Learning Process : Backend

[omarokasha1]

Please Keep Daily Documenting your Learning Process Here.

[omarokasha1]

We need to Document ( Installation - Usage - Hello World Example - Links for DOcumentation for each one ) : 1)Node JS Installation  https://nodejs.org/en/docs/guides/getting-started-guide/

1) Express JS Installation  • mkdir myapp • cd myapp • npm init • npm install express –save Hello world Example https://expressjs.com/en/starter/hello-world.html

2) MongoDB Installation for ubuntu • wget -qO - https://www.mongodb.org/static/pgp/server-5.0.asc | sudo apt-key add - • sudo apt-get install gnupg • echo "deb [ arch=amd64,arm64 ] https://repo.mongodb.org/apt/ubuntu focal/mongodb-org/5.0 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-5.0.list • sudo apt-get update • sudo apt-get install -y mongodb-org

Installation for windows • https://docs.mongodb.com/manual/tutorial/install-mongodb-on-windows/

3) IDEs

• visual studio code
• postman to test api

[omarokasha1]

@omda07 We need to invest more in the documentation Omda, This is one of the most important Issues to see it is documentation .

For Examples for some Questions Must be Asked and Answered :

1) Which libraries you used through the development process? 2) From Where you start to Learn these tools? 3) You need to document in the code how to manipulate this code to for example change the Registeration from Email usage to Phone Number Usage ? if we want to depend on For example just username Registeration ? How can we start Handling the Dabatase ?

We need to ensure through your learning Journey That your Friends @KareemAhmed22 @mariamyoussefwiliam @mirette3 @AsimAyman @youssefelgebaly Can start how can edit in the backend through just your Documetnation and can understand this code .

These are just a suggestion Question If you didn't document Day by Day you will lose the track of Documentation Everything.

@mirette3 : I will follow up with you to ensure that the documentation for the backend is up and Running by the end of tomorrow Even if We stop Development and Finalizing all Documentation Needed to be on track of Documentation .

That is all for Now.

[omda07]

From Where you start to Learn these tools?

Tutorial Node js
Documentation Node js Docs

Tutorial Express js Documentation Express js Docs

Arabic tutorial API Tutorial
English Crash Course API Tutorial en

Which libraries you used through the development process?

• bcrypt to encrypt the password
• exprss js
• express async errors to handle any error async like connect to DB
• joi to validate the inputs
• jsonwebtoken to generate token that have user info
• mongoose it’s the database
• lodash to take just input that needed
• winston to save the errors in log in file
• winston-mongodb to save the errors in log in the database
• compression to compress the request

  packages in development environment

• dotenv to store constant strings like database URL connection
• modemon when click on ctrl + s restart the server automatically

Structure of code

there are 5 folders

• config folder for save errors log
• node_modules built in generated that have packages files
• middleware
• models for schema models
• routes for rest api (Request , Response)

  there are 5 files

• .env to store constant values
• .gitignore to ignore files not upload them to github
• error.log that have errors logs
• package-lock built in generated that have packages code
• package have project information and dependence of packages
• server file that begin start when the project run

HTTP response status codes

• You can change status code dependent on the error HTTP Status Codes

  For example:

• status code is 404 not found

  let user = await Users.findOne({ email }).lean()
  // if not exist return an error messge
  if (!user) {
     // status code is 404 not found
      return res.status(404).json({ status: 'false', message: 'Invalid email or password' })
  }

• status code is 401 Unauthorized

  const token = req.header('x-auth-token')
  if (!token) {
    // status code is 401 Unauthorized
      res.status(401).send('access denied not auth......')
  }

  Build Server

  
  //* initial start
  app.use(bodyParser.json())
  //* mongoose connection(database url)
  mongoose.connect(process.env.DATABASE_URL, { useNewUrlParser: true, useUnifiedTopology: true, }).then(
  () => console.log('connected to database')).catch((error) => logger.error(error))

// copmresed requests app.use(compression())

// import register const usersRegister = require('./routes/register') app.use('/register', usersRegister) // import login const usersLogin = require('./routes/login') app.use('/login', usersLogin) // import profile const userProfile = require('./routes/profile') app.use('/profile', userProfile) // import changepassword const changePassword = require('./routes/changePassword') app.use('/api/changePassword', changePassword) // import courses const newCourse = require('./routes/courses') app.use('/api/course', newCourse)

// if write invalide url or end point send to user an error message app.all('*', (req, res, next) => { res.status(404).json({ status: 'false', message: 'Page not found !' }) }) // listen on port 8080 local host app.listen(8080, () => logger.info('server started 8080 ....'))

# Build User Schema 
###### You can add or remove any attribute
- userName must be in lowercase to be unique and make all users name completely different   
```sh
const UserSchema = new mongoose.Schema({
    userName: { type: String,unique:true, required: true, lowercase:true,minlength: 3, maxlength: 44 },
    email: { type: String, required: true, maxlength: 254 },
    password: { type: String, required: true, minlength: 8, maxlength: 1024 },
    phone: { type: Number, unique: true, minlength: 11, maxlength: 11 },
    isAdmin: { type: Boolean }m
 userEducation:  {
        university: { type: String, },
        major: { type: String, },
        faculty: { type: String, },
        experince: { type: String, },
        grade: { type: String, },
        interest: 
            [{type:String}]

    } ,
})

Schema validation using joi package

You can add or remove any attribute from your schema

• regex(/[a-zA-Z]/) to begin with char

  
  function validateUser(user) {
  const JoiSchema = Joi.object({
  
      userName: Joi.string().min(3).max(44).required().regex(/[a-zA-Z]/).lowercase(),
  
      email: Joi.string().email().max(254).required(),
  
      password: Joi.string().min(8).max(512).required()
  
     phone: Joi.string().min(11).max(11),
  
      gender: Joi.string(),
  
      imageUrl: Joi.string(),
  
      birthDay: Joi.string(),
  
      country: Joi.string(),
  
      city: Joi.string(),
  
      bio: Joi.string(),
  
  }).options({ abortEarly: false });
  
  return JoiSchema.validate(user)

}

```sh
//*validation on user inputs in login
function validateUserLogin(user) {
    const JoiSchema = Joi.object({

        email: Joi.string().email().min(3).max(25).required(),

        password: Joi.string().min(8).max(512).required()

    }).options({ abortEarly: false });

    return JoiSchema.validate(user)
}

Build Registration

• you can change any attributes independent on schema's attributes

  // Take inputs from user for example
  const { userName, email, password: plainTextPassword } = req.body

• remove white spaces from userName

  let userNameCheck =userName.replace(/\s+/g, '')

• Use validate function

  const validateError = validateUser(req.body)
  
  // if validate error just send to user an error message
  if (validateError.error) {
      return res.json({ error: validateError.error.details[0].message })
  }

• check in database by any required attribute you want from schema for example by email

  
  let user = await Users.findOne({ email }).lean()

if (user) { return res.status(200).json({ status: 'false', message: 'email already in use' }) }

- You can change any required attribute form schema the change the message
```sh
let user = await Users.findOne({ userName }).lean()

if (user) {
return res.status(200).json({ status: 'false', message: 'userName already in use' })
}

• If validate then

  try {
      // take from user userName , email and password and not care for any value else using lodash package
      user = new Users(_.pick(req.body, ['userName', 'email', 'password']))
  
      // encrypt the password using bcrypt package
     // 10 is a vale of salt length to generate or salt to use (related by security)
      user.password = await bcrypt.hash(plainTextPassword, 10)
      // save userName without spaces
       user.userName = userNameCheck
      // generate token that have his id using jsonwebtoken package
      const token = jwt.sign({ id: user.id }, 'privateKey')
  
      // then save the user
      await user.save()
  
      // send his token in header and his data in body
      return res.header('x-auth-token', token).json(_.pick(user, ['_id', 'userName', 'email']))
  } catch (error) {
   if (error.code === 11000) {
          return res.json({ status: 'false', message: 'in use' })
        }
        throw error
  
  }

Build Login

• Take inputs from user for example const { email, password: plainTextPassword } = req.body you can change any attributes independent on schema's required attributes

• Use validate function

  const validateError = validateUser(req.body)
  
  // if validate error just send to user an error message
  if (validateError.error) {
      return res.json({ error: validateError.error.details[0].message })
  }

• check in database by any required attribute you want from schema for example by email

  let user = await Users.findOne({ email }).lean()
  // if not exist return an error messge
  if (!user) {
      return res.status(200).json({ status: 'false', message: 'Invalid email or password' })
  }

• You can change any required attribute from schema then change the message.

  let user = await Users.findOne({ userName }).lean()
  // if not exist return an error messge
  if (!user) {
      return res.status(200).json({ status: 'false', message: 'Invalid userName or password' })
  }

• If validate then

  try {
      // compare between password and encrypted password of user  using `bcrypt.compare`
      const checkPassword = await bcrypt.compare(req.body.password, user.password)
  
      // if password doesnt match return to user an error message 
      if (!checkPassword) {
          return res.status(200).json({ status: 'error', error: 'Invalid email or password' })
      }
  
      // generate token that have his id and if admin or not using `jwt.sign`
      const token = jwt.sign({ id: user._id, isAdmin: user.isAdmin }, 'privateKey')
  
      return res.json({ status: 'ok', token: token })
  } catch (error) {
  // error code 11000 for duplicated attribute in database
    if (error.code === 11000) {
          return res.json({ status: 'false', message: 'in use' })
        }
        throw error
  
  }

  Build middleware

  authentication middleware

  check if user have token (auth)

module.exports =function (req, res, next) {
    // get the token from header called x-auth-token 
    const token = req.header('x-auth-token')
    if (!token) {
        res.status(401).send('access denied not auth......')
    }

    try {
        // decode the token to get the user info using `jwt.verify` from package jsonwebtoken
        const decodeToken = jwt.verify(token, 'privateKey')
        req.user = decodeToken
        next()

    } catch (er) {
        res.status(400).send('wrong token ......')
    }
}

getCourses middleware

module.exports = async function getCourses(req, res, next) {
    let course
    try {
 // find the courses with author
      course = await Course.find().populate('author','-__V').select('-__v')
      if (!course) {
        return res.status(200).json({ status: 'false', message: 'Cannot find courses' })
      }
      res.course = course
    } catch (err) {
      return res.status(500).json({ message: err.message })
    }

    res.course = course
    next()
  }

Change Password

change password inside the app for user that logged in

router.post('/', async (req, res) => {
    // take the password from user and validate it
    const { password: plainTextPassword } = req.body

    // take the token from header
    const token = req.header('x-auth-token')

    // validate the password if not string
    if (!plainTextPassword || typeof plainTextPassword !== 'string') {
        return res.status(200).json({ status: 'false', message: 'Invalid password' })
    }
    // validate the password if less than 8 char
    if (plainTextPassword.length < 8) {
        return res.status(200).json({
            status: 'false',
            message: 'Password too small. Should be atleast 8 characters'
        })
    }

    try {
        // decode the token to get user data
        const user = jwt.verify(token, 'privateKey')
        console.log(user)

        // get user id 
        const id = user.id
        console.log(id)

        // incrypt new password
        const newPassword = await bcrypt.hash(plainTextPassword, 10)

        // find the user by id and change the password
        await User.updateOne(
            { _id: id },
            {
                $set: { password: newPassword }
            }
        )
        res.status(200).json({ status: 'ok', message: 'password changed' })
    } catch (error) {
        res.json({ status: 'false', message: error.message })
    }
})

Build Profile

middleware auth check first if user logged in and have a token

get('/', auth, async (req, res) => {
    // find the user info by his id and not show the password at response using `select`
    const profile = await User.findById(req.user.id).select('-password -__v')

    res.json({ profile })
})

Build Course Schema

• courses must have an author for each course so we need to get the author id to fetch his data with the course

• to do this we need to take a reference from user schema

  
  const CourseSchema = new mongoose.Schema({
  totalTime: { type: String, },
  lastUpdate: { type: String,},
  requiremnets: { type: String,  },
  title: { type: String,  },
  price: { type: String,  },
  discount: { type: String,  },
  language: { type: String,  },
  description: { type: String,  },
  review: { type: String,  },
  imageUrl: { type: String,  },
  
  author:{
  
      type:mongoose.Schema.Types.ObjectId ,
      ref:'User'
  }
  ,})

# Build Get Courses 

```sh
// Getting all
//* using getcourses middleware
router.get('/',getCourses, async (req, res) => {
  res.status(200).json({status : "ok",courses:res.course})
})

[omarokasha1]

@omda07 I am still waiting as we agreed yesterday to have some Examples based on each questions to understand what exactly to change for example :

check in database by any required attribute you want from schema for example by email let user = await Users.findOne({ email }).lean()

if (user) { return res.status(404).json({ status: 'false', message: 'email already in use' }) }

You can make it like :

let user = await Users.findOne({ username }).lean()

if (user) { return res.status(404).json({ status: 'false', message: 'email already in use' }) }

To change the feedback message you can change here from

if (user) { return res.status(404).json({ status: 'false', message: 'email already in use' }) }

to if (user) { return res.status(404).json({ status: 'false', message: 'Hi, This is an Error' }) }

---

• another question is // encrypt the password using bcrypt package user.password = await bcrypt.hash(plainTextPassword, 10)

What is the 10 here ? You need to clear in the comments of the code what is each value refer to

---

userName: { type: String, required: true, minlength: 3, maxlength: 44 }, email: { type: String, required: true, maxlength: 254 },

How can I add more validation to ensure for example : 1) the Username can't start with Sympols or Numbers 2) Username can't have spaces 3) Username can't be duplicated like email Live while I am writing on Flutter GUI I validate if this username is used before In the database or not . To make it more clear I am writing first char "O" this less than 3 Paramters the FLutter Team will Raise flag that is less than 3 Char but after haveing for example "OOO" how we check instant without click on registration button and send that this username is booked from example . 4) In username is "OOO" is different from "ooo" is the validation function compare with taking in consideration the Capital of the Chars ?

---

}).options({ abortEarly: false });

What is this line refer to ?

---

https://github.com/omarokasha1/TheFirstProject/blob/186e8bbef167fa6f0cbbd9b7fcc79bffa3498e77/loginAndRegister/server.js

Where is the documentation / Comments for this Code ?

---

After Have a some time in the backend code here is my Thoughts :

It is Very Important @omda07 and @mirette3 to have next Documentation : 1) What is the Structure of the Code 2) What is automatic Generated by tools and We didn't edit or Developed anything at and What we changed in some files and what we developed ? 3) I can see that in this path https://github.com/omarokasha1/TheFirstProject/tree/backend/loginAndRegister we have 5 Folders and 5 FIles what is the usage from each one ? 4) What is these status Numbers ? What are they referring to ? we need a table with the definition of each number . 5) We need a table of definition that will have a keyword like subscriber ? 6) Check Change Password Code , you need to make a lot of comments with some questions like :

• what is this ? const JWT_SECRET = 'kdhakjdhwdhqwiu;hdl/akjd;lakhdulhdw$$@$#^324uoqdald' 7) I think we need to make a Journey for the backend to show that for example : Starting from what is start with the server start without getting any inquiry from flutter or frontend What happen in the code when we receive a inquiry for login how the code interact with the database What happen in the code when we receive a inquiry for Registration how the code interact with the database What happen when i request to change my password all of these things need to be clear .

Again @omda07 and @mirette3 We need to have a skill called beginner mindset that will enable us to help others understand the code without making them study everything to can easily make all possible edits .

**### _

• [ ] So @mirette3 and @omda07 I need an Expected time to see all these changes documented ?

_**

[youssefelgebaly]

Great job Ahmed, please add a method to install this project and how to Run the project on a local Server

download backend project

• you can download from here backend

Import Backend project to Visual studio code IDE

1. Open Visual studio code IDE.
   • File → OpenFloder → Choosing the project from the device
2. Click project to import to Visual studio code

Run the project on a local Server

• In the command line, run cd to change directories to the folder we just cloned from GitHub.

  $ cd ~/workspace

• add those lines in package.js file

  "scripts": {
  "start": "nodemon server.js"
  },

• run npm start which will start the local server.

  $ npm start