Sketch

Client-server system representing an ASCII art drawing canvas. It implements:

• JSON based RESTful endpoint
• Two canvas operations - rectangle drawing and flood-fill
• Erlang DETS based canvas persistence mechanism (no DB needed!)
• Phenix LiveView based client (read only)

Install and run locally

• Clone repo with git clone https://github.com/Kociamber/sketch.git (or unzip the package if you got it from Joanna ;])
• Enter the folder (cd sketch) and perform required setup with mix setup
• Start the endpoint with mix run or iex -S mix phx.server (with interactive console)

Usage

To access LiveView based client visit localhost:4000 from your browser.

After the setup your local storage is empty - you can quickly create (an assignment test fixture based) canvas you can run the seedfile with mix seed.

To "clear" your storage run mix clear_storage or simply delete sketch_storage file from the project's root directory.

Browser's routes:

    /      - shows all locally stored canvases
    /:id   - shows a specific canvas

JSON endpoint requests routes:

• post /canvas: creates, persists and returns empty canvas, no body params required
• get /canvas: returns a list of currently stored canvases
• get /canvas/:id: returns canvas by id, no body params required
• put /canvas/:id: performs flood or rectangle draw operation, returns "updated" canvas (requred body params below)
• delete /canvas/:id - removes canvas and returns deleted structure, no body params required

Body params required for put (canvas drawing operation) - drawing rectangle:

{"operation":"rectangle","x":7, "y":10,"width":40,"height":15,"fill_char":"#", "outline_char":"+"}

• all params are mandatory (besides fill_char and outline_char - only one of them must be present)
• all numeric values must be integers greater than or equal 0
• fill_char and outline_char can be only strings of length 1

Flood operation required params:

{"operation":"flood","x":3, "y":3,"fill_char":"7"}

• all params are mandatory
• all numeric values must be integers greater than or equal 0
• fill_char can be only a strings of length 1

The server is performing request parameters validation and in case of missing or incorrect values json error message is being returned.

Sample API calls

Get a list of all stored canvases:

curl -H "Content-Type: application/json" -X GET http://localhost:4000/api/canvas/

Create new canvas:

curl -H "Content-Type: application/json" -X POST http://localhost:4000/api/canvas/

Get canvas by id:

curl -H "Content-Type: application/json" -X GET http://localhost:4000/api/canvas/:canvas_id

Perform rectangle drawing operation:

curl -H "Content-Type: application/json" -X PUT -d '{"operation":"rectangle","x":1, "y":2,"width":5,"height":5,"fill_char":"#"}' http://localhost:4000/api/canvas/:canvas_id

Perform fill-flood operation:

curl -H "Content-Type: application/json" -X PUT -d '{"operation":"flood","x":3, "y":2,"fill_char":"^"}' http://localhost:4000/api/canvas/:canvas_id

Remove canvas from the storage:

curl -H "Content-Type: application/json" -X DELETE http://localhost:4000/api/canvas/:canvas_id

Return JSON structure

All operations are returning a canvas of following structure:

{"canvas":{"content":{"0":{"0":"-","1":"-","2":"-","3":"-","4"},...,"id":"ee25fbec-2767-11eb-8a6f-784f436f155b"}}}