Make use of GLOBALS['TSFE']->getPageRenderer()->addMetaTag()

[thomaszbz]

Reported by @georg-tiefenbrunn via https://forge.typo3.org/issues/62154 :

I stumbled upon this because I got multiple description tags using EXT:news which adds meta tags using its MetaTagViewHelper which uses $GLOBALS['TSFE']->getPageRenderer()->addMetaTag(). Tags are built using Fluid's TagBuilder, which always adds ' />' to empty tags.

Thus EXT:news adds following meta tags:

<meta name="description" content="example description" />
<meta property="og:description" content="example description" />

EXT:metaseo later adds its own meta tags:

<meta name="description" content="example description">
<meta name="DC.Description" content="example description">

One quick solution is to change the fluid templates of EXT:news and disable the meta tag generation.

A much better solution would be to use $GLOBALS['TSFE']->getPageRenderer()->addMetaTag() (and addHeaderData) in EXT:metaseo to add the header data to prevent duplicate tags with same content.

[thomaszbz]

#39 with 1c00ab5 perfectly prepares this refactoring step. Just that I'd like to see

• objects instead of arrays per meta tag
• Lists/ArrayLists instead of arrays which contain keys to empty arrays or empty strings
• Use of SPL or corresponding framework support for data structure, still capable for use with Fluid.
• Use of a function getTags() and containsTag($tagName) or similar