---

labels:

- 'Stage-Beta'

summary: 'XEP-0355 (Namespace Delegation) implementation'

...

Introduction

============

Namespace Delegation is an extension which allows server to delegate

some features handling to an entity/component. Typical use case is an

external PEP service, but it can be used more generally when your

preferred server lack one internal feature and you found an external

component which can do it.

Details

=======

You can have all the details by reading the

[XEP-0355](http://xmpp.org/extensions/xep-0355.html). Only the admin

mode is implemented so far.

Usage

=====

To use the module, like usual add **"delegation"** to your

modules\_enabled. Note that if you use it with a local component, you

also need to activate the module in your component section:

    modules_enabled = {

            [...]

            "delegation";

    }

    [...]

    Component "youcomponent.yourdomain.tld"

        component_secret = "yourpassword"

        modules_enabled = {"delegation"}

then specify delegated namespaces **in your host section** like that:

    VirtualHost "yourdomain.tld"

        delegations = {

            ["urn:xmpp:mam:0"] = {

                filtering = {"node"};

                jid = "pubsub.yourdomain.tld";

            },

            ["http://jabber.org/protocol/pubsub"] = {

                jid = "pubsub.yourdomain.tld";

            },

        }

Here all MAM requests with a "node" attribute (i.e. all MAM pubsub

request) will be delegated to pubsub.yourdomain.tld. Similarly, all

pubsub request to the host (i.e. the PEP requests) will be delegated to

pubsub.yourdomain.tld.

**/!\ Be extra careful when you give a delegation to an entity/component,

it's a powerful access, only do it if you absoly trust the

component/entity, and you know where the software is coming from**

Configuration

=============

The configuration is done with a table which map delegated namespace to

namespace data. Namespace data MUST have a **jid** (in the form **jid =

"delegated@domain.tld"**) and MAY have an additional **filtering**

array. If filtering is present, request with attributes in the array

will be delegated, other will be treated normally (i.e. by Prosody).

If your are not a developper, the delegated namespace(s)/attribute(s)

are most probably specified with the external component/entity you want

to use.

The pseudo-namespace `http://jabber.org/protocol/disco#items:*` is used

to delegate remaining disco#items (i.e. items nodes not already handled

by Prosody itself).

Compatibility

=============

If you use it with Prosody 0.9 and a component, you need to patch

core/mod\_component.lua to fire a new signal. To do it, copy the

following patch in a, for example, /tmp/component.patch file:

    diff --git a/plugins/mod_component.lua b/plugins/mod_component.lua

    --- a/plugins/mod_component.lua

    +++ b/plugins/mod_component.lua

    @@ -85,6 +85,7 @@

                    session.type = "component";

                    module:log("info", "External component successfully authenticated");

                    session.send(st.stanza("handshake"));

    +               module:fire_event("component-authenticated", { session = session });

                    return true;

            end

Then, at the root of prosody, enter:

`patch -p1 < /tmp/component.patch`

  ----- ----------------------------------------------------

  0.10  Works

  0.9   Need a patched core/mod\_component.lua (see above)

  ----- ----------------------------------------------------

Note

====

This module is often used with mod\_privilege (c.f. XEP for more

details)