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Customising the CMS /

Moderators: martimiz, Sean, Ed, biapar, Willr, Ingo, swaiba

Override a function from SiteTree with a module

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5 Posts   3848 Views

John Silver

Community Member, 10 Posts

13 August 2009 at 4:15am

I'd like to override the function MetaTags from \sapphire\core\model\SiteTree.php. Of course I could just extend SiteTree with a new Page.php, but I want to make my new MetaTags available as a module.

I tried the following:
- created a new folder inside the silverstripe
- created a new "_config.php" with the following content:

DataObject::add_extension('SiteTree', 'SiteTreeExtensions');

-created a file "code/SiteTreeExtensions.php" with the following content:
class SiteTreeExtensions extends DataObjectDecorator {
	public function MetaTags($includeTitle = true) {
		$tags = "XXX";

		return $tags;

When check the output, I still get the text from the "old" MetaTag-function.

Is it simply not possible to override functions, or am I doing it wrong?


Community Member, 271 Posts

15 August 2009 at 3:22pm

Maybe you can rip some code from the MetaManager:

John Silver

Community Member, 10 Posts

18 August 2009 at 8:02pm

Thanks for the answer, I will check it out.


Community Member, 253 Posts

18 August 2009 at 11:25pm

This might not at all be what you are trying to do, but it might be useful to you:

John Silver

Community Member, 10 Posts

19 August 2009 at 10:17pm

Pigeon: Thanks, that was not exactly what I was looking for, but the site is great and has lots of other interesting stuff.

Martijn: Great Extension, but it's also not quite what I'm looking for. I want to overwrite the "MetaTags" function so I can call "$MetaTags(0)" in my template and get the output generated by my module.

For now I solved it by overwriting the function in the controller, but I think that's not very clean. The original function is located in SiteTree, which is the model.


	DataObject::add_extension('SiteTree', 'SiteTreeExtension');
	DataObject::add_extension('Page_Controller', 'SiteTreeExtension_Controller');


class SiteTreeExtension extends DataObjectDecorator {

class SiteTreeExtension_Controller extends Extension {

	public function MetaTags($includeTitle = true) {
		// Vars
		$version = SapphireInfo::Version();
		$charset = ContentNegotiator::get_encoding();
		$currentLang = i18n::convert_rfc1766(Translatable::get_current_locale());
		$lastChangedDate = date("Y-m-d\TH:i:sP", strtotime($this->owner->LastEdited));
		// Set Array
		$metaData = array(
			array("generator", "SilverStripe $version -"),
			array("Content-type" , "text/html; charset=$charset"),
			array("keywords" , Convert::raw2att($this->owner->MetaKeywords)),
			array("description" , Convert::raw2att($this->owner->MetaDescription)),
			array("Content-Language" , $currentLang),
			array("date" , $lastChangedDate)
		$tags = "";
		foreach($metaData as $metaLine) {
			$tags .= $metaLine[1] != "" ? "<meta name=\"$metaLine[0]\" content=\"$metaLine[1]\" />\n" : "";
		if ($this->ExtraMeta) {
			$tags .= $this->ExtraMeta."\n";
		$this->extend('updateMetaTags', $tags);
		$this->extend('MetaTags', $tags);
		return $tags;


(Obviously far from being finished)