The default page title defined in the layout file can be extended (PREPEND/APPEND) or replaced (SET) with a title specific for the current view.
Such behavior I've also been expecting for the HeadMeta view helper. Now I cannot find any proper way to "extend" the default descrition/keywords, that I defined in the layout file.
Instead of it I can add a further meta tag with append(...)/appendName(...) (similary to adding style or script file with HeadLink or HeadScript). But it doesn't make sense for descrition and keywords meta tags.
Is there a recommended approach to handle this? How to handle the description/keywords meta tags?
Here is a quick&dirty workaroud, I'm currently using (for a clean solution instead of an ugly workaround changes at the framework are needed):
HeadMeta view helper
<?php
namespace MyNamespace\View\Helper;
use stdClass;
use Zend\View;
use Zend\View\Exception;
use Zend\View\Helper\HeadMeta as ZendHeadMeta;
use Zend\View\Helper\Placeholder\Container\AbstractContainer;
class HeadMeta extends ZendHeadMeta {
const DELIMITER = ' - ';
/**
* @see \Zend\View\Helper\HeadMeta::__invoke()
*/
public function __invoke($content = null, $keyValue = null, $keyType = 'name', $modifiers = array(), $placement = AbstractContainer::APPEND) {
parent::__invoke($content, $keyValue, $keyType, $modifiers, $placement);
return $this;
}
/**
* @see \Zend\View\Helper\HeadMeta::append()
*/
public function append($value) {
if ($value->name == 'description') {
$this->updateDescription($value, AbstractContainer::APPEND);
} else if ($value->name == 'keywords') {
$this->updateKeywords($value, AbstractContainer::APPEND);
} else {
parent::append($value);
}
}
/**
* @see \Zend\View\Helper\HeadMeta::prepend()
*/
public function prepend($value) {
if ($value->name == 'description') {
$this->updateDescription($value, AbstractContainer::PREPEND);
} else if ($value->name == 'keywords') {
$this->updateKeywords($value, AbstractContainer::PREPEND);
} else {
parent::prepend($value);
}
}
// Not working correctly!
// Can cause a
// Fatal error: Maximum function nesting level of '100' reached, aborting!
/**
* @see \Zend\View\Helper\HeadMeta::set()
*/
public function set($value) {
if ($value->name == 'description') {
$this->updateDescription($value, AbstractContainer::SET);
} else if ($value->name == 'keywords') {
$this->updateKeywords($value, AbstractContainer::SET);
} else {
parent::set($value);
}
}
/**
* If a description meta already exsists, extends it with $value->content,
* else creates a new desctiprion meta.
* @param \stdClass $value
* @param string $position
*/
public function updateDescription(\stdClass $value, $position = AbstractContainer::SET) {
$descriptionExists = false;
foreach ($this->getContainer() as $item) {
if ($this->isDescription($item)) {
switch ($position) {
case AbstractContainer::APPEND:
$descriptionString = implode(static::DELIMITER, array($item->content, $value->content));
break;
case AbstractContainer::PREPEND:
$descriptionString = implode(static::DELIMITER, array($value->content, $item->content));
break;
case AbstractContainer::SET:
default:
$descriptionString = $value->content;
break;
}
$item->content = $descriptionString;
$descriptionExists = true;
}
}
if (!$descriptionExists) {
switch ($position) {
case AbstractContainer::APPEND:
parent::append($value);
break;
case AbstractContainer::PREPEND:
parent::prepend($value);
break;
case AbstractContainer::SET:
default:
parent::set($value);
break;
}
}
}
/**
* If a keywords meta already exsists, extends it with $value->content,
* else creates a new keywords meta.
* @param \stdClass $value
* @param string $position
*/
public function updateKeywords(\stdClass $value, $position = AbstractContainer::SET) {
$keywordsExists = false;
foreach ($this->getContainer() as $item) {
if ($this->isKeywords($item)) {
switch ($position) {
case AbstractContainer::APPEND:
$keywordsString = implode(', ', array($item->content, $value->content));
break;
case AbstractContainer::PREPEND:
$keywordsString = implode(', ', array($value->content, $item->content));
break;
case AbstractContainer::SET:
default:
$keywordsString = $value->content;
break;
}
$item->content = $keywordsString;
$keywordsExists = true;
}
}
if (!$keywordsExists) {
parent::append($value);
}
}
/**
* @return description meta text
*/
public function getDescription() {
$description = null;
foreach ($this->getContainer() as $item) {
if ($this->isKeywords($item)) {
$description = $item->content;
break;
}
}
return $description;
}
/**
* @return keywords meta text
*/
public function getKeywords() {
$keywords = null;
foreach ($this->getContainer() as $item) {
if ($this->isKeywords($item)) {
$keywords = $item->content;
break;
}
}
return $keywords;
}
/**
* Checks, whether the input $item is an approproate object for $this->container
* and wheter it's a description object (its name is "description")
* @param stdClass $item
* @throws Exception\InvalidArgumentException
* @return boolean
*/
public function isDescription(stdClass $item) {
if (!in_array($item->type, $this->typeKeys)) {
throw new Exception\InvalidArgumentException(sprintf(
'Invalid type "%s" provided for meta',
$item->type
));
}
return $item->name == 'description';
}
/**
* Checks, whether the input $item is an approproate object for $this->container
* and wheter it's a keywords object (its name is "keywords")
* @param stdClass $item
* @throws Exception\InvalidArgumentException
* @return boolean
*/
public function isKeywords(stdClass $item) {
if (!in_array($item->type, $this->typeKeys)) {
throw new Exception\InvalidArgumentException(sprintf(
'Invalid type "%s" provided for meta',
$item->type
));
}
return $item->name == 'keywords';
}
}
/module/Application/view/layout/layout.phtml
<?php
$this->headMeta()->appendName(
'description',
$this->translate('default description')
);
$this->headMeta()->appendName(
'keywords',
implode(', ', array(
$this->translate('default keyword 1'),
$this->translate('default keyword 2'),
$this->translate('default keyword 3'),
))
);
echo $this->headMeta();
?>
view script
<?php
$this->headMeta()->setName('keywords', implode(
', ',
array(
$this->translate('view specific keyword 1'),
$this->translate('view specific keyword 2'),
$this->translate('view specific keyword 3'),
)
));
$this->headMeta()->setName('description', 'view specific description');
?>