Making a NAPTR rdata

[anpenik]

Hi,

I'm trying to create a NAPTR record, which contains regexp !^(.*)$!tel:\1! in the following way

s = f"10 50 \"U\" \"E2U+pstn:tel\" \"!^(.*)$!tel:\\1;mcc={mcc};mnc={j['mnc']};code={j['code']};region={j['region']};rn=D{j['region']}{j['mnc']}!\""
rd = rdata.from_text(1, rdatatype.NAPTR, s, relativize=False)

Unfortunately

File /usr/local/lib/python3.13/site-packages/dns/tokenizer.py:127, in Token.unescape(self)
    125 i += 1
    126 if not (c2.isdigit() and c3.isdigit()):
--> 127     raise dns.exception.SyntaxError
    128 codepoint = int(c) * 100 + int(c2) * 10 + int(c3)
    129 if codepoint > 255:

SyntaxError: Text input is malformed.

Is there any way to achieve my goal?

[rthalley]

You need to account for escaping both in python AND in the DNS zonefile format, as it too uses backslash for escaping. So you need to escape the escapes! This works:

import dns.rdata
import dns.rdatatype

s = f"10 50 \"U\" \"E2U+pstn:tel\" \"!^(.*)$!tel:\\\\1!\" ."
print(s)
rd = dns.rdata.from_text(1, dns.rdatatype.NAPTR, s, relativize=False)
print(rd)