Kotlin-Ktor and postgres backend

Introduction

Here lays a demonstration of my growing interest in Kotlin language and Ktor server framework. It's an example with complex Graph algorithms.

Flow

To start the application you need to:

deploy the docker compose
sign up to the system /signup
log in to get access token /login
send post request with token to /hirearchy to create the hierarchy of the organization
send post request with token to /hierarchy/{name}/supervisors to get the supervisors of the user

Starting the application

Go to the root directory of the project and deploy the application with following command:

docker-compose up

for shutting down the deployment:

docker-compose down -v

You might need root user access as well

What it does?

We have REST API to post the JSON below. This JSON represents an Person -> Person relationship that looks like this:

{
   "Pete": "Nick",
   "Barbara": "Nick",
   "Nick": "Sophie",
   "Sophie": "Jonas"
}

In this case, Nick is a supervisor of Pete and Barbara, Sophie supervises Nick. The supervisor list is not always in order.

   curl --request POST -sLv \
        --url 'http://localhost:3000/hierarchy' \
        --header "Content-Type: application/json" \
        --header "Authorization: Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJhdWQiOiJodHRwOi8vMC4wLjAuMDo4MDgwL2hpZXJhcmNoeSIsImlzcyI6Imh0dHA6Ly8wLjAuMC4wOjgwODAvIiwiZXhwIjoxNjUwNDkwNzUwLCJ1c2VybmFtZSI6ImphbmUifQ.Xfn4JEOHo-Px7vy0TVyo3malCFlj3eFvzAJejqlefPM" \
        --data '{"Nick":"Barbara","Barbara":"Nick","Elias":"Levi"}'

The response to querying the endpoint where the root is at the top of the JSON nested dictionary. For instance, previous input would result in:

      curl --request GET -sLv \
           --url 'http://localhost:3000/hierarchy' \
           --header "Content-Type: application/json" \
           --header "Authorization: Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJhdWQiOiJodHRwOi8vMC4wLjAuMDo4MDgwL2hpZXJhcmNoeSIsImlzcyI6Imh0dHA6Ly8wLjAuMC4wOjgwODAvIiwiZXhwIjoxNjUwNDkwNzUwLCJ1c2VybmFtZSI6ImphbmUifQ.Xfn4JEOHo-Px7vy0TVyo3malCFlj3eFvzAJejqlefPM"

the response will be:

{
 "Jonas": {
   "Sophie": {
     "Nick": {
       "Pete": {},
       "Barbara": {}
     }
   }
 }
}

Query for a specific Person it's the hierarchy:

curl --request GET -sLv \
     --url 'http://localhost:3000/hierarchy/Nick/supervisors'\
     --header "Content-Type: application/json" \
     --header "Authorization: Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJhdWQiOiJodHRwOi8vMC4wLjAuMDo4MDgwL2hpZXJhcmNoeSIsImlzcyI6Imh0dHA6Ly8wLjAuMC4wOjgwODAvIiwiZXhwIjoxNjUwNDkwNzUwLCJ1c2VybmFtZSI6ImphbmUifQ.Xfn4JEOHo-Px7vy0TVyo3malCFlj3eFvzAJejqlefPM"

the response of the query will be:

{ "Nick": {
     "Sophie": {
       "Jonas": {}
     }      
  }
}

Sophie is the supervisor of the Nick and Jonas is supervisor of the supervisor of the Nick

It's secured by JWT authentication

      curl --request POST -sL \
           --url 'http://localhost:3000/signup'\
           --header "Content-Type: application/json" \
           --data '{"username":"jane","password":"doe"}'

      curl --request POST -sL \
           --url 'http://localhost:3000/login'\
           --header "Content-Type: application/json" \
           --data '{"username":"jane","password":"doe"}'

The response will be the access token

       {"token":"eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJhdWQiOiJodHRwOi8vMC4wLjAuMDo4MDgwL2hpZXJhcmNoeSIsImlzcyI6Imh0dHA6Ly8wLjAuMC4wOjgwODAvIiwiZXhwIjoxNjUwMTU3NjIxLCJ1c2VybmFtZSI6ImpvaG4ifQ.LSJUte7oy9Kv7qkozI3APBzPxHVZ56GID-n0lRIKvdY"}

Also, you can use following Postman JSON collection file and test the application from Postman

To deploy the test environment and test the application: