[SR-Users] Caseless regex

[Marat Gareev]

Daniel,

"(?i)^test$" is just an example, actually regex is a little
more complicated.

In this case, libpcre3 is a good way to use PCRE expressions.

Thanks!

вт, 13 окт. 2020 г. в 16:48, Daniel-Constantin Mierla <miconda at gmail.com>:

> Hello,
>
> libpcre3 is known to be very fast, not sure you will notice any
> performance impact because of runtime regular expression parsing,
> everything being done in memory and for sure not with simple expressions
> like "(?i)^test$". This happens because the parameters can have
> variables, which are first evaluated, then used for matching.
>
> Anyhow, a variant of the function with static parameter for regex can be
> added easily.
>
> On the other hand, you seem to compare with a full value, so you can just
> use string comparison functions:
>
>   *
> https://www.kamailio.org/docs/modules/stable/modules/textops.html#textops.f.cmp_str
>
> Cheers,
> Daniel
> On 13.10.20 15:22, Marat Gareev wrote:
>
> Henning, Daniel,
> thanks for your replies.
>
> 1. I don't want to use a Regex module because it might have a performance
> impact.
>
>> Matches the given string parameter against the regular expression
>> pcre_regex, which is compiled in runtime into a PCRE object.
>>
>
> 2.  I was surprised to find that the operator "=~" is case insensitive:
> if (regcomp(re, (char*) exp->r.param,
> REG_EXTENDED|REG_NOSUB|REG_ICASE) ){
> LM_CRIT("bad re \"%s\"\n", (char*) exp->r.param);
> pkg_free(re);
> return E_BAD_RE;
> }
> so that enough for me:
> $tU =~ "^test$"
> Btw, what if I need case sensitive validation? Should I use the Regex
> module?
>
> Regards,
> Marat
>
> вт, 13 окт. 2020 г. в 14:17, Daniel-Constantin Mierla <miconda at gmail.com>:
>
>> Hello,
>>
>> adding some more details to mention that regex operations done by the
>> core (the =~ operator) use the libc posix regex functions, which do not
>> support extended syntax. Also, these operations done by core use the case
>> insensitive flag.
>>
>> As mentioned by Henning, regex should be an alternative, or maybe
>> dialplan if one wants db-storage+caching of those regex rules.
>>
>> Moreover, if the above are not enough, a kemi embedded interpreter (e.g.,
>> app_lua, app_python) can be used with inline execution in kamailio.cfg
>> routing blocks -- those external scripting languages should have many
>> options for regex matching.
>>
>> Cheers,
>> Daniel
>> On 13.10.20 13:04, Henning Westerholt wrote:
>>
>> Hello,
>>
>>
>>
>> just an idea, have you already tried this module:
>> https://www.kamailio.org/docs/modules/stable/modules/regex.html
>>
>>
>>
>> Cheers,
>>
>>
>>
>> Henning
>>
>>
>>
>> --
>>
>> Henning Westerholt – https://skalatan.de/blog/
>>
>> Kamailio services – https://gilawa.com
>>
>>
>>
>> *From:* sr-users <sr-users-bounces at lists.kamailio.org>
>> <sr-users-bounces at lists.kamailio.org> *On Behalf Of *Marat Gareev
>> *Sent:* Tuesday, October 13, 2020 10:55 AM
>> *To:* Kamailio (SER) - Users Mailing List <sr-users at lists.kamailio.org>
>> <sr-users at lists.kamailio.org>
>> *Subject:* [SR-Users] Caseless regex
>>
>>
>>
>> Hello,
>>
>>
>>
>> Is it possible write more readable regular expression
>>
>> if ($tU =~ "(?i)^test$") {
>>
>>     ...
>>
>> }
>>
>> instead of "^[tT][eE][sS][tT]$"?
>>
>>
>>
>> On the first option, I get the error:
>>
>> 0(47250) ERROR: <core> [core/rvalue.c:3038]: fix_match_rve(): Bad regular
>> expression
>>
>>
>>
>> Regards,
>>
>> Marat
>>
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>>
>> --
>> Daniel-Constantin Mierla -- www.asipto.comwww.twitter.com/miconda -- www.linkedin.com/in/miconda
>> Funding: https://www.paypal.me/dcmierla
>>
>> _______________________________________________
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>>
> --
> Daniel-Constantin Mierla -- www.asipto.comwww.twitter.com/miconda -- www.linkedin.com/in/miconda
> Funding: https://www.paypal.me/dcmierla
>
>
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