# &adminguide;

## Overview

The modules is a Resource List Server implementation following the specification in RFC 4662 and RFC 4826.

The server is independent from local presence servers, retrieving presence information with Subscribe-Notify messages.

The module uses the presence module as a library, as it requires a resembling mechanism for handling Subscribe. Therefore, in case the local presence server is not collocated on the same machine with the RL server, the presence module should be loaded in a library mode only (see doc for presence module).

It handles subscription to lists in an event independent way.The default event is presence, but if some other events are to be handled by the server, they should be added using the module parameter "rls_events".

It works with XCAP server for storage. There is also the possibility to configure it to work in an integrated_xcap server mode, when it only queries database for the resource lists documents. This is useful in a small architecture when all the clients use an integrated server and there are no references to exterior documents in their lists.

The same as presence module, it has a caching mode with periodical update in database for subscribe information. The information retrieved with Notify messages is stored in database only.

## Dependencies

### &osips; Modules

The following modules must be loaded before this module:

- a database module.

- signaling.

- tm.

- presence- in a library mode.

- pua.

- xcap.

### External Libraries or Applications

- libxml-dev.

## Exported Parameters

### `rlsubs_table`(str)

The name of the db table where resource lists subscription information is stored.

Default value is rls_watchers.

#### Set `rlsubs_table` parameter

    ...
    modparam("rls", "rlsubs_table", "rls_subscriptions")
    ...

### `rlpres_table`(str)

The name of the db table where notified event specific information is stored.

Default value is rls_presentity.

#### Set `rlpres_table` parameter

    ...
    modparam("rls", "rlpres_table", "rls_notify")
    ...

### `clean_period` (int)

The period at which to check for expired information.

Default value is 100.

#### Set `clean_period` parameter

    ...
    modparam("rls", "clean_period", 100)
    ...

### `waitn_time` (int)

The timer period at which the server should attempt to send Notifies with the updated presence state of the subscribed list or watcher information.

Default value is 50.

#### Set `waitn_time` parameter

    ...
    modparam("rls", "waitn_time", 10)
    ...

### `max_expires` (int)

The maximum accepted expires for a subscription to a list.

Default value is 7200.

#### Set `max_expires` parameter

    ...
    modparam("rls", "max_expires", 10800)
    ...

### `hash_size` (int)

The dimension of the hash table used to store subscription to a list. This parameter will be used as the power of 2 when computing table size.

Default value is 9 (512).

#### Set `hash_size` parameter

    ...
    modparam("rls", "hash_size", 11)
    ...

### `xcap_root` (str)

The address of the xcap server.

Default value is NULL.

#### Set `hash_size` parameter

    ...
    modparam("rls", "xcap_root", "http://192.168.2.132/xcap-root:800")
    ...

### `to_presence_code` (int)

The code to be returned by rls_handle_subscribe function if the processed Subscribe is not a resource list Subscribe. This code can be used in an architecture with presence and rls servers collocated on the same machine, to call handle_subscribe on the message causing this code.

Default value is 0.

#### Set `to_presence_code` parameter

    ...
    modparam("rls", "to_presence_code", 10)
    ...

### `rls_event` (str)

The default event that RLS handles is presence. If some other events should also be handled by RLS they should be added using this parameter. It can be set more than once.

Default value is "presence".

#### Set `rls_event` parameter

    ...
    modparam("rls", "rls_event", "dialog;sla")
    ...

### `presence_server` (str)

The address of the presence server. It will be used as outbound proxy for Subscribe requests sent by the RLS server to bouncing on and off the proxy and having to include special processing for this messages in the proxy's configuration file.

#### Set `presence_server` parameter

    ...
    modparam("rls", "presence_server", "sip:pres@opensips.org:5060")
    ...

### `server_address` (str)

The address of the server that will be used as a contact in sent Subscribe requests and 200 OK replies for Subscribe messages for RLS. It is compulsory.

#### Set `server_address` parameter

    ...
    modparam("rls", "server_address", "sip:rls@opensips.org:5060")
    ...

## Exported Functions

### `rls_handle_subscribe()`

This function detects if a Subscribe message should be handled by RLS. If not it replies with the configured to_presence_code. If it is, it extracts the dialog info and sends aggregate Notify requests with information for the list.

This function can be used from REQUEST_ROUTE.

#### `rls_handle_subscribe` usage

    ...
    For presence and rls on the same machine:
    	modparam(rls, "to_presence_code", 10)

    	if(is_method("SUBSCRIBE"))
    	{
    		$var(ret_code)= rls_handle_subscribe();

    		if($var(ret_code)== 10)
    				handle_subscribe();

    		t_release();
    	}

    For rls only:
    	if(is_method("SUBSCRIBE"))
    	{
    		rls_handle_subscribe();
    		t_release();
    	}

    ...

### `rls_handle_notify()`

This function has to be called for Notify messages sent by presence servers in reply to the Subscribe messages sent by RLS.

This function can be used from REQUEST_ROUTE.

It can return 3 codes:

- 1 - the Notify was inside a dialog that was recognized by the RLS server and was processed successfully.

- 2 - the Notify did not belog to a dialog initiated by the RLS server.

- -1 - an error occurred during processing.

#### `rls_handle_notify` usage

    ...
    if(method=="NOTIFY")
        rls_handle_notify();
    ...

## Exported MI Functions

### `rls_update_subscriptions`

Triggers updating backend subscriptions after a resources-list or rls-services document has been updated.

Name: rls_update_subscriptions

Parameters:

- presentity_uri : the uri of the user who made the change and whose subscriptions should be updated

MI FIFO Command Format:

    :rls_update_subscriptions:fifo_reply
    sip:alice@atlanta.com
    _empty_line_

## Installation

The module requires 2 table in OpenSIPS database: rls_presentity and rls_watchers.The SQL syntax to create them can be found in rls-create.sql script in the database directories in the opensips/scripts folder. You can also find the complete database documentation on the project webpage, &osipsdbdocslink;.