textops Module

Andrei Pelinescu-Onciul

   FhG FOKUS

Edited by

Andrei Pelinescu-Onciul

Daniel-Constantin Mierla

   Copyright © 2003 FhG FOKUS
     __________________________________________________________

   Table of Contents
   1. User's Guide

        1.1. Overview

              1.1.1. Known Limitations

        1.2. Dependencies

              1.2.1. OpenSER Modules
              1.2.2. External Libraries or Applications

        1.3. Exported Functions

              1.3.1. search(re)
              1.3.2. search_body(re)
              1.3.3. search_append(re, txt)
              1.3.4. search_append_body(re, txt)
              1.3.5. replace(re, txt)
              1.3.6. replace_body(re, txt)
              1.3.7. replace_all(re, txt)
              1.3.8. replace_body_all(re, txt)
              1.3.9. subst('/re/repl/flags')
              1.3.10. subst_uri('/re/repl/flags')
              1.3.11. subst_user('/re/repl/flags')
              1.3.12. subst_body('/re/repl/flags')
              1.3.13. filter_body(content_type)
              1.3.14. append_to_reply(txt)
              1.3.15. append_hf(txt)
              1.3.16. append_hf(txt, hdr)
              1.3.17. insert_hf(txt)
              1.3.18. insert_hf(txt, hdr)
              1.3.19. append_urihf(prefix, suffix)
              1.3.20. is_present_hf(hf_name)
              1.3.21. append_time()
              1.3.22. is_method(name)
              1.3.23. remove_hf(hname)
              1.3.24. has_body(), has_body(mime)
              1.3.25. is_privacy(privacy_type)

        1.4. Known Limitations

   2. Developer's Guide
   3. Frequently Asked Questions

   List of Examples
   1-1. search usage
   1-2. search_body usage
   1-3. search_append usage
   1-4. search_append_body usage
   1-5. replace usage
   1-6. replace_body usage
   1-7. replace_all usage
   1-8. replace_body_all usage
   1-9. subst usage
   1-10. subst_uri usage
   1-11. subst usage
   1-12. subst_body usage
   1-13. filter_body usage
   1-14. append_to_reply usage
   1-15. append_hf usage
   1-16. append_hf usage
   1-17. insert_hf usage
   1-18. insert_hf usage
   1-19. append_urihf usage
   1-20. is_present_hf usage
   1-21. append_time usage
   1-22. is_method usage
   1-23. remove_hf usage
   1-24. has_body usage
   1-25. is_privacy usage
     __________________________________________________________

Chapter 1. User's Guide

1.1. Overview

   The module implements text based operations over the SIP
   message processed by OpenSER. SIP is a text based protocol and
   the module provides a large set of very useful functions to
   manipulate the message at text level, e.g., regular expression
   search and replace, Perl-like substitutions, checks for method
   type, header presence, insert of new header and date, etc.
     __________________________________________________________

1.1.1. Known Limitations

   search ignores folded lines. For example,
   search("(From|f):.*@foo.bar") doesn't match the following From
   header field:
From: medabeda
 <sip:medameda@foo.bar>;tag=1234
     __________________________________________________________

1.2. Dependencies

1.2.1. OpenSER Modules

   The following modules must be loaded before this module:

     * No dependencies on other OpenSER modules.
     __________________________________________________________

1.2.2. External Libraries or Applications

   The following libraries or applications must be installed
   before running OpenSER with this module loaded:

     * None.
     __________________________________________________________

1.3. Exported Functions

1.3.1. search(re)

   Searches for the re in the message.

   Meaning of the parameters is as follows:

     * re - Regular expression.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, BRANCH_ROUTE.

   Example 1-1. search usage
...
if ( search("[Ss][Ii][Pp]") ) { /*....*/ };
...
     __________________________________________________________

1.3.2. search_body(re)

   Searches for the re in the body of the message.

   Meaning of the parameters is as follows:

     * re - Regular expression.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, BRANCH_ROUTE.

   Example 1-2. search_body usage
...
if ( search_body("[Ss][Ii][Pp]") ) { /*....*/ };
...
     __________________________________________________________

1.3.3. search_append(re, txt)

   Searches for the first match of re and appends txt after it.

   Meaning of the parameters is as follows:

     * re - Regular expression.
     * txt - String to be appended.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, BRANCH_ROUTE.

   Example 1-3. search_append usage
...
search_append("[Oo]pen[Ss]er", " SIP Proxy");
...
     __________________________________________________________

1.3.4. search_append_body(re, txt)

   Searches for the first match of re in the body of the message
   and appends txt after it.

   Meaning of the parameters is as follows:

     * re - Regular expression.
     * txt - String to be appended.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, BRANCH_ROUTE.

   Example 1-4. search_append_body usage
...
search_append_body("[Oo]pen[Ss]er", " SIP Proxy");
...
     __________________________________________________________

1.3.5. replace(re, txt)

   Replaces the first occurrence of re with txt.

   Meaning of the parameters is as follows:

     * re - Regular expression.
     * txt - String.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, BRANCH_ROUTE.

   Example 1-5. replace usage
...
replace("openser", "OpenSER SIP Proxy");
...
     __________________________________________________________

1.3.6. replace_body(re, txt)

   Replaces the first occurrence of re in the body of the message
   with txt.

   Meaning of the parameters is as follows:

     * re - Regular expression.
     * txt - String.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, BRANCH_ROUTE.

   Example 1-6. replace_body usage
...
replace_body("openser", "OpenSER SIP Proxy");
...
     __________________________________________________________

1.3.7. replace_all(re, txt)

   Replaces all occurrence of re with txt.

   Meaning of the parameters is as follows:

     * re - Regular expression.
     * txt - String.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, BRANCH_ROUTE.

   Example 1-7. replace_all usage
...
replace_all("openser", "OpenSER SIP Proxy");
...
     __________________________________________________________

1.3.8. replace_body_all(re, txt)

   Replaces all occurrence of re in the body of the message with
   txt.

   Meaning of the parameters is as follows:

     * re - Regular expression.
     * txt - String.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, BRANCH_ROUTE.

   Example 1-8. replace_body_all usage
...
replace_body_all("openser", "OpenSER SIP Proxy");
...
     __________________________________________________________

1.3.9. subst('/re/repl/flags')

   Replaces re with repl (sed or perl like).

   Meaning of the parameters is as follows:

     * '/re/repl/flags' - sed like regular expression. flags can
       be a combination of i (case insensitive), g (global) or s
       (match newline don't treat it as end of line).
       're' - is regular expresion
       'repl' - is replacement string - may contain
       pseudo-varibales
       'flags' - substitution flags (i - ignore case, g - global)

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, BRANCH_ROUTE.

   Example 1-9. subst usage
...
# replace the uri in to: with the message uri (just an example)
if ( subst('/^To:(.*)sip:[^@]*@[a-zA-Z0-9.]+(.*)$/t:\1\u\2/ig') ) {};

# replace the uri in to: with the value of avp sip_address (just an exam
ple)
if ( subst('/^To:(.*)sip:[^@]*@[a-zA-Z0-9.]+(.*)$/t:\1$avp(sip_address)\
2/ig') ) {};

...
     __________________________________________________________

1.3.10. subst_uri('/re/repl/flags')

   Runs the re substitution on the message uri (like subst but
   works only on the uri)

   Meaning of the parameters is as follows:

     * '/re/repl/flags' - sed like regular expression. flags can
       be a combination of i (case insensitive), g (global) or s
       (match newline don't treat it as end of line).
       're' - is regular expresion
       'repl' - is replacement string - may contain
       pseudo-varibales
       'flags' - substitution flags (i - ignore case, g - global)

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, BRANCH_ROUTE.

   Example 1-10. subst_uri usage
...
# adds 3463 prefix to numeric uris, and save the original uri (\0 match)
# as a parameter: orig_uri (just an example)
if (subst_uri('/^sip:([0-9]+)@(.*)$/sip:3463\1@\2;orig_uri=\0/i')){$

# adds the avp 'uri_prefix' as prefix to numeric uris, and save the orig
inal
# uri (\0 match) as a parameter: orig_uri (just an example)
if (subst_uri('/^sip:([0-9]+)@(.*)$/sip:$avp(uri_prefix)\1@\2;orig_uri=\
0/i')){$

...
     __________________________________________________________

1.3.11. subst_user('/re/repl/flags')

   Runs the re substitution on the message uri (like subst_uri but
   works only on the user portion of the uri)

   Meaning of the parameters is as follows:

     * '/re/repl/flags' - sed like regular expression. flags can
       be a combination of i (case insensitive), g (global) or s
       (match newline don't treat it as end of line).
       're' - is regular expresion
       'repl' - is replacement string - may contain
       pseudo-varibales
       'flags' - substitution flags (i - ignore case, g - global)

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, BRANCH_ROUTE.

   Example 1-11. subst usage
...
# adds 3463 prefix to uris ending with 3642 (just an example)
if (subst_user('/3642$/36423463/')){$

...
# adds avp 'user_prefix' as prefix to username in r-uri ending with 3642
if (subst_user('/(.*)3642$/$avp(user_prefix)\13642/')){$

...
     __________________________________________________________

1.3.12. subst_body('/re/repl/flags')

   Replaces re with repl (sed or perl like) in the body of the
   message.

   Meaning of the parameters is as follows:

     * '/re/repl/flags' - sed like regular expression. flags can
       be a combination of i (case insensitive), g (global) or s
       (match newline don't treat it as end of line).
       're' - is regular expresion
       'repl' - is replacement string - may contain
       pseudo-varibales
       'flags' - substitution flags (i - ignore case, g - global)

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, BRANCH_ROUTE.

   Example 1-12. subst_body usage
...
if ( subst_body('/^o=(.*) /o=$fU ') ) {};

...
     __________________________________________________________

1.3.13. filter_body(content_type)

   Filters multipart body by leaving out all other body parts
   except the first body part of given type.

   Meaning of the parameters is as follows:

     * content_type - Content type to be left in the body.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, BRANCH_ROUTE.

   Example 1-13. filter_body usage
...
if (has_body("multipart/mixed")) {
    if (filter_body("application/sdp") {
        remove_hf("Content-Type");
        append_hf("Content-Type: application/sdp\r\n");
    } else {
        xlog("Body part application/sdp not found\n");
    }
}
...
     __________________________________________________________

1.3.14. append_to_reply(txt)

   Append txt as header to the reply.

   Meaning of the parameters is as follows:

     * txt - String which may contains pseudo-variables.

   This function can be used from REQUEST_ROUTE, BRANCH_ROUTE,
   ERROR_ROUTE.

   Example 1-14. append_to_reply usage
...
append_to_reply("Foo: bar\r\n");
append_to_reply("Foo: $rm at $Ts\r\n");
...
     __________________________________________________________

1.3.15. append_hf(txt)

   Appends 'txt' as header after the last header field.

   Meaning of the parameters is as follows:

     * txt - Header field to be appended. The value can contain
       pseudo-variables which will be replaced at run time.

   Note: Headers which are added in main route cannot be removed
   in further routes (e.g. failure routes). So, the idea is not to
   add there any headers that you might want to remove later. To
   add headers temporarely use the branch route because the
   changes you do there are per-branch.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, BRANCH_ROUTE.

   Example 1-15. append_hf usage
...
append_hf("P-hint: VOICEMAIL\r\n");
append_hf("From-username: $fU\r\n");
...
     __________________________________________________________

1.3.16. append_hf(txt, hdr)

   Appends 'txt' as header after first 'hdr' header field.

   Meaning of the parameters is as follows:

     * txt - Header field to be appended. The value can contain
       pseudo-variables which will be replaced at run time.
     * hdr - Header name after which the 'txt' is appended.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, BRANCH_ROUTE.

   Example 1-16. append_hf usage
...
append_hf("P-hint: VOICEMAIL\r\n", "Call-ID");
append_hf("From-username: $fU\r\n", "Call-ID");
...
     __________________________________________________________

1.3.17. insert_hf(txt)

   Inserts 'txt' as header before the first header field.

   Meaning of the parameters is as follows:

     * txt - Header field to be inserted. The value can contain
       pseudo-variables which will be replaced at run time.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, BRANCH_ROUTE.

   Example 1-17. insert_hf usage
...
insert_hf("P-hint: VOICEMAIL\r\n");
insert_hf("To-username: $tU\r\n");
...
     __________________________________________________________

1.3.18. insert_hf(txt, hdr)

   Inserts 'txt' as header before first 'hdr' header field.

   Meaning of the parameters is as follows:

     * txt - Header field to be inserted. The value can contain
       pseudo-variables which will be replaced at run time.
     * hdr - Header name before which the 'txt' is inserted.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, BRANCH_ROUTE.

   Example 1-18. insert_hf usage
...
insert_hf("P-hint: VOICEMAIL\r\n", "Call-ID");
insert_hf("To-username: $tU\r\n", "Call-ID");
...
     __________________________________________________________

1.3.19. append_urihf(prefix, suffix)

   Append header field name with original Request-URI in middle.

   Meaning of the parameters is as follows:

     * prefix - string (usually at least header field name).
     * suffix - string (usually at least line terminator).

   This function can be used from REQUEST_ROUTE, FAILURE_ROUTE,
   BRANCH_ROUTE.

   Example 1-19. append_urihf usage
...
append_urihf("CC-Diversion: ", "\r\n");
...
     __________________________________________________________

1.3.20. is_present_hf(hf_name)

   Return true if a header field is present in message.

   Note

        The function is also able to distinguish the compact names. For
        exmaple "From" will match with "f"

   Meaning of the parameters is as follows:

     * hf_name - Header field name.(long or compact form)

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, BRANCH_ROUTE.

   Example 1-20. is_present_hf usage
...
if (is_present_hf("From")) log(1, "From HF Present");
...
     __________________________________________________________

1.3.21. append_time()

   Adds a time header to the reply of the request. You must use it
   before functions that are likely to send a reply, e.g., save()
   from 'registrar' module. Header format is: "Date: %a, %d %b %Y
   %H:%M:%S GMT", with the legend:

     * %a abbreviated week of day name (locale)
     * %d day of month as decimal number
     * %b abbreviated month name (locale)
     * %Y year with century
     * %H hour
     * %M minutes
     * %S seconds

   Return true if a header was succesfully appended.

   This function can be used from REQUEST_ROUTE, FAILURE_ROUTE,
   BRANCH_ROUTE.

   Example 1-21. append_time usage
...
append_time();
...
     __________________________________________________________

1.3.22. is_method(name)

   Check if the method of the message matches the name. If name is
   a known method (invite, cancel, ack, bye, options, info,
   update, register, message, subscribe, notify, refer, prack),
   the function performs method ID testing (integer comparison)
   instead of ignore case string comparison.

   The 'name' can be a list of methods in the form of
   'method1|method2|...'. In this case, the function returns true
   if the SIP message's method is one from the list. IMPORTANT
   NOTE: in the list must be only methods defined in OpenSER with
   ID (invite, cancel, ack, bye, options, info, update, register,
   message, subscribe, notify, refer, prack, publish; for more
   see: http://www.iana.org/assignments/sip-parameters).

   If used for replies, the function tests the value of method
   field from CSeq header.

   Meaning of the parameters is as follows:

     * name - SIP method name

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, and BRANCH_ROUTE.

   Example 1-22. is_method usage
...
if(is_method("INVITE"))
{
    # process INVITEs here
}
if(is_method("OPTION|UPDATE"))
{
    # process OPTIONs and UPDATEs here
}
...
     __________________________________________________________

1.3.23. remove_hf(hname)

   Remove from message all headers with name "hname"

   Returns true if at least one header is found and removed.

   Meaning of the parameters is as follows:

     * hname - header name to be removed.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE and BRANCH_ROUTE.

   Example 1-23. remove_hf usage
...
if(remove_hf("User-Agent"))
{
    # User Agent header removed
}
...
     __________________________________________________________

1.3.24. has_body(), has_body(mime)

   The function returns true if the SIP message has a body
   attached. The checked includes also the "Content-Lenght" header
   presence and value.

   If a paramter is given, the mime described will be also checked
   against the "Content-Type" header.

   Meaning of the parameters is as follows:

     * mime - mime to be checked against the "Content-Type"
       header. If not present or 0, this check will be disabled.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE and BRANCH_ROUTE.

   Example 1-24. has_body usage
...
if(has_body("application/sdp"))
{
    # do interesting stuff here
}
...
     __________________________________________________________

1.3.25. is_privacy(privacy_type)

   The function returns true if the SIP message has a Privacy
   header field that includes the given privacy_type among its
   privacy values. See
   http://www.iana.org/assignments/sip-priv-values for possible
   privacy type values.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE and BRANCH_ROUTE.

   Example 1-25. is_privacy usage
...
if(is_privacy("id"))
{
    # do interesting stuff here
}
...
     __________________________________________________________

1.4. Known Limitations

   Search functions are applied to the original request, i.e.,
   they ignore all changes resulting from message processing in
   OpenSER script.
     __________________________________________________________

Chapter 2. Developer's Guide

   The module does not provide any API to use in other OpenSER
   modules.
     __________________________________________________________

Chapter 3. Frequently Asked Questions

   3.1. Where can I find more about OpenSER?
   3.2. Where can I post a question about this module?
   3.3. How can I report a bug?

   3.1. Where can I find more about OpenSER?

   Take a look at http://www.openser.org/.

   3.2. Where can I post a question about this module?

   First at all check if your question was already answered on one
   of our mailing lists:

     * User Mailing List -
       http://lists.openser.org/cgi-bin/mailman/listinfo/users
     * Developer Mailing List -
       http://lists.openser.org/cgi-bin/mailman/listinfo/devel

   E-mails regarding any stable OpenSER release should be sent to
   <users@lists.openser.org> and e-mails regarding development
   versions should be sent to <devel@lists.openser.org>.

   If you want to keep the mail private, send it to
   <team@lists.openser.org>.

   3.3. How can I report a bug?

   Please follow the guidelines provided at:
   http://sourceforge.net/tracker/?group_id=139143.
