====== Grails 3 Project Directories ======
{{:grails_3_project_directories.png?direct |}}
The image on the left shows the structure of a Grails 3 project. We will talk about those interesting ones here.

===== build.gradle =====
This is not a directory, but it is import for defining dependencies for your web-app.

===== assets =====
This directory is good for storing images, JavaScripts, and CSS style sheets. In fact by default, Grails 3 project has already created 3 sub-directories ''images'', '' javascripts'', and ''stylesheets'' there. When a Grails 3 project created, it will automatically include jQuery 2.x and Bootstrap 3.x there.

You will find two files called application.css and application.js. Those are for ''Assert Pipeline'' to work with. Open the file to take a look and you will know what they do.

===== conf =====
This directory contains the application config files (application.yml, application.groovy), the logback config file, and the spring resources config file. Unless you need to mess up with your own beans, otherwise, the most useful files is ''application.yml'' for application configuration such as data source, cache, running port, etc, and/or ''application.groovy'' for spring security plug-in config.

===== controller =====
For putting grails controllers here. The controller name, and its method names will automatically mapped to your project URL. For example, if you have a controller called Home, and a method called index(), you will have a URL http://YOUR_SITE/home/index that mapped to the index() method. Yes, it is done automatically. Grails controller is prototype by default.

===== domain =====
Here is for domain class objects. By convention, it the classes default here will mapped the your database according to the your data source setting in 'application.yml' file.

===== i18n =====
For storing the text for your webapp in different languages. The text can be obtained by the following code. The locale will be defined by what the requester web browser submitted. If not such code find in the specific properties file, it will always fallback to the code in ''messages.properties''.
<code>
<g:message code="YOUR_MESSAGE_CODE_NAME"/>
</code>

===== init =====
There are two files. ''Application.groovy'' and ''Bootstrap.groovy''. Application use for starting up the web app, and Bootstrap is where your put the code if you run something to be run when the web app initialize, or being destroyed.

===== services =====
To put Grails service here. Usually functions that involved database transaction will be put into a service. By default Grails service is singleton.

===== views =====
Place for storing Groovy Server Pages (gsp) files. By creating a controller (in Grails cli), grails will automatically create a directory with the same name as the controller here, and the controller can easily render the gsp file here by. It will render the gsp file, and pass the ''someObject'' to that gsp.
<code>
respond([], view: 'NAME_OF_THE_GSP_FILE', model: [someObject: someObject])
</code>

===== src =====
This file is a good place for command objects, and view objects, or your own tools/libraries.