Grails

Archived

This page has been archived and will receive no further updates.

Resources

Grails Best Practices

Installation

Use the installation instructions from the Grails documentation: https://grails.org/download.html

The current recommended installation method is SDKMAN:

Install SDKMAN

http://sdkman.io/install.html
Install Grails
```
sdk install grails X.X.X
```

Configure Java with SDKMAN

sdk install java openjdk-8 /usr/lib/jvm/java-8-openjdk-amd64
sdk use java openjdk-8

Basics

Organization

grails-app
- /controllers
  - The C in MVC
  - Keep controllers as thin as possible (most logic should go into a service)
- /domain
  - The M in MVC
  - Code specific to one domain can also be put here. If it’s logic spread across domains, don’t put it here. Put it in a service or /src
- /services
  - “Services in Grails are the place to put the majority of the logic in your application” (http://docs.grails.org/2.5.6/guide/services.html)
  - One factor to consider is services support transactions and Spring dependency injection
- /views
  - The V in MVC. These are mostly GSP pages, a mix of HTML and Groovy
  - Keep views as as thin as possible (most logic should go into a service)
/src/groovy
- Put everything else here

Add a page

At a minimum, the page must be added as an action to the controller:
```
class BookController {
    def testpage() {}
```
Optionally, add a GSP page in the controller directory under the views directory with the same name as the action. E.g.:

myapp/grails-app/views/book/testpage.jsp
The URL to the page will be in the format http://site/app/controller/action, e.g:

http://localhost:8080/myapp/book/testpage

Setup

Create .gitignore

grails integrate-with --git

Controllers

Create a controller

grails create-controller book

Services

https://grails.github.io/grails-doc/latest/guide/services.html

Create a service

grails create-service servicename

If the service is related to a particular domain class, give it the same name:

grails create-service Book

(creates service BookService)

Call a service from a controller

http://stackoverflow.com/a/6250979/399105

Define the service outside the action:

class BookController {
    def bookService
    def list {
        bookService.listBooks()
    }

Scripts

Types of scripts

Gant scripts
- Specialized scripts, run like this:
```
grails my-script
```
Groovy scripts
- Normal Groovy scripts with access to the Grails environment, run like this:
```
grails run-script scripts/MyScript.groovy
```

Accessing the database from a Grails script

http://stackoverflow.com/q/675514/399105

Console

Open the GUI console

grails console

To access classes from your package

import myapp.*

My wiki