Convexter is a simple currency conversion API.

Implementation of a Rest API for conversion between a pair of currencies using the external currencylayer service.

Requiments:

1. Must be able to use the free version of the currencylayer api
2. The base coin from the API is the USD
3. Transactions should persist in the database having the following schema in the [POST]/conversion:
   • user_id
   • origin_currency
   • target_currency
   • conversion_tax
   • timestamps
4. The success transaction must have the following response:

{
    "transactionId": "value",
    "userId": "value",
    "originCurrency": "value",
    "targetCurrency": "value",
    "originValue": 0.00,
    "targetValue": 0.00,
    "conversionTax": 0.000,
    "conversionDateTime": "0000-00-00 00:00:00.000000",
    "total_value": "0.00"
}

5. Besides an endpoint to create a conversion, the following endpoints should exist:
   • [GET]/conversions
   • [GET]/conversions/:user_id

NOTE

One of the new implementations of the api it's the conversion_tax that is the tax of the given conversion on top of the external API, in an example, the conversion from 10 USD to BRL is 100 BRL, but the conversion tax is 0.10 (10%), the total value will be 110 BRL.

The API uses the following schema as a service to get a new conversion from the external API

Since this repo uses the free version of gigalixir which has a small pool size, the migrations are not used in github actions and instead should be run manually by the command gigalixir ps:migrate -a $APP_NAME, after any deploys with new migrations you should wait for the full deploy cycle and run the command above.

The repo uses the following schema as a CI/CD for new merges into master

The demo of this application can be found deployed at Gigalixir, it's using the Free Tier version, the app url can be found at https://convexter.gigalixirapp.com/.

In the Insomnia_collection.json you can change the enviroment to gigalixir and try it out.

To start your Convexter server:

• Clone this repository with git clone https://github.com/er-jpg/convexter.git
• Edit .env.example to use your currencylayer API Access Key
• Rename .env.example to .env
• Export your enviroment to bash using export $(cat .env | sed 's/#.*//g' | xargs)
• Install dependencies with mix deps.get
• Create and migrate your database with mix ecto.setup
• Start Phoenix endpoint with mix phx.server or inside IEx with iex -S mix phx.server

Import the Insomnia colletion in Insomnia_collection.json and run the endpoints with the given examples.

To run tests in your application:

• Run mix test

To check test coverage in code:

• Run mix coveralls

The current test coverage in the application is

COV    FILE                                        LINES RELEVANT   MISSED
  0.0% lib/convexter.ex                                9        0        0
 80.0% lib/convexter/application.ex                   41        5        1
100.0% lib/convexter/currencylayer_api.ex             13        1        0
  0.0% lib/convexter/currencylayer_api/behaviou        4        0        0
  0.0% lib/convexter/mailer.ex                         4        0        0
  0.0% lib/convexter/repo.ex                           5        0        0
 65.0% lib/convexter/transaction.ex                  159       20        7
 93.3% lib/convexter/transaction/convert.ex           56       15        1
  0.0% lib/convexter_web.ex                           78        1        1
 81.8% lib/convexter_web/controllers/convert_co       39       11        2
 50.0% lib/convexter_web/controllers/fallback_c       24        2        1
  0.0% lib/convexter_web/endpoint.ex                  48        0        0
  0.0% lib/convexter_web/gettext.ex                   24        0        0
 80.0% lib/convexter_web/router.ex                    45        5        1
 80.0% lib/convexter_web/telemetry.ex                 72        5        1
100.0% lib/convexter_web/views/changeset_view.e       19        2        0
100.0% lib/convexter_web/views/convert_view.ex        26       12        0
 66.7% lib/convexter_web/views/error_helpers.ex       33        3        1
100.0% lib/convexter_web/views/error_view.ex          16        1        0
  0.0% test/support/channel_case.ex                   36        3        3
100.0% test/support/conn_case.ex                      39        3        0
 50.0% test/support/data_case.ex                      51        6        3
100.0% test/support/fixtures/transaction_fixtur       25        2        0
[TOTAL]  77.3%

Run code analysis with strict mode:

• Run mix credo

Points to be refactored

• user_id param in [GET]/conversions/:user_id should be a query param
• diagram of the API concept in README
• CI/CD diagram of the application
• more explict desciption of new features
• remove logic from view

• Official website: https://www.phoenixframework.org/
• Guides: https://hexdocs.pm/phoenix/overview.html
• Docs: https://hexdocs.pm/phoenix
• Forum: https://elixirforum.com/c/phoenix-forum
• Source: https://github.com/phoenixframework/phoenix

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