Chat App

Installation

In order to get the app running follow the steps listed below:

Make sure you have docker installed locally on your machine.
Make sure to have docker-compose installed locally on your machine.
after dowing the above steps clone the app from this repo.
after cloning open the terminal, run cd chat_app
after being in the repo directory in your machine run docker-compose up
the app should be running on http://localhost:5000/
run docker container exec -it chat_app_api_1 /bin/bash in a new window.
run rails db:setup to create the databases and seed.
the app has seeds to help you test manually (see sections below)
if you needed to reindex the messages table run rails c then Messages.reindex (you can also use searchkick tasks out of the console)

Stack Used in this Demo and the why behind it.

Stack Used:

Ruby On Rails for the apis.
Mysql as the relational storage.
SideKiq for background processing.
Elastic search for doing full text search.
Redis for performance opmization along with Sidekiq.

Why

For the purpose of this demo I used Redis and Sidekiq to perform queueing for tasks in the back-end while compared to using queues like RabittMq or SQS and their better persistent for messages I used redis since this is a demo. Of course queues like fifo queues in this case would be a better choice specially if another languages or apps are used for handling part of the requests. also they are more reliable than redis.

I wish I could use GOLang, or Elixir for handling the parallel requests because of their great support for concurrency, But since I do not have perior expiernce with them and not having time to learn them due to my busy scheule I decided to make all requests handled by the ROR api and handled as much as race conditions as possible.

I'm a big fan of GO, Elixir, and Rust so learning them would be a joy as they do complement areas where ruby is not an option in them. Keep an eye on this repo, as when I learn Go, or Elixir I will be writing a new version of it with them.

Further Imporvements to the current stack

Using Go, or Elixir, plush adding a Queue server for communicating with the Go app.

Further Improvements to the app.

No serializtion currently done nor pagination. so futher adding draper, active_model_searilazer or any better alternative will an option to provide serilazation out of the box and remove the none DRY current serialzation which is currently fine for the app size. Adding authentication and enriching the app with other features would be the next step as needed.

the application is composed of there main entities subject which has many chats which in turn has many messages

Api end points:

No authentication is made yet in the app so you can try GET requests in the browser directy, and use curl for other requests.

GET /subjects for retriving the subjects from the api (no pagination yet is done in the app)
POST /subjects for creating subjects, the returned response will be a json object containing the token. you have to send the subject name in the payload.
POST /subjects/:subject_token/chats for creating a chat in a specific topic. The order of the chat will be returned and same applies when creating messages.
GET /subjects/:subject_token/chats/:order for showing a chat in a subject using its order (its number in the subject it belongs to)
DELETE /subjects/:subject_token/chats/:order for deletig a specific chat.
GET /subjects/:subject_token/chats/:order/search for searchin for messagins within a chat by body text ( body should be passed as query parameter)
POST /subjects/:subject_token/chats/:chat_order/messages for creating a message. payload must contain a body for the message.
PUT /subjects/:subject_token/chats/:chat_order/messages/:order for updating a message in a specific chat.
DELETE /subjects/:subject_token/chats/:chat_order/messages/:order for deleting a message.

Testing

Most of the app has tests as most of it was written using TDD.

Convention within specs

When adding specs make sure to refer to the chat subject as topic to elminate the confusion with rspec's subject variable. This is the current convention we use in this app when writting tests.

how to run the tests

to run the tests follow the folling steps.

open a new terminal window from your cloned repo directory.
make sure to run docker-compose up -d
run docker container exec -it chat_app_api_1 /bin/bash
run rspec
you can do the last two step at once by running this command docker container exec -it chat_app_api_1 rspec

Plans for making the tests better

using the swagger gem for testing apis and generating docs will be a next step.
no automated tests currently done for load testing the app api for race conditions, so this would an important add on.
adding testprof gem for keeping anlysis about the app so we can use to enhance tests speed the more we add tests.
adding more tests coverage to models and areas that do not have tests yet.

Abdullah-F / chat_app