[OpenSIPS-Users] [NEW] New Pseudo-Variables (branch and contacts manipulation)

Bogdan-Andrei Iancu bogdan at voice-system.ro
Mon Jul 6 13:24:53 CEST 2009


OpenSIPS 1.6 (current trunk) comes with new additions to the 
Pseudo-Variables set:

1) Message Contact processing

$ct - **reference to contact instance/body from the contact header. A 
contact instance is "display_name + URI + contact_params" or "*" . As a 
Contact header may contain multiple Contact instances and a message may 
contain multiple Contact headers, an index was added to the $ct variable:

    * $ct -first contact instance from message
    * $(ct[n]) - the n-th contact instance form the beginning of
      message, starting with index 0
    * $(ct[-n]) - the n-th contact instance form the end of the message,
      starting with index -1 (the last contact instance)

$ct.fields() -  reference to the sub-fields of a contact instance/body 
(see above). Supported fields are:

    * name - display name
    * uri - contact uri
    * q - q param (value only)
    * expires - expires param (value only)
    * methods - methods param (value only)
    * received - received param (value only)
    * params - all params (including names)

Scenario Example - iterate through all contacts of a REGISTER, to check 
the registered contacts:

    $var(i) = 0;
    while( $(ct[$var(i)])!=NULL ) {
        if ( (ct.fields(uri)[$var(i)])!=NULL )
            xlog("-------contact $var(i) -> $(ct.fields(uri)[$var(i)])\n");
            if ( $(ct.fields(uri)[$var(i)]{uri.host})==""   ) {
                sl_send_reply("401","Forbidden IP in contact");
       } else {
            xlog("-------contact $var(i) is STAR\n")
       $var(i) = $var(i) + 1;

2) Branch processing

$branch - simple variable to write into in order to create a new branch:
    $branch = "sip:user at domain.org";

$(branch(fields)[N]) - this variable provides read/write access to all 
fields/attributes of an already existing branch (priorly created with 
append_branch() ). The fields of the branch are:

    * uri - the RURI of the branch (string value)
    * duri - destination URI of the branch (outbound proxy of the
      branch) (string value)
    * q - q value of the branch (int value)
    * path - the PATH string for this branch (string value)
    * flags - the branch flags of this branch (int value)
    * socket - the local socket to be used for relaying this branch
      (string value)

The variable accepts also index *$(branch(uri)[1])* for accessing a 
specific branch (multiple branches can be defined at a moment). The 
index starts from 0 (first branch). If the index is negative, it is 
considered the n-th branch from the end ( index -1 means the last branch).
To get all branches, use the * index - $(branch(uri)[*]).

This pseudo-variable was introduce to solve the need of inspecting and 
changing the branches that were automatically added by module functions 
(like uac_redirect, registrar, lcr, etc).

Usage Example:

    # creates the first branch
    $branch = "sip:tester at opensips.org";
    # creates the second branch
    $du = "sip:";
    append_branch("sip:foo at bar.com","0.5");

    # display branches
    xlog("----- branch 0: $(branch(uri)[0]) , $(branch(q)[0]), 
$(branch(duri)[0]), $(branch(path)[0]), $(branch(flags)[0]), 
$(branch(socket)[0]) \n");
    xlog("----- branch 1: $(branch(uri)[1]) , $(branch(q)[1]), 
$(branch(duri)[1]), $(branch(path)[1]), $(branch(flags)[1]), 
$(branch(socket)[1]) \n");

    # do some changes over the branches
    $branch(uri) = "sip:user at domain.ro"; # change the URI for the first 
    $(branch(q)[0]) = 1000; # change q to 1.00 for the first branch
    $(branch(socket)[1]) = NULL; # reset the socket of the second branch
    $branch(duri) = NULL; # reset the destination URI of the first branch

Scenario Example - iterate through all existing branches and display them:

    if (lookup("location")) {
           $var(i) = 0;
           while( $(brnach(uri)[$var(i)])!=NULL ) {
                xlog("-------branch $var(i) -> $(branch(uri)[$var(i)])\n");
                $var(i) = $var(i) + 1;

3) Startup time stamp

$TS - unix timestamp for the


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