Slick

Want to get started quickly? Check out the Slick site template!

Slick is a static site generator written and configured using Haskell. It's the spiritual successor to my previous static-site generator project SitePipe; but is faster, simpler, and more easily used in combination with other tools.

Slick provides a small set of tools and combinators for building static websites on top of the Shake build system. Shake is adaptable, fast, reliable, and caches aggressively so it's a sensible tool for static-site builds, but figuring out how to get started can be a bit abstract. Slick aims to answer the question of 'how do I get a site building?' while giving you the necessary tools and examples to figure out how to accomplish your goals.

See the hackage docs for in depth help on available combinators.

If you would rather see live examples than documentation, you can check out:

• my own blog at https://chrispenner.ca source
• cvlad's blog at https://cvlad.info source

Overview

Here's a quick overview of what Slick can do:

• Slick uses the Shake build tool; the same used by ghcide! We recommend using

  Development.Shake.Forward

  ; it auto-discovers which resources it should cache as you go! This means a blazing fast static site builder without all the annoying dependency tracking.
• Slick provides helpers for loading in blog-post-like things using Pandoc under the hood;
  • This means that if Pandoc can read it, you can use it with Slick!
  • Write your blog posts in Markdown or LaTeX and render it to syntax-highlighted HTML!
  • Slick processes Pandoc (and LaTeX) metadata into a usable form (as an Aeson Value object) which you can manipulate as you please.
• Slick provides combinators for rendering Mustache templates
  • Slick wraps Justus Adam's Mustache library and provides cached template rendering with awareness of changes to templates, partials, and Mustache objects.
  • It's a thin wrapper so you can still use things like Mustache functions, etc. if you like!
• Provides only the individual tools without opinions about how to wire them up; if you want to load blog posts from a database and render them out using Blaze html; well go ahead, we can help with that!
• Provides caching of arbitrary (JSON serializable) objects using Shake resulting in super-fast rebuild times!

Another static site generator? What about Hakyll/Jekyll?

Yup, yet another static site generator. I've tried using Hakyll and Jekyll on different occasions and found there was too much magic going on with all of the monadic contexts for me to understand how to customize things for my use-cases. Even adding simple tags/categories to my blog seemed far more complex then it needed to be; Hakyll specifically got me really bogged down; what was the Compiler monad? How does an Item work? How do I add a custom field? Why couldn't I just edit data directly like I'm used to doing in Haskell? They seemed a bit too opinionated without giving me escape hatches to wire in my own functionality. If they're working for you, then great! But they weren't working for me, so that's where SitePipe and subsequently Slick came from.

Quick Start

Want to get started quickly? Check out the Slick site template and follow the steps there.

Example Site:

Here's an example of using slick to build an ENTIRE blog with full automatic asset caching.

{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE DeriveAnyClass #-}
{-# LANGUAGE OverloadedStrings #-}

module Main where
import           Control.Lens
import           Control.Monad
import           Data.Aeson                 as A
import           Data.Aeson.Lens
import           Development.Shake
import           Development.Shake.Classes
import           Development.Shake.Forward
import           Development.Shake.FilePath
import           GHC.Generics               (Generic)
import           Slick
import qualified Data.Text                  as T
outputFolder :: FilePath
outputFolder = "docs/"
-- | Data for the index page
data IndexInfo =
  IndexInfo
    { posts :: [Post]
    } deriving (Generic, Show, FromJSON, ToJSON)
-- | Data for a blog post
data Post =
    Post { title   :: String
         , author  :: String
         , content :: String
         , url     :: String
         , date    :: String
         , image   :: Maybe String
         }
    deriving (Generic, Eq, Ord, Show, FromJSON, ToJSON, Binary)
-- | given a list of posts this will build a table of contents
buildIndex :: [Post] -> Action ()
buildIndex posts' = do
  indexT  "index.html") indexHTML
-- | Find and build all posts
buildPosts :: Action [Post]
buildPosts = do
  pPaths  Action Post
buildPost srcPath = cacheAction ("build" :: T.Text, srcPath) $ do
  liftIO . putStrLn $ "Rebuilding post: " <> srcPath
  postContent  "html"
      withPostUrl = _Object . at "url" ?~ String postUrl
  -- Add additional metadata we've been able to compute
  let fullPostData = withPostUrl $ postData
  template  T.unpack postUrl) . T.unpack $ substitute template fullPostData
  -- Convert the metadata into a Post object
  convert fullPostData
-- | Copy all static files from the listed folders to their destination
copyStaticFiles :: Action ()
copyStaticFiles = do
    filepaths 
        copyFileChanged ("site" > filepath) (outputFolder > filepath)
-- | Specific build rules for the Shake system
--   defines workflow to build the website
buildRules :: Action ()
buildRules = do
  allPosts 
Not pictured above is:

• Using custom Pandoc readers to load other document types, there are many helpers for this in the slick library
• Using custom build tools like sassy css or js minifiers; you can do these things using Shake directly.

Caching guide

Shake takes care of most of the tricky parts, but there're still a few things you need to know.

Cache-busting in Slick works using

Development.Shake.Forward

cacheAction

When using

cacheAction

Binary

{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE DeriveAnyClass #-}

import Data.Aeson (ToJSON, FromJSON)
import Development.Shake.Classes (Binary)
import GHC.Generics (Generic)
-- | Data for a blog post
data Post =
    Post { title   :: String
         , author  :: String
         , content :: String
         , url     :: String
         , date    :: String
         , image   :: Maybe String
         }
    deriving (Generic, Eq, Ord, Show, FromJSON, ToJSON, Binary)

If you need to run arbitrary shell commands you can use

cache

readFile'

readFile'

Shake has many dependency tracking combinators available; whenever possible you should use the shake variants of these (e.g.

copyFileChanged

readFile'

writeFile'

Note: You'll likely need to delete

.shake

Main.hs