GeoNode#10995 Faceting: thesauri

geonode/facets/apps.py

@@ -38,6 +38,16 @@ def ready(self):
 
         urlpatterns += urls.urlpatterns
 
+        init_thesaurus_providers()
+
+
+def init_thesaurus_providers():
+    # should be called at startup and whenever records in Thesaurus or ThesaurusLabel change
+    from geonode.facets.providers.thesaurus import create_thesaurus_providers
+
+    for provider in create_thesaurus_providers():
+        register_facet_provider(provider)
+
 
 def register_facet_provider(provider: FacetProvider):
     logging.info(f"Registering {provider}")

geonode/facets/providers/thesaurus.py

@@ -0,0 +1,95 @@
+import logging
+
+from django.db.models import Count
+
+from geonode.base.models import Thesaurus, ResourceBase
+from geonode.facets.models import FacetProvider, DEFAULT_FACET_TOPICS_LIMIT
+
+logger = logging.getLogger(__name__)
+
+
+class ThesaurusFacetProvider(FacetProvider):
+    """
+    Implements faceting for a given Thesaurus
+    """
+
+    def __init__(self, identifier, title, order, labels: dict):
+        self._name = identifier
+        self.label = title
+        self.order = order
+        self.labels = labels
+
+    @property
+    def name(self) -> str:
+        return self._name
+
+    def get_info(self, lang="en") -> dict:
+        return {
+            "name": self._name,
+            "key": "tkeyword",
+            "label": self.labels.get(lang, self.label),
+            "type": "thesaurus",
+            "hierarchical": False,
+            "order": self.order,
+        }
+
+    def get_facet_items(self, queryset=None, lang="en", page: int = 0, limit: int = DEFAULT_FACET_TOPICS_LIMIT) -> dict:
+        logging.debug("Retrieving facets for %s", self._name)
+
+        if not queryset:
+            queryset = ResourceBase.objects
+
+        q = (
+            queryset.filter(tkeywords__thesaurus__identifier=self._name, tkeywords__keyword__lang=lang)
+            .values("tkeywords", "tkeywords__keyword__label")
+            .annotate(count=Count("tkeywords"))
+            .order_by("-count")
+        )
+
+        cnt = q.count()
+        start = page * limit
+        end = start + limit
+
+        ret = {
+            "total": cnt,
+            "start": start,
+            "page": page,
+            "limit": limit,
+        }
+
+        logging.debug("Found %d facets for %s", cnt, self._name)
+        logging.debug(" ---> %s\n\n", q.query)
+        logging.debug(" ---> %r\n\n", q.all())
+
+        topics = [
+            {"key": r["tkeywords"], "label": r["tkeywords__keyword__label"], "count": r["count"]}
+            for r in q[start:end].all()
+        ]
+
+        ret["items"] = topics
+
+        return ret
+
+
+def create_thesaurus_providers() -> list:
+    # this query return the list of thesaurus X the list of localized titles
+    q = (
+        Thesaurus.objects.filter(facet=True)
+        .values("identifier", "title", "order", "rel_thesaurus__label", "rel_thesaurus__lang")
+        .order_by("order")
+    )
+
+    # coalesce the localized labels
+    ret = {}
+    for r in q.all():
+        identifier = r["identifier"]
+        t = ret.get(identifier, None)
+        if not t:
+            t = {k: r[k] for k in ("identifier", "title", "order")}
+            t["labels"] = {}
+        if r["rel_thesaurus__lang"] and r["rel_thesaurus__label"]:
+            t["labels"][r["rel_thesaurus__lang"]] = r["rel_thesaurus__label"]
+        ret[identifier] = t
+
+    logging.info("Creating providers for %r", ret)
+    return [ThesaurusFacetProvider(t["identifier"], t["title"], t["order"], t["labels"]) for t in ret.values()]