# servant-effectful-template

A work in progress Nix starting template for web projects utilizing

- [Haskell](https://wiki.haskell.org/Haskell)
- [Effectful](https://github.com/haskell-effectful/effectful)
- [Lucid](https://github.com/chrisdone/lucid)
- [PostgreSQL](https://www.postgresql.org/)
- [Servant](https://github.com/haskell-servant/servant)

The repository has a simple CRUD implementation of a "Users" API which demonstrates how to use included effects, create your own effects, write/compose HTML using Lucid, and bubble errors to Servant's `ServerError` type.

How to navigate this codebase (as of revision 77131c4a):

- Core
  - Application data types
  - Effect definitions
  - Utility function for lifting IO to effectful's IOE
- Database
  - Database effect handler
  - Table definitons as functions
  - Helper functions for constructing SQL queries
- Handlers
  - Request handlers in the Eff monad
- Logger
  - Logging implementation using the Database effect for logging to PSQL
  - Logging implementation to stdout
- Main
  - Application entry point and initialization
  - Creates a PostgreSQL connection pool to include in the Reader effect
  - Effect stack runner for real database interactions
  - Debugging effect stack that mocks database interactions and logs to stdout instead
- Routes
  - Type level route definitions for Servant
- Views
  - Lucid2 HTML templating and composition functions