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== redirect

=== Purpose

To redirect flow from one action to the next using an HTTP redirect.

=== Examples

[source,groovy]
----
redirect(action: "show")

redirect(controller: "book", action: "list")

redirect(controller: "book", action: "list", namespace: "publishing")

redirect(controller: "book", action: "list", plugin: "publishingUtils")

redirect(action: "show", id: 4, params: [author: "Stephen King"])

redirect(controller: "book", action: "show", fragment: "profile")

redirect(uri: "book/list")

redirect(url: "https://www.blogjava.net/BlueSUN")

redirect(Book.get(1))

// For 302 Moved Temporarily
redirect(action: "foo", permanent: false)

// For 307 Temporary Redirect
redirect(action: "foo", permanent: false, moved: false)

// For 301 Moved Permanently Redirect (moved is default true)
redirect(action: "foo", permanent: true)

// For 308 Permanent Redirect
redirect(action: "foo", permanent: true, moved: false)

----

=== Description

Redirects the current action to another action, optionally passing parameters and/or errors. When `namespace` is omitted, Grails resolves the target controller namespace automatically. If the target is the current controller, Grails uses the current request namespace. If exactly one controller has the target name, Grails uses that controller's namespace, whether the controller is namespaced or not. You only need to set `namespace` when more than one controller shares the same name. To issue a redirect from a namespaced controller to a controller that is not in a namespace, specify `namespace: null` as shown below. By default, the redirect code will be MOVED_TEMPORARILY (302).

[source,groovy]
----
class SomeController {
    static namespace = 'someNamespace'

    def index() {
        // issue a redirect to PersonController which does not define a namespace
        redirect action: 'list', controller: 'person', namespace: null
    }
}
----

=== Parameters

`redirect(Map params)`

* `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
* `namespace` (optional) - the namespace of the controller to redirect to. If omitted, the namespace is inferred from the target controller; you only need to set it when more than one controller shares the name. Use `namespace: null` to target a non-namespaced controller.
* `plugin` (optional) - the name of the plugin which provides the controller
* `id` (optional) - the id to use in the link
* `fragment` (optional) - The link fragment (often called anchor tag) to use
* `mapping` (optional) - The <<namedMappings,named URL mapping>> to use to rewrite the link
* `params` (optional) - a map containing request parameters
* `url` (optional) - a map containing the action, controller, id, etc.
* `absolute` (optional) - If `true` (default) will prefix the link target address with the value of the `grails.serverURL` property from `application.yml`, or http://localhost:8080 if there is no value in `application.yml` and not running in the production environment. If `false` a partial URI is generated for the `Location` header.
* `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.
* `permanent` (optional) - Defaults to `false`.  If `true`, the redirect will be issued with a PERMANENT style HTTP status code. If `moved` is true: MOVED_PERMANENTLY (301). Otherwise, PERMANENT_REDIRECT (308).
* `moved` (optional) - Defaults to `true`.  When `true`, the redirect will be issued with a MOVED style HTTP status code. If `permanent` is true: MOVED_PERMANTENTLY (301). Otherwise, MOVED_TEMPORARILY (302).

=== Domain Class

`redirect(Object domainClass)`

A special case is if a domain class is passed into `redirect`, it will use the `LinkGenerator` to create the URL. For example, `redirect(Book.get(1))` will generate a redirect to `/book/show/1`.
