landschaften-service

landschaften-service is a Haskell service for landschaften, the visual explorer for paintings and their concepts.

It uses Stack for the build tool and Servant for the server and API.

Preparing to run the app

If you've never the run the app before, you will need to initialize it.

stack setup 
stack init

After initialization, run a one-time compilation and test:

stack test --fast

Running app locally

Set ENV variables and run the app

This Haskell app uses Stack, which defaults to a pure nix environment, where env-vars are not available.

To enable them, we pass the --no-nix-pure flag when starting the app (exec landschaften-servce).

$ export PORT=8080 
$ export DB_URL="postgresql://localhost:5432/bilder" 
$ stack --no-nix-pure exec landschaften-service

... PORT and DB_URL above are examples; be sure to use your own :)

Confirm app is running properly by making a CURL request

To confirm that it works by making a CURL request.

http://localhost:8080/query -X POST -H "Content-Type: text/plain; charset=utf-8" --data "{\"constraints\": [ {\"column\": \"timeframe\", \"values\": [\"1501-1550\"]}, {\"column\": \"school\", \"values\": [\"French\", \"Italian\", \"Spanish\", \"German\"]}, {\"column\": \"name\", \"values\": [\"scarf\", \"deer\"]}]}"

Run tests (Hspec)

Tests are defined as specs, per Hspec.
The hspec-discover pragma (see test/Spec.hs) will discover and run any specs.

There are several ways to run the tests.

Compile app and run tests once:

stack test --fast

Alternatively, enter the ghci and reload changes and rerun tests as often as you like:

stack exec ghci test/Spec.hs

Once in the ghci, use :r to reload app changes and :main to run the tests.

Recompiling during development (Steel Overseer)

I recommend using Steel Overseer to recompile upon source code changes.

The app's own steel-overseer file is .sosrc:

- patterns:
  - .*\.hs$
  - ^my-thing.cabal$
  - ^stack.yaml$
  commands:
  - stack build
  - stack exec landschaften-service