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<refentry id="module.avp"
          xmlns:serdoc="http://sip-router.org/xml/serdoc">
  <refmeta>
    <refentrytitle>avp</refentrytitle>
    <manvolnum>7</manvolnum>
  </refmeta>
  <refnamediv>
    <refname>avp</refname>
    <refpurpose>Manipulation of Attributes</refpurpose>
  </refnamediv>

  <refsect1>
    <title>Description</title>
    <para>
      The <command>avp</command> module provides various functions for
      the manipulation of attributes.
    </para>
    <para>
      The name is a left-over from earlier versions of SER where attributes
      were called ‘attribute-value pairs’ or AVPs for short.
    </para>
  </refsect1>

  <refsect1>
    <title>Functions</title>

    <refsect2 xml:id="function.append_attr_hf">
      <title>
        <function>append_attr_hf</function>
        (<symbol>hf</symbol>,
         <optional><symbol>attribute</symbol></optional>)
      </title>
      <para>
        Allowed in request and failure processing.
      </para>
      <para>
        The <function>append_attr_hf()</function> function appends a
        new header field value to the header field named by the argument
        <symbol>hf</symbol>. The new value will be populated with the
        content of the attribute named by the argument
        <symbol>attribute</symbol>. If the argument is missing, the content
        is taken from the attribute with same name as the header field.
      </para>
     </refsect2>

    <refsect2 xml:id="function.attr2uri">
      <title>
        <function>attr2uri</function>
        (<symbol>attribute</symbol>,
        <serdoc:optional><symbol>part</symbol></serdoc:optional>)
       </title>
      <para>
        Allowed in request and failure processing.
      </para>
      <para>
        The <function>attr2uri()</function> function sets the Request-URI
        to the content of the attribute named by the argument
        <symbol>attribute</symbol>. If the argument <symbol>part</symbol>
        is present, only the part of the Request-URI identified by it
        will be changed. This mimiks the behavior of many of the core
        functions that allow manipulation of the Request-URI.
      </para>
      <para>
        The following values are allowed for the <symbol>part</symbol>
        argument:
      </para>
      <variablelist>
        <varlistentry>
          <term><literal>domain</literal>, <literal>host</literal></term>
          <listitem>
            replace the host part of the Request-URI,
          </listitem>
        </varlistentry>
        <varlistentry>
          <term>
            <literal>domainport</literal>, <literal>hostport</literal>
          </term>
          <listitem>
            replace the host and port parts of the Request-URI,
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>port</literal></term>
          <listitem>
            replace the port part of the Request-URI,
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>prefix</literal></term>
          <listitem>
            prefix the content of the attribute to the username part of
            the Request-URI,
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>strip</literal></term>
          <listitem>
            the attribute contains an integer specifying the number of
            characters to be stripped off the beginning of the username
            part of the Request-URI,
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>strip_tail</literal></term>
          <listitem>
            the attribute contains an integer specifyin the number of
            characters to be stripped off the end of the username part of
            the Request-URI,
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>uri</literal></term>
          <listitem>
            replace the entire Request-URI,
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>user</literal>, <literal>username</literal></term>
          <listitem>
            replace the username part of the Request-URI,
          </listitem>
        </varlistentry>
        <varlistentry>
          <term>
            <literal>userpass</literal>,
            <literal>usernamepassword</literal>
          </term>
          <listitem>
            replace the username and password parts of the Request-URI.
          </listitem>
        </varlistentry>
      </variablelist>
    </refsect2>

    <refsect2 xml:id="function.attr_destination">
      <title>
        <function>attr_destination</function>
        (<symbol>attribute</symbol>)
      </title>
      <para>
        Allowed in request and failure processing.
      </para>
      <para>
        The <function>attr_destination()</function> function sets the
        destination URI to the content of the attribute named by the
        argument <symbol>attribute</symbol>.
      </para>
      <para>
        If the destination URI is set, the request will be send to the
        address determined from that URI instead of the Request-URI. It
        will carried over into branches together with the Request-URI when a
        call to <serdoc:func>append_branch</serdoc:func> is made.
      </para>
    </refsect2>

    <refsect2 xml:id="function.attr_equals">
      <title>
        <function>attr_equals</function>
        (<symbol>attribute</symbol>, <symbol>value</symbol>)
      </title>
      <para>
        Allowed in request, reply, and failure processing.
      </para>
      <para>
        The <function>attr_equals()</function> function checks whether
        the attribute identified by the argument <symbol>attribute</symbol>
        exists and its value is identical the the value given by the
        argument <symbol>value</symbol>. If so, it returns
        <literal>true</literal> and <literal>false</literal> otherwise.
      </para>
    </refsect2>

    <refsect2 xml:id="function.attr_equals_xl">
      <title>
        <function>attr_equals_xl</function>
        (<symbol>attribute</symbol>, <symbol>value</symbol>)
      </title>
      <para>
        Allowed in request, reply, and failure processing.
      </para>
      <para>
        The <function>attr_equals()</function> function checks whether
        the attribute identified by the argument <symbol>attribute</symbol>
        exists and its value is identical to the xl string given by the
        argument <symbol>value</symbol>.  If so, it returns
        <literal>true</literal> and <literal>false</literal> otherwise.
      </para>
      <para>
        For more information on xl strings, see
        <serdoc:module>xprint</serdoc:module>.
      </para>
    </refsect2>

    <refsect2 xml:id="function.attr_exists">
      <title>
        <function>attr_exists</function>
        (<symbol>attribute</symbol>)
      </title>
      <para>
        Allowed in request, reply, and failure processing.
      </para>
      <para>
        The <function>attr_exists()</function> function checks whether
        an attribute by the name given by the name of
        <symbol>attribute</symbol> exists and returns
        <literal>true</literal> in this case or <literal>false</literal>
        otherwise.
      </para>
    </refsect2>

    <refsect2 xml:id="function.attr_to_reply">
      <title>
        <function>attr_to_reply</function>
        (<symbol>hf</symbol>,
        <serdoc:optional><symbol>attribute</symbol></serdoc:optional>)
      </title>
      <para>
        Allowed in request and failure processing.
      </para>
      <para>
        The <function>attr_to_reply()</function> function adds a new
        header fields value to the final response that will eventually
        be sent upstream. The name of the header field is given by the
        argument <symbol>hf</symbol>. The content will be taken from an
        attribute. If the argument <symbol>attribute</symbol> is present,
        it contains the name of the attribute. Otherwise, the header field
        name from the argument <symbol>hf</symbol> will be taken as the
        name.
      </para>
    </refsect2>

    <refsect2 xml:id="function.del_attr">
      <title>
        <function>del_attr</function>
        (<symbol>attribute</symbol>)
      </title>
      <para>
        Allowed in request, reply, and failure processing.
      </para>
      <para>
        The <function>del_attr</function> function deletes the attribute
        identified by the argument <symbol>attribute</symbol>.
      </para>
    </refsect2>

    <refsect2 xml:id="function.del_attrs">
      <title>
        <function>del_attrs</function>
        (<symbol>group</symbol>)
      </title>
      <para>
        Allowed in request, reply, and failure processing.
      </para>
      <para>
        The <function>del_attrs()</function> function deletes all
        attributes from the group of attributes identified by the
        attribute prefix given through the argument <symbol>group</symbol>.
        For example, to delete all attributes of the From user, call
      </para>
      <programlisting>
        del_attrs("$fu");
      </programlisting>
    </refsect2>

    <refsect2 xml:id="function.dump_attrs">
      <title>
        <function>dump_attrs</function>
        (<serdoc:optional><symbol>group</symbol></serdoc:optional>)
      </title>
      <para>
        Allowed in request, reply, and failure processing.
      </para>
      <para>
        The <function>dump_attrs()</function> dumps a list of the existing
        attributes and their values to the system log. If the
        <symbol>group</symbol> argument is present, it contains an
        attribute namespace prefix and limits the output to the attrbutes
        in that namespace.
      </para>
    </refsect2>

    <refsect2 xml:id="function.flags2attr">
      <title>
        <function>flags2attr</function>
        (<symbol>attribute</symbol>)
      </title>
      <para>
        Allowed in request, reply, and failure processing.
      </para>
      <para>
        The <function>flags2attr()</function> function stores the current
        state of all the flags in compact form in the attribute identified
        by the argument <symbol>attribute</symbol>.
      </para>
    </refsect2>

    <refsect2 xml:id="function.insert_attr_hf">
      <title>
        <function>insert_attr_hf</function>
        (<symbol>hf</symbol>,
         <serdoc:optional><symbol>attribute</symbol></serdoc:optional>)
       </title>
       <para>
         Allowed in request and failure processing.
       </para>
       <para>
         The <function>insert_attr_hf()</function> function inserts a
         header field value to the header field named by the argument
         <symbol>hf</symbol> with the value of the attribute identified
         by the argument <symbol>attribute</symbol>. If there are already
         values for that header field, the new value will be prepended
         before any existing value.
       </para>
       <para>
         If the optional argument <symbol>attribute</symbol> is missing,
         the name of the attribute is taken from the name of the header
         field in argument <symbol>hf</symbol>.
       </para>
     </refsect2>

    <refsect2 xml:id="function.print_attr">
      <title>
        <function>print_attr</function>
        (<symbol>attribute</symbol>)
      </title>
      <para>
        Allowed in request, reply, and failure processing.
      </para>
      <para>
        The <function>print_attr()</function> function prints the content
        of the attribute identified by the argument
        <symbol>attribute</symbol> to the system log.
      </para>
      <para>
        For a more flexible way of printing messages to the system log
        that allows to print extra information together with the attribute
        value, see the <serdoc:module>xprint</serdoc:module> module.
      </para>
    </refsect2>

    <refsect2 xml:id="function.replace_attr_hf">
      <title>
        <function>replace_attr_hf</function>
        (<symbol>hf</symbol>,
        <serdoc:optional><symbol>attribute</symbol></serdoc:optional>)
      </title>
      <para>
        Allowed in request and failure processing.
      </para>
      <para>
        The <function>replace_attr_hf()</function> function removes all
        header field values of the header field named by the argument
        <symbol>hf</symbol> and adds a new header field value with the
        content of the attribute identified by the argument
        <symbol>attribute</symbol>. If the argument
        <symbol>attribute</symbol> is missing, the content of the new
        header field value will be taken from an argument with the same
        name as the header field.
      </para>
    </refsect2>

    <refsect2 xml:id="function.set_attr">
      <title>
        <function>set_attr</function>
        (<symbol>attribute</symbol>, <symbol>value</symbol>)
      </title>
      <para>
        Allowed in request, reply, and failure processing.
      </para>
      <para>
        The <function>set_attr()</function> function is a synonym for
        the <serdoc:func>set_sattr</serdoc:func> function and sets the
        attribute identified by the argument <symbol>attribute</symbol>
        to the string contained in the argument <symbol>value</symbol>.
      </para>
      <para>
        Like <serdoc:func>set_sattr</serdoc:func>, it is identical to
        assinging an string using the assignment operator and is
        deprecated.
      </para>
    </refsect2>

    <refsect2 xml:id="function.set_iattr">
      <title>
        <function>set_iattr</function>
        (<symbol>attribute</symbol>, <symbol>value</symbol>)
      </title>
      <para>
        Allowed in request, reply, and failure processing.
      </para>
      <para>
        The <function>set_iattr()</function> function sets the attribute
        identified by the argument <symbol>attribute</symbol> to the
        integer value contained in the argument <symbol>value</symbol>.
        If the attribute does not yet exist, it is created.
      </para>
      <para>
        This function is identical to assinging an integer using the
        assignment operator and
        is only kept to retain compatibility with earlier versions of SER.
        It therefore is deprecated and may be removed in the future.
      </para>
    </refsect2>

    <refsect2 xml:id="function.set_sattr">
      <title>
        <function>set_sattr</function>
        (<symbol>attribute</symbol>, <symbol>value</symbol>)
      </title>
      <para>
        Allowed in request, reply, and failure processing.
      </para>
      <para>
        The <function>set_sattr()</function> function sets the attribute
        identified by the argument <symbol>attribute</symbol> to the
        string contained in the argument <symbol>value</symbol>. If the
        attribute does not yet exist, it is created.
      </para>
      <para>
        This function is identical to assinging an string using the
        assignment operator and
        is only kept to retain compatibility with earlier versions of SER.
        It therefore is deprecated and may be removed in the future.
      </para>
    </refsect2>

    <refsect2 xml:id="function.subst_attr">
      <title>
        <function>subst_attr</function>
        (<symbol>attribute</symbol>, <symbol>subst</symbol>)
      </title>
      <para>
        Allowed in request, reply, and failure processing.
      </para>
      <para>
        The <function>subst_attr()</function> function manipulates the
        content of the attribute identified by the argument
        <symbol>attribute</symbol> using a subst expression.
      </para>
      <para>
        A subst expression is identical to the expression used by the
        <serdoc:bin>sed</serdoc:bin> program’s s command.
      </para>
      <!-- XXX We should either explain them in detail here, or in textops
               or in the admin guide. In any case, there needs to be a
               reference to the explanation.
        -->
    </refsect2>

    <refsect2 xml:id="function.xlfix_attr">
      <title>
        <function>xlfix_attr</function>
        (<symbol>attribute</symbol>)
      </title>
      <para>
        Allowed in request, reply, and failure processing.
      </para>
      <para>
        The <function>xlfix_attr()</function> function evaluates the xl
        string contained in the attributed identified by the argument
        <symbol>attribute</symbol> and stores the result of the evaluation
        in the same attribute.
      </para>
      <para>
        For more information on xl strings, see
        <serdoc:module>xprint</serdoc:module>.
      </para>
    </refsect2>

    <refsect2 xml:id="function.xlset_attr">
      <title>
        <function>xlset_attr</function>
        (<symbol>attribute</symbol>, <symbol>value</symbol>)
      </title>
      <para>
        Allowed in request, reply, and failure processing.
      </para>
      <para>
        The <function>xlset_attr()</function> function sets the attribute
        identified by the argument <symbol>attribute</symbol> to the
        evaluated xl string given by the argument <symbol>value</symbol>.
      </para>
      <para>
        For more information on xl strings, see
        <serdoc:module>xprint</serdoc:module>.
      </para>
    </refsect2>

    <refsect2 xml:id="function.xlset_destination">
      <title>
        <function>xlset_destination</function>
        (<symbol>value</symbol>)
      </title>
      <para>
        Allowed in request processing only.
      </para>
      <para>
        The <function>xlset_destination()</function> function sets the
        destination URI to the evaluated content of the xl string given
        by the argument <symbol>value</symbol>.
      </para>
      <para>
        For details on xl strings, see <serdoc:module>xprint</serdoc:module>.
      </para>
    </refsect2>

  </refsect1>

  <refsect1>
    <title>Module Parameters</title>

    <refsect2 xml:id="module.avp.xlbuf_size">
      <title><parameter>xlbuf_size</parameter></title>
      <serdoc:paraminfo>
        <serdoc:paramtype>integer</serdoc:paramtype>
        <serdoc:paramdefault>256</serdoc:paramdefault>
      </serdoc:paraminfo>
      <para>
        The <parameter>xlbuf_size</parameter> parameter defines the size
        of the buffer that used for evaluation of xl strings. The evaluated
        string cannot be larger than the size given by this parameter.
      </para>
    </refsect2>
  </refsect1>

  <refsect1 role="manpage">
    <title>See Also</title>
    <simplelist type="inline">
      <member><serdoc:sbin>ser</serdoc:sbin></member>
      <member><serdoc:file>ser.cfg</serdoc:file></member>
      <member><serdoc:module>avp_db</serdoc:module></member>
      <member><serdoc:module>avp_radius</serdoc:module></member>
    </simplelist>
  </refsect1>

</refentry>

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