🚀 Nestjs BareBones Controllers & ReqObjects

🧩 features

typescript(disciplined)

oops(SOLID principles)

scalable/testable/loosely coupled production grade architecture boilerplate setup

👶 steps(understanding the blueprint)

npm i -g @nestjs/cli

            # cmd line
            nest -v

            # config your nest backend
            nest new nest-basics-api

            # choices
            npm or yarn or pnpm

**app.module.ts is the root of the api**

**everything is imported inside app.module and then this is exported and bootstrapped inside main.ts to create the nest backend**

🔧 building the api

1. 📩 Controllers

**Handles incoming request from client and sends back response**

** ✏ never write the buisness logic inside the controllers**

In nest we define controllers via decorators that provide meta data about what functionality a particular code block will have

**the access decorators import @nestjs/common**

Controllers
                    |- student.controller.ts

            # student.controller.ts
            import { Controller } from @nestjs/common

            # Controller will tell nest that this is a controller based class

            @Controller('students')
            class StudentController {

            }

**every single route inside studentController is going to start as /students**

**it can be specified with a @Get() decorator that this is a get request**

@Get()
            getStudents(){
                // return all students data
            }

**make sure to import the student.controller.ts inside the app.module.ts**

✔ running dev server first time

npm run start:dev
                # make sure the main.ts is just under the src directory

nested routes like /students/:studentId

            @Get('/:studentId')
            getStudentById(){
                return "Get Student By Id"
            }

🐱‍🚀🐱‍🚀🐱‍🚀TIRED OF REPETATIVE CONTROLLERS SETUP🐱‍🚀🐱‍🚀🐱‍🚀

Creating controllers through nestcli 🐱‍👤

https://docs.nestjs.com/controllers

            nest g controller <controllerName> --no-spec
            # only add --no-spec flag if you dont need unit test file for this controller

best practice is to put similir prefix routes in seprate controller

# to run tests
                npm run test:watch

2. Request Objects (extracting pieces of info from request like params)

make use @param () decorator in Nest for GET

# student object in student ID
                @Get('/:studentId')
                getStudentById(
                    @Param () params: {studentId: string}
                ) {
                    console.log(params)
                    return 'Get Student By Id';
                }

further it can be simplified while the required params can be destructured at the time of decorator defination

            # @Param('destructuredObjectFromParams')
            @Param ('studentId') studentId: string
            console.log(studentId)

make use @Body () decorator in Nest for POST

@Post()
                createStudent(
                    @Body() body
                ) {
                    return `Create's New Student with details\n ${JSON.stringify(body)}`;
                }

use @Body & @Parma together for PUT

@Put('/:studentId')
                updateStudentById(
                    @Param('studentId') studentId: string,
                    @Body() body
                ) {
                    return `Update's\n student id: ${JSON.stringify(studentId)}\n with new data ${body}`;
                }

Further their are @Query, @Session, @Next and @ip() that can be useful refer- https://docs.nestjs.com/controllers#request-object

@Put('/:studentId')
                updateTeacherOfStudentById(
                    @Param('teachersId') teachersId: string,
                    @Param('studentId') studentId: string,
                    @Ip() clientIP: string 
                ) {
                    return `clientIP: ${clientIP}\nUpdate's Teacher with ID: ${teachersId}\n Associated To Student With Id: ${studentId}`;
                }