": "^1.2.1", "redis": "~0.10.1" } }
解决方案incorect syntax, you must read property of db.collection, but you call that. Example:
db.collection['products']!!! db.collection['text'].save({ title: title, author: author, text: text }, callback); }; module.exports.findBookByTitle = function (db, title, callback) { db.collection['text'].findOne({ title: title }, function (err, doc) { if (err || !doc) callback(null); else callback(doc.text); }); }; module.exports.findProductsByName = function (db, name, callback) { db.collection['products'].findOne({For example
var object = { 'some_value': 'value', 'some_methid': function(){ return 'method result'} }
You can read and set property 'some_value', for example:
object['some_value'] // return 'value' object.some_value // return 'value'// STEP 2
Ok, in your methods of database.js you pass db variable, but this is not of db instance, it is mongoose model, and you must write like this:
module.exports.findBookByTitle = function (model, title, callback) { model.findOne({ title: title }, function (err, doc) { if (err || !doc) callback(null); else callback(doc.text); }); }; module.exports.findProductsByName = function (model, name, callback) { model.findOne({ name: name }, function (err, doc) { if (err || !doc) callback(null); else callback(doc.products); }); };
这篇关于TypeError：db.collection不是一个函数，CAN NOT GET的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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