Resourcing API

Matthew Chhay's Resourcing API using the Spring Boot framework in Java and MySQL.

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Table of Contents

• Introduction
• Features
• Technologies Used
• Tools Used
• Project Status
• MVP
  • Jobs
  • Temps
  • Payloads
  • Assumptions
• Going beyond the MVP
• Setup
• Requirements
• For launching locally and further development
• Issues discovered during development
  • Problem 1 - PATCH is not supported
  • Problem 2 - PATCH is not updating
  • Problem 3 - Infinite recursion between job and temp relationship
• Room for Improvement

Introduction

An API where consumers can create, update, and fetch jobs or temporary workers. Built using Spring Boot, Java and MySQL.

Features

• Fetch all jobs or temps
• Create a job or a temp
• Fetch all jobs assigned to a temp or not
• A relationship with jobs and temps

Technologies Used

• Java 17 and Maven Project
• Spring Boot 3.0.1
  • Spring Web - build web, including RESTful, applications using Spring MVC
  • Spring Boot DevTools - provides fast application restarts, LiveReload, and configurations for enhanced development experience
  • Spring Data JPA - Persist data in SQL stores with Java Persistence API using Spring Data and Hibernate
  • MySQL Driver - mySQL JDBC and R2DBC driver
  • Validation - bean validation with hibernate validator
• MySQL Workbench
• Postman

Tools Used

• Spring Initializr - create a Spring app
• Postman - test endpoints and methods
• Spring Boot Dashboard VS Code Extension

Project Status

Project is ongoing

MVP

Jobs

Method	URL	Action	Created & works on Postman?
GET	jobs	Fetch all jobs	✓
GET	jobs/{id}	Fetch job by {id}	✓
GET	jobs?assigned={true|false}	Filter jobs by whether a job is assigned to a temp or not	✓
POST	jobs	Create new job	✓
PATCH	jobs/ {id}	Update job by {id}, e.g. assigning a temp to a job	✓

Temps

Method	URL	Action	Created & works on Postman?
GET	temps	Fetch all temps	✓
GET	temps/{id}	Fetch temp by {id}	✓
GET	temps/tree	Fetch whole tree of temps	✗
GET	temps?jobId={jobId}	Fetch temps that are available for a job based on the jobs date range	✓
POST	temps	Create new temp	✓
PATCH	temps	Update temp by {id}, e.g. new name	✓

Payloads

// GET /jobs/{id}
{
	"id": ...,
	"name": ...,
	"startDate": ...,
	"endDate": ...,
	"temp": {
		"id": ...,
		"firstName": ...,
		"lastName": ...,
	} // temp can also be null if a temp hasn't been assigned to the job
}

// GET /temps/{id}
{
	"id": ...,
	"firstName": ...,
	"lastName": ...,
	"jobs": [{
		"id": ...,
		"name": ...,
		"startDate": ...,
		"endDate": ...,
		}, ...] // can be empty if temp hasn't been assigned to jobs
}

Assumptions

• Temps can only have one job at a time (can’t be doing 2 jobs on the same date)
• Temps can have many jobs, and job can have 1 temp assigned
• Should be able to assign existing temps to jobs via POST /jobs & PATCH /jobs/{id}
• Must use a relational database

Going beyond the MVP

• Temps should be able to manage other temps (will require an additional field)
• When you request a temp record it should display the reports of that temp
• Should be represented in the database as a nested set
• GET /temps/tree - should display the whole tree of temps

Setup

Requirements

• Java 17
• MySQL Server

For launching locally and further development

1. Git clone this repo git@github.com:chhaymatt/resourcing-api.git
2. Modify src/main/resources/application.properties file with your device's credentials (e.g. different username or password)
3. Create resourcing database in mysql workbench create database resourcing; on localhost 3306
4. Run ./mvnw spring-boot:run or from file src/main/java/com/matthewchhay/resourcingapi/ResourcingApiApplication.java
5. Confirm API returns "Hello World from Job' by using Postman and GET localhost:9876/jobs/test

Issues discovered during development

Problem 1 - PATCH is not supported

Unable to patch a job and console logs/Postman state the method is not supported.

How did I solve it?

1. Confirmed the job exists by GET /jobs/1
2. Searched online and discovered how to enable debug in application.properties logging.level.root=DEBUG
3. Saw a post online and someone mentioned about them not passing in the {id}
4. Checked the JobController and realised I doubled up on the URL, it was going to /jobs/jobs/1 instead of /jobs/1
5. Removed additional /jobs in the @PatchMapping and error no longer appears

Problem 2 - PATCH is not updating

• Patching a job returns the original job instead of the patched payload

How did I solve it?

1. Enabled debug mode, noticed JobUpdateDTO and compared file with JobCreateDTO
2. Realised missing JobUpdateDTO constructor
3. Added JobUpdateDTO constructor and it is working, considering combining both DTOs into one file

Problem 3 - Infinite recursion between job and temp relationship

API stops working when using a relational database

How did I solve it?

1. Attempt 1: Adding @JsonManagedReference and @JsonBackReference to the entities with the relational field stops infinite recursion because jobs references temp and temp also references jobs, however the entity with @JsonBackReference will not appear in the payload
2. Attempt 2: Adding @JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "id") to both entities allows both fields to appear but not ideal because getting all jobs will show all temps and jobs which is not neat
3. Attempt 3: Replaced @JoinColumn(name = "temp") with @JsonIgnoreProperties(value = { "jobs" }) on the job entity and added @JsonIgnoreProperties(value = { "temp" }) to the temp entity. Issue resolved adopting this annotation/decorator.

Room for Improvement

• Moved HTTP status from the @Service to the @Controller
• A temp cannot assign themselves, e.g. Ashley -> Ashley
• A temp cannot assign themselves through a different temp, e.g. Ashley -> Matt -> Ashley
• Create Factory Seeder for jobs and temps
• Create E2E tests
• Create Github Action to run tests on every commit