--- a/libervia/backend/plugins/plugin_xep_0103.py	Tue Dec 03 00:11:00 2024 +0100
+++ b/libervia/backend/plugins/plugin_xep_0103.py	Tue Dec 03 00:12:38 2024 +0100
@@ -15,18 +15,18 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from typing import Dict, Any
+from typing import Self
 
+from pydantic import BaseModel, Field
 from twisted.words.xish import domish
 
+from libervia.backend.core import exceptions
 from libervia.backend.core.constants import Const as C
 from libervia.backend.core.i18n import _
 from libervia.backend.core.log import getLogger
-from libervia.backend.core import exceptions
 
 log = getLogger(__name__)
 
-
 PLUGIN_INFO = {
     C.PI_NAME: "URL Address Information",
     C.PI_IMPORT_NAME: "XEP-0103",
@@ -37,45 +37,87 @@
     C.PI_HANDLER: "no",
     C.PI_DESCRIPTION: _("""Implementation of XEP-0103 (URL Address Information)"""),
 }
+NS_URL_DATA = "http://jabber.org/protocol/url-data"
 
-NS_URL_DATA = "http://jabber.org/protocol/url-data"
+
+class Desc(BaseModel):
+    """
+    Model for the <desc/> element.
+    """
+
+    content: str
+    xml_lang: str | None = None
+
+
+class URLData(BaseModel):
+    """
+    Model for the <url-data/> element.
+    """
+
+    url: str
+    desc: list[Desc] = Field(default_factory=list)
+
+    @classmethod
+    def from_element(cls, element: domish.Element) -> Self:
+        """Create a URLData instance from a <url-data> element or its parent.
+
+        @param url_data_elt: The <url-data> element or a parent element.
+        @return: URLData instance.
+        @raise exceptions.NotFound: If the <url-data> element is not found.
+        """
+        if element.uri != NS_URL_DATA or element.name != "url-data":
+            child_url_data_elt = next(element.elements(NS_URL_DATA, "url-data"), None)
+            if child_url_data_elt is None:
+                raise exceptions.NotFound("<url-data> element not found")
+            else:
+                element = child_url_data_elt
+        kwargs = {
+            "url": element["target"],
+            "desc": [
+                Desc(content=str(desc_elt), xml_lang=desc_elt.getAttribute("xml:lang"))
+                for desc_elt in element.elements(NS_URL_DATA, "desc")
+            ],
+        }
+        return cls(**kwargs)
+
+    def to_element(self) -> domish.Element:
+        """Build the <url-data> element from this instance's data.
+
+        @return: <url-data> element.
+        """
+        url_data_elt = domish.Element((NS_URL_DATA, "url-data"))
+        url_data_elt["target"] = self.url
+        for desc in self.desc:
+            desc_elt = url_data_elt.addElement((NS_URL_DATA, "desc"))
+            if desc.xml_lang:
+                desc_elt["xml:lang"] = desc.xml_lang
+            desc_elt.addContent(desc.content)
+        return url_data_elt
 
 
 class XEP_0103:
     namespace = NS_URL_DATA
 
     def __init__(self, host):
-        log.info(_("XEP-0103 (URL Address Information) plugin initialization"))
+        log.info(f"plugin {PLUGIN_INFO[C.PI_NAME]!r} initialization")
         host.register_namespace("url-data", NS_URL_DATA)
 
-    def get_url_data_elt(self, url: str, **kwargs) -> domish.Element:
+    def generate_url_data(self, url: str, **kwargs) -> URLData:
         """Generate the element describing the URL
 
         @param url: URL to use
         @param extra: extra metadata describing how to access the URL
         @return: ``<url-data/>`` element
         """
-        url_data_elt = domish.Element((NS_URL_DATA, "url-data"))
-        url_data_elt["target"] = url
-        return url_data_elt
+        url_data = URLData(url=url, **kwargs)
+        return url_data
 
-    def parse_url_data_elt(self, url_data_elt: domish.Element) -> Dict[str, Any]:
+    def parse_url_data_elt(self, url_data_elt: domish.Element) -> URLData:
         """Parse <url-data/> element
 
         @param url_data_elt: <url-data/> element
             a parent element can also be used
-        @return: url-data data. It's a dict whose keys correspond to
-            [get_url_data_elt] parameters
+        @return: URLData instance
         @raise exceptions.NotFound: no <url-data/> element has been found
         """
-        if url_data_elt.name != "url-data":
-            try:
-                url_data_elt = next(url_data_elt.elements(NS_URL_DATA, "url-data"))
-            except StopIteration:
-                raise exceptions.NotFound
-        try:
-            data: Dict[str, Any] = {"url": url_data_elt["target"]}
-        except KeyError:
-            raise ValueError(f'"target" attribute is missing: {url_data_elt.toXml}')
-
-        return data
+        return URLData.from_element(url_data_elt)