codecygen/101-ejs-templating-engine-with-mvc-mongodbwithmongoose

Practice App

Starting the app for the first time:

• npm i
• Create a database called "shopping-website" in MySQL
• Create .env file and provide the given content.

URL="mongodb+srv://UserName:[email protected]/DBName?retryWrites=true&w=majority"
EXPRESS_SESSION_KEY="your-secret-key"

• Start server with "npm start" command which will trigger "nodemon start".

MVC Pattern (Model View Controller):

Model:

• Responsible for representing your data.
• Responsible for managing your data (saving, fetching...).
• Does not matter if you manage data in memory, files, databases.
• Contains data related logic.

View:

• What the users see.
• Should not contain too much logic (HTML, Handlebars, Pug, EJS...).

Controller:

• Connects "Model" and "View".
• Responsible of establishing the communication of both in both directions.

Model View Controller (MVC) in this Project

• The MVC pattern helps you break up the frontend and backend code into separate components.
• Model View Controller principles are applied in this project.
• There will be "views", "controllers" and "models" folders to make the project easier to divide into its related logical categories.
• "views" folder stores the front end data in it.
• "controllers" folder stores the specific route controlling functions. These functions are then exported into routes folder. They are basically the list of functions which controls the specific page's behaviors.
• "models" folder stores the "users.json" file which has all the usernames and user ages. These info is pulled by "/display/users" page.

Notes:

• In "req.body.myFormInput", "myFormInput" is extracted from forms. You can also extract all form inputs with "req.body" only.
• In "req.params.myLink", "myLink" is extracted from the entered link. for example in "http://localhost:3000/:myLink", "myLink" is a dynamic link. For more info, check "router.get("/products/:productId", shopController.getProduct);" in the project. You can also extract all parameters with "req.params" only.
• "req.query.myQuery" gives the "myQuery" info. For example when we enter "http://localhost:3000/products?myQuery=true", "req.query.myQuery" will return "true". The extracted value will always be a string. For more info, refer to "router.get("/edit-product/:productId", adminController.editProduct);" in the project.

Database (MongoDB):

• MongoDB is used for this project. "mongodb" and "uuidv4" packages are needed to be installed from "npm" for access to the database.

• environmental variables used for this project. I put these variables inside

URL="mongodb+srv://UserName:[email protected]/DBName?retryWrites=true&w=majority"
EXPRESS_SESSION_KEY="your-secret-key"

• Mongoose-Connect-Database
  Basically, "./Model/database/dbConnection.js" is used in "./index.js" to connect to database.
• MongoDB-Create-And-Associate-Models
  "./Model/database/dbAssociation.js" is used in ./index.js so that all model associations and models are properly set. We need to only import dbAssociations.js in index.js.
• Express-Session-Keep-Cookie-in-req.session
  express-session is a package and it keeps some session files in it so the selected admin will be known by the system.
• Mongoose-Queries All query related info kept inside "/Model/tables/orderTable.js", "/Model/tables/productTable.js" and "/Model/tables/userTable.js".
• Mongoose-Populate This is a method that is supposed to work but I could not get it working in this project. Gives me null because I did not properly define it.

Also the following methods work with find, findOne, findById and findOneAndUpdate methods as stated in the picture down below.

const user = await User.findById(userId).populate("productId");

// Basically it says only show userName, userAge as a result
// but populate the productId section by pulling the _id of the Product model
// also only populate it with productName and no other details of that product.
const user = await User.findById(userId).select("userName", "productId", "productName").populate("productId", "productName");

Solution: it means here that productId is directing us to "_id" field of Product Model. Basically it searches through User model and tries to find User._id === userId. Also populates the productId by finding Product._id === productId then puts all product details under that user as well.