Read DB entries dynamically in TypoScript - html

Question

I have the following setup for my Typo3 installation:
TypoScript:
lib.responsiveImage = IMAGE
lib.responsiveImage {
default = IMAGE
default{
file {
import.current = 1
treatIdAsReference = 1
}
altText.data = DB:sys_file_reference:26:alternative
titleText.data = current
}
}
Which produces the following output Tag (unneccessary content deleted; important is the alt and the title tag):
<img class="img-responsive" srcset="XY.jpg" alt="AltText" title="26" sizes="(min-width: 1200px) 1100px">
As you can see, current delivers the correct uid of "26". The database query via DB:sys_file_reference:26:alternative delivers the correct "AltText".
However -> How could i achieve that dynamically?
I tried something like this
DB:sys_file_reference:{current}:alternative
but this doesnt worked. current should be the uid of an FileReference
(Also altText.data = file:current:alternative gives me an Error: No File Object)

Answer 1

Maybe the use of the FILES element is safer:
lib.responsiveImage = FILES
lib.repsonsiveImage {
references.current = 1
renderObj = IMAGE
renderObj {
file.import.data = file:current:uid
file.treatIdAsReference = 1
altText.data = file:current:alternative
titleText.data = file:current:title
emptyTitleHandling = useAlt
}
}

Answer 2

Luckily i found a solution:
default = IMAGE
default{
file {
import.current = 1
treatIdAsReference = 1
}
sourceCollection < tt_content.image.20.1.sourceCollection
layout < tt_content.image.20.1.layout
layoutKey = srcset
altText.data.dataWrap = DB:sys_file_reference:{current}:alternative
altText.wrap = |
}
If you use dataWrap the {current}works as expected!