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<section id="textopsx.functions" xmlns:xi="http://www.w3.org/2001/XInclude">
    <title>Functions</title>

	<section id="textopsx.f.msg_apply_changes">
		<title>
		<function moreinfo="none">msg_apply_changes()</function>
		</title>
		<para>
		Use this function to apply changes performed on SIP message content. Be
		careful when using this function;  due to special handling of changes
		to the SIP message buffer so far, using this function might change
		the behaviour of your config.  Do test your config properly!
		</para>
   		<para>
		The function returns true (1) on success. If it is failure before the
		new content is build, the function returns false (-1), the old content
		is still in place. If parsing of the new content is failing, the
		function stops executions of the config file (the internal structure
		is no longer valid for config processing, like it happens when a
		broken message is received from network).
		</para>
		<para>
		This function can be used from REQUEST_ROUTE or ONREPLY_ROUTE.
		</para>
		<example>
		<title><function>msg_apply_changes()</function> usage</title>
		<programlisting format="linespecific">
...
append_hf("My-Header: yes\r\n");
if(msg_apply_changes())
{
    # msg buffer has a new content
    if(is_present_hf("My-Header"))
    {
        # will get here always
    }
}
...
</programlisting>
		</example>
	</section>

    <section id="textopsx.f.change_reply_status">
	<title>
	    <function>change_reply_status(code, reason)</function>
	</title>
	<para>
		Intercept a SIP reply (in an onreply_route) and change its status code 
		and reason phrase prior to forwarding it.
	</para>
	<para>Meaning of the parameters is as follows:</para>
	<itemizedlist>
	    <listitem>
		<para><emphasis>code</emphasis> - Status code.
		</para>
	    </listitem>
	    <listitem>
		<para><emphasis>reason</emphasis> - Reason phrase.
		</para>
	    </listitem>
	</itemizedlist>
   		<para>
		This function can be used from ONREPLY_ROUTE.
		</para>
	<example>
	    <title><function>change_reply_status</function> usage</title>
	    <programlisting>
...
onreply_route {
    if (@status == "603") {
        change_reply_status(404, "Not Found");
        exit;
    }
}
...
	    </programlisting>
	</example>
    </section>

	<section id="textopsx.f.remove_body">
		<title>
		<function moreinfo="none">remove_body()</function>
		</title>
		<para>
		Use this function to remove the body of SIP requests or replies.
		</para>
		<para>
		This function can be used from ANY_ROUTE.
		</para>
		<example>
		<title><function>remove_body()</function> usage</title>
		<programlisting format="linespecific">
...
remove_body();
...
</programlisting>
		</example>
	</section>

	<section id="textopsx.f.keep_hf">
		<title>
		<function moreinfo="none">keep_hf(regexp)</function>
		</title>
		<para>
			Remove headers that don't match the regular expression regexp.
			Several header are ignored always (thus not removed): Via, From,
			To, Call-ID, CSeq, Content-Length, Content-Type, Max-Forwards,
			Contact, Route, Record-Route -- these can be removed one by one
			with remove_hf().
		</para>
		<para>
		This function can be used from ANY_ROUTE.
		</para>
		<example>
		<title><function>keep_hf()</function> usage</title>
		<programlisting format="linespecific">
...
keep_hf("User-Agent");
...
</programlisting>
		</example>
	</section>

	<section id="textopsx.f.fnmatch">
		<title>
		<function moreinfo="none">fnmatch(value, expr [, flags])</function>
		</title>
		<para>
			Match the value against the expr using shell-style pattern
			for file name matching (see man page for C function fnmatch()).
			It is known to be faster and use less-memory than regular expressions.
		</para>
		<para>
			Parameter 'flags' is optional and can be 'i' to do case insensitive
			matching.
		</para>
		<para>
		This function can be used from ANY_ROUTE.
		</para>
		<example>
		<title><function>fnmatch()</function> usage</title>
		<programlisting format="linespecific">
...
if(fnmatch("$rU", "123*"))
{
    ...
}
...
</programlisting>
		</example>
	</section>

    <section id="textopsx.f.append_hf_value">
	<title>
	    <function>append_hf_value(hf, hvalue)</function>
	</title>
	<para>
		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.
	</para>
	<para>Meaning of the parameters is as follows:</para>
	<itemizedlist>
	    <listitem>
		<para><emphasis>hf</emphasis> - Header field to be appended. Format: HFNAME [ [IDX] ].
		If index is not specified new header is inserted at the end of message.
		</para>
	    </listitem>
	    <listitem>
		<para><emphasis>hvalue</emphasis> - Value to be added, config var formatting supported.
		</para>
	    </listitem>
	</itemizedlist>
	<example>
	    <title><function>append_hf_value</function> usage</title>
	    <programlisting>
...
append_hf_value("foo", "gogo;stamp=$Ts")   # add new header
append_hf_value("foo[1]", "gogo")  # add new value behind first value
append_hf_value("foo[-1]", "$var(Bar)") # try add value to the last header, if not exists add new header
...
	    </programlisting>
	</example>
    </section>

    <section id="textopsx.f.insert_hf_value">
	<title>
	    <function>insert_hf_value(hf, hvalue)</function>
	</title>
	<para>
		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 <function>appenf_hf_value</function>.
	</para>
	<para>Meaning of the parameters is as follows:</para>
	<itemizedlist>
	    <listitem>
		<para><emphasis>hf</emphasis> - Header field to be appended. Format: HFNAME [ [IDX] ].
		If index is not specified new header is inserted at the top of message.
		</para>
	    </listitem>
	    <listitem>
		<para><emphasis>hvalue</emphasis> - Value to be added, config var formatting supported.
		</para>
	    </listitem>
	</itemizedlist>
	<example>
	    <title><function>insert_hf_value</function> usage</title>
	    <programlisting>
...
insert_hf_value("foo[2]", "gogo")
insert_hf_value("foo", "$avp(foo)")   # add new header at the top of list
insert_hf_value("foo[1]", "gogo") # try add to the first header
...
	    </programlisting>
	</example>
    </section>

    <section id="textopsx.f.remove_hf_value">
	<title>
	    <function>remove_hf_value(hf_par)</function>
	</title>
	<para>
		Remove the header value from existing header, Note that a header may consist of comma delimited list of values.
	</para>
	<para>Meaning of the parameters is as follows:</para>
	<itemizedlist>
	    <listitem>
		<para><emphasis>hf_par</emphasis> - Header field/param to be removed. Format: HFNAME [ [IDX] ] [. PARAM ]
		If asterisk is specified as index then all values are affected.
		</para>
	    </listitem>
	</itemizedlist>
	<example>
	    <title><function>remove_hf_value</function> usage</title>
	    <programlisting>
...
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
...
	    </programlisting>
	</example>
    </section>

    <section id="textopsx.f.remove_hf_value2">
	<title>
	    <function>remove_hf_value2(hf_par)</function>
	</title>
	<para>
		Remove specified header or parameter. It is expected header in Authorization format (comma delimiters are not treated as multi-value delimiters).

	</para>
	<para>Meaning of the parameters is as follows:</para>
	<itemizedlist>
	    <listitem>
		<para><emphasis>hf_par</emphasis> - Header/param to be removed. Format: HFNAME [ [IDX] ] [. PARAM ]
		If asterisk is specified as index then all values are affected.
		</para>
	    </listitem>
	</itemizedlist>
	<example>
	    <title><function>remove_hf_value2</function> usage</title>
	    <programlisting>
...
remove_hf_value2("foo")  # remove foo[1]
remove_hf_value2("foo[*]")  # remove all foo's headers, the same as remove_hf_header("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
...
	    </programlisting>
	</example>
    </section>

    <section id="textopsx.f.assign_hf_value">
	<title>
	    <function>assign_hf_value(hf, hvalue)</function>
	</title>
	<para>
		Assign value to specified header value / param.
	</para>
	<para>Meaning of the parameters is as follows:</para>
	<itemizedlist>
	    <listitem>
			<para><emphasis>hf_para</emphasis> - Header field value / param to be appended.
				Format: HFNAME [ [IDX] ] [. PARAM]
		If asterisk is specified as index then all values are affected.
		</para>
	    </listitem>
	    <listitem>
			<para><emphasis>hvalue</emphasis> - Value to be assigned, config var
				formatting supported. If value is empty then no equal sign apears in param.
		</para>
	    </listitem>
	</itemizedlist>
	<example>
	    <title><function>assign_hf_value</function> usage</title>
	    <programlisting>
...
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)
...
	    </programlisting>
	</example>
    </section>

    <section id="textopsx.f.assign_hf_value2">
	<title>
	    <function>assign_hf_value2(hf, hvalue)</function>
	</title>
	<para>
		Assign value to specified header. It is expected header in Authorization format (comma delimiters are not treated as multi-value delimiters).
	</para>
	<para>Meaning of the parameters is as follows:</para>
	<itemizedlist>
	    <listitem>
		<para><emphasis>hf_para</emphasis> - Header field value / param to be appended. Format: HFNAME [ [IDX] ] [. PARAM]
		If asterisk is specified as index then all values are affected.
		</para>
	    </listitem>
	    <listitem>
			<para><emphasis>hvalue</emphasis> - Value to be assigned, config var formatting supported.
				If value is empty then no equal sign apears in param.
		</para>
	    </listitem>
	</itemizedlist>
	<example>
	    <title><function>assign_hf_value2</function> usage</title>
	    <programlisting>
...
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)
...
	    </programlisting>
	</example>
    </section>

    <section id="textopsx.f.include_hf_value">
	<title>
	    <function>include_hf_value(hf, hvalue)</function>
	</title>
	<para>
		Add value in set if not exists, eg. "Supported: path,100rel".
	</para>
	<para>Meaning of the parameters is as follows:</para>
	<itemizedlist>
	    <listitem>
		<para><emphasis>hf</emphasis> - Header field name to be affected.
		</para>
	    </listitem>
	    <listitem>
		<para><emphasis>hvalue</emphasis> - config var formatting supported.
		</para>
	    </listitem>
	</itemizedlist>
	<example>
	    <title><function>include_hf_value</function> usage</title>
	    <programlisting>
...
include_hf_value("Supported", "path");
...
	    </programlisting>
	</example>
    </section>

    <section id="textopsx.f.exclude_hf_value">
	<title>
	    <function>exclude_hf_value(hf, hvalue)</function>
	</title>
	<para>
		Remove value from set if exists, eg. "Supported: path,100rel".
	</para>
	<para>Meaning of the parameters is as follows:</para>
	<itemizedlist>
	    <listitem>
		<para><emphasis>hf</emphasis> - Header field name to be affected.
		</para>
	    </listitem>
	    <listitem>
		<para><emphasis>hvalue</emphasis> - config formatting supported.
		</para>
	    </listitem>
	</itemizedlist>
	<example>
	    <title><function>exclude_hf_value</function> usage</title>
	    <programlisting>
...
exclude_hf_value("Supported", "100rel");
...
	    </programlisting>
	</example>
    </section>

    <section id="textopsx.f.hf_value_exists">
	<title>
	    <function>hf_value_exists(hf, hvalue)</function>
	</title>
	<para>
		Check if value exists in set. Alternate select <emphasis>@hf_value_exists.HF.VALUE</emphasis>
		may be used. It returns one or zero.
	</para>
	<para>Meaning of the parameters is as follows:</para>
	<itemizedlist>
	    <listitem>
		<para><emphasis>hf</emphasis> - Header field name to be affected. Underscores are treated as dashes.
		</para>
	    </listitem>
	    <listitem>
		<para><emphasis>hvalue</emphasis> - config var formatting supported.
		</para>
	    </listitem>
	</itemizedlist>
	<example>
	    <title><function>hf_value_exists</function> usage</title>
	    <programlisting>
...
if (hf_value_exists("Supported", "100rel")) {

}

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

}
...
	    </programlisting>
	</example>
    </section>

	<section>
	<title>Selects</title>
    <section id="textopsx.sel.hf_value">
	<title>@hf_value</title>
	<para>
		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 # (&lt; &amp; &gt; 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 (&lt; &amp; &gt; 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
	</para>
	<para>Meaning of the parameters is as follows:</para>
	<itemizedlist>
	    <listitem>
		<para><emphasis>HFNAME</emphasis> - Header field name. Underscores are treated as dashes.
		</para>
	    </listitem>
	    <listitem>
		<para><emphasis>IDX</emphasis> - Value index, negative value counts from bottom
		</para>
	    </listitem>
	    <listitem>
		<para><emphasis>PARAM_NAME</emphasis> - name of parameter
		</para>
	    </listitem>
	</itemizedlist>
	<example>
	    <title><function>@hf_value select</function> usage</title>
	    <programlisting>
...
$a = @hf_value.my_header[1].my_param;
xplog("L_ERR", "$sel(@hf_value.via[-1]), $sel(@hf_value.from.tag)\n");
$b = @hf_value.p_associated_uri;

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

$prt = @hf_value2.authorization.integrity_protected;
...
	    </programlisting>
	</example>
    </section>
    <section id="textopsx.sel.hf_value2">
	<title>@hf_value2</title>
	<para>
		TBA.
	</para>
    </section>
    <section id="textopsx.sel.hf_value_exists">
	<title>@hf_value_exists</title>
	<para>
		TBA.
	</para>
    </section>

    </section>

</section>