<!-- Module User's Guide -->

<chapter>
	
	<title>&adminguide;</title>
	
	<section id="overview" xreflabel="Overview">
	<title>Overview</title>
	<para>
	ALIAS_DB module can be used as an alternative for user aliases
	via usrloc. The main feature is that it does not store all adjacent
	data as for user location and always uses database for search (no
	memory caching).
	</para>
	<para>
	Having no memory caching, search speed might decrease but 
	provisioning is easier. With very fast databases like MySQL, speed
	penalty can be lowered. Also, search can be performed on different
	tables in the same script.
	</para>
	</section>
	<section  id="dependenciesid" xreflabel="Dependencies">
	<title>Dependencies</title>
	<section>
		<title>&osips; Modules</title>
		<para>
		The following modules must be loaded before this module:
			<itemizedlist>
			<listitem>
			<para>
				<emphasis>database module</emphasis> (mysql, dbtext, ...).
			</para>
			</listitem>
			</itemizedlist>
		</para>
	</section>
	<section>
		<title>External Libraries or Applications</title>
		<para>
		The following libraries or applications must be installed before 
		running &osips; with this module loaded:
			<itemizedlist>
			<listitem>
			<para>
				<emphasis>None</emphasis>.
			</para>
			</listitem>
			</itemizedlist>
		</para>
	</section>
	</section>
	<section id="exported_parameters" xreflabel="Exported Parameters">
	<title>Exported Parameters</title>
	<section id="param_db_url" xreflabel="db_url">
		<title><varname>db_url</varname> (str)</title>
		<para>
		Database URL.
		</para>
		<para>
		<emphasis>
			Default value is <quote>&defaultrodb;</quote>.
		</emphasis>
		</para>
		<example>
		<title>Set <varname>db_url</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("alias_db", "db_url", "&exampledb;")
...
</programlisting>
		</example>
	</section>
	
	<section id="param_user_column" xreflabel="user_column">
		<title><varname>user_column</varname> (str)</title>
		<para>
		Name of the column storing username.
		</para>
		<para>
		<emphasis>
			Default value is <quote>username</quote>.
		</emphasis>
		</para>
		<example>
		<title>Set <varname>user_column</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("alias_db", "user_column", "susername")
...
</programlisting>
		</example>
	</section>
	
	<section id="param_domain_column" xreflabel="domain_column">
		<title><varname>domain_column</varname> (str)</title>
		<para>
		Name of the column storing user's domain.
		</para>
		<para>
		<emphasis>
			Default value is <quote>domain</quote>.
		</emphasis>
		</para>
		<example>
		<title>Set <varname>domain_column</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("alias_db", "domain_column", "sdomain")
...
</programlisting>
		</example>
	</section>
	
	<section id="param_alias_user_column" xreflabel="alias_user_column">
		<title><varname>alias_user_column</varname> (str)</title>
		<para>
		Name of the column storing alias username.
		</para>
		<para>
		<emphasis>
			Default value is <quote>alias_username</quote>.
		</emphasis>
		</para>
		<example>
		<title>Set <varname>alias_user_column</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("alias_db", "alias_user_column", "auser")
...
</programlisting>
		</example>
	</section>
	
	<section id="param_alias_domain_column" xreflabel="alias_domain_column">
		<title><varname>alias_domain_column</varname> (str)</title>
		<para>
		Name of the column storing alias domain.
		</para>
		<para>
		<emphasis>
			Default value is <quote>alias_domain</quote>.
		</emphasis>
		</para>
		<example>
		<title>Set <varname>alias_domain_column</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("alias_db", "alias_domain_column", "adomain")
...
</programlisting>
		</example>
	</section>
	
	<section id="param_domain_prefix" xreflabel="domain_prefix">
		<title><varname>domain_prefix</varname> (str)</title>
		<para>
		Specifies the prefix to be stripped from the domain in R-URI before
		doing the search.
		</para>
		<para>
		<emphasis>
			Default value is <quote>NULL</quote>.
		</emphasis>
		</para>
		<example>
		<title>Set <varname>domain_prefix</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("alias_db", "domain_prefix", "sip.")
...
</programlisting>
		</example>
	</section>
	
	<section id="param_append_branches" xreflabel="append_branches">
		<title><varname>append_branches</varname> (int)</title>
		<para>
			If the alias resolves to many SIP IDs, the first is replacing
			the R-URI, the rest are added as branches.
		</para>
		<para>
		<emphasis>
			Default value is <quote>0</quote> (0 - don't add branches;
			1 - add branches).
		</emphasis>
		</para>
		<example>
		<title>Set <varname>append_branches</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("alias_db", "append_branches", 1)
...
</programlisting>
		</example>
	</section>
	</section>
	
	<section id="exported_functions" xreflabel="exported_functions">
	<title>Exported Functions</title>
	<section id="func_alias_db_lookup" xreflabel="alias_db_lookup()">
		<title>
		<function moreinfo="none">alias_db_lookup(table_name, [flags])</function>
		</title>
		<para>
		The function takes the R-URI and search to see whether it is an alias
		or not. If it is an alias for a local user, the R-URI is replaced with
		user's SIP uri.
		</para>
		<para>
		The function returns TRUE if R-URI is alias and it was replaced by
		user's SIP uri.
		</para>
		<para>Meaning of the parameters is as follows:</para>
		<itemizedlist>
		<listitem>
			<para><emphasis>table_name (string)</emphasis> - the name of the
				table to search for the alias
			</para>
		</listitem>
		<listitem>
			<para><emphasis>flags (string, optional)</emphasis> - set of
			character flags to control the alias lookup process:
			</para>
			<itemizedlist>
			<listitem>
				<para><emphasis role='bold'>d</emphasis> - do not use domain URI part in
				the alias lookup query (use only a username-based lookup). By
				default, both username and domain are used.
				</para>
			</listitem>
			<listitem>
				<para><emphasis role='bold'>r</emphasis> - do reverse alias lookup - lookup
				for the alias mapped to the current URI (URI 2 alias 
				translation); normally, the function looks up for the URI 
				mapped to the alias (alias 2 URI translation).
				</para>
			</listitem>
			</itemizedlist>
		</listitem>
		</itemizedlist>
		<para>
		This function can be used from REQUEST_ROUTE, FAILURE_ROUTE.
		</para>
		<example>
		<title><function>alias_db_lookup()</function> usage</title>
		<programlisting format="linespecific">
...
alias_db_lookup("dbaliases", "rd");
alias_db_lookup("dba_$(rU{s.substr,0,1})");
...
</programlisting>
		</example>
	</section>


	<section id="func_alias_db_find" xreflabel="alias_db_find()">
		<title>
		<function moreinfo="none">alias_db_find(table_name, input_uri, output_var, [flags])</function>
		</title>
		<para>
		The function is very similar to <function>alias_db_lookup()</function>,
		but instead of using fixed input (RURI) and output (RURI) is able to
		get the input SIP URI from a pseudo-variable and place the result back
		also in a pseudo-variable.
		</para>
		<para>
		The function is useful as the alias lookup does not affect the request
		itself (no RURI changes), can be used in a reply context (as it does 
		not work with RURI only) and can be used for others URI than the RURI
		(To URI, From URI, custom URI).
		</para>
		<para>
		The function returns TRUE if any alias mapping was found and returned.
		</para>
		<para>Meaning of the parameters is as follows:</para>
		<itemizedlist>
		<listitem>
			<para><emphasis>table_name (string)</emphasis> - the name of the table to
				search for the alias
			</para>
		</listitem>
		<listitem>
			<para><emphasis>input_uri (string)</emphasis> - a SIP URI to look up
			</para>
		</listitem>
		<listitem>
			<para><emphasis>output_var (var)</emphasis> - a variable to hold
				the SIP URI result
			</para>
		</listitem>
		<listitem>
			<para><emphasis>flags (string, optional)</emphasis> (optional) - set of flags 
			(char based flags) to control the alias lookup process:
			</para>
			<itemizedlist>
			<listitem>
				<para><emphasis>d</emphasis> - do not use domain URI part in
				the alias lookup query (use only a username-based lookup). By
				default, both username and domain are used.
				</para>
			</listitem>
			<listitem>
				<para><emphasis>r</emphasis> - do revers alias lookup - lookup
				for the alias mapped to the current URI (URI 2 alias 
				translation); normally, the function looks up for the URI 
				mapped to the alias (alias 2 URI translation).
				</para>
			</listitem>
			</itemizedlist>
		</listitem>
		</itemizedlist>
		<para>
		This function can be used from REQUEST_ROUTE, BRANCH_ROUTE,
			LOCAL_ROUTE, STARTUP_ROUTE, FAILURE_ROUTE and ONREPLY_ROUTE.
		</para>
		<example>
		<title><function>alias_db_find()</function> usage</title>
		<programlisting format="linespecific">
...
# do revers alias lookup and find the alias for the FROM URI
alias_db_find("dbaliases", $fu, $avp(from_alias), "r");
...
</programlisting>
		</example>
	</section>


	</section>
</chapter>

