XCAP_CLIENT module

Admin Guide

Overview

The modules is an XCAP client for OpenSIPS that can be used by other modules. It fetches XCAP elements, either documents or part of them, by sending HTTP GET requests. It also offers support for conditional queries. It uses libcurl library as a client-side HTTP transfer library.

The module offers an xcap client interface with general functions that allow requesting for an specific element from an xcap server. In addition to that it also offers the service of storing and update in database the documents it receives. In this case only an initial request to the module is required - xcapGetNewDoc-which is like a request to the module to handle from that point on the referenced document so as to promise that the newest version will always be present in database.

The update method is also configurable, either through periodical queries, applicable to any kind of xcap server or with an MI command that should be sent by the server upon an update.

The module is currently used by the presence_xml module, if the ‘integrated_xcap_server’ parameter is not set.

Dependencies

OpenSIPS Modules

The following modules must be loaded before this module:

xcap.

External Libraries or Applications

The following libraries or applications must be installed before running OpenSIPS with this module loaded:

libxml-dev.
libcurl-dev.

Exported Parameters

periodical_query(int)

A flag to disable periodical query as an update method for the documents the module is responsible for. It could be disabled when the xcap server is capable to send the exported MI command when a change occurs or when another module in OpenSIPS handles updates.

To disable it set this parameter to 0.

Default value is “1”.

...
modparam("xcap_client", "periodical_query", 0)
...

query_period(int)

Should be set if periodical query is not disabled. Represents the time interval the xcap servers should be queried for an update

To disable it set this parameter to 0.

Default value is “100”.

...
modparam("xcap_client", "query_period", 50)
...

Exported Functions

None to be used in configuration file.

Exported MI Functions

refreshXcapDoc

MI command that should be sent by an xcap server when a stored document changes.

Name: refreshXcapDoc

Parameters:

document uri: the uri of the document
xcap server port: the port of the xcap server

MI FIFO Command Format:

...
:refreshXcapDoc:fifo_reply
/xcap-root/resource-lists/users/eyebeam/buddies-resource-list.xml
8000
_empty_line_
...

Developer Guide

The module exports a number of functions that allow selecting and retrieving an element from an xcap server and also registering a callback to be called when a MI command refreshXcapDoc is received and the document in question is retrieved.

bind_xcap_client_api(xcap_client_api_t* api)

This function allows binding the needed functions.

...
typedef struct xcap_client_api {

  /* xcap node selection and retrieving functions*/
  xcap_get_elem_t get_elem;
  xcap_nodeSel_init_t int_node_sel;
  xcap_nodeSel_add_step_t add_step;
  xcap_nodeSel_add_terminal_t add_terminal;
  xcap_nodeSel_free_t free_node_sel;
  xcapGetNewDoc_t getNewDoc; /* an initial request for the module
  fo fetch this document that does not exist in xcap db table
  and handle its update*/

  /* function to register a callback to document changes*/
  register_xcapcb_t register_xcb;
}xcap_client_api_t;
...

get_elem

Field type:

...
typedef char* (*xcap_get_elem_t)(char* xcap_root,
xcap_doc_sel_t* doc_sel, xcap_node_sel_t* node_sel);
...

This function sends a HTTP request and gets the specified information from the xcap server.

The parameters signification:

xcap_root - the XCAP server address;

doc_sel - structure with document selection info;

Parameter type:
...
typedef struct xcap_doc_sel
{
  str auid; /* application defined Unique ID*/
  int type; /* the type of the path segment
        after the AUID  which must either
        be GLOBAL_TYPE (for "global") or
        USERS_TYPE (for "users") */
  str xid; /* the XCAP User Identifier
        if type is USERS_TYPE */
  str filename;
}xcap_doc_sel_t;
...

node_sel - structure with node selection info;

Parameter type:
...
typedef struct xcap_node_sel
{
step_t* steps;
step_t* last_step;
int size;
ns_list_t* ns_list;
ns_list_t* last_ns;
int ns_no;

}xcap_node_sel_t;

typedef struct step
{
str val;
struct step* next;
}step_t;

typedef struct ns_list
{
int name;
str value;
struct ns_list* next;
}ns_list_t;
...

The node selector is represented like a list of steps that will be represented in the path string separated by ’/’ signs. The namespaces for the nodes are stored also in a list, as an association of name and value, where the value is to be included in the respective string val field of the step. To construct the node structure the following functions in the xcap_api structure should be used: ‘int_node_sel’, ‘add_step’ and if needed, ‘add_terminal’. If the intention is to retrieve the whole document this argument must be NULL.

register_xcb

Field type:

...
typedef int (*register_xcapcb_t)(int types, xcap_cb f);
...

‘types’ parameter can have a combined value of PRES_RULES, RESOURCE_LISTS, RLS_SERVICES, OMA_PRES_RULES and PIDF_MANIPULATION.
the callback function has type:

...
typedef int (xcap_cb)(int doc_type, str xid, char* doc);
...

Contributors

By Commit Statistics

Top contributors by DevScore⁽¹⁾, authored commits⁽²⁾ and lines added/removed⁽³⁾

#	Name	DevScore	Commits	Lines++	Lines—
1.	Anca Vamanu	37	14	2180	218
2.	Bogdan-Andrei Iancu (@bogdan-iancu)	15	12	51	61
3.	Stefan Darius (@dariusstefan)	11	5	374	81
4.	Daniel-Constantin Mierla (@miconda)	9	7	22	19
5.	Henning Westerholt (@henningw)	8	6	60	49
6.	Saúl Ibarra Corretgé (@saghul)	6	3	56	90
7.	Razvan Crainea (@razvancrainea)	5	3	6	9
8.	Dan Pascu (@danpascu)	4	2	9	10
9.	Liviu Chircu (@liviuchircu)	4	1	73	73
10.	Romanov Vladimir	3	1	31	23

All remaining contributors: Ovidiu Sas (@ovidiusas), Vlad Paiu (@vladpaiu), Konstantin Bokarius, UnixDev, Edson Gellert Schubert.

(1) DevScore = author_commits + author_lines_added / (project_lines_added / project_commits) + author_lines_deleted / (project_lines_deleted / project_commits)

(2) including any documentation-related commits, excluding merge commits

(3) ignoring whitespace edits, renamed files and auto-generated files

By Commit Activity

#	Name	Commit Activity
1.	Stefan Darius (@dariusstefan)	Jun 2026 - Jul 2026
2.	Razvan Crainea (@razvancrainea)	Sep 2011 - Jun 2026
3.	Vlad Paiu (@vladpaiu)	Mar 2014 - Mar 2014
4.	Liviu Chircu (@liviuchircu)	Mar 2014 - Mar 2014
5.	Bogdan-Andrei Iancu (@bogdan-iancu)	Feb 2008 - Jan 2013
6.	Ovidiu Sas (@ovidiusas)	Jan 2013 - Jan 2013
7.	Saúl Ibarra Corretgé (@saghul)	Nov 2012 - Jan 2013
8.	Anca Vamanu	Aug 2007 - Feb 2010
9.	Romanov Vladimir	Mar 2009 - Mar 2009
10.	UnixDev	Feb 2009 - Feb 2009

All remaining contributors: Henning Westerholt (@henningw), Dan Pascu (@danpascu), Daniel-Constantin Mierla (@miconda), Konstantin Bokarius, Edson Gellert Schubert.

(1) including any documentation-related commits, excluding merge commits

Documentation

Contributors

Last edited by: Razvan Crainea (@razvancrainea), Bogdan-Andrei Iancu (@bogdan-iancu), Saúl Ibarra Corretgé (@saghul), Anca Vamanu, Henning Westerholt (@henningw), Daniel-Constantin Mierla (@miconda), Konstantin Bokarius, Edson Gellert Schubert.

License

All documentation files (i.e. .md extension) are licensed under the Creative Common License 4.0