PHP Class FluidTYPO3\Vhs\ViewHelpers\TryViewHelper
Attempts to render child content. If an Exception is encountered
while rendering, instead the
f:else child node is rendered,
if it is present. If
f:else is not used, no output is returned.
Can be used to perform complex translations of Exception messages
which can occur. Can naturally also be used to provide a great
deal of additional information about every possible Exception-type
error which Fluid can encounter (and there are many).
Note that this is a Condition ViewHelper which means you can use
the
f:then child node but it differs from regular Conditions by
also allowing the template developer to skip the
f:then child
node and use the direct tag content as the "TRUE" condition and
add an
f:else which is only rendered in case of an Exception
during rendering.
Also note that you can use the
then and
else attributes; the
then attribute is what is attempted rendered and the
else
attribute is what is rendered if retrieving the
then attribute's
value fails. Which clearly only makes sense if for example complex
inline ViewHelpers are used in the attributes.
### Example usage
#### Please note that this is a theoretical example!
The example is theoretical in one major aspect: v:format.json.decode
throws an Exception which Fluid displays as a string always - abstract
from this and imagine that a plain Exception happens on errors.
Displayed only if the JSON decode worked. Much more code and many more
ViewHelpers can go here. Now, imagine that this block spans so much code
that potentially there could come an Exception from many additional places
(for example from Widgets) and you cannot be sure where the Exception comes
from but still want to tell the user what exactly went wrong and provide
an error code which makes sense to send to developers if problems persist:
Error in "{exception.trace.0.class
-> v:iterator.explode(glue: '_')
-> v:iterator.pop()
-> v:format.replace(substring: 'ViewHelper', replacement: ''}"
{exception.code}
{exception.message}
Value: {exception.trace.0.args.0}´´
...or if you want a shorter version...
{v:try(then: '{badObject -> v:format.json.encode()}', else: '{"validJson": "validValue"')}
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Open project: fluidtypo3/vhs
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