OpenSER Pseudo-variables for Version 1.1.x

Authors of initial tutorial:
Elena-Ramona Modroiu
  <ramona (at) rosdev.ro>
Bogdan-Andrei Iancu
  <bogdan (at) voice-system.ro>
Daniel-Constantin Mierla
  <miconda (at) gmail.com>

The term “pseudo-variable” is used for special tokens that can be given as parameters to different script functions and they will be replaced with a value before the execution of the function.

The beginning of a “pseudo-variable” is marked by the character “$”. If you want to have the character “$” just double it “$$”.

There is a set of predefined pseudo-variables, which have the name composed from one to three letters, and special pseudo-variables that are references to dynamic fields (AVP and Headers)

Pseudo-variables can be used with many modules of OpenSER, among them:

* acc * avpops * textops * uac * xlog

Predefined pseudo-variables are listed in alphabetical order.

$$ - represents the character '$'

$ar - realm from Authorization or Proxy-Authorization header

$au - username from Authorization or Proxy-Authorization header

$br - reference to request's first branch

$bR - reference to request's all branches

$ci - reference to body of call-id header

$cl - reference to body of content-length header

$cs - reference to body of cseq header

$ct - reference to body of contact header

$cT - reference to body of content-type header

$dd - reference to IP domain of destination uri (IP from the NAT)

$di - reference to Diversion header URI

$dp - reference to port of destination uri

$dP - reference to transport protocol of destination uri

$ds - reference to destination set

$du - reference to destination uri

$fd - reference to domain in URI of 'From' header

$fn - reference to display name of 'From' header

$ft - reference to tag parameter of 'From' header

$fu - reference to URI of 'From' header

$fU - reference to username in URI of 'From' header

$mb - reference to SIP message buffer

$mf - reference to flags set for current SIP request

$mF -reference to flags set for current SIP request in hexa

$mi - reference to SIP message id

$ml - reference to SIP message length ybcslmio, http://lynntownship.org/ clomid, bbcqumby

$od - reference to domain in request's original URI

$op - reference to port of original R-URI

$oP - reference to transport protocol of original R-URI

$ou - reference to request's original URI

$oU - reference to username in request's original URI

$pp - reference to process id (pid)

$rd - reference to domain in request's URI

$rb - reference to message body

$rc - reference to returned code by last invoked function

$rm - reference to request's method

$rp - reference to port of R-URI

$rP - reference to transport protocol of R-URI

$rr - reference to reply's reason

$rs - reference to reply's status

$rt - reference to URI of refer-to header

$ru - reference to request's URI

$rU - reference to username in request's URI

$Ri - reference to IP address of the interface where the request has been received

$Rp - reference to the port where the message was received

$si - reference to IP source address of the message

$sp - reference to the source port of the message

$fs - reference to the forced socket for the message sending (if any)

$td - reference to domain in URI of 'To' header

$tn - reference to display name of 'To' header

$tt - reference to tag parameter of 'To' header

$tu - reference to URI of 'To' header

$tU - reference to username in URI of 'To' header

$Tf - reference string formatted time

$Ts - reference to unix time stamp

$ua - reference to user agent header field

$re - reference to Remote-Party-ID header URI

$avp(id[N]) - represents the value of N-th AVP identified by 'id'.

The 'id' can be:

* “[si]:name” - name is the id of an AVP; 's' and 'i' specifies if the id is string or integer. If missing, it is considered to be string. * “$name” - the name is an AVP alias

$hdr(name[N]) - represents the body of the N-th header identified by 'name'. If [N] is omitted then the body of the first header is printed. The first header is got when N=0, for the second N=1, a.s.o. To print the last header of that type, use -1, no other negative values are supported now. No white spaces are allowed inside the specifier (before }, before or after {, [, ] symbols). When N='*', all headers of that type are printed.

The module should identify most of compact header names (the ones recognized by OpenSER which should be all at this moment), if not, the compact form has to be specified explicitly. It is recommended to use dedicated specifiers for headers (e.g., %ua for user agent header), if they are available – they are faster.

These pseudo variables are used by xlog module to print messages in many colors using escape sequences. The other modules ingnore them or throw error if they met these pseudo-variables.

$Cxy - reference to an escape sequence. “x” represents the foreground color and “y” represents the background color.

Colors could be:

* x : default color of the terminal * s : Black * r : Red * g : Green * y : Yellow * b : Blue * p : Purple * c : Cyan * w : White

A few examples of usage.

Example 1. Pseudo-variables usage

...
modparam("avpops", "avp_aliases", "uuid=I:50")
...
route {
...
    avp_write("caller_id", "$uuid");
    avp_printf("$avp(i:20)", "$avp($uuid): $fu");
    xdbg("$Cbgi:20$Cxx [$avp(i:20)] $Cbrcseq$Cxx=[$hdr(cseq)]\n");
...
}
...

This document is valid for following OpenSER versions:

- OpenSER Devel v1.1.x

dissertation editing