silverstripe-translatable/code/controller/TranslatableCMSMainExtension.php

<?php
/**
 * @package translatable
 */
class TranslatableCMSMainExtension extends Extension {

	private static $allowed_actions = array(
		'createtranslation',
	);

	function init() {
		$req = $this->owner->getRequest();

		// Ignore being called on LeftAndMain base class,
		// which is the case when requests are first routed through AdminRootController
		// as an intermediary rather than the endpoint controller
		if(!$this->owner->stat('tree_class')) return;

		// Locale" attribute is either explicitly added by LeftAndMain Javascript logic,
		// or implied on a translated record (see {@link Translatable->updateCMSFields()}).
		// $Lang serves as a "context" which can be inspected by Translatable - hence it
		// has the same name as the database property on Translatable.
		$id = $req->param('ID');
		if($req->requestVar("Locale")) {
			$this->owner->Locale = $req->requestVar("Locale");
		} else if($id && is_numeric($id)) {
			$record = DataObject::get_by_id($this->owner->stat('tree_class'), $id);
			if($record && $record->Locale) $this->owner->Locale = $record->Locale;
		} else {
			$this->owner->Locale = Translatable::default_locale();
			if ($this->owner->class == 'CMSPagesController') {
				// the CMSPagesController always needs to have the locale set,
				// otherwise page editing will cause an extra
				// ajax request which looks weird due to multiple "loading"-flashes
				$getVars = $req->getVars();
				if(isset($getVars['url'])) unset($getVars['url']);
				return $this->owner->redirect(Controller::join_links(
					$this->owner->Link(),
					$req->param('Action'),
					$req->param('ID'),
					$req->param('OtherID'),
					($query = http_build_query($getVars)) ? "?$query" : null
				));
			}
		}
		Translatable::set_current_locale($this->owner->Locale);

		// If a locale is set, it needs to match to the current record
		$requestLocale = $req->requestVar("Locale");
		$page = $this->owner->currentPage();
		if(
			$req->httpMethod() == 'GET' // leave form submissions alone
			&& $requestLocale
			&& $page
			&& $page->hasExtension('Translatable')
			&& $page->Locale != $requestLocale
			&& $req->latestParam('Action') != 'EditorToolbar'
		) {
			$transPage = $page->getTranslation($requestLocale);
			if($transPage) {
				Translatable::set_current_locale($transPage->Locale);
				return $this->owner->redirect(Controller::join_links(
					$this->owner->Link('show'),
					$transPage->ID
					// ?locale will automatically be added
				));
			} else if ($this->owner->class != 'CMSPagesController') {
				// If the record is not translated, redirect to pages overview
				return $this->owner->redirect(Controller::join_links(
					singleton('CMSPagesController')->Link(),
					'?Locale=' . $requestLocale
				));
			}
		}

		// collect languages for TinyMCE spellchecker plugin.
		// see http://wiki.moxiecode.com/index.php/TinyMCE:Plugins/spellchecker
		$langName = i18n::get_locale_name($this->owner->Locale);
		HtmlEditorConfig::get('cms')->setOption(
			'spellchecker_languages',
			"+{$langName}={$this->owner->Locale}"
		);

		Requirements::javascript('translatable/javascript/CMSMain.Translatable.js');
		Requirements::css('translatable/css/CMSMain.Translatable.css');
	}

	function updateEditForm(&$form) {
		if($form->getName() == 'RootForm' && SiteConfig::has_extension("Translatable")) {
			$siteConfig = SiteConfig::current_site_config();
			$form->Fields()->push(new HiddenField('Locale','', $siteConfig->Locale));
		}
	}

	function updatePageOptions(&$fields) {
		$fields->push(new HiddenField("Locale", 'Locale', Translatable::get_current_locale()));
	}

	/**
	 * Create a new translation from an existing item, switch to this language and reload the tree.
	 */
	function createtranslation($data, $form) {
		$request = $this->owner->getRequest();

		// Protect against CSRF on destructive action
		if(!SecurityToken::inst()->checkRequest($request)) return $this->owner->httpError(400);

		$langCode = Convert::raw2sql($request->postVar('NewTransLang'));
		$record = $this->owner->getRecord($request->postVar('ID'));
		if(!$record) return $this->owner->httpError(404);

		$this->owner->Locale = $langCode;
		Translatable::set_current_locale($langCode);

		// Create a new record in the database - this is different
		// to the usual "create page" pattern of storing the record
		// in-memory until a "save" is performed by the user, mainly
		// to simplify things a bit.
		// @todo Allow in-memory creation of translations that don't
		// persist in the database before the user requests it
		$translatedRecord = $record->createTranslation($langCode);

		$url = Controller::join_links(
			$this->owner->Link('show'),
			$translatedRecord->ID
		);

		// set the X-Pjax header to Content, so that the whole admin panel will be refreshed
		$this->owner->getResponse()->addHeader('X-Pjax', 'Content');

		return $this->owner->redirect($url);
	}

	function updateLink(&$link) {
		$locale = $this->owner->Locale ? $this->owner->Locale : Translatable::get_current_locale();
		if($locale) $link = Controller::join_links($link, '?Locale=' . $locale);
	}

	function updateLinkWithSearch(&$link) {
		$locale = $this->owner->Locale ? $this->owner->Locale : Translatable::get_current_locale();
		if($locale) $link = Controller::join_links($link, '?Locale=' . $locale);
	}

	function updateExtraTreeTools(&$html) {
		$locale = $this->owner->Locale ? $this->owner->Locale : Translatable::get_current_locale();
		$html = $this->LangForm()->forTemplate() . $html;
	}

	function updateLinkPageAdd(&$link) {
		$locale = $this->owner->Locale ? $this->owner->Locale : Translatable::get_current_locale();
		if($locale) $link = Controller::join_links($link, '?Locale=' . $locale);
	}

	/**
	 * Returns a form with all languages with languages already used appearing first.
	 *
	 * @return Form
	 */
	function LangForm() {
		$member = Member::currentUser(); //check to see if the current user can switch langs or not
		if(Permission::checkMember($member, 'VIEW_LANGS')) {
			$field = new LanguageDropdownField(
				'Locale',
				_t('CMSMain.LANGUAGEDROPDOWNLABEL', 'Language'),
				array(),
				'SiteTree',
				'Locale-English',
				singleton('SiteTree')
			);
			$field->setValue(Translatable::get_current_locale());
        } else {
			// user doesn't have permission to switch langs
			// so just show a string displaying current language
			$field = new LiteralField(
				'Locale',
				i18n::get_locale_name( Translatable::get_current_locale())
			);
		}

		$form = new Form(
			$this->owner,
			'LangForm',
			new FieldList(
				$field
			),
			new FieldList(
				new FormAction('selectlang', _t('CMSMain_left.GO','Go'))
			)
		);
		$form->unsetValidator();
		$form->addExtraClass('nostyle');

		return $form;
	}

	function selectlang($data, $form) {
		return $this->owner;
	}

	/**
	 * Determine if there are more than one languages in our site tree.
	 *
	 * @return boolean
	 */
	function MultipleLanguages() {
		$langs = Translatable::get_existing_content_languages('SiteTree');

		return (count($langs) > 1);
	}

	/**
	 * @return boolean
	 */
	function IsTranslatableEnabled() {
		return SiteTree::has_extension('Translatable');
	}

    /**
     * Injects the locale into a new page on creation.
     *
     * @param SiteTree $record
     * @param Form $form
     */
    public function updateDoAdd(SiteTree $record, Form $form) {
		$data = $form->getData();
        if(!isset($data['Locale'])) {
            $data['Locale'] = Translatable::get_current_locale();
        }
        $record->Locale = $data['Locale'];
    }

}