A Tic-tac-toe data store API

An API to store tic-tac-toe game state and let two players compete across the internet. It allows players to register as users of the API and play against other registered users.

The API does not currently validate game states.

API end-points

Verb	URI Pattern	Controller#Action
POST	/sign-up	users#signup
POST	/sign-in	users#signin
DELETE	/sign-out/:id	users#signout
PATCH	/change-password/:id	users#changepw
GET	/games	games#index
POST	/games	games#create
GET	/games/:id	games#show
PATCH	/games/:id	games#update
GET	/games/:id/watch	games#watch

All data returned from API actions is formatted as JSON.

---

User actions

Summary:

Request			Response
Verb	URI	body	Status	body
POST	`/sign-up`	credentials	201, Created	user
			400 Bad Request	empty
POST	`/sign-in`	credentials	200 OK	user w/token
			401 Unauthorized	empty
DELETE	`/sign-out/:id`	empty	201 Created	empty
			401 Unauthorized	empty
PATCH	`/change-password/:id`	passwords	204 No Content	user w/token
			400 Bad Request	empty

signup

The create action expects a POST of credentials identifying a new user to create, e.g. using getFormFields:

<form>
  <input name="credentials[email]" type="text" value="[email protected]">
  <input name="credentials[password]" type="password" value="an example password">
  <input name="credentials[password_confirmation]" type="password" value="an example password">
</form>

or using JSON:

{
  "credentials": {
    "email": "[email protected]",
    "password": "an example password",
    "password_confirmation": "an example password"
  }
}

The password_confirmation field is optional.

If the request is successful, the response will have an HTTP Status of 201, Created, and the body will be JSON containing the id and email of the new user, e.g.:

{
  "user": {
    "id": 1,
    "email": "[email protected]"
  }
}

If the request is unsuccessful, the response will have an HTTP Status of 400 Bad Request, and the response body will be empty.

signin

The signin action expects a POST with credentials identifying a previously registered user, e.g.:

<form>
  <input name="credentials[email]" type="text" value="[email protected]">
  <input name="credentials[password]" type="password" value="an example password">
</form>

or:

{
  "credentials": {
    "email": "[email protected]",
    "password": "an example password"
  }
}

If the request is successful, the response will have an HTTP Status of 200 OK, and the body will be JSON containing the user's id, email, and the token used to authenticate other requests, e.g.:

{
  "user": {
    "id": 1,
    "email": "[email protected]",
    "token": "an example authentication token"
  }
}

If the request is unsuccessful, the response will have an HTTP Status of 401 Unauthorized, and the response body will be empty.

signout

The signout actions is a DELETE specifying the id of the user to sign out.

If the request is successful the response will have an HTTP status of 204 No Content.

If the request is unsuccessful, the response will have a status of 401 Unauthorized.

changepw

The changepw action expects a PATCH of passwords specifying the old and new.

If the request is successful the response will have an HTTP status of 204 No Content.

If the request is unsuccessful the reponse will have an HTTP status of 400 Bad Request.

---

The sign-out and change-password requests must include a valid HTTP header Authorization: Token token=<token> or they will be rejected with a status of 401 Unauthorized.

Game actions

All games action requests must include a valid HTTP header Authorization: Token token=<token> or they will be rejected with a status of 401 Unauthorized.

All of the game actions, except for watch, follow the RESTful style.

Games are associated with users, player_x and player_o. Actions, other than update, will only retrieve a game if the user associated with the Authorization header is one of those two users. If this requirement is unmet, the response will be 404 Not Found, except for the index action which will return an empty games array.

Summary:

Request			Response
Verb	URI	body	Status	body
GET	`/games[?over=]`	n/a	200, OK	games found
The optional `over` query parameter restricts the response to games with a matching `over` property.			200, OK	empty games
The default is to retrieve all games associated with the user..			401 Unauthorized	empty
POST	`/games`	n/a	201, Created	game created
			401 Unauthorized	empty
			400 Bad Request	errors
GET	`/games/:id`	n/a	200, OK	game found
			401 Unauthorized	empty
			404 Not Found	empty
PATCH	`/games/:id`	empty	200, OK	game joined
			400 Bad Request	errors
			400 Bad Request	empty
PATCH	`/games/:id`	game delta	200, OK	game updated
			400 Bad Request	errors
			404 Not Found	empty

index

The index action is a GET that retrieves all the games associated with a user. The response body will contain JSON containing an array of games, e.g.:

{
  "games": [
    {
      "id": 1,
      "cells": ["o","x","o","x","o","x","o","x","o"],
      "over": true,
      "player_x": {
        "id": 1,
        "email": "[email protected]"
      },
      "player_o": {
        "id": 3,
        "email": "[email protected]"
      }
    },
    {
      "id": 2,
      "cells": ["","","","","","","","",""],
      "over": false,
      "player_x": {
        "id": 3,
        "email": "[email protected]"
      },
      "player_o": {
        "id": 1,
        "email": "[email protected]"
      }
    }
  ]
}

If the over query parameter is specified the results will be restricted accordingly.

If there are no games associated with the user, the response body will contain an empty games array, e.g.:

{
  "games": [
  ]
}

create

The create action expects a POST with an empty body (e.g '' or '{}' if JSON). If the request is successful, the response will have an HTTP Status of 201 Created, and the body will contain JSON of the created game with player_x set to the user calling create, e.g.:

{
  "game": {
    "id": 3,
    "cells": ["","","","","","","","",""],
    "over": false,
    "player_x": {
      "id": 1,
      "email": "[email protected]"
    },
    "player_o": null
  }
}

If the request is unsuccessful, the response will have an HTTP Status of 400 Bad Request, and the response body will be JSON describing the errors.

show

The show action is a GET specifing the id of the game to retrieve. If the request is successful the status will be 200, OK, and the response body will contain JSON for the game requested, e.g.:

{
  "game": {
    "id": 1,
    "cells": ["o","x","o","x","o","x","o","x","o"],
    "over": true,
    "player_x": {
      "id": 1,
      "email": "[email protected]"
    },
    "player_o": {
      "id": 3,
      "email": "[email protected]"
    }
  }
}

update

join a game as player 'o'

This update action expects an empty (e.g '' or '{}' if JSON) PATCH to join an existing game.

If the request is successful, the response will have an HTTP Status of 200 OK, and the body will be JSON containing the game joined, e.g.:

{
  "game": {
    "id": 1,
    "cells": ["","","","","","","","",""],
    "over":false,
    "player_x": {
      "id": 1,
      "email": "[email protected]"
      },
    "player_o": {
      "id": 3,
      "email":
      "[email protected]"
    }
  }
}

If the request is unsuccessful, the response will have an HTTP Status of 400 Bad Request, and the response body will be empty (game cannot be joined, player_o already set or user making request is player_x) or JSON describing the errors.

update a game's states

This update action expects a PATCH with changes to to an existing game, e.g.:

<form>
  <input name="game[cell][index]" type="text" value="0">
  <input name="game[cell][value]" type="text" value="x">
  <input name="game[over]" type="text" value="false">
</form>

{
  "game": {
    "cell": {
      "index": 0,
      "value": "x"
    },
    "over": false
  }
}

If the request is successful, the response will have an HTTP Status of 200 OK, and the body will be JSON containing the modified game, e.g.:

{
  "game": {
    "id": 1,
    "cells": ["x","","","","","","","",""],
    "over":false,
    "player_x": {
      "id": 1,
      "email": "[email protected]"
      },
    "player_o": {
      "id": 3,
      "email":
      "[email protected]"
    }
  }
}

If the request is unsuccessful, the response will have an HTTP Status of 400 Bad Request, and the response body will be JSON describing the errors.

watch

The watch action is handled differently than all the others. Because watch implements a streaming source of data, we'll use a wrapper around the html5 object EventSource to handle the events sent.

You can find the wrapper here. The wrapper is also available from the deployed app at the path /js/resource-watcher-0.1.0.js.

The events that watch implements let you know when a game has been updated. By using this interface you can write code that lets a player see another's move almost as it happens. Updates to the game from one player's browser are sent to the other's browser.

You create a watcher object using the resourceWatcher function. This function takes two parameters, the watch url and a configuration object which must contain the Authorization token, and may contain an optional timeout in seconds, e.g.:

let gameWatcher = resourceWatcher('<server>/games/:id/watch', {
      Authorization: 'Token token=<token>'[,
      timeout: <timeout>]
});

By default, watching a game times-out after 120 seconds.

You should add a handler for change and error events. The error events are not the most informative. The change event may pass to your handler an object with a root key of "timeout" or "heartbeat".

Otherwise, it will pass an object with a root key of "game". Each key in this object will contain an array of length 2. The first element of such an array will contain the value for that key before the update. The last element will contain the value after the update. The code example that follows shows handling the most important case, a change to the game board.

gameWatcher.on('change', function (data) {
  console.log(data);
  if (data.game && data.game.cells) {
    const diff = changes => {
      let before = changes[0];
      let after = changes[1];
      for (let i = 0; i < after.length; i++) {
        if (before[i] !== after[i]) {
          return {
            index: i,
            value: after[i],
          };
        }
      }

      return { index: -1, value: '' };
    };

    let cell = diff(data.game.cells);
    $('#watch-index').val(cell.index);
    $('#watch-value').val(cell.value);
  } else if (data.timeout) { //not an error
    gameWatcher.close();
  }
});

gameWatcher.on('error', function (e) {
  console.error('an error has occurred with the stream', e);
});

License

1. All content is licensed under a CC­BY­NC­SA 4.0 license.
2. All software code is licensed under GNU GPLv3. For commercial use or alternative licensing, please contact [email protected].