TodoApi api

I have a policy that if I'm doing take home challenges, I use them as an oportunity to learn something. With that in mind, I have implemented a graphql api using phoenix 1.3 beta and absinthe, a graphql library for elixir.

The Api covers the following features

1. signup as a user
2. signin as the user (jwt based)
3. creating todos
4. viewing all todos
5. deleting todos
6. adding labels to a todo
7. removing a label from a todo

I also added a reasonable amount of unit test coverage to make sure everything runs smoothly.

There are 3 database tables Users have many todos and todos have many labels. Instead of having labels belong to many through a join table, I opted instead to have each label belong only to a single todo and use a compound unique constraint to ensure database integrity.

I rather like the gmail system of labels so instead of strict groupings, you can apply tags to a todo. a todo can have multiple tags and multiple todos can have a tag. We can query based on the inclusion of said tags.

The top level is an umbrella app with two subapps.

todo_api contains the database validation logic for the application.

todo_api_web contains the graphql specific parts. I also stubbed out a webpack frontend build system.

Setup

You're going to need to install the latest elixir as well as postgresql

brew install elixir

once you clone the repo, you need to install the dependencies

mix deps.get

From there you'll need to modify apps/todo_api/config/dev.exs for your database settings

# Configure your database
config :todo_api, TodoApi.Repo,
  adapter: Ecto.Adapters.Postgres,
  username: "postgres",
  password: "postgres",
  database: "todo_api_dev",
  hostname: "localhost",
  pool_size: 10

Unfortunately, phoenix1.3 is still in beta, you'll need to cd into the database sub application to run the database tasks.

cd apps/todo_api/
mix ecto.reset

This will create a user in the database which you can login with

email: "[email protected]",
password: "foobar677",

to run the server

mix phx.server

runnign the tests

once you've edited the apps/todo_api/config/test.exs file, you can fun the tests.

mix test

sample queries

Note: You'll need an app like graphiql to test the queries.

Signup

mutation Signup {
  signup(email: "[email protected]", password: "ferngully", password_confirmation: "ferngully") {
    id
    email
    jwt
  }
}

Signin

mutation Signin {
  signin(email: "[email protected]", password: "ferngully") {
    id
    email
    jwt
  }
}

Note: the rest of the endpoints require a jwt header. I had to impliment a custom jwt handler to give a graphql appropriate response. you can see it in apps/todo_api_web/lib/jwt_manager.ex. Once you get the jwt, you'll need to set your http header Authorization: "Bearer #{jwt}".

Create a todo

mutation CreateTodo {
  createTodo(content: "go sleading", description: "nothing", labels: ["yoloswag", "going awesome"]) {
    id
    content
    description
    done
    labels {
      id
      text
    }
  }
}

Update a Todo

mutation UpdateTodo {
  updateTodo(id:"9661b898-205b-4ca8-9ef7-d6c98d71146f", done: true) {
    id
    content
    description
    done
  }
}

Delete a todo

mutation DeleteTodo {
  deleteTodo(id:"c4a82f70-5956-493a-a122-d627b545b2f7") {
		id
  }
}

note id is the TODO id, not the label

Add a label to a todo

mutation AddLabel {
	addLabel(id: "ff04ca18-2af8-4c66-93a9-5fcf79695fba", label: "buffoon") {
    id

  }
}

removing a label

mutation RemoveLabel {
	removeLabel(id: "ff04ca18-2af8-4c66-93a9-5fcf79695fba", label: "buffoon") {
    id

  }
}

finding all the todos

{
  todos {
    id
    content
    description
    done
    labels {
      id
      text
    }
  }
}

with labels (for grouping)

{
  todos(labels: ["yoloswag"]) {
    id
    content
    description
    done
    labels {
      id
      text
    }
  }
}