cards-http-service

A simple demo of a stateful REST API service for a deck of cards.

API

A few of the POST endpoints are duplicated as GET endpoints to simplify testing in a browser. For example, it is possible to return a card by hitting GET /cards/return?card=qd in a browser, rather than using curl (or similar).

Session management

The service maintains a unique session for each browser client that connects to it. The sessions are maintained by setting the "session" cookie. Each session corresponds to a unique deck of cards view for the client. This is currently not going to work if the cookies are not enabled.

Session persistence

The sessions can be optionally persisted through server restarts:

./cards-http-service --sessions-persist-to path/to/file --sessions-restore-from path/to/file

The service will attempt to parse the --sessions-restore-from file on startup and restore sessions from it. On shutdown, the service will write sessions to the --sessions-persist-to file. This mechanism is not foolproof (it will not work if the service hard-crashes). However, it should take care of most other cases.

A valid sessions persistence file will look something like the one below (session-id serialized-deck-string):

LnLgk_JPEZpRRtW9I5TUoM8M229EzcWTrmtz49YY4J4= thjhqhkhad2d3d
_yxvxLANbcXLPbPbKsPDZ2LLLS7gtzuozhQ0VYiLCZ8= 6c7c8c9ctcjcqckcah2h

Install & run

go install github.com/AntonAverchenkov/cards-http-service
$GOPATH/bin/cards-http-service

Alternatively, the service can be run from docker:

docker build -t cards-http-service .
docker run -it -p 127.0.0.1:8080:8080/tcp cards-http-service

Testing

Unit tests

go test -short -v ./...

Integration tests

The following will run integration tests inside of the test-client container. The test-client will send requests to the service running in cards-http-service and assert that the responses are as expected within an internal network.

docker-compose -f integration_test.compose.yaml up -d
docker-compose -f integration_test.compose.yaml exec test-client go test
docker-compose -f integration_test.compose.yaml down

Testing in browser

Try the following endpoints in one or more browser clients:

• http://localhost:8080/
• http://localhost:8080/cards
• http://localhost:8080/cards/shuffle
• http://localhost:8080/cards/deal
• http://localhost:8080/cards/return?card=ac

Short-form card encoding for /cards/return endpoint

The /cards/return?card={card} endpoing accepts both the long-form and the short-form representations of a card. For example, to return jack of spades to the deck either of the following will work:

• /cards/return?card=jack%20of%20spades
• /cards/return?card=js

Below is the full list of card suits and values, along with their short-form representations:

Suit	Short
clubs	c
diamonds	d
spades	s
hearts	h

Value	Short
ace	a
two	2
three	3
four	4
five	5
six	6
seven	7
eight	8
nine	9
ten	t
jack	j
queen	q
king	k