Collection of general purpose ViewHelpers usable in the Fluid templating engine that's bundled with the TYPO3 CMS.

A quick explanation can be read in this README.

Examples, tips and tricks can be found in the Wiki: https://github.com/FluidTYPO3/vhs/wiki

Can be found online at:

http://fedext.net/viewhelpers/vhs.html

Download and install as TYPO3 extension. That's it. There are no configuration options apart from the arguments which each ViewHelper accepts.

Although there are no static TypoScript files which can be included, VHS does support a few key settings which are defined in TypoScript:

• plugin.tx_vhs.settings.debug = 1 can be used to enable general debugging, which affects:
  • Asset inclusions are debugged right before inclusion in the page
• plugin.tx_vhs.settings.asset.debug = 1 can be used to enable debug output from individual Asset ViewHelper instances. Applies when a ViewHelper uses the "debug" parameter (where this is supported) and/or when plugin.tx_vhs.settings.debug = 1.
• plugin.tx_vhs.settings.useDebugUtility which causes VHS to use Extbase's DebugUtility to dump variables. If this setting is not defined a value of 1 is assumed.

VHS contains a highly useful feature which enables you to define Assets (CSS/JS/etc) in Fluid templates, PHP and TypoScript. What's different from the traditional ways of including such Assets (in Fluid or otherwise) all are used differently, controlled differently and probably worst of all, not all of them are integrator friendly (as in: allows Assets to be affected using TypoScript). VHS Assets solves all of this.

The following Fluid usage:

<v:asset.script path="fileadmin/demo.js" />

Is the exact same as ths PHP:

Tx_Vhs_Asset::createFromFile('fileadmin/demo.js');

Which is a short form of:

Tx_Vhs_Asset::createFromSettings(array(
	'name' => 'demo',
	'path' => 'fileadmin/demo.js'
));

Which is itself a short form of:

$asset = Tx_Vhs_Asset::getInstance();
// or alternatively, if this fits better in your other code:
$asset = $objectManager->get('Tx_Vhs_Asset');
// then:
$asset->setName('demo');
$asset->setPath('fileadmin/demo.js');
$asset->finalize(); // manually created Assets must be finalized before they show up.

The PHP above does the exact same as this TypoScript:

plugin.tx_vhs.settngs.asset.demo.path = fileadmin/demo.js

Which is a short form of:

plugin.tx_vhs.settings.asset.demo {
	name = demo
	path = fileadmin/demo.js
}

In summary: regardless of where and how you use VHS Assets, they always use the same attributes, they always behave the same, support the same features (such as dependency on other Assets regardless of inclusion order and addressing Assets by a group name to affect multiple Assets - and even rendering JS/CSS as if the file was a Fluid template).

The API for inclusion changes but the result is the same.

But the real benefit of VHS Assets comes in the form of the TypoScript integration, which lets you override settings of individual Assets (regardless of how they were originally defined - Fluid, PHP, TypoScript) by setting their attributes in TypoScript. This allows integrators to control every aspect of every Asset (but not the ones included in traditional ways) all the way down to replacing the script source or CSS content that gets inserted or moving JS file(s) which used by be merged, to a new CDN server without even breaking dependencies and execution order.

To affect VHS Assets through TypoScript, the following settings can be used:

plugin.tx_vhs.settings.asset.ASSETNAME {
	content = Text # Text which overrides content
	path = FileReference # If set, turns Asset into a file inclusion
	name = Text a-zA-Z0-9_ # Can be used to change the name of an Asset on-the-fly, but watch out for dependencies
	overwrite = Integer 0/1 # If set to `1` this Asset is permitted to overwrite existing, identically named Assets
	dependencies = CSV # list of comma-separated Asset names upon which the current Asset depends; affects loading order
	group = Text a-zA-Z0-9_ # Group name, default "fluid". By grouping Assets the settings used on the group will apply to Assets
	debug = Integer 0/1 # If `1` enables debug output of each asset
	standalone = Integer 0/1 # If `1` instructs VHS to process this Asset as standalone, excluding it from merging
	allowMoveToFooter = Integer 0/1 # If `0` prevents Assets from being included in the page footer. Used by style-type Assets.
	trim = Integer 0/1 # If `1` enables trimming of whitespace from beginning and end of lines when merging Assets
	namedChunks = Integer 0/1 # If `0` prevents Asset name from being inserted as comment above the Asset body in merged files
}
plugin.tx_vhs.settings.assetGroup.ASSETGROUPNAME {
	# this object supports the following properties only. When applied to a group the settings are used by each
	# Asset in that group, unless overridden directly in the Asset's attributes or through TypoScript as above.
	# SUPPORTED PROPERTIES: overwrite, dependencies, group, debug, standalone, allowMoveToFooter, trim and namedChunks
	# Please note: changing the "group" property changes the name of the group which means another group configuration
	# must be added which configures that group. Otherwise settings may be ignored.
}
plugin.tx_vhs.settings.asset {
	# this object supports every property which "assetGroup" supports except for the "group" and "dependencies" properties.
}
plugin.tx_vhs.assets {
	mergedAssetsUseHashedFilename = 0 # If set to a 1, Assets are merged into a file named using a hash if Assets' names.
}

You can configure VHS to write path prepends in two ways, one of which allows you to create a so-called "cookie-free domain" on which requests will contain fewer headers. Normally, setting config.absRefPrefix causes your resources' paths to be prefixed with a domain, but using this approach will always prepend a domain name which cannot be "cookie-free". VHS allows an alternative setting for path prefix, which can be set to a secondary domain name (pointing to the same virtual host or not) which sets no cookies, causing all asset tags to be written with this prefix prepended:

plugin.tx_vhs.settings.prependPath = http://static.mydomain.com/

The setting affects every relative-path resource ViewHelper (NB: this does not include links!) in VHS, which is why it is not placed inside the "asset" scope. If you need to output this prefix path in templates you can use the v:page.staticPrefix ViewHelper - it accepts no arguments and only outputs the setting if it is set. For example, using f:image will not prefix the image path but manually creating an <img /> tag and using f:uri.image as src argument will allow you to prefix the path.

To use the ViewHelpers in your Fluid templates simply add the namespace:

{namespace v=Tx_Vhs_ViewHelpers}

Using the namespace name "v" is not required but it is recommended. It's a single character like the "f" namespace but is visually easy to distinguish from "f".

Many of the VHS ViewHelpers make particular sense when used with their inline syntax. Special care was taken to allow compact notations such as this:

<f:for each="{myQueryResult -> v:iterator.sort(sortBy: 'name')}" as="record">
	...
</f:for>

In the above case the sorted QueryResult is used only in the specific loop, preserving the order of the original QueryResult.

Multiple chained syntax is also possible:

{bytes->v:math.division(b: 1024)->v:math.round()->f:format.number()} KB

Which will first take variable {bytes} and divide by 1024 to get a float KB size. Then round that off to a whole integer and finally use f:format.number to ensure a localized display of thousands and decimal separators. Which is fairly neat considering how such an operation would appear if constructed in, for example, a Domain Object's getter method. The alternative would be to create a highly customized "Format/KilobyteSizeViewHelper" or similar.

ViewHelpers for which this makes special sense are the formatting and math ViewHelpers. These work well when applied in sequences such as the above or cases such as this:

{text -> v:format.trim() -> v:format.markdown()}

Naturally, the tag-based usage is supported the same way as the above but with one caveat which one should always be aware of; that Fluid will render whitespace characters between tags so that when you break your nested ViewHelper tags into multiple lines you will risk causing data type mismatch errors - especially when using v:math which can result in quite large expressions which would be very tempting to break into individual lines.

Regarding nesting of ViewHelpers you should note that v:format.trim does remove extra whitespace - but it also converts the returned value to a string which could potentially be misinterpreted when used as numeric values.

It is highly recommended to use the inline annotation when your return values have a specific type before being output. Which is exactly the case when working with the v:math.* ViewHelpers.

• PHP 5.3.3: Due to errors in the class loader, you should recompile / upgrade to a more recent version. PHP 5.3.7 is recommended at least

Understanding the Abstraction Instability Chart and Pyramid Chart.