@hackage loli2009.8.18

A minimum web dev DSL in Haskell

loli

A minimum web dev DSL

Example

First app

-- myapp.hs

import Network.Loli
import Hack.Handler.Happstack
import MPS.Light ((-))
import Prelude hiding ((-))

main = run . loli - get "/" (text "loli power")

Install and compile:

cabal update
cabal install loli
cabal install hack-handler-happstack

ghc --make myapp.hs
./myapp

check: http://localhost:3000

Routes

Verbs

get "/" - do
  -- something for a get request

post "/" - do
  -- for a post request

put "/" - do
  -- put ..

delete "/" - do
  -- ..

Captures

get "/say/:user/:message" - do
  text . show =<< captures

-- /say/jinjing/hello will output
-- [("user","jinjing"),("message","hello")]

Static

-- public serve, only allows `./src`
public (Just ".") ["/src"]

Views root

-- in `./views`, can be changed by
views "template"

Template

Text Template

import Network.Loli.Template.TextTemplate

get "/hi/:user" - output (text_template "hello.html")

-- in hello.html
<html>
<title>hello</title>
<body>
  <p>hello $user</p>
</body>
</html>

Local binding

get "/local-binding" - do
  bind "user" "alice" - output (text_template "hello.html")

Batched local bindings

get "/batched-local-binding" - do
  context [("user", "alice"), ("password", "foo")] - 
    text . show =<< locals

Partials

Partials are treated the same as user supplied bindings, i.e. the rendered text is available to the rest of templates, referenced by user supplied keywords.

with single partial

import Network.Loli.Template.ConstTemplate

get "/single-partial" - do
  partial "user" (const_template "const-user") - do
    text . show =<< template_locals

with batched partials

get "/group-partial" - do
  partials 
    [ ("user", const_template "alex")
    , ("password", const_template "foo")
    ] - output (text_template "hello.html")

Layout

Local

get "/with-layout" - do
  with_layout "layout.html" - do
    text "layout?"

-- in layout.html
<html>
<body>
  <h1>using a layout</h1>
  $content
</body>
</html>

Global

layout "layout.html"

By passed

get "/no-layout" - do
  no_layout - do
    text "no-layout"

Mime types

-- treat .hs extension as text/plain
mime "hs" "text/plain"

Filters

-- before takes a function of type (Env -> IO Env)
before - \e -> do
  putStrLn "before called"
  return e

-- after takes that of type (Response -> IO Response)
after return

On the fly router switcher

The router can be switched at any time, it will effect any route path that follows.

router loli_router

Hack integration

Use hack middleware

import Hack.Contrib.Middleware.ETag
import Hack.Contrib.Middleware.Lambda

middleware etag
middleware lambda

Convert loli into a hack application

-- in Network.Loli.Engine

loli :: Unit -> Application

Note

use the git version ...

Wiki

Reference