grails create-controller

class BookController { … }

class BookController {
    def list = {
        // do controller logic
        // create model
        return model
    };
}

def index = {
   redirect(action:list)
}

def defaultAction = "list"

class BookController {
    def find = {
        def findBy = params["findBy"]
        def appContext = servletContext["appContext"]
        def loggedUser = session["logged_user"]
        // do stuff
        // return model
        return model
    };
}

def delete = {
    def b = Book.get( params['id'] )
    if(!b) {
        flash['message'] = "User not found for id ${params['id']}"
        redirect(action:list)
    }
    … // remaining code
}

def save = {
  def b = new Book()
  b.properties = params
  b.save()
}

def sc = new SaveCommand()
bindData(sc, params)

def show = {
    def b = Book.get( params['id'] )
    return [ book : b ]
}

class BookController {
    def List books
    def List authors
    def list = {
           books = Book.list()
           authors = Author.list()
    }
}

render "Hello World!"

// write some markup
render {
   for(b in books) {
      div(id:b.id, b.title)
   }
}
// render a specific view
render(view:'show')
// render a template for each item in a collection
render(template:'book_template', collection:Book.list())
// render some text with encoding and content type
render(text:"<xml>some xml</xml>",contentType:"text/xml",encoding:"UTF-8")

class OverviewController {
    def login = {}
    def find = {
        if(!session["logged_user"])
           redirect(action:login)
        .....
    };
}

redirect(action:login)
// or
redirect(action:"/another/action")

redirect(action:"/another/action", params:["myparam":"myvalue"])

class ChainController {
    def firstInChain = {
        chain(action:secondInChain,model:["step1":new Object()])
    }
    def secondInChain = {
        chain(action:thirdInChain,model:["step2":new Object()])
    };
    def thirdInChain= {
        return ["step3":new Object()])
    };
}

["step1":object1, "step2":object2, "step3":object3]

class ChainController {
    def nextInChain = {
        def model = chainModel["myModel"]
        .....
    };
}

chain(action:"/another/action", model:["step1":object1], params:["myparam":"param1"])

def beforeInterceptor = {
       println 'Tracing action ${actionUri}'
}

def beforeInterceptor = [action:this.&auth,except:'login']
// defined as a regular method so its private
def auth() {
     if(!session.user) {
            redirect(action:'login')
            return false
     }
}
def login = {
     // display login page
}

def afterInterceptor = { model ->
       println 'Tracing action ${actionUri}'
}

def beforeInterceptor = [action:this.&auth,except:'login']

def beforeInterceptor = [action:this.&auth,except:['login','register']]

def beforeInterceptor = [action:this.&auth,only:['secure']]

Upload Form: <br />
<g:form action="upload" method="post" enctype="multipart/form-data">
<input type="file" name="myFile" />
<input type="submit" />
</g:form>

def upload = {
def f = request.getFile('myFile')
if(!f.empty) {
f.transferTo( new File('someotherloc') )
}
else {
flash.message = 'file cannot be empty'
redirect(action:'uploadForm')
}
}

class Image {
def byte[] myFile
}

def img = new Image()
img.properties = params

class Image {
def String myFile
}

class UploadCommand {
def byte[] myFile
}

def upload = {
def uc = new UploadCommand()
bindData(uc, params)
assert uc.myFile != null
}

def CountryService countryService