TYPO3 Core

Can you please provide more context ? The request object "should" be there in the rendering context. Do you render some kind of StandaloneView or something like that ?
Where do you use the CObjectViewHelper ?

I have extended the tt_content with various fields and want to render it on fluid with <f:cObject typoscriptObjectPath="lib.tx_maagitproduct.contentElement">{product.uid}</f:cObject>.

The typoscript is:
lib.tx_maagitproduct.contentElement = RECORDS
lib.tx_maagitproduct.contentElement {
tables = tt_content
source.current = 1
dontCheckPid = 1
}