Hello World

data Bool = True | False deriving (Eq, Show)

I'm finding the live loading in the browser sometimes dies while I'm editing the code. My setup is on MacOs Mojave/Firefox and I'm editing the haskell code directly using VI/nerdtree. The IHP development server is still running but I'm getting a log of: StatusServer: Cannot stop as not running and the page formatting in the browser isn't updating.Is there a simple way of restarting the Server without killing the development environment and running the start script again?

I was just wondering if an "IHP Forum" Topic would be a good idea? That way any suggestions/improvements for the IHP Forum could be discussed there. It might also be a place to raise small bug fixes that are too small to justify a pull request? E.g. I noticed in the EditView thread body is a "textField" rather than a "textareaField" which makes fixing posts tricky.

It's time for the next release of IHP: 20200904 🎉

Major Changes

• Composite Primary Key Support: You can now use tables that have a primary key consisting of multiple columns. This helps you to handle complex database schemas with IHP. To use this new feature, just define a composite PK in your Schema.sql like this:

CREATE TABLE order_trucks (
    order_id BIGSERIAL NOT NULL,
    truck_id BIGSERIAL NOT NULL,
    PRIMARY KEY(order_id, truck_id)
);

This feature has been contributed by @ruhatch 🎉

• Improved Error Screen when a request parameter is missing: Errors caused by calls to param now have a beautiful error screen telling you about what do next. It also displays all submitted params, so you can quickly spot whether there was a typo.

I started learning IHP and after finishing the "Your first project" part in the IHP Guide, I saw how actions where used as routes in two ways:

• <a href={pathTo NewPostAction}><...
• <a href={ShowPostAction}><...

Changing any of them to the other breaks neither of them

Now, looking at the HSX Guide, it states:

"If the variable is any other custom Haskell data structure: it will first be converted to a string representation by calling show on it. You can add a custom ToHtml (import it from IHP.HtmlSupport.ToHtml) instance, to customize rendering a data structure."

As I looked at the ToHtml class, I reasoned it should probably work in the way, that if there is no ToHtml Instance for a "custom haskell data structure", it will just use the Show instance of ToHtml, which is derived for any generated Controller Actions. I figured, this must mean in the conversion process from hsx to html, there is no explicit use of Show but ToHtml is used for any data, defaulting to its Show instance.

If I'm right, does that mean, that there are generated ToHtml instances for the Controller Actions, which would convert them? A derived Show instance of a normal algebraic data structure would just return the typical string representation said structures, so there must be a conversion to a href-compatible path. I couldn't find the ToHtml instances, but still with or without pathTo, the action gets translated to a path in HSX(Maybe I'm wrong here?). pathTo's usage would be to manually change a path, and if no change of the path is needed, one can just write "{Action}" to get the standard path to it.

Maybe I misunderstand something crucial here, and I would be happy to change that. My future self thanks you!

It's time for the next release of IHP: 20200918 🎉

Major Changes

It's time for the next release of IHP: v20201002 🎉

Major Changes

Hi - I've recently started using IHP for a personal blog and am finding it a real pleasure so far. One thing that slightly surprises me is that it seems storing the blog posts in the database seems to be the only way to go. This feels a little cumbersome, because I then have to write them via the front-end, and maintain a Controller for doing so (I haven't yet figured out how to hide this from the users). Ideally I would like to just write markdown files using vim and then somehow put them up as blog posts. I realize that at the moment the database is the only storage mechanism, but is there an idiomatic approach you'd take to facilitate a workflow like that? Obviously I can write them as markdown files and then copy/paste them into newly created posts on the front-end, so it's not exactly a huge deal, but if there's an obvious work-around I'd like to know.

Thanks for a great piece of software!

Chris

I have the latest version of VS Code (on Ubuntu Linux) and I am trying to follow the instructions in the recent video about Haskell integration to VS code. But when I try to get the command to set the environment variable as described in the video, there is no command available in the drop down as shown in the video. The written documentation linked to from the video does not deal with this.

It's time for the next release of IHP: v20201030 🎉 This release mainly focus on improving existing functionality and making things more stable :)

Major Changes

Hi,

I'm following the First App tutorial and I'm running into this error when creating a controller named 'Posts'.

What could have gone wrong? And how can I get going again?

To reproduce:

• sudo ihp-new blog
• sudo chown -R user:users blog/
• cd blog
• ./start
• Create DB model and press 'Update DB';
• Enter Code-gen; add controller 'Posts', preview; -- up to here all goes well
• press 'Generate' and the compile window gives compile errors.

[ 5 of 19] Compiling Web.Types        ( Web/Types.hs, interpreted )
[ 6 of 19] Compiling Web.Routes       ( Web/Routes.hs, interpreted )

Web/Routes.hs:7:20: error:
    Not in scope: type constructor or class ‘StaticControllerinstance’
  |
7 | instance AutoRoute StaticControllerinstance AutoRoute PostsController
  |                    ^^^^^^^^^^^^^^^^^^^^^^^^
[ 7 of 19] Compiling Web.Controller.Prelude ( Web/Controller/Prelude.hs, interpreted ) [Web.Types changed]
Failed, six modules loaded.

I'm running on Nixos.

Here's the output of ihp-troubleshoot:

$ bash ihp-troubleshoot
Checking that the current directory is an IHP project:
+ Found Main.hs
+ Found start
Checking nix:
+ Nix installed
Checking direnv:
+ Found .envrc
+ direnv loads .envrc
+ ghci is loaded from nix store
Checking .ghci:
+ Found .ghci
+ .ghci permissions are ok
Checking IHP:
+ Symlink build/ihp-lib exists
+ Symlink build/ihp-lib target exists
+ IHP used from nix
Checking Cachix:
- Cachix config is missing. Is cachix installed?
cat: /home/user/.config/nix/nix.conf: No such file or directory
- digitallyinduced.cachix.org binary cache missing. Try 'cachix use digitallyinduced'
cat: /home/user/.config/nix/nix.conf: No such file or directory
+ No legacy cachix key found
Debugging Details:
GHCI Output:
GHCi, version 8.8.3: https://www.haskell.org/ghc/  :? for help
package flags have changed, resetting and loading new packages...
Loaded GHCi configuration from /home/user/ihp/blog2/.ghci
IHP> ok
IHP> Leaving GHCi.
build/ihp-lib Target:
/nix/store/gdlksfh4afv3dk8wkcmwsn670rf5kjkl-ghc-8.8.3-with-packages/lib/IHP
Direnv Output:
direnv exec path /nix/store/c6sh3476va60wqck3iam87vbj93k34rg-direnv-2.21.2-bin/bin/dir\
env
DIRENV_CONFIG /home/user/.config/direnv
bash_path /nix/store/xadrr3l5jvkkm3g3lb2g81j5wz51zqdv-bash-interactive-4.4-p23/bin/bas\
h
disable_stdin false
warn_timeout 5s
whitelist.prefix []
whitelist.exact map[]
Loaded RC path /home/user/ihp/blog2/.envrc
Loaded watch: ".envrc" - 2020-10-31T16:46:21+01:00
Loaded watch: "../../.local/share/direnv/allow/dc29e63ea60b0ec67c0788bfb8089bf6f3a8f3c\
b69b08b9f7ed4427f70bc67fa" - 2020-10-31T16:46:21+01:00
Loaded RC allowed false
Loaded RC allowPath
Found RC path /home/user/ihp/blog2/.envrc
Found watch: ".envrc" - 2020-10-31T16:46:21+01:00
Found watch: "../../.local/share/direnv/allow/dc29e63ea60b0ec67c0788bfb8089bf6f3a8f3cb\
69b08b9f7ed4427f70bc67fa" - 2020-10-31T16:46:21+01:00
Found RC allowed true
Found RC allowPath /home/user/.local/share/direnv/allow/dc29e63ea60b0ec67c0788bfb8089b\
f6f3a8f3cb69b08b9f7ed4427f70bc67fa
which direnv Output:
/nix/store/gdlksfh4afv3dk8wkcmwsn670rf5kjkl-ghc-8.8.3-with-packages/bin/ghci
default.nix:
let
    ihp = builtins.fetchGit {
        url = "https://github.com/digitallyinduced/ihp.git";
        rev = "a8030dd1e4041a0353f63d03b4ffb836cb2bd95c";
    };
OS:
Linux

It's time for the next release of IHP: v20201016 🎉

Major Changes

It's time for the next release of IHP: v20201030 🎉 This release mainly focus on improving existing functionality and making things more stable :) Since the last release we also reached an important milestone: IHP is now the second biggest haskell framework measured by GitHub stars - just 5 months after it's initial public release. The future of haskell web dev is happening right here 🚀

Major Changes

Time for the next release of IHP: v20201213 🎉

Major Changes

Hi there,

I have developed the backend for a web app as an HTTP API (using Servant + Warp), and I would like to use IHP to develop the web part against this HTTP API.

As far as I can see, IHP starts at the database schema level, and generates its own HTTP API from this. However, I would like to tell IHP about my HTTP API and then develop a web app against this. Is this possible currently? If so, how?

Thank you in advance :)

Hi, sorry for the noise, but I'm trying to join the Slack from the URL https://ihp.digitallyinduced.com/Slack, but I get an error saying "This link is no longer active". Can you update the link?

Hello!

I got started with IHP recently and think it's fantastic so far. One issue I've had is related to the performance of the Haskell Language Server in an IHP project.

When it starts up, I've noticed it will peg a few cores of my CPU for a number of minutes, during which time the language server features are unavailable. This happens on both of my machines, one of which is a fairly powerful desktop, and doesn't occur when using the language server in non-IHP Haskell projects. I was wondering if this is a known issue and whether it's likely to improve in the future. Thank you!