2 May
2023
2 May
'23
4:10 a.m.
Hello,
indeed, it is somehow confusing, because in terms of evaluating the
return code in logical expression, 'false' means the return code was
negative and 'true' means it was positve.
Then the core keywords 'true' and 'false' are just aliases to 1 and 0
for use with core parameters, but their meaning is not related to
logical evaluation of function's return code.
Someone decided like 20 years ago to have this kind of logical
evaluation and it continued to be like that till now.
There was a regression at some point when return 0 was no longer
exiting, being fixed at some point. One may notice the behaviour change
if run same config before and after.
In general is not good to just return the value from execution of a
function, but evaluate to true or false and return explicitly own
values. Instead of
return x()
do:
if(x()) {
return 1;
} else {
return -1;
}
Cheers,
Daniel
On 01.05.23 01:10, Patrick Wakano wrote:
Thanks very much for the clarification Daniel!
Appreciate it!
However it does seem that some modules have inconsistencies with
return values now. So, for instance, the is_ip_rfc918() says it will
return true or false
(https://kamailio.org/docs/modules/5.6.x/modules/ipops.html#ipops.f.is_ip_rf…
- most functions of this module return true or false) and then when
used directly with return, it terminates execution. Based on your
explanation, it shouldn't return true or false, but likely -1 or 1,
which would never be considered 'return 0'
Also, the below code works in version 5.4, but terminates execution in
version 5.6, so are you aware of changes in this behaviour in version
5.5 or 5.6 (before the 5.7 changes you mentioned)?
route[is_src_private]
{
return is_ip_rfc1918("$si");
}
request_route
{
...
if (route(is_src_private)) {
xlog("L_NOTICE", "SRC private\n");
} else {
xlog("L_NOTICE", "SRC public\n");
}
...
}
Best regards!
Patrick
On Fri, 28 Apr 2023 at 16:29, Daniel-Constantin Mierla
<miconda(a)gmail.com> wrote:
Hello,
false is 0 and it was actually designed for setting global
parameters, not for use as comparison with functions return code
or as parameter for return from route blocks. Like:
log_stderror = false
The grammar of the language defines a coupe of token variants for
same purpose:
YES "yes"|"true"|"on"|"enable"
NO "no"|"false"|"off"|"disable"
Where YES is replaced by 1 and NO is replaced by 0:
<INITIAL>{YES} { count(); yylval.intval=1;
yy_number_str=yytext; return NUMBER; }
<INITIAL>{NO} { count(); yylval.intval=0;
yy_number_str=yytext; return NUMBER; }
In the devel version (upcoming 5.7.0), the evaluation of return
mode can be controlled by core parameter return_mode, allowing to
switch to a more "standard" mode, similar to other scripting
languages -- see:
-
https://www.kamailio.org/wikidocs/cookbooks/devel/core/#return_mode
Cheers,
Daniel
On 28.04.23 08:14, Patrick Wakano wrote:
--
Daniel-Constantin Mierla -- www.asipto.com
www.twitter.com/miconda -- www.linkedin.com/in/miconda
Kamailio World Conference - June 5-7, 2023 - www.kamailioworld.com
Hi list,
Hope you are all well!
I'm using Kamailio version 5.6.4 (installed from the repo
rpm.kamailio.org/centos/7 <http://rpm.kamailio.org/centos/7>) and
noticed that every route that uses "return false" is exiting the
script, instead of returning.... This was not the case on version
5.4.6 as the same script is running fine.....
From this page
https://www.kamailio.org/wikidocs/tutorials/faq/main/#how-is-the-function-r…,
I would think that when a route returns false, it would return -1
and not stop execution, since negative is equal to false, but it
is actually stopping (same as return 0)...
So, as an example, this test code doesn't work as expected. In
case the source is a public IP, the script doesn't print the "SRC
public" it just exits and then of course every other logic meant
to be done is not executed....
route[is_src_private]
{
if (is_ip_rfc1918("$si")) {
return true;
}
return false;
#return is_ip_rfc1918("$si"); *# this doesn't work too in
case the $si is a public IP*
}
request_route
{
...
if (route(is_src_private)) {
xlog("L_NOTICE", "SRC private\n");
} else {
xlog("L_NOTICE", "SRC public\n");
}
...
}
If is_src_private is changed to return -1 instead of false, then
it all works fine.
Also, I noticed that the following code will print "TEST: 0" in
case the $si is public and then stop execution. So looks like
false is really being converted to 0, but I guess that's
unexpected... anyway apologies if I'm missing something obvious....
route[is_src_private]
{
$var(t) = false;
if (is_ip_rfc1918("$si")) {
$var(t) = true;
}
xlog("L_ERR", "TEST: $var(t)\n");
return $var(t);
}
I could not find a recent ticket or email related to this
situation and I've already spent hours trying to understand what
is the logic/problem here, so would anyone have been across a
similar case that could provide some insight and clarify what is
the expected behaviour of the *false* usage (and boolean in
general if possible)?
Thank you,
Kind regards,
Patrick Wakano
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www.twitter.com/miconda <http://www.twitter.com/miconda> --
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Kamailio World Conference - June 5-7, 2023 - www.kamailioworld.com
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