2 May
2018
2 May
'18
5:50 p.m.
Hello,
I'm a a bit confused as to when string concatenation will work in kamailio
config file. So far I have identified the following cases:
Working:
As part of the right hand side of an assignment:
$var(x) = "string1" + "string2";
String argument of some functions:
xlog("L_ERR", "string1" + "string2" + DEFINED_STRING +
'\n');
Conditional Statements:
if ( ru =~ "$" + "sip:" + $var(user) ) {
Not Working:
In string transformations (the fact that quotes is not part of the argument
should give a hint though:
$var(x) = $(var(y){s.replace,match,"repl1" + "repl2"});
String argument of some other functions:
append_hf_value("P-Asserted-Identity", "<" +
"$var(new_pai)" + ">");
lookup("location", "sip:$var(username)@" + SIP_REALM_DEFINITION));
In module parameter definitions:
modparam("nathelper", "sipping_from", "sip:keepalive@" +
SIP_REALM_DEFINITION)
So far, I have found this to be fairly consistent, except for use within
functions. For example, string concatenation works for the second argument
of xlog, but not for the string arguments of append_hf_value() or lookup().
Is there anyway to know this for each function beforehand, or is my only
choice to go through trial and error here? Thanks!
BR,
George
2 May
2 May
6:05 p.m.
You are correct that concatenation vs interpolation works and doesn't work in slightly
inconsistent ways, for instance function string arguments vs assignment.
The $_s() transformation may help make life easier.
On May 2, 2018 10:50:53 AM EDT, George Diamantopoulos <georgediam(a)gmail.com> wrote:
Hello,
I'm a a bit confused as to when string concatenation will work in
kamailio
config file. So far I have identified the following cases:
Working:
As part of the right hand side of an assignment:
$var(x) = "string1" + "string2";
String argument of some functions:
xlog("L_ERR", "string1" + "string2" + DEFINED_STRING +
'\n');
Conditional Statements:
if ( ru =~ "$" + "sip:" + $var(user) ) {
Not Working:
In string transformations (the fact that quotes is not part of the
argument
should give a hint though:
$var(x) = $(var(y){s.replace,match,"repl1" + "repl2"});
String argument of some other functions:
append_hf_value("P-Asserted-Identity", "<" +
"$var(new_pai)" + ">");
lookup("location", "sip:$var(username)@" + SIP_REALM_DEFINITION));
In module parameter definitions:
modparam("nathelper", "sipping_from", "sip:keepalive@" +
SIP_REALM_DEFINITION)
So far, I have found this to be fairly consistent, except for use
within
functions. For example, string concatenation works for the second
argument
of xlog, but not for the string arguments of append_hf_value() or
lookup().
Is there anyway to know this for each function beforehand, or is my
only
choice to go through trial and error here? Thanks!
BR,
George
-- Alex
--
Sent via mobile, please forgive typos and brevity.
8:07 p.m.
Hello,
indeed, there is some inconsistency here brought in after the merge with
SIP Express Router back in 2008.
Traditionally, Kamailio (or openser before 2008) didn't support
concatenation expressions as function parameters. That came via SER
branch and it is not available everywhere in a consistent and coherent
way (even for the code of modules imported from SER).
If you want to be in the safe side from Kamailio behaviour point of
view, as I never got into using SER style, here are some hints based on
what I typically do:
- use concatenation expressions with '+' only in assignments, like:
$var(x) = "string1" + "string2";
- use dynamic strings with variables as function parameters, like:
xlog("L_ERR", "string $var(x) more-string $var(y)\n");
- use and assignment to a private variable first or $_s(...) variable
on positions that expect a string or a var, such as transformation
parameters, like:
$var(r) = "repl1" + "repl2";
$var(x) = $(var(y){s.replace,match,$var(r)});
Cheers,
Daniel
On 02.05.18 17:05, Alex Balashov wrote:
You are correct that concatenation vs interpolation
works and doesn't work in slightly inconsistent ways, for instance function string
arguments vs assignment.
The $_s() transformation may help make life easier.
On May 2, 2018 10:50:53 AM EDT, George Diamantopoulos <georgediam(a)gmail.com>
wrote:
--
Daniel-Constantin Mierla
www.twitter.com/miconda -- www.linkedin.com/in/miconda
Kamailio World Conference - May 14-16, 2018 - www.kamailioworld.com
Hello,
I'm a a bit confused as to when string concatenation will work in
kamailio
config file. So far I have identified the following cases:
Working:
As part of the right hand side of an assignment:
$var(x) = "string1" + "string2";
String argument of some functions:
xlog("L_ERR", "string1" + "string2" + DEFINED_STRING +
'\n');
Conditional Statements:
if ( ru =~ "$" + "sip:" + $var(user) ) {
Not Working:
In string transformations (the fact that quotes is not part of the
argument
should give a hint though:
$var(x) = $(var(y){s.replace,match,"repl1" + "repl2"});
String argument of some other functions:
append_hf_value("P-Asserted-Identity", "<" +
"$var(new_pai)" + ">");
lookup("location", "sip:$var(username)@" + SIP_REALM_DEFINITION));
In module parameter definitions:
modparam("nathelper", "sipping_from", "sip:keepalive@" +
SIP_REALM_DEFINITION)
So far, I have found this to be fairly consistent, except for use
within
functions. For example, string concatenation works for the second
argument
of xlog, but not for the string arguments of append_hf_value() or
lookup().
Is there anyway to know this for each function beforehand, or is my
only
choice to go through trial and error here? Thanks!
BR,
George
-- Alex
--
Sent via mobile, please forgive typos and brevity.
_______________________________________________
Kamailio (SER) - Users Mailing List
sr-users(a)lists.kamailio.org
https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
8:52 p.m.
Thank you both, this has been quite informative. I wasn't also aware of the
$_s() PV, it's handy indeed. Three more clarifications:
- Will $_s() work before the routing part of the config file, and
specifically with pre-processor definitions? For example in the following:
modparam("nathelper", "sipping_from",
$_s(sip:keepalive@SIP_REALM_DEFINITION
))?
- Will providing PVs in a dynamic string work with all functions, even for
those currently not supporting string concatenation? E.g.:
append_hf_value("P-Asserted-Identity", "<$var(new_pai)>");
If yes, I assume this will only work for PVs, as preprocessor defined
strings won't be substituted if the parser finds their labels enclosed in
quotes. In other words, the following won't work:
append_hf_value("P-Asserted-Identity",
"<$var(new_pai);SOME_DEF>");
- I assumed this would work in the first example, but maybe I should ask
explicitly. Will pre-processor defines work with the $_s() PV? Is this
valid at all?
$_s($ru;SOME_PREPROC_DEF=$var(value))
BR,
George
On 2 May 2018 at 20:07, Daniel-Constantin Mierla <miconda(a)gmail.com> wrote:
Hello,
indeed, there is some inconsistency here brought in after the merge with
SIP Express Router back in 2008.
Traditionally, Kamailio (or openser before 2008) didn't support
concatenation expressions as function parameters. That came via SER
branch and it is not available everywhere in a consistent and coherent
way (even for the code of modules imported from SER).
If you want to be in the safe side from Kamailio behaviour point of
view, as I never got into using SER style, here are some hints based on
what I typically do:
- use concatenation expressions with '+' only in assignments, like:
$var(x) = "string1" + "string2";
- use dynamic strings with variables as function parameters, like:
xlog("L_ERR", "string $var(x) more-string $var(y)\n");
- use and assignment to a private variable first or $_s(...) variable
on positions that expect a string or a var, such as transformation
parameters, like:
$var(r) = "repl1" + "repl2";
$var(x) = $(var(y){s.replace,match,$var(r)});
Cheers,
Daniel
On 02.05.18 17:05, Alex Balashov wrote:
--
Daniel-Constantin Mierla
www.twitter.com/miconda -- www.linkedin.com/in/miconda
Kamailio World Conference - May 14-16, 2018 - www.kamailioworld.com
_______________________________________________
Kamailio (SER) - Users Mailing List
sr-users(a)lists.kamailio.org
https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
You are correct that concatenation vs
interpolation works and doesn't
work in slightly inconsistent ways, for
instance function string arguments
vs assignment.
The $_s() transformation may help make life easier.
On May 2, 2018 10:50:53 AM EDT, George Diamantopoulos <
georgediam(a)gmail.com> wrote:
Hello,
I'm a a bit confused as to when string concatenation will work in
kamailio
config file. So far I have identified the following cases:
Working:
As part of the right hand side of an assignment:
$var(x) = "string1" + "string2";
String argument of some functions:
xlog("L_ERR", "string1" + "string2" + DEFINED_STRING +
'\n');
Conditional Statements:
if ( ru =~ "$" + "sip:" + $var(user) ) {
Not Working:
In string transformations (the fact that quotes is not part of the
argument
should give a hint though:
$var(x) = $(var(y){s.replace,match,"repl1" + "repl2"});
String argument of some other functions:
append_hf_value("P-Asserted-Identity", "<" +
"$var(new_pai)" + ">");
lookup("location", "sip:$var(username)@" + SIP_REALM_DEFINITION));
In module parameter definitions:
modparam("nathelper", "sipping_from", "sip:keepalive@" +
SIP_REALM_DEFINITION)
So far, I have found this to be fairly consistent, except for use
within
functions. For example, string concatenation works for the second
argument
of xlog, but not for the string arguments of append_hf_value() or
lookup().
Is there anyway to know this for each function beforehand, or is my
only
choice to go through trial and error here? Thanks!
BR,
George
-- Alex
--
Sent via mobile, please forgive typos and brevity.
_______________________________________________
Kamailio (SER) - Users Mailing List
sr-users(a)lists.kamailio.org
https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
8:58 p.m.
On Wed, May 02, 2018 at 08:52:03PM +0300, George Diamantopoulos wrote:
- Will $_s() work before the routing part of the
config file, and
specifically with pre-processor definitions? For example in the following:
modparam("nathelper", "sipping_from",
$_s(sip:keepalive@SIP_REALM_DEFINITION
))?
No. Transformations work in route script only.
- Will providing PVs in a dynamic string work with all
functions, even for
those currently not supporting string concatenation? E.g.:
append_hf_value("P-Asserted-Identity", "<$var(new_pai)>");
Only for functions which support PV interpolation. That's most
functions nowadays, but not some of the older ones from OpenSER <= 1.2.
If yes, I assume this will only work for PVs, as
preprocessor defined
strings won't be substituted if the parser finds their labels enclosed in
quotes. In other words, the following won't work:
append_hf_value("P-Asserted-Identity",
"<$var(new_pai);SOME_DEF>");
It will if SOME_DEF was defined via #!subst.
- I assumed this would work in the first example, but
maybe I should ask
explicitly. Will pre-processor defines work with the $_s() PV? Is this
valid at all?
$_s($ru;SOME_PREPROC_DEF=$var(value))
Not if SOME_PREPROC_DEF is a #!defined constant, no. But it will work if
it's a #!subst, as is also the case if it appears in strong constants.
#!subst "/SOME_PREPROC_DEF/xyz/"
$var(x) = 'abc123';
xlog("L_INFO", "$_s($ru;SOME_PREPROC_DEF=$var(x))\n");
May 02 13:57:42 allegro-1.evaristesys.com /usr/local/sbin/kamailio[13998]: INFO:
<script>: sip:s@10.150.20.2;xyz=abc123
-- Alex
--
Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
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4 comments
3 participants
participants (3)
-
Alex Balashov -
Daniel-Constantin Mierla -
George Diamantopoulos