zacck-zz / bleacher_reactions

In memory reactions API for a challenge by Andela

BleacherReport

This is a tiny api that handles recording of actions to and in memory database, for fast concurrent reads and supports write atomicity. The project is basically a JSON API backed by an ETS table.

To start your Phoenix server:

• Install dependencies with mix deps.get Now you can visit localhost:4000/api from your browser.

Sampling

With the server running as above you can do a number of actions

1. You can post to localhost:4000/api/react with a JSON payload like the ones below

%{
        "type" => "reaction",
        "action" => "add",
        "content_id" => content_id,
        "user_id" => "some_user_id",
        "reaction_type" => "fire"
      }

or to remove an reaction

 %{
        "type" => "reaction",
        "action" => "remove",
        "content_id" => content_id,
        "user_id" => "some_user_id",
        "reaction_type" => "fire"
      }

2. There is a get endpount at localhost:4000/api/reaction_counts/:some_id This endpoint expect an existing content id and will return a positive count or error, nil in the case of non existing counts

Sample Requests

$ curl --request POST -H 'Content-Type: application/json' --data '{"user_id": "uid", "content_id": "cid", "type": "reaction", "action": "add", "reaction_type": "fire"}' http://localhost:4000/api/react/
{"user_id":"uid","content_id":"cid"}

$ curl --request POST -H 'Content-Type: application/json' --data '{"user_id": "u2id", "content_id": "cid", "type": "reaction", "action": "add", "reaction_type": "fire"}' http://localhost:4000/api/react/
{"user_id":"u2id","content_id":"cid"}

$ curl http://localhost:4000/api/reaction_counts/cid
{"reaction_count":{"fire":2},"content_id":"cid"}

Notes

• This can be greatly improved by making our Cache use structs, this would include making structs of the data at the edges(controllers)
• While this will be fairly performant up to around 30 - 40k requests a second at such a point we need to start considering using constructs such as GENSTAGE as the cache wrapper GenServer could becomea bottleneck and here backpressure would be helpful
• This can be tested more, perhaps property tests to discover the Cache behaviour with random instructions
• The typespecs in this project can be confirmed using something like dialyzer, didnt use it here as it takes time.
• Maybe phoenix is overkill, perhaps a plug endpoint would have sufficed ...

License

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