yesod_tutorial init

Init of the project

Goal

The goal of this chapter is to create the scaffolded site and make it work.

Init

First we need to create a new Yesod project, let's call it micropost:

$ yesod init
Welcome to the Yesod scaffolder.
I'm going to be creating a skeleton Yesod project for you.

What is your name? We're going to put this in the cabal and LICENSE files.

Your name: davidbe
Welcome davidbe.
What do you want to call your project? We'll use this for the cabal name.

Project name: micropost
Yesod uses Persistent for its (you guessed it) persistence layer.
This tool will build in either SQLite or PostgreSQL or MongoDB support for you.
We recommend starting with SQLite: it has no dependencies.

    s     = sqlite
    p     = postgresql
    mongo = mongodb
    mysql = MySQL (experimental)

So, what'll it be? s
That's it! I'm creating your files now...
Generating deploy/Procfile
Generating config/sqlite.yml
Generating config/settings.yml
Generating main.hs
Generating devel.hs
Generating micropost.cabal
Generating micropost.cabal
Generating .ghci
Generating LICENSE
Generating Foundation.hs
Generating Import.hs
Generating Application.hs
Generating Handler/Home.hs
Generating Model.hs
Generating Settings.hs
Generating Settings/StaticFiles.hs
Generating static/css/bootstrap.css
Generating templates/default-layout.hamlet
Generating templates/default-layout-wrapper.hamlet
Generating templates/normalize.lucius
Generating templates/homepage.hamlet
Generating config/routes
Generating templates/homepage.lucius
Generating templates/homepage.julius
Generating config/models
Generating messages/en.msg
Generating tests/main.hs

---------------------------------------

                         ___
                            {-)   |\
                       [m,].-"-.   /
      [][__][__]         \(/\__/\)/
      [__][__][__][__]  |  |
      [][__][__][__][__][] /   |
      [__][__][__][__][__]| /| |
      [][__][__][__][__][]| || |  
  ejm [__][__][__][__][__]__,__,  \__/


---------------------------------------

The foundation for your web application has been built.


There are a lot of resources to help you use Yesod.
Start with the book: http://www.yesodweb.com/book
Take part in the community: http://yesodweb.com/page/community


Start your project:

   cd micropost && cabal install && yesod devel
 
or if you use cabal-dev:

   cd micropost && cabal-dev install && yesod --dev devel

A Yesod project is created with yesod init command. Yesod init asks 3 questions and here are the answers I gave:

1. Your name - davidbe
2. Project name - micropost
3. Database-backend - s for sqlite

After answering those questions, Yesod init will create several files. An explanation of all those files can be found in the Yesod Web Framework Book on Scaffolding and the Site Template, but in this tutorial we will touch the most important ones.

Let's try the scaffolded code out:

$ cd micropost
$ cabal install
$ yesod devel

[ Some guidance on how to handle cabal dependency errors might be in order at this point. For example, if you see "There is no available version of persistent-sqlite that satisfies ==0.6.*" then you should run "cabal install persistent-sqlite". Of course, I just realised that I'm only getting this because I normally run cabal site-wide, and the user under which I'm building my yesod projects doesn't even have a package list! Presumably if it did, cabal would install the missing dependencies. ]

When the console prints:

Devel application launched: http://localhost:3000

point the browser to http://localhost:3000/. A web-page with explaining the first steps with Yesod will appear.

If that works, you know that everything is wired up correctly.