1. Textops Module

Andrei Pelinescu-Onciul

   FhG FOKUS

   Copyright © 2003 FhG FOKUS
     __________________________________________________________________

   1.1. Overview

        1.1.1. Known Limitations

   1.2. Functions

        1.2.1. search(re)
        1.2.2. search_append(re, txt)
        1.2.3. replace(re, txt)
        1.2.4. subst('/re/repl/flags')
        1.2.5. subst_uri('/re/repl/flags')
        1.2.6. subst_user('/re/repl/flags')
        1.2.7. append_to_reply(txt)
        1.2.8. append_hf(hf)
        1.2.9. append_urihf(prefix, suffix)
        1.2.10. is_present_hf(hf_name)
        1.2.11. append_time()
        1.2.12. remove_hf(hf_name)
        1.2.13. remove_hf_re(reg_exp)
        1.2.14. append_hf_value(hf, xl_value)
        1.2.15. insert_hf_value(hf, xl_value)
        1.2.16. remove_hf_value(hf_par)
        1.2.17. remove_hf_value2(hf_par)
        1.2.18. assign_hf_value(hf, xl_value)
        1.2.19. assign_hf_value2(hf, xl_value)
        1.2.20. include_hf_value(hf, xl_value)
        1.2.21. exclude_hf_value(hf, xl_value)
        1.2.22. hf_value_exists(hf, xl_value)
        1.2.23. @hf_value selects

1.1. Overview

   This is mostly an example module. It implements text based operation
   (search, replace, append a.s.o). Many functions support xl_lib
   formating using xlog module.

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. Functions

1.2.1.  search(re)

   Searches for the re in the message.

   Meaning of the parameters is as follows:
     * re - Regular expression.

   Example 1. search usage
...
if ( search("[Ss][Ee][Rr]" ) { /*....*/ };
...

1.2.2.  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. Xl_lib formatting supported.

   Example 2. search_append usage
...
search_append("[Ss]er", " blabla");
...

1.2.3.  replace(re, txt)

   Replaces the first occurrence of re with txt.

   Meaning of the parameters is as follows:
     * re - Regular expression.
     * txt - String. Xl_lib formatting supported.

   Example 3. replace usage
...
replace("ser", "Sip Express Router");
...

1.2.4.  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).

   Example 4. 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') ) {};
...

1.2.5.  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).

   Example 5. subst 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]+)@(.*)$/sip:3463\1@\2;orig_uri=\0/i')){$
...

1.2.6.  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).

   Example 6. subst usage
...
# adds 3463 prefix to uris ending with 3642 (just an example)
if (subst_user('/3642$/36423463/')){$
...

1.2.7.  append_to_reply(txt)

   Append txt to the reply.

   Meaning of the parameters is as follows:
     * txt - String. Xl_lib formatting supported.

   Example 7. append_to_reply usage
...
append_to_reply("Foo: bar\r\n");
...

1.2.8.  append_hf(hf)

   Appends txt after the last header field.

   Meaning of the parameters is as follows:
     * hf - Header field to be appended. Xl_lib formatting supported.

   Example 8. append_hf usage
...
append_hf("P-hint: VOICEMAIL\r\n");
...

1.2.9.  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). Xl_lib
       formatting supported.
     * suffix - string (usually at least line terminator). Xl_lib
       formatting supported.

   Example 9. append_urihf usage
...
append_urihf("CC-Diversion: ", "\r\n");
...

1.2.10.  is_present_hf(hf_name)

   Return true if a header field is present in message.

Note

   Takes header field names "as is" and doesn't distinguish compact names.

   Meaning of the parameters is as follows:
     * hf_name - Header field name.

   Example 10. is_present_hf usage
...
if (is_present_hf("From")) log(1, "From HF Present");
...

1.2.11.  append_time()

   Append "Date" header containing the current date and time to the reply
   generated by SER.

   Example 11. is_present_hf usage
...
if (method == "REGISTER" ) {
    # Many user agents can use the Date header field
    # in 200 OK replies to REGISTER to synchronize
    # internal clock
    append_time();
};
...

1.2.12.  remove_hf(hf_name)

   Remove from the message all the headers with the specified name.

   Meaning of the parameters is as follows:
     * hf_name - Header field name to be removed.

   Example 12. remove_hf usage
...
remove_hf("Subject")  # strip all headers whose name is "Subject".
...

1.2.13.  remove_hf_re(reg_exp)

   Remove from the message all the headers whose names match a given
   regular expression.

   Meaning of the parameters is as follows:
     * reg_exp - Regular expression that is matched against header name
       fields.

   Example 13. remove_hf_re usage
...
remove_hf_re("Subject|P-.*|X-.*")  # strip all headers whose names match
"Subject", contain "P-" or "X-".
...

1.2.14.  append_hf_value(hf, xl_value)

   Append new header value after an existing header, if no index acquired
   append at the end of list. Note that a header may consist of comma
   delimited list of values.

   Meaning of the parameters is as follows:
     * hf - Header field to be appended. Format: HFNAME [ [IDX] ]. If
       index is not specified new header is inserted at the end of
       message.
     * xl_value - Value to be added, xl_lib formatting supported.

   Example 14. append_hf_value usage
...
append_hf_value("foo", "gogo;stamp=%Ts")   # add new header
append_hf_value("foo[1]", "gogo")  # add new value behind first value
append_hf_value("foo[-1]", "%@Bar") # try add value to the last header, if not e
xists add new header
...

1.2.15.  insert_hf_value(hf, xl_value)

   Insert new header value before an existing header, if no index acquired
   insert before first hf header. Note that a header may consist of comma
   delimited list of values. To insert value behing last value use
   appenf_hf_value.

   Meaning of the parameters is as follows:
     * hf - Header field to be appended. Format: HFNAME [ [IDX] ]. If
       index is not specified new header is inserted at the top of
       message.
     * xl_value - Value to be added, xl_lib formatting supported.

   Example 15. insert_hf_value usage
...
insert_hf_value("foo[2]", "gogo")
insert_hf_value("foo", "%$an_avp")   # add new header at the top of list
insert_hf_value("foo[1]", "gogo") # try add to the first header
...

1.2.16.  remove_hf_value(hf_par)

   Remove the header value from existing header, Note that a header may
   consist of comma delimited list of values.

   Meaning of the parameters is as follows:
     * hf_par - Header field/param to be removed. Format: HFNAME [ [IDX] ]
       [. PARAM ] If asterisk is specified as index then all values are
       affected.

   Example 16. remove_hf_value usage
...
remove_hf_value("foo")  # remove foo[1]
remove_hf_value("foo[*]")  # remove all foo's headers
remove_hf_value("foo[-1]") # last foo
remove_hf_value("foo.bar")  # delete parameter
remove_hf_value("foo[*].bar") # for each foo delete bar parameters
...

1.2.17.  remove_hf_value2(hf_par)

   Remove specified header or parameter. It is expected header in
   Authorization format (comma delimiters are not treated as multi-value
   delimiters).

   Meaning of the parameters is as follows:
     * hf_par - Header/param to be removed. Format: HFNAME [ [IDX] ] [.
       PARAM ] If asterisk is specified as index then all values are
       affected.

   Example 17. remove_hf_value2 usage
...
remove_hf_value2("foo")  # remove foo[1]
remove_hf_value2("foo[*]")  # remove all foo's headers, the same as remove_hf_he
ader("foo[*]");
remove_hf_value2("foo[-1]") # last foo
remove_hf_value2("foo.bar")  # delete parameter
remove_hf_value2("foo[*].bar") # for each foo delete bar parameters
...

1.2.18.  assign_hf_value(hf, xl_value)

   Assign value to specified header value / param.

   Meaning of the parameters is as follows:
     * hf_para - Header field value / param to be appended. Format: HFNAME
       [ [IDX] ] [. PARAM] If asterisk is specified as index then all
       values are affected.
     * xl_value - Value to be assigned, xl_lib formatting supported. If
       value is empty then no equal sign apears in param.

   Example 18. assign_hf_value usage
...
assign_hf_value("foo", "gogo")  # foo[1]
assign_hf_value("foo[-1]", "gogo")  # foo[last_foo]

assign_hf_value("foo.bar", "")
assign_hf_value("foo[3].bar", "")
assign_hf_value("foo[*]", "")  # remove all foo's, empty value remains
assign_hf_value("foo[*].bar", "")  # set empty value (ex. lr)
...

1.2.19.  assign_hf_value2(hf, xl_value)

   Assign value to specified header. It is expected header in
   Authorization format (comma delimiters are not treated as multi-value
   delimiters).

   Meaning of the parameters is as follows:
     * hf_para - Header field value / param to be appended. Format: HFNAME
       [ [IDX] ] [. PARAM] If asterisk is specified as index then all
       values are affected.
     * xl_value - Value to be assigned, xl_lib formatting supported. If
       value is empty then no equal sign apears in param.

   Example 19. assign_hf_value2 usage
...
assign_hf_value2("Authorization.integrity-protected", "\"yes\"")
assign_hf_value2("foo[-1]", "gogo")  # foo[last_foo]
assign_hf_value2("foo[*].bar", "")  # set empty value (ex. lr)
...

1.2.20.  include_hf_value(hf, xl_value)

   Add value in set if not exists, eg. "Supported: path,100rel".

   Meaning of the parameters is as follows:
     * hf - Header field name to be affected.
     * value - xl_lib formatting supported.

   Example 20. include_hf_value usage
...
include_hf_value("Supported", "path");
...

1.2.21.  exclude_hf_value(hf, xl_value)

   Remove value from set if exists, eg. "Supported: path,100rel".

   Meaning of the parameters is as follows:
     * hf - Header field name to be affected.
     * value - xl_lib formatting supported.

   Example 21. exclude_hf_value usage
...
exclude_hf_value("Supported", "100rel");
...

1.2.22.  hf_value_exists(hf, xl_value)

   Check if value exists in set. Alternate select
   @hf_value_exists.HF.VALUE may be used. It returns one or zero.

   Meaning of the parameters is as follows:
     * hf - Header field name to be affected. Underscores are treated as
       dashes.
     * value - xl_lib formatting supported.

   Example 22. hf_value_exists usage
...
if (hf_value_exists("Supported", "100rel")) {

}

if (@hf_value_exists.supported.path == "1") {

}
...

1.2.23.  @hf_value selects

   Get value of required header-value or param. Note that functions called
   'value2' works with Authorization-like headers where comma is not
   treated as value delimiter. Formats: @hf_value.HFNAME[IDX] # idx value,
   negative value counts from bottom @hf_value.HFNAME.PARAM_NAME
   @hf_value.HFNAME[IDX].PARAM_NAME @hf_value.HFNAME.p.PARAM_NAME # or
   .param., useful if requred called "uri", "p", "param"
   @hf_value.HFNAME[IDX].p.PARAM_NAME # dtto @hf_value.HFNAME[IDX].uri #
   (< & > excluded) @hf_value.HFNAME[*] # return comma delimited list of
   all values (combines headers) @hf_value.HFNAME # the same as above [*]
   but may be parsed by cfg.y @hf_value.HFNAME[*].uri # return comma
   delimited list of uris (< & > excluded) @hf_value.HFNAME.uri # the same
   as above [*] but may be parsed by cfg.y @hf_value.HFNAME[IDX].name #
   returns name part, quotes excluded @hf_value.HFNAME.name # returns name
   part of the first value @hf_value2.HFNAME # returns value of first
   header @hf_value2.HFNAME[IDX] # returns value of idx's header
   @hf_value2.HFNAME.PARAM_NAME @hf_value2.HFNAME[IDX].PARAM_NAME
   @hf_value.HFNAME[IDX].uri # return URI, quotes excluded
   @hf_value.HFNAME.p.uri # returns param named uri, not URI itself
   @hf_value.HFNAME.p.name # returns param named name, not name itself
   @hf_value.HFNAME[IDX].uri.name # any sel_any_uri nested features may be
   used @hf_value.HFNAME[IDX].nameaddr.name # select_any_nameaddr

   Meaning of the parameters is as follows:
     * HFNAME - Header field name. Underscores are treated as dashes.
     * IDX - Value index, negative value counts from bottom
     * PARAM_NAME - name of parameter

   Example 23. @hf_value select usage
...
$a = @hf_value.my_header[1].my_param;
xlog("L_ERR", "%@hf_value.via[-1], %@hf_value.from.tag\n");
$b = @hf_value.p_associated_uri;

xlog("L_ERR", "Route uris: '%@hf_value.route[*].uri'\n");
$rr = @hf_value.route.uri;

$prt = @hf_value2.authorization.integrity_protected;
...
