---

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:2"] = {

                filtering = {"node"};

                jid = "pubsub.yourdomain.tld";

            },

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

                jid = "pubsub.yourdomain.tld";

            },

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

                jid = "pubsub.yourdomain.tld";

            },

            ["urn:xmpp:delegation:2:bare:disco#info:*"] = {

                jid = "pubsub.yourdomain.tld";

            },

            ["urn:xmpp:delegation:2:bare:disco#items:*"] = {

                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. Check the

XEP for the meaning of "urn:xmpp:delegation:2:bare:disco#info:*" and

"urn:xmpp:delegation:2:bare:disco#items:*".

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

powerful access, only do it if you absolutely 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,

others will be treated normally (i.e. by Prosody).

If you are not a developer, 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`

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

  0.11  Works

  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)