EXTRACT condition

[Arsha ap]

I have flow that gets file abd.json from the server .
The extract condition Should read the file to check for {} or {"withdata,numberandspecialcharacters in it"}.
If the file has only {} then finish the flow ,if file has data then send email to user .


I tried the extract condition with different regex and offset combos ,but every time the extract condition comes with search not found comment.
Extracting Text from Files

File will have just 1 line.

Looking for suggestions.

p.s- new to uc4