I am getting really good at NodeJs and AngularJs. After building a sizable application, I have come to the conclusion that Mongoose is not for me. I want to use pure MongoDb.
I have done a pretty good job refactoring my server code. I pulled all my functions out of my routes and into controllers. Currently however, my controllers are using Mongoose and they are connected to Mongo via the schema.
Current code:
var express = require('express'),
errMsg = require('../../../utilities/errorMsg'),
MyMongooseSchema = require('./models/myMongooseModel');
module.exports = {
all: function (req, res) {
MyMongooseSchema.find({}).exec(function (err, results) {
if (err) {
....
});
}
res.send(results);
})
}
Again I do not want this. I want the dynamism of MongoDb. I tried this to no avail.
db.js:
function MongoDbConnect(dbName){
var db = 'mongodb://localhost/' + dbName;
MongoClient.connect(db, function (err, db) {
if(err){
console.log('Error connecting to database')
} else {
return db; }
});}
exports.MongoDbConnect = MongoDbConnect;
controller: [that is called from respective router]
var database = require('../../../config/db');
module.exports = {
all: function (req, res) {
var db = database.MongoDbConnect('myDbName');
db.collection('MyCollectionName').find({}, function (err, results) {
if (err) {
return res.status(400).send({
message: errMsg.getErrorMessage(err)
});
}
res.send(results);
})
}}
Obviously, this is not working.
What would be the appropriate way to create a well refactored database connection that any controller can call on, with whatever database the controller needs?
Thank you.
Hey everybody, thanks sooooo much for your help !
var mongoskin = require('mongoskin');
var db = mongoskin.db('mongodb://localhost:27017/myDatabase?auto_reconnect', {safe:true});
db.collection('Menu').find({}).toArray(function(error, menu){
if (error) return next(error);
res.send(menu || [])
})
Related
Say I have a list of models:
const documents = [{}, {}, {}];
And I want to insert these into the DB, or update them all, but only if a condition is met:
Model.update({isSubscribed: {$ne: false}}, documents, {upsert:true},(err, result) => {
});
The above signature is surely wrong - what I want to do is insert/update the documents, where the condition is met.
There is this Bulk API:
https://docs.mongodb.com/manual/reference/method/Bulk.find.upsert/
but I can't tell if it will work when inserting multiple documents.
Imagine this scenario: We have a list of employees and a form of some sorts to give them all a penalty, at once, not one by one :)
On the backend side, you would have your eg addBulk function. Something like this:
Penalty controller
module.exports = {
addBulk: (req, res) => {
const body = req.body;
for (const item of body) {
Penalty.create(item).exec((err, response) => {
if (err) {
res.serverError(err);
return;
}
});
res.ok('Penalties added successfully');
}
}
Then you'll probably have an API on your frontend that directs to that route and specific function (endpoint):
penaltyApi
import axios from 'axios';
import {baseApiUrl} from '../config';
const penaltyApi = baseApiUrl + 'penalty'
class PenaltyApi {
static addBulk(penalties) {
return axios({
method: 'post',
url: penaltyApi + '/addBulk',
data: penalties
})
}
}
export default PenaltyApi;
...and now let's make a form and some helper functions. I'll be using React for demonstration, but it's all JS by the end of the day, right :)
// Lets first add penalties to our local state:
addPenalty = (event) => {
event.preventDefault();
let penalty = {
amount: this.state.penaltyForm.amount,
unit: this.state.penaltyForm.unit,
date: new Date(),
description: this.state.penaltyForm.description,
employee: this.state.penaltyForm.employee.value
};
this.setState(prevState => ({
penalties: [...prevState.penalties, penalty]
}));
}
Here we are mapping over our formData and returning the value and passing it to our saveBulkEmployees() function
save = () => {
let penaltiesData = Object.assign([], this.state.penalties);
penaltiesData.map(penal => {
penal.employeeId = penal.employee.id;
delete penal.employee;
return penaltiesData;
});
this.saveBulkEmployees(penaltiesData);
}
...and finally, let's save all of them at once to our database using the Bulk API
saveBulkEmployees = (data) => {
PenaltyApi.addBulk(data).then(response => {
this.success();
console.log(response.config.data)
this.resetFormAndPenaltiesList()
}).catch(error => {
console.log('error while adding multiple penalties', error);
throw(error);
})
}
So, the short answer is YES, you can absolutely do that. The longer answer is above :) I hope this was helpful to you. If any questions, please let me know, I'll try to answer them as soon as I can.
I just started learning MongoDB and mongoose. Currently I have the following structure:
database -> skeletonDatabase
collection -> adminLogin
When I run db.adminLogin.find() from the command line I get:
{ "_id" : ObjectId("52lhafkjasfadsfea"), "username" : "xxxx", "password" : "xxxx" }
My connection (this works, just adding it FYI)
module.exports = function(mongoose)
{
mongoose.connect('mongodb://localhost/skeletonDatabase');
var db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', function callback () {
console.log('Conntected To Mongo Database');
});
}
My -js-
module.exports = function(mongoose)
{
var Schema = mongoose.Schema;
// login schema
var adminLogin = new Schema({
username: String,
password: String
});
var adminLoginModel = mongoose.model('adminLogin', adminLogin);
var adminLogin = mongoose.model("adminLogin");
adminLogin.find({}, function(err, data){
console.log(">>>> " + data );
});
}
My console.log() returns as >>>>
So what am I doing wrong here? Why do I not get any data in my console log? Thanks in advance for any help.
mongoose by default takes singular model names and pairs them with a collection named with the plural of that, so mongoose is looking in the db for a collection called "adminLogins" which doesn't exist. You can specify your collection name as the 2nd argument when defining your schema:
var adminLogin = new Schema({
username: String,
password: String
}, {collection: 'adminLogin'});
Had a problem with injecting it within an express route for my api so I changed it thanks to #elkhrz by first defining the schema and then compiling that one model I want to then pull like so:
app.get('/lists/stored-api', (req, res) => {
Apis.find(function(err, apis) {
if (err) return console.error(err);
res.send(apis);
});
});
I wouldn't send it to the body, I would actually do something else with it especially if you plan on making your API a production based application.
Run through this problem and read up on possible proper ways of rendering your data:
How to Pass Data Between Routes in Express
Always a good idea to practice safe procedures when handling data.
first compile just one model with the schema as an argument
var adminLogin = mongoose.model('adminLogin', adminLogin);
in your code adminLogin does not exist, adminLoginModel does;
after that ,instead to
adminLogin.find({}, function(err, data){
console.log(">>>> " + data );
});
try this
adminLogin.find(function (err, adminLogins) {
if (err) return console.error(err);
console.log(adminLogins);
is important the "s" because mongo use the plural of the model to name the collection, sorry for my english...
I have a bear model and I'm using it with blueprint REST.
// api/models/Bear.js
module.exports = {
attributes: {
name: {
type: 'string',
required: true
}
}
};
I'd like to perform some calculations to bears based on exactly the same criterias as the standard findWhere. Indeed I'd like to be able to request
GET /bear/details
exactly just like I request
GET /bear
So I could find bear details with :
complex query like ?where={}
fields like ?name=
but also sending json in body like {name: ''}
or maybe even using ?limit= etc.
The controller looks like this :
// api/controllers/BearController.js
module.exports = {
getDetails: function (req, res) {
Bear.find().exec(function (err, bears){
if (err) return res.serverError(err);
var bearsDetails = _.map(bears, function(bear) {
return {
id: bear.id,
nameLength: bear.name.length,
reversedName: bear.split('').reverse().join('')
};
});
return res.json(bearsDetails);
});
}
};
And I have a custom route that looks like this
// config/routes.js
module.exports.routes = {
'get /bear/details': 'BearController.getDetails'
}
=> How to automaticaly filter models exactly like in a findWhere request, in a custom controller, without reinventing the wheel ?
Apparently I figured it out myself digging into sails' find() source code. One can use actionUtil's parseCriteria(req). I personaly wrapped it into a service for cleanliness purpose.
Roughly :
api/services/ActionUtilService.js
module.exports = require('../../node_modules/sails/lib/hooks/blueprints/actionUtil');
api/controllers/BearController.js
module.exports = {
getDetails: function (req, res) {
let criteria = ActionUtilService.parseCriteria(req);
Bear.find(criteria).exec(function (err, bears){
if (err) return res.serverError(err);
var bearsDetails = _.map(bears, function(bear) {
return {
id: bear.id,
nameLength: bear.name.length,
reversedName: bear.split('').reverse().join('')
};
});
return res.json(bearsDetails);
});
}
};
For cleanliness I've wrapped it into
When I am inserting/updating a document in a collection, is the lock applied on the database or the collection. Suppose I have two collections and they are independant of each other in the same database and wants to do write operations on them concurrently. Is this possible?
Here is the code I am using to test this:
var assert = require('assert'),
MongoClient = require('mongodb').MongoClient,
async = require('async');
var station_list = require('./station_list.json'),
trains_list = require('./trains_list.json');
var stationList = [],
trainsList = [];
var MONGO_URL = 'mongodb://localhost:27017/test';
for(var i=0; i<station_list.stations.length; i++)
stationList.push(station_list.stations[i].station_code);
for(var i=0; i<trains_list.trains.length; i++)
trainsList.push(trains_list.trains[i].code);
console.log('trains : ' + trainsList.length + ' stations : ' + stationList.length);
populateTrains();
populateStations();
function populateTrains() {
async.eachSeries(trainsList, populateTrainDb, function (err) {
assert.equal(null, err);
});
}
function populateTrainDb(code, callback) {
MongoClient.connect(MONGO_URL, function (err, db) {
assert.equal(null, err);
var jsonData = {};
jsonData.code = code;
db.collection('trainsCon').replaceOne(
{'code' : code}, jsonData, {upsert: true, w:1}, function (err, res) {
assert.equal(null, err);
db.close();
callback();
});
});
}
function populateStations() {
async.eachSeries(stationList, populateStationDb, function (err) {
assert.equal(null, err);
});
}
function populateStationDb(code, callback) {
MongoClient.connect(MONGO_URL, function (err, db) {
assert.equal(null, err);
var jsonData = {};
jsonData.code = code;
db.collection('stationsCon').replaceOne(
{'code' : code}, jsonData, {upsert:true, w:1}, function (err, res) {
assert.equal(null, err);
db.close();
callback();
});
});
}
The two json files : station_list.json and trains_list.json have around 5000 entries. So after running the given program I get this error after a while :
C:\Users\Adnaan\Desktop\hopSmart\node_modules\mongodb\lib\server.js:242
process.nextTick(function() { throw err; })
^
AssertionError: null == { [MongoError: connect EADDRINUSE 127.0.0.1:27017]
name: 'MongoError',
message: 'connect EADDRINUSE 127.0.0.1:27017' }
at C:\Users\Adnaan\Desktop\hopSmart\testing.js:52:10
at C:\Users\Adnaan\Desktop\hopSmart\node_modules\mongodb\lib\mongo_client.js:276:20
at C:\Users\Adnaan\Desktop\hopSmart\node_modules\mongodb\lib\db.js:224:14
at null.<anonymous> (C:\Users\Adnaan\Desktop\hopSmart\node_modules\mongodb\lib\server.js:240:9)
at g (events.js:273:16)
at emitTwo (events.js:100:13)
at emit (events.js:185:7)
at null.<anonymous> (C:\Users\Adnaan\Desktop\hopSmart\node_modules\mongodb-core\lib\topologies\server.js:301:68)
at emitTwo (events.js:100:13)
at emit (events.js:185:7)
When I check the number of entries entered the database, around 4000 entries had already been entered in both the collections. So what I get from the above experiment was that an error might have occured when one write was being attempted while inside other collection a document must have been getting written.
So how should I proceed to have this concurrency without conflicting locks.
The answer to this question can be quite long and depends on various factors (MongoDB version, storage engine, type of operations you are doing, sharding, etc.). I can only recommend you to read carefully the Concurrency section of the MongoDB documentation, and in particular the lock granularity part.
Make sure to choose the right version of MongoDB first as the behaviour varies greatly from one version to another (e.g. database locking in pre-3.0 vs. collection locking for most operations in post-3.0 using NMAPv1).
I don't think it's concurrency issue with MongoDB, but I could be driver or even with test itself.
I have created a sample application couple of weeks ago to stress test MongoDB while working on a nasty bug. I used C# and MongoDB 3.0 on Windows 10. I have inserted million of documents in multithreaded environment but couldn't crash MongoDB.
Parallel.For(0, 10000, (x =>
{
var lstDocs = new List<BsonDocument>();
for (var i = 0; i < 100; i++)
{
lstDocs.Add(new BsonDocument(doc));
}
collection.InsertMany(lstDocs);
lstDocs.Clear();
}));
You can find code in gist here.
You should not be calling MongoClient.connect every time. That's causing a ton of connections to open and close all the time which is overloading mongo. You should let the MongoClient manage the connection pool. Change it so that you store the db object from MongoClient.connect. Something like this:
var db
MongoClient.connect(url, function(err, database){
db = database;
}
I am running into a question when to use which one, the following is update function for mongoose, it works fine.
// Updates an existing form in the DB.
exports.update = function(req, res) {
if(req.body._id) { delete req.body._id; }
Form.findById(req.params.id, function (err, form) {
if (err) { return handleError(res, err); }
if(!form) { return res.send(404); }
var updated = _.assign(form, req.body);
updated.formContent = req.body.formContent;
updated.save(function (err) {
if (err) { return handleError(res, err); }
return res.json(200, form);
});
});
};
Tried the following to replace the form data.
_.assign(form, req.body); // Works (update database)
_.merge(form, req.body); // Not Work (database not updating, remain the same)
_.extend(form, req.body); // Works (update database)
The above result show merge doesn't work when there is object within the post data.
Could some please explain why one is not working the others is ok. I have read the following question
Lodash - difference between .extend() / .assign() and .merge()
but i am curious to understanding which one won't update the database, but when applied with assign and extend it's working.