IHP – A Haskell web framework

IHP is a modern batteries-included haskell web framework, built on top of Haskell and Nix.

We believe that functional programing is the future of software development and want to make functional programing with haskell and nix available to anyone. We try to offer a solution which can be used by developers who have not worked with haskell yet. IHP comes with everything you need to build great web applications with haskell and nix. We have made a lot of pragmatic decision to get you started faster. This way you can just pick up haskell along the way :slight_smile:

IHP stands for Integrated Haskell Platform.

This thread was posted by one of our members via one of our automated news source trackers.


Just watching this now… looks pretty neat (and different!) you add tables and columns via the web gui - you even create controllers via it, don’t think I’ve seen that in a web framework before:

1 Like

Example controller

module Web.Controller.Posts where

import Web.Controller.Prelude
import Web.View.Posts.Index
import Web.View.Posts.New
import Web.View.Posts.Edit
import Web.View.Posts.Show
import qualified Text.MMark as MMark

instance Controller PostsController where
    action PostsAction = do
        posts <- query @Post
            |> orderByDesc #createdAt
            |> fetch
        render IndexView { .. }

    action NewPostAction = do
        let post = newRecord
        render NewView { .. }

    action ShowPostAction { postId } = do
        post <- fetch postId
            >>= pure . modify #comments (orderByDesc #createdAt)
            >>= fetchRelated #comments
        render ShowView { .. }

    action EditPostAction { postId } = do
        post <- fetch postId
        render EditView { .. }

    action UpdatePostAction { postId } = do
        post <- fetch postId
            |> buildPost
            |> ifValid \case
                Left post -> render EditView { .. }
                Right post -> do
                    post <- post |> updateRecord
                    setSuccessMessage "Post updated"
                    redirectTo EditPostAction { .. }

    action CreatePostAction = do
        let post = newRecord @Post
            |> buildPost
            |> ifValid \case
                Left post -> render NewView { .. } 
                Right post -> do
                    post <- post |> createRecord
                    setSuccessMessage "Post created"
                    redirectTo PostsAction

    action DeletePostAction { postId } = do
        post <- fetch postId
        deleteRecord post
        setSuccessMessage "Post deleted"
        redirectTo PostsAction

buildPost post = post
    |> fill @["title","body"]
    |> validateField #title nonEmpty
    |> validateField #body nonEmpty
    |> validateField #body isMarkdown

isMarkdown :: Text -> ValidatorResult
isMarkdown text =
    case MMark.parse "" text of
        Left _ -> Failure "Please provide valid Markdown"
        Right _ -> Success

Lot of unusual looking syntax :man_shrugging:


Added the IHP portal :nerd_face: