RESTful API with Node.js, Express and Postgres running in Docker

Create, read and update in a Node.js app with an Express server and Postgres database. The app is running in Docker container.

Getting Started

These instructions will get you a copy of the project up and running on your local machine for development and testing purposes.

Prerequisites

To run this project, you need to have:

  Docker for Desktop

You can download here: https://www.docker.com/

Installing and Running

• git clone git@github.com:SoutisV/RESTful_api_Docker.git
• cd root_directory_of_project
• sudo docker-compose up --build

The sudo docker-compose up --build will bring up the RESTful API and the Postgres database.

Building details

In docker-compose.yml we set up two services named api and postgres. The api is dependent on postgres.

In docker-compose.yml we also use a volume named my_dbdata for storing the database data. Even if the container and image are deleted, the volume will remain unless explicitly deleted using sudo docker system prune --volumes.

Also, during this very first build of the application, an initialization script is used for the db. It is located again in docker-compose.yml, it is called init.sql and it runs only during the first build. If you want to re-populate the Postgres db you have to delete the volume with sudo docker system prune --volumes and bring up the project again with sudo docker-compose up.

The state of the db after the init.sql looks like this: initial_state

GET Routes

• visit http://localhost:3000 , where also the README file is present.
  • /nodes , lists all available nodes
  • /node/:id , list info of specified node
  • /children/:id , list children of specified node
  • /descendants/:id , list all descendants of specified node

Running GET requests

For my GET requests i used postman : https://www.getpostman.com/downloads/ . Alternatively, you can visit in the web browser also the following URLs:

• http://localhost:3000/nodes , lists all available nodes
• http://localhost:3000/node/9 , lists info regarding node 9
• http://localhost:3000/children/3 , lists all children of node 3 (node6 and node7 of the initialized db)
• http://localhost:3000/descendants/3 , lists all descendants of node3 (node3,node6,node7,node8,node9,node10,node11 and node12 of the initialized db).

The difference between GET /children/:id and GET /descendants/:id is that the first one returns only the children of the specified node whereas the second one returns the children of a node together with all the descendants of the children of a node.

You can also curl the requests from the terminal:

• curl -v http://localhost:3000/nodes
• curl -v http://localhost:3000/node/9
• curl -v http://localhost:3000/children/3
• curl -v http://localhost:3000/descendants/3

PUT Route

• /nodes/:id , update an existing node and put it under a new parent.

It is worth noting that PUT is idempotent, meaning the exact same call can be made over and will produce the same result. This is different that POST, in which the exact same call repeated will continuously create new nodes.

Also, when a node is updated and moved under a new parent, it's descendants are also moved and dynamically adjusted with new height. Let's do our first update...

Running our first PUT request

In case you want to use postman:

• URL: http://localhost:3000/nodes/7
• Method: PUT
• Body: x-www-form-urlencoded
• Body Key: new_parent
• Body Key Value: 8

In case you want to use curl from terminal:

• curl -v -X PUT -d "new_parent=8" http://localhost:3000/nodes/7

This method will move node 7 and all it's descendants under node 8. Heights will be adjusted. Here is how it looks like now: update_state

You can check it:

• curl -v http://localhost:3000/descendants/8

POST Route

• /nodes , will create a new node under an existing parent. If a new parent is not provided then, the new node will be added as root.

Running our first POST request

In case you want to use postman:

• URL: http://localhost:3000/nodes
• Method: POST
• Body: x-www-form-urlencoded
• Body Key: new_node
• Body Key Value for new_node: 13
• Body Key: new_parent
• Body Key Value for new_parent: 8

In case you want to use curl from terminal:

• curl -v -d "new_node=13" -d "new_parent=8" http://localhost:3000/nodes

This method will add a new node 13 under existing node 8. Here is how it looks like now: post_state

You can check it:

• curl -v http://localhost:3000/descendants/8

Running POST request for adding a new root

In case you want to use postman:

• URL: http://localhost:3000/nodes
• Method: POST
• Body: x-www-form-urlencoded
• Body Key: new_node
• Body Key Value for new_node: 55

In case you want to use curl from terminal:

• curl -v -d "new_node=55" http://localhost:3000/nodes

As you can notice there is no body key new_parent. That means a new node 55 is added as root!

This method will add a new node 55 as root. Here is how it looks like now: root_state

You can check it:

• curl -v http://localhost:3000/descendants/55 , which is the same as
• curl -v http://localhost:3000/nodes

Docker commands that might come handy

All docker commands must be executed from the project directory.

• sudo docker-compose up --build , run the project and build a new image
• sudo docker-compose up , run the project without building a new image
• sudo docker system prune --volumes , deletes all volumes. Useful when you want to run the init.sql and re-populate the db with initial data.
• sudo docker image prune -a, remove all docker images
• sudo docker container ls -a, list all docker containers
• sudo docker images -a, list all docker images

Each time you want to run the project:

• sudo docker-compose up , inside the project directory