elm-http-server

Elm Http Server

A puny module for putting together HTTP-servers using Elm

Warning

Elm (along with the Elm architecture) is designed for browser-applications; This project in experimental attempt to embed the architecture inside a small Node.js Http-server program. Taking the unreasonable performance implications aside, it is fun to experience Elm as a shared language between client and server with all of it's nice properties for continuous improvement and modification. Enjoy! :)

Usage

The module is distributed through NPM:

npm install -S elm-http-server

Go to elm-package.json and expose the internal Elm-code from the module:

{       ...
    "source-directories": [
        ...
        "node_modules/elm-http-server/source"
    ],
    ...
}

Examples of usage can be found in the examples sub-directory.

Features

• Utility-modules for working with Http-Request/Response on the server
• Emulation for XmlHttpRequest to enable elm-lang/http to run on the server
• A tiny API to hook Elm's Platform.program into Http.createServer in Node.JS

JavaScript Interface

in Node.js, assuming an Elm module named Main compiled to main.elm.js in the same directory, the API can be used as such:

var Ehs = require("elm-http-server")
var Http = require("http")
var App = require("./main.elm.js")

var PORT = 3000

var ID_GEN_SIZE = 420

var onRequest = Ehs.createRequestListener(App.Main.worker(), ID_GEN_SIZE)

var onStart = function () {
    console.log("server started at http://localhost:" + PORT)
}

Http.createServer()
.on("request", onRequest)
.listen(PORT, onStart)

Importing elm-http-server automatically exposes XmlHttpRequest globally to enable usage of elm-lang/http in the Elm-modules on the server.

Elm Interface

There is a couple of tiny modules for Elm, written to facilitate some basic server-logic.

Server.Request

type alias Request =
{ id : Id
, method : Method
, headers : Dict String String
, url : String
, body : Maybe String
}

type Method
    = Get
    | Put
    | Post
    | Delete
    | Other String

listen : (Result String Request -> msg) -> Sub msg

Server.Response

html : Request.Id -> Status -> Server.Html.Document -> Response

text : Request.Id -> Status -> String -> Response

json : Request.Id -> Status -> Json.Encode.Value -> Response

empty : Request.Id -> Status -> Response

send : Response -> Cmd msg

Server.Response.Header

type alias Header = ( String, String )

contentType : String -> Header

textContent : Header

htmlContent : Header

jsonContent : Header

Server.Response.Status

type alias Status =
{ code : Int
, message : String
}

ok : Status

badRequest : Status

unauthorized : Status

notFound : Status

internalError : Status

Server.Html

document : String -> String -> Document

toString : Document -> String