createLink

Purpose

Creates a link that can be used where necessary (for example in an href, javascript, ajax call etc.)

Examples

Example controller for an application called "shop":

class BookController {
     def defaultAction="list"
     def list = { [ books: Book.list( params ) ] }
     def show = { [ book : Book.get( params['id'] ) ] }
}

Example usages for above controller:

<g:createLink action="show" id="1" /> == /shop/book/show/1
<g:createLink action="show" params="[foo: 'bar', boo: 'far']"/> == /shop/book/show?foo=bar&boo=far
<g:createLink controller="book" /> == /shop/book
<g:createLink controller="book" action="list" /> == /shop/book/list
<g:createLink url="[action:'list',controller:'book']" /> == /shop/book/list
<g:createLink controller="book" absolute="true"/> == http://portal.mygreatsite.com/book
<g:createLink controller="book" base="http://admin.mygreatsite.com"/> == http://admin.mygreatsite.com/book
<g:createLink controller = "book" action="list" params="[title:'The Shining', author:'Stephen King', id:'1']"/> == /shop/book/list/1?title=The+Shining&author=Stephen+King

Example as a method call in GSP:

<a href="${createLink(action:'list')}">my link</a>

results in:

<a href="/shop/book/list">my link</a>

Description

Attributes

action (optional) - The name of the action to use in the link, if not specified the default action will be linked
controller (optional) - The name of the controller to use in the link, if not specified the current controller will be linked
id (optional) - The id to use in the link
fragment (optional) - The link fragment (often called anchor tag) to use
mapping (optional) - The named URL mapping to use to rewrite the link
params (optional) - A map containing URL query parameters
url (optional) - A map containing the action,controller,id etc.
absolute (optional) - If set to "true" will prefix the link target address with the value of the grails.serverURL property from Config, or http://localhost:<port> if no value in Config and not running in production.
base (optional) - Sets the prefix to be added to the link target address, typically an absolute server URL. This overrides the behaviour of the absolute property, if both are specified.

Source

Show Source

def createLink = { attrs ->
    	def writer = getOut()    	// prefer URI attribute
		if(attrs['uri']) {
			writer << handleAbsolute(attrs)
			writer << attrs.uri.toString()
		}
		else {
			// prefer a URL attribute
			def urlAttrs = attrs
			if(attrs['url'] instanceof Map) {
				urlAttrs = attrs.remove('url').clone()
			}
			else if(attrs['url']) {
				urlAttrs = attrs.remove('url').toString()
			}
			if(urlAttrs instanceof String) {
				if(useJsessionId)
				writer << response.encodeURL(urlAttrs)
				else
				writer << urlAttrs
			}
			else {
				def controller = urlAttrs.containsKey("controller") ? urlAttrs.remove("controller")?.toString() : controllerName
				def action = urlAttrs.remove("action")?.toString()
				if(controller && !action) {
					GrailsControllerClass controllerClass = grailsApplication.getArtefactByLogicalPropertyName(ControllerArtefactHandler.TYPE, controller)
					String defaultAction = controllerClass?.getDefaultAction()
					if(controllerClass?.hasProperty(defaultAction))
					action = defaultAction
				}
				def id = urlAttrs.remove("id")
				def frag = urlAttrs.remove('fragment')?.toString()
				def params = urlAttrs.params && urlAttrs.params instanceof Map ? urlAttrs.remove('params') : [:]
				params.mappingName = urlAttrs.remove('mapping')
				if(request['flowExecutionKey']) {
					params."execution" = request['flowExecutionKey']
				}
				if(urlAttrs.event) {
					params."_eventId" = urlAttrs.remove('event')
				}
				def url
				if(id != null) params.id = id
				def urlMappings = applicationContext.getBean("grailsUrlMappingsHolder")
				UrlCreator mapping = urlMappings.getReverseMapping(controller,action,params)
				// cannot use jsessionid with absolute links
				if(useJsessionId && !attrs.absolute) {
					url = mapping.createURL(controller, action, params, request.characterEncoding, frag)
					def base = attrs.remove('base')
					if(base) writer << base
					writer << response.encodeURL(url)
				}
				else {
					url = mapping.createRelativeURL(controller, action, params, request.characterEncoding, frag)
					out << handleAbsolute(attrs)
					writer << url
				}
			}
		}
    }