////
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements.  See the NOTICE file
distributed with this work for additional information
regarding copyright ownership.  The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License.  You may obtain a copy of the License at

https://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied.  See the License for the
specific language governing permissions and limitations
under the License.
////


== link



=== Purpose


Creates an html anchor tag with the `href` set based on the specified parameters.


=== Examples


Example controller for an application called "shop":

[source,groovy]
----
class BookController {
    def list() {
        [books: Book.list(params)]
    }

    def show() {
        [book : Book.get(params.id)]
    }
}
----

Example usages for above controller:

[,xml]
----
<g:link action="show" id="1">Book 1</g:link>

<g:link action="show" id="${currentBook.id}">${currentBook.name}</g:link>

<g:link controller="book">Book Home</g:link>

<g:link controller="book" action="list">Book List</g:link>

<g:link controller="book" action="list" plugin="publishingUtils">Book List</g:link>

<g:link url="[action:'list',controller:'book']">Book List</g:link>

<g:link action="list" params="[sort: 'title', order: 'asc',
                               author: currentBook.author]">
     Book List
</g:link>

<g:link controller="book" absolute="true">Book Home</g:link>

<g:link controller="book" namespace="publishing">Publishing Book Home</g:link>

<g:link controller="book" base="http://admin.mygreatsite.com">Book Home</g:link>
----

Example Usage for a RESTful Resource:

[,groovy]
----
static mappings = {
    "/books"(resources: 'book')
}
----

[,xml]
----
<g:link resource="book">Book Home</g:link>
<g:link resource="book" id="${book.id}">Book Show</g:link>
<g:link resource="book" action="create">New Book</g:link>
----

Example as a method call in GSP only:

[,gsp]
----
<%= link(action:'list',controller:'book') { 'Book List' }%>
----

Results in:

[source,xml]
----
<a href="/shop/book/list">Book List</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
* `resource` (optional)   - the name of the resource url mapping to use in the link; if not specified controller should be used
* `namespace` (optional) - the namespace of the controller to use in the link
* `plugin` (optional) - the name of the plugin which provides the controller
* `elementId` (optional) - this value will be used to populate the `id` attribute of the generated href
* `id` (optional) - the id to use in the link
* `fragment` (optional) - The link fragment (often called anchor tag) to use
* `mapping` (optional) - The link:{guidePath}/theWebLayer.html#namedMappings[named URL mapping] to use to rewrite the link
* `method` (optional) - The HTTP method specified in the corresponding URL mapping
* `params` (optional) - a Map of request parameters
* `uri` (optional) - a relative URI
* `relativeUri` (optional) - Used to specify a uri relative to the current path.
* `url` (optional) - a Map containing the action, controller, id etc.
* `absolute` (optional) - If `true` will prefix the link target address with the value of the `grails.serverURL` property from the application configuration, or http://localhost:8080 if there is no setting in the 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.
* `event` (optional) - The name of a Webflow event to trigger for the flow associated with the given `action`. Requires the Webflow plugin.

