Remove all non printable symbol - how?

Questions
1

sometimes after http request i get strange responce data with unexpected line break

  response = "

mzEujGkHlTvKJVU9MAW5wXNSoSnkHBcswhEuVab52goozpkeUOzqi0nXKSGVj4mR"

ill try remove

response.response = string.gsub(response.response, '%s+', '') 
response.response = string.gsub(response.response, '^%s*(.-)%s*$', '%1')

but i have this

response = " mzEujGkHlTvKJVU9MAW5wXNSoSnkHBcswhEuVab52goozpkeUOzqi0nXKSGVj4mR"

i get first space and its - ZERO WIDTH NO-BREAK SPACE

1
11285×724 32.3 KB

empty space a randomly in responce
defold 1.9.7

2

Control character removal?: resp = resp:gsub('[%c]', '')

3

Yes it is

1
11600×900 56.3 KB

two try with errors (((

and 8 try normal

i test this space and get this

2
21600×900 43.4 KB

where does this garbage come from anyway
:sob:

4

defold 1.7.0 have this problem too ((

5

How can I reproduce this?

6

I dont know (( realy. But i find solution. i cant remove this symbol with gsub - i just get substring from 4 position in string if i cant decode responce. responce is base64 encoded data and aes encrypted and gziped )). maybe server side bug, i dont know. its very weird bug ((