MongoDB and NodeJs

MongoDB

NodeJs

Installation

We will install :

  • MongoDb
  • Node
  • Robomongo - editor

brew - package manager can be used on MacOs

/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

https://brew.sh/

Mongo Installation:

>brew install mongo
>mongod
>sudo mkdir -p /data/db
>sudo chown -Rv rasimsen /data/db
>brew services start mongo #start/stop/status

NodeJs-Mongo

Create a project

$ mkdir users => cd users
$ mkdir src
$ mkdir test
$ npm install request --save #url için
$ npm install --save mocha nodemon mongoose

mocha: unit test nodemon: mongoose : mongo db driver

src/user.js:

const mongoose=require('mongoose');
const Schema=mongoose.Schema;

const UserSchema = new Schema({
    name:String
});

const User = mongoose.model('User',UserSchema);

module.exports = User;


package.json - project details and depencies file

package.json file:

{
  "name": "users",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "mocha"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "mocha": "^5.2.0",
    "mongoose": "^5.3.10",
    "nodemon": "^1.18.6",
    "request": "^2.88.0"
  }
}

Mocha - Unit Test

Mocha is most famous test framework for javascript..

Creating data on MongoDb/Test

test/create_test.js(test file):

const assert = require('assert');

describe('Creating records',()=>{
    it('saves a user',()=>{
        assert(1+1 ===2);
    });
});

test/create_test.js(another sample):

const assert = require('assert');
const User = require('../src/user');


describe('Creating records',()=>{
    it('saves a user',(done)=>{ //<------------ 1.callback 
        const joe = new User({ name: 'Joe'});
        
        //joe.save();
        joe.save()
        .then((result) => {
            //Has joe been saved successfully?
            assert(!joe.isNew);
            done(); //<------------------- 2.callback: we should use 
        }).catch((err) => {
            console.log('Error');
        });

    });
});

Search/Find Record on Mongo

reading_test.js:

const assert = require('assert');
const User = require('../src/user');

describe('Reading users out of the database', ()=>{
    let joe;

    beforeEach((done)=>{
        joe=new User({name:'Joe'});
        joe.save()
        .then((result) => {
            done(); 
        }).catch((err) => {
            console.log('Error..');
        });
    });
    
    it('finds all users with a name of joe',(done)=>{
        User.find({ name:'Joe' })
           .then((users)=>{
               console.log(users);
               assert(users[0]._id.toString() === joe._id.toString());
               done();
           });
    });

    it('find a user with a particular id', (done)=>{
        User.findOne({_id:joe._id})
        .then((user)=>{
            assert(user.name === 'Joe');
            done();
        });
    });
});

Deleting/removing records

delete_test.js

const assert = require('assert');
const User = require('../src/user');

describe('Deleting a user',()=>{
    let joe;

    beforeEach((done)=>{
        joe = new User({name:'Joe'});
        joe.save()
        .then((result) => {
            done();
        }).catch((err) => {
            console.log('delete:error in beforeEach!');
        });
    });

    it('model instance remove',(done)=>{
        joe.remove()//it remove joe instance that we created in beforeEach method
        .then(() => User.findOne({name:'Joe'}))//to test that the object deleted, it should return null
        .then((user)=>{//then: they work sequentially
            assert(user === null);
            done();
        })
        ;
    });

    it('class method remove',(done)=>{
        //remove a bunch of records with some given criteria
        User.remove({ name:'Joe' })
        .then(()=>User.findOne({name:'Joe'}))
        .then((user)=>{
            assert(user === null);
            done();
        });
    });
 
    it('class method findAndRemove',(done)=>{
        User.findOneAndRemove({name:'Joe'})
        .then(()=>User.findOne({name:'Joe'}))
        .then((user)=>{
            assert(user === null);
            done();
        });
    });

    it('class method findByIdAndRemove',(done)=>{
        User.findByIdAndRemove(joe._id)
        .then(()=>User.findOne({name:'Joe'}))
        .then((user)=>{
            assert(user === null);
            done();
        });
    });


});

Updating records

update_test.js:

const assert=require('assert');
const User = require('../src/user');

describe('Updating records',()=>{
    let joe;

    beforeEach((done)=>{
        joe = new User({name:'Joe'});
        joe.save()
        .then(()=>done());
    });

    function assertName(operation, done){
        operation
            .then(()=>User.find({}))
            .then((users)=>{
                assert(users.length === 1);
                assert(users[0].name === 'Alex');
                done();
            });
    }

    //set and save: when you update more record(emaıl, phone, address), 
    //like a transactional update,
    //we can update all data, and then save all.
    it('instance type using set n save',(done)=>{
       console.log(joe);
       joe.set('name','Alex');
       assertName(joe.save(),done);
       console.log(joe); 
    });

    //update : directly update
    it('A model instance can update',(done)=>{
        assertName(joe.update({name:'Alex'}),done);
    });  

    it('A model class can update', (done)=>{
        assertName(
            User.update({name:'Joe',name:'Alex'}),
            done
        );
    });

    it('A model class can update one record', (done)=>{
        assertName(
            User.findOneAndUpdate({name:'Joe',name:'Alex'}),
            done
        );
    });

    it('A model class can find a record with an Id and update',(done)=>{
        assertName(
            User.findByIdAndUpdate(joe._id,{name:'Alex'}),
            done
        );
    });

});

Run the test : npm run test

$ npm run test

Automating Test

   "test": "nodemon --exec 'mocha -R min'" : formats and clear the output

If I change the code, it runs test again for changes.

{
  "name": "users",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "nodemon --exec 'mocha -R min'"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "mocha": "^5.2.0",
    "mongoose": "^5.3.10",
    "nodemon": "^1.18.6",
    "request": "^2.88.0"
  }
}

MongoDB with Node and Express

Node:Engine for running JavaScript outside of a browser environment. Can work with HTTP requests.

Express:Framework to simplify working with HTTP requests.

node-express-mongo-rest-api.png


Create a new project

$ mkdir muber
$ cd muber
$ npm init
$ code . #to open in a editor(atom, code)

to install some dependencies.. you can use SuperTest which is can be used to test HTTP endpoints.

$ sudo npm install --save nodemon mongoose express mocha
$ sudo npm install --save supertest #you can use SuperTest which is can be used to test HTTP endpoints.
$ sudo npm install --save body-parser #Parse incoming request bodies in a middleware before your handlers, available under the req.body property.

Environment Definition

node-express-mongo-environment-variable.png


Errors

(node:27919) DeprecationWarning: current URL string parser is deprecated, and will be removed in a future version. To use the new parser, pass option { useNewUrlParser: true } to MongoClient.connect.

Solution: Check your mongo version

mongo --version
If you are using version >= 3.1.0 change you mongo connection file to ->

MongoClient.connect("mongodb://localhost:27017/YourDB", { useNewUrlParser: true })
or your mongoose connection file to ->

mongoose.connect("mongodb://localhost:27017/YourDB", { useNewUrlParser: true });
Ideally, it's a version 4 feature but v3.1.0 and above is supporting it too. Check out MongoDB Github for details.

Error: TypeError: User is not a constructor Solution: Node is a case-sensetive language. Check your model or object..